Chapter 23 Strategies for Enhancement of Food Production Part 2 by TEACHING CARE online tuition and coaching classes
Sericulture is the breeding and management of silk worms for the production of silk. It has been practiced in India since second era or century B.C. The silk which is produced by silk worm is of a valuable natural protein fibre. Silk worms are the larvae of silk moths. The rearing of silk worm for the production of silk is known as sericulture.
- History of silk : Historical account of use of silk and rearing of silk worm eggs, larvae and cocoons are available from It was Lotzu the empress kwang-Ti who for the first time discovered the silk thread and its source the silk worm cocoon. The technique of sericulture was kept as a secret by the chines people. In about 550
B.C. The sericulture technique was diffused to European countries. The available mythological literature deals with facts rearing the use of silk in ancient India. By about 1000 A.D. the sericulture was in practice in China, Europe and India, China was the leading country in this field.
At present the sericulture is practiced in China, Japan, Korea, India, Brazil, Russia, France and Italy. Some of the south east asian countries. China is topmost country producing some 48% cocoons and 40.9% of row silk. Next biggest silk producing country is Japan, India is placed in third position as for as the production of silk in term in quantity is concerned.
- Silk in India : As far as silk as a fabric is concerned it is a matchless fabric second to none. Therefore, silk garments have been a favourite choice since ancient Use of silk clothes finds its mention from pre-historic period. There are description of use of silk clothes from vedic period. In Ramayana and Mahabharat period the silk clothes adored the bodies of royal princess, prince, kings and queens. It attire of the rich people. The silk clothes were used to the superiority of social and economic status. It was given in gifts by rich people and royal families.
In the medieval period the silk was a recognised commodity of commerce. The silk clothes and raw silk were imported from China and Japan. Later on it was also imported from Europe. By the Moghul period India had a rich heritage of silk clothes. The silk was imported as raw silk. It was spun into silk thread and silk clothes were woven in handlooms silk clothes became almost a craze among royal families and rich persons. A number of such looms were in operation in Banaras, and different parts of Uttar Pradesh, Kashmir became centres for the production of cocoons and rearing of silk worm. Sporadic silk textile centres were also present in South India. It was in 1905-1906 that a scientific investigation in the field of sericulture was undertaken in India by the Indian Institute of Agricultural Research at Pusa, New Delhi. It was Lefroy who conducted research on the silk worm and potentialities of silk production in India. A series of exhibitions were organised to popularize silk and attract the attention of scientists and industrialists as well towards sericulture in India.
By 1910 India started regular production of raw silk. The rearing of Bombyx mori and Autheraea species was undertaken. Silk textile industry was finally established in Kashmir, U.P. and Karnataka. Silk garments were exported by this time. Silk clothes from Bengal, Banaras and karnataka were famous even in the European markets.
- Silk in Modern Age : Sericulture as well as silk industry is firmly established in India at present is the third biggest country in the field of silk production and only next after China and Japan.
The reasons for the poor growth of sericulture in India were:
- High cost of
- Poor quality of raw
But the recent efforts by the Government of India and various state governments such as research in sericulture and training in sericulture technique, development of silk worms marketing facilities and cultivation of plants, e.g. Morus indica or shahtoot Norus alba or ‘Toot’ castor sal etc. Central Sericulture Station, Berhampore, Central Research and Training Centre, Mysore and Ranchi have been established. Various states have undertaken a programs of research, training and plantation of host plants under their rural development programs. As a result of these efforts new varieties of mulberry plants have been developed and are being cultivated. These varieties are called as M 2 and M5 varieties. They gave 100% increased yield of mulberry leaves upon which the silk worm feeds.
Different varieties of silk worm, Bombyx mori and Autherea have been developed which can be cultivated in various states. Existing races of silk worm are being improved Bivoltine species are being developed. Low production and higher yield have been achieved as a result of these efforts. India is producing 4200 metric tons of silk per annum (1980). This figure is even higher at present. India is exporting some 25% to 30% of its total silk production in the form of silk garments and fabrics. Karnataka is the biggest silk producing state followed by Jammu & Kashmir and Tamil Nadu, Madhya Pradesh is also emerging on the scene of silk production. India is producing China silk, Tasar silk or Cosa silk, Muga silk and Eri silk today.
Largest silk producing state of India is Karnataka.
The zoological name of common silk worm is Bombyx mori
Silk is obtained from Bombyx mori.
(iv) Systemic position :
Phylum – Arthropoda
Class – Insecta
Order – Lepidoptera
Family – Bombicidae and satarnidae
(a) Family – Bombicidae
- Bombyx mori : It is known as China silk worm or mulberry silk It is native of China. It has been fully domesticated for the production of silk. It produced quality of silk which is white silk or yellow silk.
- Other species of Bombyx are texior, B. fortunatax and B. meridionles. They are well Known in our country.
- Family – Saturnidae : Antheraea paphio – It belong to the family saturnidae. It is widely distributed in india in the states of Karnataka, Tamilnadu, Madhya Pradesh, Uttar Pradesh, Bihar and West bengal. It feed on and fig plants. Its favourite host plant is Arjun (Terminalia arjuna) sol (shorea robusta). It has been recently domesticated for It produced Tassar silk (kosa silk.)
- Habit and habitat : The silk worm distributed in temperate regions are diapause type i.e. they remain inactive for some time in The silk worms inhabiting some tropical regions. Are of non -diapause type they are holometabolous. The life cycle stages include egg- larvae-pupa and imago
- Adult Moth : The moth measures about 25 mm in length and wing span measures about 40-50 mm in Female moths are larger than male moths. In general univoltine races are of larger size that multivoltine.
It has whitish colour with gray marks on wings in some races. The body is divisible into head, thorax and abdomen. Head contains a pair of eyes and a pair of pectinated antennae specially larger in males. Thorax contains three pairs of legs and two pairs of wings covered with scales. Female moths are without mouth. The abdomen is plump. Digestive system is poorly developed. The excretory system consists of three pairs of malpighian tubules present at the end of mid gut. The reproductive system is very well developed in females and males.
(vii) Life History
- Copulation : The copulation lasts for about three During copulation the male sits over the female and holds her with the help of chitinous hooks. Both the moths acquire back to back’ position. The female has a scent gland at the terminal end of the abdomen, which secretes volatile secretion called pheromones to attract the male.
- Egg : Copulation is immediately followed by egg laying. The eggs are small, oval and creamy white in They become darker as they become older. Each moth lays about 500 to 2000 eggs. The eggs are glued to the under-surface of the leaves of the host plant.
In univoltine egg’s hatching takes place after one year. In multivoltine it takes place after 10-12 days.
- Larva : After hatching a larva comes out of It is called as caterpillar larva. It is 1.2 mm to 3 mm in length depending upon the race. It has grey or creamy-white colour.
The body of larva is divided into head, thorax and abdomen. The head consists of three fused segments. Mouth parts are biting and chewing type or strongly mandibulate. A pair of antennae and six pairs of are also present on head. Mandibulate mouth parts are used to cut and chew the leaves. The thorax consists of three segments. Each segment contains a pair of legs with recurved hooks. They are used for locomotion and manipulation of food during feeding. The abdomen consists of ten segments. The last and tenth segment is poorly developed. Five pairs of pseudo legs are present on 3rd, 4th, 5th , 6th and 9th abdominal segments. These are used for locomotion.
Silk is the secretion of salivary gland
- Silk gland : Among other visceral organs larva contains well-developed paired glands called silk
When fully developed, these glands becomes five time larger than the length of the larva and there weight becomes 2/5th of the total body weight. Each gland is divisible into an anterior, a middle and a posterior region. The middle portion is broad and is called as reservoir. The anterior and posterior parts are narrow. The anterior parts of both the silk glands are united to form a common duct which opens through a spinneret situated on hypopharynx. The posterior coiled part of gland secretes a protein called as fibroin. It is covered and surrounded by sericin
secreted by middle part. A pair of accessory glands or the glands of felippi open the duct of silk gland. Its secretion
Life history of (Bombyx mori)
probably lubricates the silk. The silk is secreted in liquid form, which solidifies on coming in contact with air.
The larva is voracious eater. It feeds on mulberry leaves. It may ingest about 30,000 times more than its body weight during its complete larval period and increases about 10,000 times more than the body weight of its body from the time of hatching. As the larva grows, it sheds it cuticle. This is called as moulting. The form of larva between two successive moults is called as instar. The larva has five instars:
Ist instar – from hatching to Ist moult
IInd instar – between Ist moult and IInd moult IIIrd instar – between IInd moult and IIIrd moult IVth instar – between IIIrd moult and fifth moult
Vth instar – between fifth moult and pupation
A fully-grown larva of Vth instar attains the length of 7.5 cm. It stops feeding and starts spinning the cocoon. It secretes silk thread from its spinneret and forms covering in which it encloses itself completely. It takes about 3-4 days to spin the cocoon.
- Pupa : The cocoon consists of silk The enclosed immobile larva in the cocoon is called as Pupa. The pupal stage is non- feeding and non-mobile. It remain & inactive. But the internal organs undergo drastic changes collectively called as metamorphosis and transforms itself into imago.
- Cocoon : The cocoon is white or yellow in colour. It is made up of about 1000-1200 meters long silk The thread is wound around the cocoon is concentric circles. The weight of one cocoon is about 1.8 to 2.2 gms. The pupal period lasts for about 10 to 12 days. Alkaline fluid which makes the threads of cocoon to be soft. Soft threads are cut open by the imago. A young moth comes out of cocoon.
Factors influencing the life cycle : The life cycle is influenced by the external environmental factors, such as, temperature, humidity and light. These factors control the growth of the larvae and also the quality of silk produced. The growth and moulting is controlled by hormones called juvenile hormone and ecdysone.
- Fertilization : After the moths emerge out from cocoons one female from one lot is kept with the male from another lot. They form pair and copulate. After copulation is over separated and kept with female of another Thus one male can be used to fertilize at the most two females of different lots.
- Egg laying : After fertilization the female starts laying Egg laying is completed in about 24 hours. The laid eggs are called seeds. The eggs are transferred in sterilized and tray stored at 4°C.
- Composition of silk : The silk is a secretory product of silk glands of the larva. Silk is composed of It consists of an inner part made up of fibroin protein (C30 H46 N10 O12) and is covered with an outer envelope made up of sericin protein (C30 H40 N10 O12). The silk thread contains 75-80% fibroin and 20-25% of sericin,
- Sericulture industry : Sericulture industry involves three steps, (a) mulberry cultivation (b) silkworm rearing and (c) silk
- Mulberry cultivation : Mulberry is the only food of Mulberry plants come up in any soil and in any climate. It is propagated by cuttings. The land is ploughed well 6 or 7 times in April-May and manured at the rate of 2 to 25 tons per hectare. Small pits are scooped out 2 or 3 cuttings are lanted in pit. Each cutting should be 20 to 23 cm in length with nodes. When the plants grow too high they are cut back and this is known as pruning. Pruning. Pruning will help in the production of a new flush of leaves. The plants can yield for 12 years. Every year 6 to 8 crops of leaves can obtained and the average yield per hectare is 25 to 30 metric tons of green leaves.
Species – morus indica, morus alba.
(b) Silk worm rearing – Silk worm rearing needs the following:
- Rearing house
- Rearing trays and stands
- Chandrikes as support to build the
The hybrid eggs are obtained from the sericulture department. The larvae are hatched from the eggs. The newly hatched larvae are brushed into rearing trays and tender, chopped are provided to them. Fresh leaves are offered 3 to 6 times a day and the old unconsumed leaves are cleaned periodically. From the fourth instar onwards, whole fresh leaves can be given. The consumption of leaves by the larvae increases with their age. At the end of the final instar, fully grown mature larvae are transferred from the rearing trays to chandrikes and allowed to build cocoons. Cocoons are then collected and marketed.
Grainage Management : This is done to provide good quality of seed to rearers and also to maintain the original quality. With this air grainage management is done by taking of caterpillar stage. They are protected from diseases and are provided good nutrition. An initial selection is made by observing pupal mortality rate. If the mortality rate is high, then such cocoons are rejected and are not kept for seed production. If the mortality rate is sufficiently low, their only such cocoons are selected and kept for seed production. The selected cocoons are kept for mass emergence. Before doing so the cocoons are examined and sexed. Males are kept separately and females are kept in separate lots.
- Hatching : The process by which larvae come out of the egg is known as After hatching larvae start eating mulberry leaves. The success of sericulture depends on the supply of good quality of mulberry leaves; therefore the hatching must coincide with good mulberry season. Now a days controlled hatching is done by placing the eggs in low temperature. The eggs are turned and moved with the help of a feather. Now -a-days the eggs are kept in mulberry leaves in sterilised trays. If hatching is to be delayed or controlled, the eggs are kept in separate trays and refrigerated for a suitable time.
The caterpillars which hatch out are kept in separate groups according to their age.
- Supply of seeds to rearers : Under this step the are supplied with seeds. The seeds are of two qualities, e., eggs and 2nd instar larvae. Beginner rearers are supplied with 2nd instar larvae, which experienced rearers can purchase egg. This is important operation. For this purpose government has established many silk worm seed centres from where the rearers get their seeds at fair price.
- Rearing of Caterpillars : The caterpillars are reared at room temperature in shady places at about 60 to 70% The mulberry leaves supplied to Ist and 2nd instar larvae are well chopped, fresh and kept in wet clothes so as to keep them fresh. The caterpellars eat voraciously and grow in size and moult. The form of larvae between two successive moults is known as instars. Larvae have five instars. The last or 5th instar larvae stop feeding and undergo pupation.
- Spinning of Cocoons : Full grown 5th instar larvae secrete a pasty material from its silk It moves its head to and fro, secreting a silk thread. The spinning larvae are picked up and kept in spinning trays. The trays are kept in slanting position towards the sun. Within a period of three days spinning is and larvae are transformed into pupae enclosed in cocoons.
A good quality of cocoon is judged by the quantity of raw silk, filament length, strength and splitting power.
The cocoons are marketed and sold.
- Post Cocoon Processing : It included following stages:
- Stifling : The process of killing the cocoons is termed as Eight to ten day-old cocoons are selected and dipped in hot water to kill the pupae in the cocoons. If cocoons are not dipped in hot water the silk worm cuts hole in the cocoon and hence the silk thread is destroyed.
- Reeling : The silk threads from the killed cocoons are removed and wound round a large wheel and then transferred to This operation is called as reeling and the silk is called as reeled silk.
- Spinning : Damaged cocoons or the damaged outer layer of silk is separated and spun into This is known as spun silk.
The raw silk is boiled, stretched, purified and washed again and again to shining lustre. Reeled silk or spun silk is marketed and sold.
- Problems of Sericulture : The sericulture industry is facing a number of
- Need for Research : There is a great need to better methods of rearing the silk This is necessary to improve the yield of raw silk and reduce the cost of production.
- In order to improve the quality and yield of raw silk improved varieties of silk worm are developed by hybridization and There is a need for the improvement of genetic quality of the silk worm.
For research and training in sericulture the Government has opened Research and Service Station in many states. A Central Silk Board has been established at Bangalore the ministry of commerce.
- Diseases : A number of diseases are caused to silk These diseases result in the low yield and reduce the quality of silk.
Disease of silkworm
- Pebrine : It is the most important disease of silkworms. It is caused by a sporozoan called Nosema The full grown caterpillar is attacked. The infection spreads successive generations through eggs of a infected moth therefore eggs from healthy moths alone should be taken for rearing worms.
- Muscardine : It is a fungal disease caused by Beauveria bassiana and transmitted by spores carried by All stages of caterpillar are attacked.
- Flacherie : It is a bacterial disease caused by Bacillus Digestion in the affected caterpillar gets disturbed Regular feeding of the larvae and maintaining hygenic conditions will prevent the disease.
- Grasserie : The causative agent of this disease is the nuclear polyheadrosis The affected larvae become swollen and like a bag of granules, the body fluid becomes thick and cloudy and the larvae die.
- Economic Potentialities of Cultivating Silk in Madhya Pradesh : Madhya Pradesh is the largest state with respect to land area and has rich subtropical vegetation. Thus Madhya Pradesh holds vast economic potentialities of cultivating silk Sericulture is an important rural cottage industry. The tribal and other rural population in south east and east M.P. is favourably disposed for the cultivation of silk. Once M.P. was not a significant state in the list of silk producing states of India but due to the efforts of Madhya Pradesh Government in the direction of promoting sericulture today it, is the second largest state after Karnataka in the field of production of row
- Efforts made by Government of P. to Promote Sericulture in state : A directorate of silk has been organised under the Panchayat and Rural Development Department to make concentrated efforts. These activities have been divided in two categories :
- Kosa silk Area : It extends in the eastern and south eastern parts of the state. This area is predominated by tribal population and is spread in the districts of Balaghat and
- Mulberry silk Area : It is spread in the western and middle parts of the state including the districts of Indore, Dhar, Dewas, Khandwa, Ujjain, Shajapur, Raigarh, Mandsaur, Guna and For the promotion of the production of Kosa silk (now Mulberry silk) following efforts are being made.
- Kosa Seed Centre : Twelve Kosa seed centres have been established to provide scientific and technical information to the Kosa silk worm rearers. These centres also provide disinfected improved kosa seeds and caterpillars to the
- Kosa Guidance and Training Centre : Madhya Pradesh Government has established 67 centres which meet the basic needs of supplying disinfected improved seeds of Kosa silk and impart training and guidance to the
- Nursery : To meet the needs of the host plant and supply of leaves to the rearers the government has established nurseries of Terminalia tomentosa and Terminalia arjuna. Plantation of host plants has been undertaken in 296 hectares of land and 1285 hectares of land is proposed to be covered under this
- The construction of two grainage, one cold storage, one cocoon market and one reeling factory is being
- Kosa Regional Research centre has been established to help the rearers to increase the yield and improve the quality of
- Mulberry silk Plans : To promote the mulberry silk production in P. certain efforts have been made in the direction by the Madhya Pradesh Government. These are
- Establishment of Nursery : To increase the production of host plant Mulberry silk worm, the Morus indica, nurseries have been
- Mulberry silk seed centres have been
- Integrated rural development projects have prepared for the production of Mulberry
- Establishment of regional research centre and reeling
- Demonstration and publicity
Madhya Pradesh Government has allocated 476.22 lac of rupees for the development plans of silk For the year 1985-86 a target of 80,000 kg. of Kosa silk and 8356 kg. of Mulberry silk.
Apiculture is the science of rearing honeybees for obtaining honey, wax and venom. It is a profitable money- making hobby. It forms a cottage industry, when carried out on a large scale.
Three species of honey bees are commonly found in india vig. Apis indica (The small indian bee). Apis florea (The little indian bee) and. Apis dorsata (the giant bee) other important species include Apis milifera (the common European bee) and apis adamsoni (the African bee) In india the commonly domesticated species are Apis milifera and Apis Indica.
- Honeybee-Apis : Like termites, honeybees are social insects known for producing honey and beeswax, and for living in very highly organized These feed upon nectar and pollen of flowers, possess “sucking and chewing” mouth parts, and undergo complete metamorphosis. Each colony has its own nest called honeycomb or beehive. The hive is thirty to ninety centimetres. It comprises thousands of small, symmetrical and hexagonal chambers, called “cells”, made up of beeswax. Karl Marx Commented that the architectural arrangement of “cells” in a beehive puts the best of human- made architecture to shame. The ”cells” are used for storing honey and pollen breads, as well as, for rearing the brood.
Beehives are found upon tree branches, or hanging from ceilings of old abandoned houses, or inside caves and hollow stems of old trees.
- Division of labour and polymorphism : Each beehive harbours a colony of thousands of polymorphic bees belonging to a single The polymorphic individuals are of three main types (i) a single queen (fertile female)(ii) one to a few hundred drones (fertile males) and (iii) thousands (upto 60,000) of worker bees (sterile females).
- The queen : She is the supreme being in a colony, because all the main activities in the hive revolve around her. She normally lives for about five years, and does nothing except laying eggs. That is why, she possesses immensely developed ovaries, a large abdomen, and a body which is nearly five times larger and about three times heavier than that of a worker In other features, she is degenerate, having small wings and poorly developed legs, mouth parts, sting, brain, etc. She has no salivary or wax glands. Hence she can either produce honey or wax nor can she fly out of the hive. She therefore, depends for food completely upon worker bees. Although she can use her sting, but it is mainly used as an ovipositor for laying eggs. She lays about fifteen lac of eggs during her lifetime. Normally one to three thousand eggs are per day. Egg-laying is a seasonal activity occurring during winters and spring in our country.
- The drones : These are smaller, but stouter than the queen, with broader abdomen, longer appendages, and larger wings, brain and eyes. These also lack salivary and wax glands, and depend for food upon worker bees. These even lack a sting and, hence have no Their sole function is to fertilize the queen. Hence, during breeding season, these are well-fed by the workers, and can be often seen flying near the hive, enjoying or chasing and mating with young queens in fight. After breeding season, in the following summer, the drones are neglected and eventually driven out of the hive to die of hunger and heat.
- The workers : These are considerably darker and smaller, and most robust with strongest mouth parts and well- developed wings. Their body is densely covered with hair like bristles. These possess four pairs of pocket- like wax- secreting glands upon ventral surface of second to fifth abdominal segments. The wax is chewed by means of mandibles and, then used in constructing new ”cells” in the The legs of worker bees are modified to collect pollen. When these bees visit flowers for sucking nectar, numerous pollen grains stick to their bristles and mouth parts. The legs are equipped with “pollen brushes” of stiff bristles which brush off the pollen from various parts of body and collect these in two ”pollen baskets”. The latter are pit like concavities upon dorsal surface of the wide tibia of hind legs (= metathoracic legs).
Due to their heavy-duty life, the worker bees live only for two to four months. Each worker bee spends its life in tireless tail. We can say that it has no childhood, because as it becomes an adult bee, it starts working for the colony from the very first day. Its functions change with age. Accordingly, the worker bees of a hive fall under age- groups or castes as follows:
- Scavenger or Sanitary bees : For the first three days, each worker bee acts as a scavenger, cleaning the wall and floors of abandoned, empty ”cells” of the colony for
- House or Nurse bees : From the fourth day onwards, each worker bee feeds the earlier brood, like a foster mother, with a mixture of honey and At times, it flies out but only around the hive just to become familiar with its surroundings. From the seventh day, the maxillary glands of a worker bee begin to function. These secrete ”royal jelly” with which the bee now starts feeding young larvae, the queen and those older larvae which are destined to develop into future queens, From the twelfth to the eighteenth day, each worker bee develops wax glands and works upon the architecture of the hive. Wax is secreted in the form of thin scales. Middle legs scrap the scales, bring these in between the mandibles for chewing and mixing with saliva and, then, mould and use these in constructing new ”cells”. These bees also repair old cells, filling, cementing and varnishing cracks and crevices of these cells by means of a bee-glue called propolis. Propolis is prepared from resins collected by the bees from.
- Life History : Queen lays about 2,000 eggs a The eggs are laid in the comb, one in each cell. They hatch out into larvae in three days. They are fed on royal jelly for a few days. But the larva which develops into the queen will be fed on royal jelly continuously.
During breeding the queen bee flies in the air along with the males. This phenomenon is called nuptial flight. During nuptial flight the queen copulates with a male Copulation occurs in the air. Then the bees return to the comb and the queen starts laying eggs.
- Bee-Hive : Honey bee is one of the few domesticated insects. In modern days bee colonies are reared in artificial wooden boxes for maximum production of honey and wax. The artificial box where the bee colony is maintained and managed is called hive. The place where hives are kept and managed is called
There are different models of hive; but the most common model in use is Newton’s hive designed by Rev.
Fr. Newton. The hive is in the form of a wooden stand. The hive has two chambers. One is the upper and the second one is the lower. The upper chamber is called super or honey chamber. The lower chamber is called brood chamber. The queen is kept in the brood chamber. The two chambers are separated by a wire grid called queen excluder. The holes in the queen excluder are so smaller that they prevent the entry of the queen into the super,
but allows other bees to pass through. As a result the eggs are laid only in the brood chamber. The super chamber is meant for storing honey.
Life history of Apis indica
The brood chamber is placed on a bottom board. This board extends forwards as an alighting board on which the bees rest for some time before entering the hive. The brood chamber has an entrance through which the bees enter. The super chamber has a ventilator. The super is covered ovary by a roof.
Honey mainly consist of monosaccharides
Both the chambers contain about 7 rectangular wooden frames called comb frames arranged vertically. The vertical frames are filled with comb foundation sheet. These sheets are made of wax and contain hexagonal imprints. They are detachable. They are available in the market.
A set of bees with a queen is introduced into a hive. They construct the comb in the vertical frames starting from the comb foundation sheets. Honey is collected in the combs of super and the eggs, larvae and the young ones are kept in the combs of brood chamber. When all the cells are filled with honey, the cells are capped or closed by a thin layer of wax.
- Honey extraction : Honey is stored in combs of super It is extracted from the comb by a simple machine called honey extractor. It has a drum containing a rack inside to hold the super frames. It is made to rotate by a set of two-gear wheels, operated by a handle.
The super frames are removed from the hive. The caps of the comb cells are cut off by a double edged knife. Then the frames are fixed in the rack and the rack is made to rotate by operating the handle. The honey is forced out into the drum from the comb cells. From the drum the honey is collected in vessels through an exit present in the drum.
(vi) Location of Apiary
- The hives should be set, in places where there are plenty of flowering
- They should be placed in shady places.
- The place should be neat and clean and free from any obnoxious
- There should be clean drinking water near by because each bee colony requires two glasses of water per day for their survival
- Honey bees should be protected from garden lizard and
- Black ants steal So water should be placed at the base of the stand.
- Wasps kill honey So protection should be provided against wasps.
- Wax-moth damages the So the combs must be ” protected from wax-moths.
- Formation of honey : Honey is a viscous sugary fluid formed from the nectar within the stomach of the honey bee. The bees visit flower, suck the nectar, store it in the stomach and return to the hive. In the stomach the nectar is processed. It is regurgitated and swallowed repeatedly for about 240 times. Then the processed nectar is deposited in the comb cells. This processed nectar is called unripe honey or green honey. It contains about 80% The unripe honey is converted into ripe honey by evaporation. This evaporation is facilitated by two methods. They are 1. The workers set up an additional circulation of air in the comb by beating their wings and 2. The worker bees carry nectar several times from one cell to another until the unripe honey becomes viscous. The ripe honey contains less than 20% water. When the honey becomes ripe, the cells are capped or closed. The honey in the unsealed cell is unripe.
- Chemical composition : Honey contains nearly 80 different substances of importance to human The important chemicals are as follows:
- It contains a large amount of glucose or
- It contains proteins as well as
- The vitamins present in honey are A, B1, B2, B3 , B6, C, E and K.
- A variety of enzymes are present in honey. They include diastase, invertase, saccharase, catalase peroxidases and
- It contains many organic acids. The most important organic acid is formic acid; other organic acids are malic acid, citric acid, tartaric acid and oxalic
- It contains a variety of minerals like Ca, Na, K, Mg, Fe,Cl,P,S
- Value of Honey – Honey is a valuable food and Its uses are summarised below:
- As it has high content of sugar it is used as a Until last century before the discovery of sugar throughout most of human history honey was the only available sweetener.
- Honey has a high calorific One kilogram of honey has 3350 calories while 1 litre of milk contains only 310 calories.
- Many athletes drink honey before games and between events in order to restore the energy used
- Doctors prescribe honey for old people and children who need to build up their strength
- Honey contains biogenic stimulators e., substances that heighten the activity of organisms. It has been proved that cuttings from trees, planted after treatment in a solution of honey, take root easily and grow well.
- Honey is used to heal
- It is used to cause free
- It is used as a means of easing the
- It is a good tonic for
- It facilitates digestion and improves
- It prevents a running It is a sure remedy for cold and cough.
- Honey is used as medicines for children to treat complaints of the
- Honey is good for kidney patients. People suffering from kidney stones are a divised to take a table spoon of honey, lemon-juice and olive
- Bee wax : Bee wax is secreted by the abdominal gland of bees. It is used for the construction of comb. It is an yellowish solid insoluble in water. It is used for the preparation of paints, varnishes, candles, models, etc. It is used as a ground substance for the preparation of ointments, creams It has many industrial uses. It is used extensively in engineering industries, railways, textiles, leather industries etc.
- Bee venom : Bee venom is secreted by the poison-glands of stings. Bee venom is a curative toxin in It is transparent and it has a bitter burning taste. It is acidic in nature. It contains formic acid, histamine, tryptophan, sulphur, many proteins, volatile oils, enzymes like hyaluronidase and phospholipase and magnesium phosphate. Clinically it has the following uses :
- It is an active remedy for
- It is used to treat certain eye diseases like keratoconjunctivitis (inflammation of cornea), iris (inflammation of iris), iridocytis (inflammation of iris and ciliary body).
- It is used to cure skin diseases like tuberculosis of the
- The cholesterol level in blood falls by the treatment of bee
- Bee venom controls blood
- Waggle Dance of Honeybees : The exploitation of food sources by honeybees has been studied for decades, but its study still offers important challenges for One of these areas of research concerns the extent to which honeybees communicate the location of food to other bees.
The communication of honeybees is remarkable because the so-called language of the bees uses a variety of stimuli to impart information about the environment. Karl von Frisch, famous ethologist, carried out many detailed bee experiments in the 1940 and was able to determine that when a foraging bee returns to the hive, it performs a waggle dance.
- Waggle Dance : A worker bee that returns to a hive laden with nectar and pollen stimulates other experienced workers to leave the hive and visit productive pollen and nectar Inexperienced workers are also recruited to leave the hive and search for nectar and pollen, but stronger stimuli are needed to elicit their searching behaviour. In the darkness of the hive, the incoming bee performs what researchers have described as a round dance and a waggle dance. Throughout the dancing, other workers contact the dancing bee with their antennae and mouth parts, picking up the odours associated with pollen, nectar and other objects in the vicinity of the incoming bee’s food source.
- The dance, which indicates the distance and the direction of a food source, has a figure pattern. As the bee moves between the 2 loops of the figure it buzzes noisily and shakes its entire body in so-called Distance to the food source is believed to the indicated by the number of waggles and or the amount of time taken to complete the straight run. The straight run also indicates the location of the food. Outside the hive, the dance is done on a horizontal surface and the straightaway indicates the exact direction of the food. Inside the hive, the dance is performed on the comb, which is vertical, and the angle of the straightaway to that of the direction of gravity is the same as the angle of the food source to the sun. In other words, a 40° angle to the lefts of vertical means that food is 40° to the left of the sun.
As mentioned, honeybees can use the sun as a compass because their biological clock allows them to compensate for the movement of the sun in the sky. In the dark hive, bees use a combination of the tactile and
auditory communication. Through touch, bees can determine the direction and waggles of the dance. Not only the waggles but also the buzzing noises of the dancer tell the distance to the food source.
These observations indicate that bees communicate information regarding distance, direction and kind of food to other bees when returning from a foraging trip. Thus, the exploitation of pollen and nectar is a very efficient process and is one source of evidence of the highly evolved nature of the honeybee colony.
Lac is the resinous secretion produced by lac insect as protective covering around its body. It belongs to genera Laccifera or Tachardia Lacifera lacca is the common Indian lac insect. It lives on the trees of fig family namely kikar, ber (Zizyphus mauritiana), babul (Acacia nilotica), dhak or palas (Butea monisperma), kusum (schleichera oleosa), Katha or khair (Acacia catechu), peepal (Ficus religiosa) and gular (Ficus glomerata).
Lac insect feeds upon the sap of its host plant like any other sap sucking insect. It is found in India and Philipine islands.
- Male and female chambers : The adult male and female insects live on the tree twigs enclosed in thick capsules or chambers The male chamber are elongated and cigar- shaped. Each male chamber has a branchial aperture in its anterior part. There is an opening in the posterior part of the chamber which is covered by an opereculum. The male insect can crawl out through this opening.
The female chamber is smaller and rounded. It has a branchial aperture in its anterior part and a tubercular or anal opening in the posterior part. A ridge extends in the mid-dorsal line of female chamber, which indicates the posterior end of the last larval skin.
- Male and female lac insects : The lac insects have a sluggish and almost sedentary life, living inside the Therefore , these have become degenerated, without wings and distinct legs. However. the female is more degenerated. It has a bag -like body with a small reduced antenna. The eyes legs and wings are lost during metamorphosis. The male lac insect is red in colour. It has an incipient head with antennae and eyes. The thorax has three pairs of legs and abdomen carries genital sheath, penis and a pair of long caudal setae, one on either side of genital sheath.
The wings may be present or absent. Because of the absence of mouth parts, the insect is incapable of feeding.
- Life-cycle : The male lac insect crawls out of its chamber by pushing open the operculum reaches the female chamber and fertilizes the female through the
anal or tubercular opening of female shell. The male dies soon after copulation. The female secretes more resin forming a large sized chamber. Thus the secretion by females mainly contributes to lac.
Oviposition takes place into a space inside the female chamber made by the contraction of the body of female. This space is called incubating chamber. Each female lays 200-300 eggs. The eggs hatch into red coloured larvae. These crawl out of the female’s incubating chamber. The mass emergence of larvae is called swarming.
Each larva is boat-shaped in appearance and is about 1/2 mm in length. Its head bears paired antennae and the ocelli. The mouth parts are of
piercing and Sucking type with maxillae and mandibles together forming the sucking tube or
proboscis. Its thorax is three segmented and each thoracic segment carries a pair of walking legs. The abdomen bears a pair of long caudal setae.
- Attachment of larvae to new shoots : The larvae on emergence craw1 on the twigs of any one of the host trees mentioned earlier and settle down on the undersurface of new These prefer young succulent
shoots. These force their proboscis through the bark and insert it into the phloem tissue and start feeding. Here these metamorphose into the adult insects and by secreting lac enclose themselves into the chambers.
- Secretion of Lac : The secretion forms a shining layer over their bodies in the beginning but hardens and becomes opaque later The secretion is produced by the cutaneous glands of the skin and is deposited around three openings the two branchial apertures at the anterior end and anal opening at the posterior end. The secretion is in the form of waxy filaments which have a woolly white appearance. On coming in contact with air, these join to from a continuous covering. Further, lac secretion continues inside this coating so that lac deposition adds to the thickness of the coating. With growth of larva and addition of lac the adjacent chambers of different larvae coalesce with one another forming a more or less continuous encrustation.
- Lac Cultivation : In order to obtain lac, lac insects are cultured and the technique of lac production is known as the lac culture. It involves proper care and regular pruning of the host plants, propagation of insects, and collection and processing of lac, For the purpose of propagation the older branches containing crusts are tied with new branches and this method is called oculation. When new crusts are formed, the old twigs are removed (approximately 20-30 cm long) and this is known as
After inoculation, lac insects come out of the old crusts. At this stage they are known as nymphs. The nymphs hatch out from eggs laid by the females in the old crusts. The coming out of nymphs from the old crusts is known as swarming, some of the nymphs become winged or wingless male and others become female. These nymphs explore new branches. The thousands of nymphs settle side by side, and the resinous secretion builds up around them and completely encases them. The nymphs undergo several moults. Most of them develop into females and some into males. The females remain in small cavities in the resinous mass from which they never come out.
- Extraction of Lac : The largest yield of lac and dye are obtained by harvesting the infested twigs while females are still The harvesting is done twice a year in June and November. The encrused twigs are pruned and lac scrapped from them. This is known as stick lac. It is grounded and sieved. The resulting granular lac is called seed lac, and the fine particles the dust lack. The seed lac is washed, melted spread out in a thin layer and dried thus forming the shellac of commerce. The dust lac is used for making toys, shellac is used in the preparation of varnishes, paints and polishes; in making gramophone records and in filling ornaments like bangles and bracelets. It is used as insulating material.
Lac insects are highly useful to man. They yield lac, the utility of which discussed above. Besides this, a red dye is obtained from the body of female acts. The dye is used by women to colour the soles of the their feet, skin. Lac insects are also used for curing lung and stomach troubles.
(viii) Damages Caused to Lac Crop
- Lac crops is reported to be damaged by squirrels, rats, and
- Certain insects also attack lac
- Parasites : Eight species of chalcidoids live as parasites in the body of lac insects. These deposit their eggs into the body of insects through their anal
- Predators : Eublemma amabilis and Holcocerea pulverea are the two lepdoteran predators that damage about 35% of the lac cells. Their females lay eggs on or near the encrustation. The larvae that hatch out bore through the lac deposit and feed on lac
(ix) Precautions to be Taken During Lac Culture
- Lac intended to be used as brood should be cut at or near the swarming period, never more than one week
- Lac to be used as brood must be healthy and resistant to the parasite and predator’s
- Lac used as brood should be removed after a maximum period of 3 weeks from the date of swarming.
- All brood lac after use and the lac cut from the tree should be scrapped from the sticks to destroy larvae and pupae of predators of
- Lac should not be stored after It should be treated as soon as possible.
- Fumigation and water immersion immediately after cutting are also helpful in the disinfection of Lac by
- Economic importance of Lac : Lac is used in the preparation of sealing wax (shellac), paints, varnish, the manufacture of photographic materials, electrical goods. Lac is also used in the preparation of bracelets, buttons, toys and in filling hollow gold ornaments. Lac is also utilized in confectionery trade and in artificial leather and pottery. Gramophone industry used to consume 30-40% of the annual production in the preparation of
- Cultivation of Lac in India : India has monopoly in the production of lac. It is about 75% of the world’s total output. Approximately 40 lakh ponds of lac is produced. Bihar M.P. and west Bengal are major lac producing states in India. Thailand is major competitor of India as it shares 25% of the total exports. India exports about 1,80,400 of lac The use of lac is being gradually replaced by plastic.
Poultry includes the birds like chicken (hen), ducks, geese and turkey. Poultry farming deals with the rearing of them for their eggs and meat. Fowls are widely distributed as domesticated animal since time immemorial, but in the present century, it has become an important small scale industry due to modern need for palatable and nutritive food which it provides in the form of eggs as well as adult animal. An egg laying poultry bird is called hen and the poultry birds groomed for obtaining meat are called chicken or broilers. Birds specially chicken grown for meat only is known as Broiler Poultry is closely related to the problems of nutrition. Poultry and poultry products like eggs are a rich source of animal protein and a right kind of fat for good health.
India and the neighbouring countries, like Burma, Sri Lanka are the original home of the red jungle fowl (Gallus gallus). It seems that Aseel or Malay fowl were carried to Europe through the Middle East about 2,000 years ago and have given rise to the present-day European breeds.
- Poultry farming v/s livestock rearing : Poultry birds are easy to raise, can be acclimatised to a wide range of climatic conditions, have short life span and are prolific breeders and thus poultry farming is advantageous over livestock rearing. Moreover, poultry farming requires less space and easy to manage and maintain and brings fast returns. Hens have an average yield of 60 eggs per year, but high yielding varieties can produce more than 240 eggs in a
Poultry contributes about Rs. 7,500 crores to the gross national product (GNP) of India. India ranks fifth in the world’s egg production. Egg is one such food commodity which cannot be adulterated. The average per capita consumption is about 32 eggs and 600 grams of poultry meat a year. At present poultry is estimated to provide employment to about seven lakh families.
- Raising of poultry – Fowl house : Fowls can be reared in the hills of India without houses, but in the plains, well- ventilated and illuminated, dry houses are essential. A house of 1.8 x 1.5 x 1.5 m has sufficient accommodation for six fowls. An open shed or verandah must be attached to this house as run to the fowls for The fowl house may be either of wood or brick and the roof is made up of corrugated iron sheets, thatch or wood. The floor is littered with chopped straw, paddy husk, dry leaves or groundnut hulls. The fowl house must be rat- proof, with proper drainage. The house and shed should be cleaned daily. Fowls of different ages are kept in separate houses. In regions with moderate climate, they are kept in cages (coops).
- Feed : The quality and balanced quantity of food material are the back-bones of poultry. The feed given to poultry birds should contain all the essential nutrients like carbohydrates, fats, proteins, minerals and The feed usually consists of mashed cereals like bajra, wheat, maize, jowar, ragi, rice bran and oil cakes. The fish meal’ prepared from the wastes of fish processing industry and meat meal’ prepared from the wastes of meat processing industry is also used to feed poultry birds. The skimmed milk is highly nutritive for young chicks and should be given
in clean vessels. The green food as fresh tender grass, garlic, lettuce, onions, etc. are important for poultry and should be given uncooked.
- Breeds of fowls : The whole poultry industry is centred round the fowls so the selection of good breed of birds for particular area is essential. The selection of fowl breed should be based on the object with which fowls are Some important indigenous breeds of domestic fowl (desi hens) include Aseel, karaknath, Basara, Chittagong, Ghagus, Brahma and Cochin. Desi hens are hardy (strong) and possess natural immunity against common diseases, but they are small, slow growing, and lay small- sized and less number of eggs. The average egg production of a desi hen is about 60 eggs per annum, which is very poor. Keeping this fact in mind , a large number of poultry birds have been imported, bred and acclimatised to local conditions. Some of these are excellent egg layers while others are good meat producing birds. Some of the high egg-yielding exotic breeds of hens which have been successfully acclimatised in India include white Leghorn, Rhode Island Red, Black Minorca, Plymouth Rock, Light Sussex and New Hampshire. White Leghorn is one of the most popular egg breeds all over the world. The local varieties of hen (disi hens) have been cross bred with the high-yielding varieties of exotic breeds to obtain new breeds which combine the good characteristics of both the breeds. The new improved breeds (hybrid breeds) of poultry birds grow fast, take less feed, lay more bigger-sized eggs, and are more resistant to diseases. ILS – 82, B – 77 HH – 260 are some important improved, high yielding breeds developed in India by cross breeding. The ILS-82 and B – 77 breeds lay about 200 eggs, whereas HH – 260 breeds lay more than 260 eggs per annum.
- Diseases of poultry : The poultry keeper should always be careful against the Some important diseases of poultry birds are fowl pox, ranikhet (viral), fowl cholera, salmonellosis, diarrhoea, coryza (bacterial) and aspergillosis (fungal) However, the most common disease amongst fowls is Ranikhet disease, caused by a virus. The disease affects the fowls of all ages. In this disease bird opens the beak, becomes thristy, suffers from fever and yellowish – white diarrhoea occurs. It is followed by nervous symptoms like twisting of the head, circular waling and paralysis. The birds become very weak and die within two to three days. Mortality is very high about 98 to 100 per cent. But, with better management, proper housing and nutrition and timely vaccination of the chicks, the disease can be controlled very effectively.
- Ranikhet diseases is found in Hens
- Other poultry birds : Besides domestic fowl, other birds like ducks, turkeys, etc are also Ducks comprise about 6 per cent of the total poultry population in India. They are more abundant in the southern and eastern parts of India. Muscori, pekin, Aylesbury, Campbell, India Runner and Syhlet meta are some important breeds ducks. Narfold, British white, Broad Breasted Bronze and Beltsville small white are some important breeds of turkeys in India.
- Poultry development in India : Poultry is one of the important components of the farmer’s economy as it provides additional income and job opportunities to a large number of rural population in the shortest possible Central poultry breeding farms at Bombay, Bhubaneswar, Hessarghatta and Chandigarh engaged in scientific poultry breeding programme developed high egg producing hybrids and fast growing broiler breeds. Central Duck Breeding Farm at Hessarghatta is catering to requirements of high egg producing khaki campbell breeding stock duckling. The poultry industry has grown rapidly in India in the last twenty years from a backyard farming activity to a modern and highly scientific industry. As a result of government’s efforts, during the seventh plan period, egg and broiler production registered a compound growth rate of 7.3 per cent and 18 per cent respectively. The egg production is estimated to be about 26.1 billion in 1994-95.
- Broiler or fryer – The chicken use for
- Brooding – Living and brood out egg for incubation in particular
- Cannibalism – Peeking of fowls among them
- Cockerel – Young male
- Rooster – Mature male
Fishes are a valuable and easily accessible source of food, rich in protein, highly nutritious and easily digestible. By the aquatic animals, they are abundantly available from sea, rivers, lakes, ponds and marshes.
Aquaculture is the production of useful aquatic plants and animals such as fishes, prawns, shrimps, lobsters, crabs, molluscs by the proper utilization of small and large bodies of water. Pisciculture is the production and breeding of fishes by man in ponds.
India has abundant marine and inland fish resources. It has a cost line extending to 4667 Km long and a continental shelf of 2,59,00 square Km offering good scope for fish production. The fish production has increased many folds since India got independence. During 1990-91 the annual fish production of our country has been 38.22 lakh tons. The per capita consumption of fish in India is estimated at 1.51 Kg/year. India is at present the 6th foremost seafood producing nations in the world.
- History : From pre-historic period, fishes have used as protein rich diet for human beings. The popularity of fishes has been mentioned in our religious books like Ramayana and Mahabharata
In west Bengal, Bihar and orissa, the fish industry is about 1,500 years old. In Bengal every family traditionally has atleast one pond for fishes.
Classsification of cultivable fish species :
|Zoological name||Common Name||Areas of availability|
|(a) Fresh water fishes|
|1. Catla catla||Catla||All over India common in Krishna and Godavari rivers|
|2. Labeo rohita||Rohu||North, East and South India|
|3. Labeo calbasu||Calbasu||North and South India|
|4. Cirhinus mrigala||Mrigal||North and South India|
|5. Mystus singhala||Singhala||All over India|
|6. Heteropneustes fossilaris||Singhi||All over India|
|7. Wallago attu||Malli||North, east and South India|
|8. Clarius batrachus||Fresh water shark magur||All over India|
|(b) Brackish water fishes|
|9. Chanos chanos||Milk fish||A.P.coast|
|10. Mugil cephalus||Grey mullet||East coast|
|11. Laters calcorifer||Perch||East coast|
|(c) Marine fishes|
|12. Sardinella longiceps||Oil sardine||West and south coasts|
|13. Harpodon heherius||Bombay duck||Maharastra coast|
|14. Hilsa ilisha||Hilsa/ Indian shed||Coastal India|
|15. Stromateus sinensis||Pomfret||Indo pacific coast|
|16. Anguilla anguilla||Eel||Coastal India|
|17. Aluitheronema||Salmon||East and west coast|
|18. Cyano-glossus semifas- ciatus||Flat fish||East coast of India|
- Culture method : The success in fish culture and the high production of table – size fish through carp culture depends largely on the designing and construction of ponds. The basic principles involved in designing and construction of carp culture ponds are of very specialized nature and vary form region to region depending upon several factors like topography, soil types, water supply The requirements with regard to the designing and construction of fish farm are entirely different from those attributed to agriculture and animal husbandry farms.
- Types of Ponds : Ponds for carp culture may be broadly classified into three types : (a) the nursery ponds, (b) the rearing ponds and (c) the stocking ponds. The ponds which are small and shallow are used for raising fry from spawn (4-5 mm to 25-30 mm) may be termed as Nursery ponds or Nurseries. Ponds used for rearing fry upto fingerling stage (50 mm and above) are known as Rearing The rearing ponds are slightly larger but not proportionately deep and are used for rearing fry
upto fingerling (50 mm & above) stage. While ponds which are used for stocking fry/fingerlings to obtain table-size fish may be called as stocking ponds. The stocking ponds are still larger and deeper (0.2 to 2.0 ha in size and 2 m to 2.5 m in depth).
- Species Composition and Species Densities : Rearing of dietetically compatible species is one of the fundamental principles in fish culture. The divergent feeding habits of the Indian major carps and of the exotic Chinese carps are therefore taken advantage of in mixed culture. This divergence of feeding habits develop, as stated earlier, from advance fry stage and yet limited over- lapping in feeding habits is but to be expected. In view of this, trials were made with two, Four and six species compositions, within which variation in species densities or ratios were also attempted. Some of the combinations tried were as follows :
Silver carp + Grass carp :: 1:1
Catla + Rohu + mrigal :: 2:4:4
Silver carp + grass carp+ common carp :: 4:3:3 Catla + Rohu + Mrigal + common carp :: 3:4:1:2 Catla + Rohu + mrigal + Grass carp :: 8:3:1:4 Silver Carp + grass carp + common
Carp + Rohu :: 2.4:1.2:2:2.4
Catla + Rohu + Mrigal + Silver
Carp + Common Carp :: 2.4:4.8:1.0:2.4:2.4
(v) Types of Breeding
(A Fish Farm)
- Natural Breeding Habits : Major carps are essentially river fishes. They normally do not breed in confined waters Major carps breed in rivers throughout monsoon month’s i.e. June to August. Major carps exhibit local migration in monsoon After travelling some distance against current in flowing waters, they enter shallow marginal inundated waters, where they breed. These fishes do not exhibit any parental care. Ova are small, numerous and fertilization is external. Females lay eggs and the males sprinkle its milt over the eggs which are fertilized by inter- mixing of water, Milt or seminal fluid milky white non-sticky and non-granular. Milt consists of innumerable microscopic structures called spermatozoa. These spermatozoa have small head. During the period of their existance, they are extremely active inhabiting a constant jerking motion.
There is sexual dimorphism in major carps. Females are generally larger than males Following factors are important which influence spawning of major carps.
|(1) Right stage maturity of fish||(2)||Heavy monsoon floods|
|(3) Extensive shallow spawning grounds||(4)||Current and flow of water|
|(5) Optimum temperature||(6)||High dissolved oxygen|
|(7) Increased pH||(8)||Turbidity|
(9) Mineral solution and insuspension. (10) Instinct and physiological effect on fish.
(11) Endocrine secretion
Optimum temperature seem to be essential for breeding but major carp have known to breed over a wide range of temperature between 40 C – 400 C. Some have suggested that excessive dissolved oxygen is essential but carps have bred in water where the dissolved oxygen was actually reduced due to mixture of pollutants after the floods. pH from 7.5 to
8.3 are recorded to be suitable for spawning. Turbidity do not seem to be essential for breeding of major carps. Fish spawning induced by lightening and thunder is also doubtful. Cloudy day, however, seemed favourable for breeding of carps. Endocrine and sex stimulating hormone of pituitary gland and series of subsequent physiological changes are important for spawning
- Bundh Breeding of Indian Major Carps : Indian major carps i.e. catla catla, Labeo rohita and Cirhinus mrigala do not naturally breed in confined waters though they attain sexual maturity in these Their natural breeding takes place in rivers, certain reservoirs and in artificially constructed bundh type tanks where. Favourable conditions stimulate than for spawning Bundhs breeding contribute a lot to induce breeding of major carp fish.
The history of establishment of bundhs, as a source of major carp seed production is not clear. This type of bundh breeding appears to have originated from west bengal State , especially from the districts of Midnapore and Bankura with the expansion of fish culture industry in India, the bundhs have been established in several other States namely Madhya pradesh, Bihar, Uttar Pradesh, Andhra Pradesh, Rajasthan, Haryana and Punjab. The bundhs are of two types viz., Wet bundh and dry bundh.
- Dry Bundh : A dry bundh is a shallow depression enclosed by earthen walls, (locally known as bundh) on three sides and an extensive catchment area on the fourth. Bundhs get flooded during the south-west monsoon, but remain completely dry for a considerable period during the remaining part of the
The topography of the land has a great role to play in the location and distribution of the dry bundhs. In bankura district of west Bengal, most of the dry bundhs, are fed with water from storage tanks, constructed in the upland area.
- Wet Bundh : The wet bundh is a perennial pond located on the slope of a vast catchment area of undulating terrain, with proper embankments having an inlet facing towards the upland and an outlet towards the opposite lower During summer, the deeper portion of the pond retains water containing breeders. The remaining portion is dry and is used for agriculture.
- Induced breeding : One of the dependable source of quality seed supply is by inducing major carps to breed in ponds by the use of pituitary hormone injections. Pituitary extract for inducing fish to breed is used extensively in many countries. Use of fish pituitary extracts for stimulating spawning of Indian Major carp is met with considerable success in recent The cost of seed production by induced breeding is very low as compared to the collection made from natural resources.
- Hormone Injection : Major carps do not breed in ponds due to the fact that the environmental factors which are responsible for spawning in natural habitats are absent in confined Sex stimulating hormones of the pituitary gland play an important role in the maturation of gonads and spawning in fishes.
The pituitary extract can be kept effectively and utilized successfully in inducing spawing of major carps through injection.
The method of injection of pituitary extract are following types.
(i) Intramuscular (ii) Intra paritonial (iii) Intracranial
(vii) Economic importance of fishes
- Oils : Fish oils are employed in leather industry for
Fish body oils are also employed in the manufacture of candles, lubricants, cutting oils etc. Liver oil is a valuable source of vitamin A and Liver oils are of medicinal use.
- Fish protein : It is used for edible and industrial
- Fish Meal : Waste products of fish are utilized for preparing feed for poultry, pigs and Cattle.
- Fish glue : It is a product mainly of tail regions of fishes such as cod, Haddock, pollack, Hake
- Ising glasses (It is use for Comb, Purse, Riben and forming of
- Controller of
Pearl is a concretion formed by molluscs. It consists of nacre or mother of pearl. It is characterised by iridescence and translucence.
Pearls is produced by the marine molluscs such as pearl oyster and mussel.
- Types of pearls : Pearls are of seven They are the following –
- Lingha pearl : This is the best quality pearl obtained from marine
- Seed pearls : The small pearls are called seed
- Baroque pearls : These are spherical pearls formed inside the
- Blister pearls : These are pearls attached to the They are half-spherical in shape.
- Oriental pearls : These are true pearls with a great lustre, beauty and a smooth
- Natural pearls : These are the pearls obtained from pearl oysters of deep
- Cultured pearls : These are the pearls obtained from cultivated species of pearl
- Composition of pearl : The pearl is formed of The nacre is formed of two substances namely a
calcium carbonate which is in the form of argonite or calcite and an albuminoid substance called conchiolin.
- Pearl-producing animals : Pearls are produced by bivalve There are marine as well as fresh water animals.
- Pinctada vulgaris
- Pinctada fucata
- Pinctada chemnitzi
- Pinctada margaritifera
- Pinctada anomioides
- Pinctada atropurputea
- Placuna blacenta
- Placuna maxima
- Unio margaritifera
- Cultivable species : Pearls are intensively produced by cultivating pearl oysters. The most important molluscs cultivated for pearls are Pinctada vulgaris.
- Biology of pearl oysters : Pearl oysters are sedentary They are attached to rocks. They have two values. One valve is cemented to the rocks and the other free. They spawn twice in a year. The eggs are hatched into free swimming larvae. The larvae sink to the bottom of the water and develop into young oysters called spats. They grow to their maximum size in four or five years.
- Pearl formation : The pearl oysters produce pearl as an adaptation against outside When a foreign material such as a sand grain or a parasite happens to enter the body it adheres with the mantle. The mantle epithelium at once grows over the material in the form of a sac and encloses it. This mantle epithelium starts secreting concentric layers of nacre around the foreign material. The completed structure is called pearl.
- Culture of pearls : The culture of pearls is a complex but sensitive It involves the following
- Collection of oysters.
- Preparation of graft
- Preparation of
- Rearing of oysters and
- Collection of oysters : Oysters for pearl culture are
obtained by three methods. They are as follows :
- Pearl oysters are collected from the Of the sea.
- Spats (young oysters) are collected by placing cages in spat- falling areas of the
- In the laboratory eggs of pearl oysters are fertilized and young once are
- Preparation of graft tissue : The piece of tissue which is inserted into the oyster is called graft tissue It is cut off from the mantle of another The graft must be in the form of a square of 2
- 2 mm in
- Preparation of nucleus : The nucleus is a foreign material which is inserted into the oyster. It is in the form of a of 2 mm in It is prepared from the shell of molluscs
- Implantation : The oyster is placed on a The foot is
exposed. A small incision is made on the foot. On this incision the graft tissue is placed. The nucleus is placed on the tissue. Then the oyster is released in cages. The entire operation should be completed in 30 minutes.
- Rearing of oysters : The operated oyster are placed in cages and the cages are suspended from rafts in the This type of culturing oysters is called raft culture.
- Harvesting : Pearls attain their maximum in three After three years, the oysters are removed from cages and the pearl is taken out. Chemically pearl is made up of CaCO3 and conchiolin.