Samacheer Class 11 Bio Zoology - Trends in Economic Zoology

• Vermicomposting provides excellent organic manure for sustainable agro-practices.
• Marketing of vermicompost can provide a supplementary income.
• Vermicompost is rich in essential plant nutrients.
• It improves soil structure, texture, aeration, and water holding capacity and prevents soil erosion.
• It is rich in nutrients and an eco-friendly amendment to soil for farming and terrace gardening,
• It enhances seed germination and ensures good plant growth.

Worker bees perform a variety of essential tasks throughout their lifetime, with their duties changing as they age in a process called temporal polyethism. During the first half of her life, lasting approximately three weeks, the worker bee performs indoor duties within the hive. She secretes royal jelly from her hypopharyngeal glands to feed the larvae and the queen, and prepares bee-bread, which is a mixture of pollen and honey, to nourish the developing larvae. She feeds the queen bee and takes care of her needs, maintains the health and cleanliness of the queen, and also feeds and cares for the drones. The worker bee secretes beeswax from special glands on her abdomen and uses this wax to build and repair the hexagonal combs that form the structure of the hive. She continuously cleans the cells of the comb and fans the beehive with her wings to maintain proper temperature and humidity and to evaporate excess moisture from nectar. As she matures, she assumes the role of a soldier bee and guards the entrance of the hive, protecting it from intruders and potential threats. In the second half of her life, lasting approximately three weeks, the worker bee transitions to foraging duties. She searches for and gathers pollen from flowers, which is essential for protein nutrition of the colony. She collects nectar, which is processed into honey as an energy source for the hive. She also gathers propolis, a resinous substance used to seal and sterilize the hive, and collects water for various hive functions. These diverse roles ensure the survival and productivity of the entire bee colony.

• The rearing of silkworm on a commercial scale is called sericulture.
• It is an agro-based industry comprising of
• Cultivation of food plants for the silkworms.
• Rearing of silkworms.
• Reeling and spinning of silk.
• Silk fibers are utilized in preparing silk clothes.
• Silk is used in industries and for military purposes.
• Silk is used in the manufacture of fishing fibres, parachutes, cartridge bags, insulation coils for telephone, wireless receivers, tyres of racing cars, filter fibres, in medical dressings and suture materials.

Economic importance of fish:-
Fishes form a rich source of protein food and provide a good staple food to tide over the nutritional needs of man. Fish species such as sardines, mackerel, tuna, herrings have high amino acids concentration particularly histidine which is responsible for the meaty flavor of the flesh. It is rich in fat such as omega 3 fatty acids. Minerals such as calcium, magnesium, phosphorus, potassium, iron, manganese, iodine and copper.
Some of the fish by-products are: Fish oil is the most important fish by-product. It is derived from fish liver and from the fish body.
Fish liver oil is derived from the liver which is rich in vitamin A and D, whereas fish body oil has high content of iodine, not suitable for human consumption, but is used in the manufacture of laundry soaps, paints and cosmetics. Fish meal is prepared from fish waste after extracting oil from the fish.
The dried wastes are used to prepare food for pig, poultry and cattle. The wastes obtained during the preparation of fish meal are widely used as manure.
Isinglass is high-grade collagen produced from dried air bladder or swim bladder of certain fishes viz. catfish and carps. The processed bladder which is dissolved in hot water forms gelatin having adhesive property. It is primarily used for clarification of wine, beer and vinegar.

Lac, a resinous secretion of the lac insect (Kerria lacca), holds considerable economic importance across various industries. It is extensively used as a high-quality sealing wax and as an adhesive, particularly in the precise assembly of optical instruments due to its excellent adhesive properties and insulating capabilities. In the electrical industry, lac's natural insulating properties make it valuable for components. It is also a key ingredient in the preparation of shoe and leather polishes, providing a protective and glossy finish. Furthermore, lac serves as a protective coating for wood, enhancing its durability and appearance. Its application extends to laminating paperboard, photographs, and plastic molded articles, offering protection and a smooth finish. Additionally, lac is utilized as a filling material for gold ornaments, providing bulk and support.

• Shellac with denatured alcohol is used to remove dust on the walls.
• Coating of metals with shellac prevents rusting.
• Shellac coating on citrus fruits increases their shelf life.

Artificial insemination (AI) offers several significant advantages in animal breeding programs. Firstly, it increases the rate of conception by allowing the precise timing of insemination and the use of high-quality semen. Secondly, AI helps to prevent the spread of genital diseases between animals, as the collection and insemination process can be managed under hygienic conditions, avoiding direct contact. A crucial benefit is the ability to collect semen from bulls that may be injured or unable to mate naturally, yet possess desirable genetic traits, thus maximizing their breeding potential. Finally, AI overcomes geographical barriers, enabling the successful breeding of superior animals that are located far apart, facilitating the dissemination of valuable genetics across wider regions and improving herd quality efficiently.

There are two methods of animal breeding, namely inbreeding and outbreeding.
1. Inbreeding:
Breeding between animals of the same breed for 4-6 generations is called inbreeding.
2. Outbreeding:
The breeding between unrelated animals is called outbreeding. It is done in three ways;
* Outcrossing: It is the breeding between unrelated animals of the same breed but having no common ancestry. The offspring of such a cross is called an outcross.
* Crossbreeding: Breeding between a superior male of one breed with a superior female of another breed. The cross-bred progeny has superior traits (hybrid vigour or heterosis).
* Interspecific hybridization: In this method of breeding mating is between male and females of two different species.

Multiple Ovulation Embryo Transfer Technology (MOET) is an advanced reproductive biotechnology used to propagate animals with desirable traits and characteristics. This technique involves stimulating a superior female to produce multiple eggs through hormonal treatment, which are then fertilized and the resulting embryos are transferred to surrogate mothers. MOET significantly reduces the generation interval and accelerates the breeding program, allowing for rapid production of high milk-yielding females and high-quality meat-yielding bulls in a considerably shorter time period compared to conventional breeding methods. This technology is particularly valuable in livestock improvement programs as it enables the rapid multiplication of genetically superior animals and helps establish herds with improved productivity and quality traits.

Ducks possess several distinctive anatomical and behavioral characteristics that make them well-adapted to aquatic life. Their body is fully covered with oily feathers that are water-resistant and prevent water from penetrating to the skin. Beneath their skin, ducks have a substantial layer of fat that provides insulation and further prevents them from getting wet, allowing them to remain in water for extended periods. Ducks are primarily nocturnal or crepuscular layers, typically laying their eggs at night or early in the morning. Their feeding habits are omnivorous and opportunistic; they feed on rice bran, kitchen wastes, waste fish, snails, and various aquatic organisms, making them efficient scavengers. These adaptations collectively make ducks highly suitable for rearing in diverse environments and contribute to their economic importance in poultry farming.

• Vermi wash is a liquid collected after the passage of water through a column of vermibed.
• It is useful as a foliar spray to enhance plant growth and field.

Cooking is a critical step in silk production where the cocoons are soaked in hot water at a temperature of 95° to 97°C for 10 to 15 minutes. This process softens the sericin, which is the gum-like substance that binds the silk filaments together within the cocoon. By softening this binding material, the silk threads become easier to unwind and separate during the reeling process. Cooking also kills the pupae inside the cocoon, preventing the emergence of the adult moth which would break the continuous silk filament. The duration and temperature of cooking must be carefully controlled to ensure optimal results without damaging the quality of the silk fibers.

Cooking is a vital preparatory process in sericulture where cocoons are soaked in hot water maintained at a temperature of 95° to 97°C for a duration of 10 to 15 minutes. This heat treatment softens the sericin, which is the adhesive gum binding the silk filaments together within the cocoon structure. The softening of sericin facilitates the unwinding and separation of silk threads during subsequent reeling operations. Additionally, cooking serves to kill the pupae inside the cocoons, preventing the emergence of adult moths that would rupture the cocoon and break the continuous silk filament. Proper cooking ensures that the silk threads remain intact and can be efficiently extracted as long, continuous strands suitable for textile production.

The primary objectives of animal breeding are to enhance the genetic potential of livestock for improved productivity and quality. This includes accelerating the growth rate of animals to reach market weight faster, and increasing the output of valuable products such as milk, meat, and eggs. Furthermore, animal breeding aims to improve the overall quality of animal products, making them more desirable for consumers. Another crucial objective is to enhance the resistance of animals to diseases, thereby reducing mortality rates and the need for extensive veterinary interventions. Finally, breeding programs often focus on increasing the reproductive rate of animals, ensuring a consistent and healthy population for sustained production.

Cultivable fishes possess several key characteristics that make them suitable for farming. Firstly, they exhibit a high growth rate, enabling them to reach marketable size within a relatively short period. Secondly, these species are adaptable and readily accept supplementary diets provided by aquaculturists, which is crucial for efficient growth. Thirdly, they are hardy, demonstrating a robust ability to withstand common diseases and parasitic infections that can plague aquaculture environments. For polyculture systems, it is essential that different species can coexist without exhibiting aggressive behavior or negatively impacting each other. Lastly, cultivable fishes should possess high food conversion efficiency, meaning they can effectively convert the feed they consume into body mass, minimizing waste and optimizing production.

External factors affecting fish culture are environmental and physical conditions that significantly influence the growth, reproduction, and survival of cultured fish. Temperature plays a crucial role as it affects metabolic rates, feeding behavior, and breeding cycles of fish species. Light influences fish behavior, feeding patterns, and reproductive cycles, with photoperiod being particularly important for triggering breeding in many species. Water quality parameters are critical, including pH which affects fish physiology and enzyme function, hardness which influences osmoregulation, and salinity which determines the type of fish that can be cultured in specific water bodies. Dissolved oxygen is essential for respiration and must be maintained at adequate levels to prevent fish mortality. Water current and turbidity also affect fish culture, as currents influence oxygen distribution and feeding efficiency, while turbidity affects light penetration and visibility for feeding. Rainfall and flooding can alter water chemistry, temperature, and oxygen levels, potentially causing stress or mortality in cultured fish populations. These external factors must be carefully monitored and managed to ensure optimal conditions for successful fish culture and production.

Silk has numerous important uses across various industries and applications. In the textile industry, silk fibers are primarily utilized in preparing high-quality silk clothes and garments known for their lustrous appearance and smooth texture. Modern silk production often combines silk fibers with other natural or synthetic fibers to create blended fabrics such as Teri-Silk and Cot-Silk, which offer improved durability and cost-effectiveness while maintaining silk's desirable properties. Silk is extensively dyed and printed to produce ornamental and decorative fabrics, with Eri-silk and spun silk being commonly used for such applications. Beyond textiles, silk has significant industrial and military applications. It is used in manufacturing fishing lines and nets, parachutes for aerospace applications, cartridge bags for ammunition, insulation coils for telephone and wireless communication equipment, and tires for racing cars where its strength and elasticity are valued. In the medical and healthcare field, silk is utilized as filter fibers for various filtration purposes, medical dressings for wound care, and suture materials for surgical procedures due to its biocompatibility and strength. These diverse applications demonstrate the versatility and economic importance of silk as a natural fiber in modern society.

• The house of honey bees is a beehive.
• The hive consists of hexagonal cells made up of wax secreted by the abdomen of a worker bee.
• These hives are found hanging vertically from the rocks. building or branches of trees.
• The young stages of the honey bee accommodate the lower and central cells of the hive.
• In the rock beehives, there are separate cells for queens, workers, and drones.

Prawn fishery can be broadly categorized based on the aquatic environment from which the prawns are harvested. The shallow water prawn fishery is predominantly found along the west coast of India, operating in relatively shallow marine or estuarine areas. Estuaries and backwaters, including brackish water bodies like the Ennur, Pulicat, and Chilka lakes, as well as the riverine estuaries of the Ganga and Brahmaputra, support significant prawn fisheries. Freshwater prawn fishery involves the capture of prawns from inland rivers and lakes across India. Marine prawn fishery, which is the most extensive, primarily targets prawns belonging to the family Penaeidae and is conducted along the entire Indian coastline.

Inbreeding is a form of selective breeding where mating occurs between closely related animals of the same breed for a minimum of four to six generations. This practice aims to increase the proportion of homozygous individuals within the population. While inbreeding can help to fix desirable traits, it also has significant effects. It leads to an increase in homozygosity, which can bring both beneficial and detrimental genes to the forefront. A major consequence is the exposure of harmful recessive genes, as individuals are more likely to be homozygous for these undesirable traits. This often results in reduced fertility and vigor, a phenomenon known as inbreeding depression, and can lead to a decline in the overall fitness of the population.

Earthworms can be classified based on their habitat and feeding habits. The first group consists of 'humus formers' or epigeic earthworms, which live on the surface of the soil, primarily in the upper organic layers. They feed on decaying organic matter and are typically darker in color due to the pigments in their ingested food. These earthworms are particularly valuable for vermicomposting, as they efficiently break down organic waste. The second group comprises 'humus feeders' or endogeic earthworms, which are burrowing species. They create horizontal burrows within the soil and play a crucial role in aerating the soil, improving its structure, and mixing humus throughout the soil profile, thereby enhancing its fertility.

• It is used for making candles.
• It is used for making waterproofing materials.
• It is used for making home appliances polishes for leather.
• It is used in pharmaceutical industries.

• It is used as sealing wax.
• It is used as a good insulator.
• It is used in the preparation of shoes and leather polishes.
• It is a protective coating of wood.
• It is used in the preparation of plastic moulded articles.
• It is used as a filling material for gold ornament.

• Milk is a rich source of vitamin A, B 2, B 1
• It is a complete food for infants.
• Dairy products such as yoghurt cheese butter ice cream condensed milk, milk powder are produced from milk.

Types of Movements:
* Vermicompost is the compost produced by the action of earthworm in association with all other organisms in the compost unit.
* Vermicompost bed may be selected on upland or an elevated level.
* We have to construct a cement pit of 3 x 2 x 1m size over the ground surface using bricks.
* The vermibed should not be exposed to direct sunlight.
* The first layer of vermibed contains gravel at about 5 cm in height followed by coarses and to a thickness of 3.5 cm which will facilitate the draniage of excess water.
* The unit can now be loaded with digested biomass or animal dung.
* Earthworms such as periyonyx excavatus Eisenia fetida or Eudrilus eugeniae are introduced on the top.
* Earthworms release their castings on the surface.
* Vermiwash is a liquid collected after the passage of water through a column of vermibed. It is useful as a foliar spray to enhance plant growth.

• This moth is unisexual.
• Just after emergence male moth copulates with females for 2-3 hours.
• Just after copulation female starts laying about 400-500 eggs.
• The eggs after ten days of incubation hatch into larva called a caterpillar.
• The newly hatched caterpillar is about 3mm in length and is pale yellowish-white colour.
• The mandibulate type of mouthparts adapted to feed easily on the mulberry leaves.
• After 1st, 2nd, 3rd and 4th moulting caterpillars get transformed into 2nd, 3rd, 4th and 5th instars respectively.
• It develops salivary glands, stops feeding and undergoes pupation.
• The cafter pillars stop feeding and moves towards the comer among the leaves and secrete a sticky fluid through their silk gland.
• The secreted fluid comes out through spinnerret which hardens on exposure to air and is wrapped around the body of cater pillar in the forms of a covering called a cocoon.
• The length of continous thread secreted a caterpillar for the formation of cocoon is about 1000 -1200 metres.
• The pupal period lasts for 10-12 days and the pupae cut through the cocoon and emerge into adult moth.
• In larvel stages the larvae moults for 3 or 4 times or 5 times and become a matured moth.

• Vermicompost is rich in essential plant nutrients.
• It improves soil structure texture aeration and water holding capacity and prevents soil erosion.
• Vermicompost is rich in nutrients and an eco-friendly amendment soil for farming and terrace gardening.
• It enhances seed germination and ensures good plant growth.

Following steps are taken for the insertion of the nucleus:
a. Fitness of oyster for operation:
The selected oysters for the insertion of the nucleus should be healthy and strong enough to overcome the stress during operation.
b. Preparation of graft tissues:
The piece of tissue which is inserted inside the mantle is called as ‘GRAFT’ tissue. The outer edges of these graft squares must be known because nacre secreting cells are found only on the outer surface of the mantle so it is essential to keep the outer surface in contact with the inserted nucleus.
c. Preparation of the nucleus:
Any small particle may function as a nucleus to initiate the pearl formation but it is reported that the calcareous nucleus is the best because the deposition of nacre was found to be more on the calcareous nucleus.
d. Insertion of the nucleus:
For the insertion of the nucleus, oysters are fixed in a desk clamp in the position of the right valve facing upward. Mantle folds are smoothly touched to expose the foot and the main body mass, followed by an incision into the epithelium of the foot and a slender channel into the main mass of one graft tissue which functions as a bed for the nucleus.
e. Post-operation care:
Nucleated oysters are placed into cages and suspended into seawater and attached with floating rafts to a depth of 2 to 3 meters for about 6 to 7 days to recover from the shocks due to operation. This period of 6 to 7 days is known as the ‘Recovery period’. About 3000 to 3600 nucleated oysters are kept in different cages suspended in seawater at 2 to 3 meters depth for 3 to 6 years and undisturbed except at the time of clearing and inspection.
f. Harvesting of pearl:
Pearls are harvested in the month of December to February which may slightly vary according to climatic conditions. After the completion of 3 years of the insertion of the nucleus, pearl oysters are harvested from the sea and the pearls are taken out from the shell.
g. Clearing of pearls:
After taking out the pearls from the oyster’s shell they are washed properly, cleared with the soap solution.

Silkworms are susceptible to various pests and diseases that can significantly impact sericulture. Pests include predators such as birds (crows, kites), ants, and rats, which feed on silkworms at different stages of their life cycle. Diseases are also a major concern, with several common ailments affecting silkworms. Pebrine is a protozoan disease caused by Nosema bombycis, which infects the larvae and reduces cocoon quality. Flacherie is a bacterial disease, often caused by bacteria like Streptococcus and Staphylococcus, affecting mature larvae and leading to their death. Grasserie is a viral disease caused by the Bombyx mori nuclear polyhedrosis virus, characterized by the swelling and bursting of infected larvae. White Muscardine is a fungal disease caused by the fungus Beauveria bassiana, which infects the silkworms, turning them white and mummified.

In the honey bee, a highly organized division of labour is found.
* There are three types of honey bees seen in the colony.
* There are one queen 10000 – 30000 workers and a few hundred drones in a colony.
Queen bee:
* It feeds on royal Jelly.
* It is only function is to lay eggs throughout its life span.
* During breeding season in winter, a unique flight takes place by the queen bee followed by several drones is called nuptial flight.
* After mating the queen bee lays about 15 lakh eggs in two to four years.
Worker bee:
* These are sterile females.
* Worker bee lives in a worker well and it takes, about 21 days to develop from the egg to adult, and its life span is about six weeks.
Works:
* It secretes royal Jelly.
* Prepares bee – bread to feed the larvae.
* Takes care of the queen and drones.
* Secretes bee wax.
* In the last three weeks, she searches and gathers the pollen nectar.
Drones:
* The drone develops from an unfertilized egg.
* It lives in a chamber called a drone cell.
* The only duty of the drone is to fertilize the queen and it is called the king of the colony.

• Stand – It is a basal part of the hive and is adjusted to make a slope for rainwater to drain.
• Bottom board – It is situated above the stand. It has two gates one gate is an entrance the other acts as an exit.
• Brood chamber – It is an important part of the hive. It is provided with 5 to 10 frames arranged one above the other through which the workers can easily pass.
• The frame is composed of a wax – sheet which is held in a vertical position up by a couple of wires.
• It is strong that can be used repeatedly.
• Super – It is a chamber without cover and base. It is provided with many frames to provide additional space for expansion of the hive.
• Inner cover – It is a wooden piece used for covering the super with many holes for proper ventilation.
• Top cover – It is meant for protecting the colonies from rains. It is covered with a sheet which is plain and sloping.

Methods of Animal breeding:
There are two methods of animal breeding, namely inbreeding and outbreeding:
1. Inbreeding:
Breeding between animals of the same breed for 4-6 generations is called inbreeding. Inbreeding increases homozygosity and exposes the harmful recessive genes.
Continuous inbreeding reduces fertility and even productivity, resulting in “inbreeding depression”. This can be avoided by breeding selected animals of the breeding population and they should be mated with superior animals of the same breed but unrelated to the breeding population. It helps to restore fertility and yield.
2. Outbreeding:
The breeding between unrelated animals is called outbreeding. Individuals produced do not have common ancestors for 4-6 generations.
Outbreeding helps to produce new and favourable traits, to produce hybrids, with superior qualities, and helps to create new breeds. New and favourable genes can be introduced into a population through outbreeding.

• A typical rearing house 6 m x 4m x 3.5m is constructed on an elevated place under shade to accommodate 100 days.
• The windows and ventilators should be covered with a nylon net to restrict the entry of uziflies and other insects.
• The selected healthy silk moths are allowed to mate for 4 hours.
• The female moth is kept in a dark plastic bed it lays about 400 eggs in 24 hours.
• The small larvae hatch between 7 – 10 days.
• The larvae are kept in trays at a temperature of about 20°C-25°C.
• As the larvae grow they are transferred to fresh leaves on clean trays.
• Their maturity is achieved in about 45 days.
• At this stage, the salivary glands start secreting silk to spin cocoons.

1. Deepwater culture – Aquaponics is a technique which is a combination of aquaculture and growing plants in non – soil media.
* It is a raft-based method.
* In this method, the raft floats in water plants are kept in the holes of the raft, and the root floats in water. Fast-growing plants are cultivated.
2. Media-based method – It involves growing plants in inert planting media likely pellets or shales.
This method is applicable for home and hobby scale systems. A large number of fruiting plants leafy green plants herbs can be cultivated.
3. Nutrient film technique – It involves the passage of nutrient-rich water through a narrow trough or pvc pipe.
Plants are kept in the holes of the pipe to allow the roots to be in free contact with the water stream.
4. Aquavertica or vertical aquaponics – Plants are stacked in top of each other in tower systems.
This method is suitable for growing leafy green, strawberries and crops that do not need supporting solid substratum to grow.

Cattle are classified into three main groups based on their primary economic purpose and characteristics. The first group comprises dairy breeds or milch breeds, which are high milk-yielding cattle with extended lactation periods, making them ideal for dairy farming operations. Examples of dairy breeds include Sindhi, Gir, Sahiwal, Jersey, Brown Swiss, and Holstein cattle, all of which have been selectively bred to maximize milk production. The second group consists of draught purpose breeds, which are cattle specifically developed for agricultural work and labor. Bullocks of these breeds are particularly valued for their strength and endurance in pulling heavy loads and plowing fields. Examples of draught purpose breeds include Kangayam and Malvi cattle. The third group comprises dual purpose breeds, which serve both dairy and draught functions within agricultural systems. In these breeds, cows are selected for milk production while bullocks are used for draught purposes, providing farmers with both dairy products and agricultural labor from the same breed. Examples of dual purpose breeds include Ongole and Hariana cattle, which are well-adapted to Indian agricultural conditions and have been traditionally utilized for both milk production and farm work.

Natural breeding, also known as Bundh breeding, refers to special types of ponds where natural riverine conditions or any natural water resources are managed and maintained for the breeding of culturable fishes. These bundhs are constructed in large low-lying areas that can accommodate large quantities of rainwater during monsoon seasons. The design of such bundhs incorporates shallow areas that serve as spawning grounds where fishes can reproduce naturally under conditions that closely mimic their natural habitat. The water management in these bundhs is done in such a way that it maintains the temperature, oxygen levels, and other environmental parameters suitable for fish breeding. The shallow spawning grounds provide adequate space and suitable substrate for egg deposition and fertilization. This method of breeding is cost-effective and relies on natural processes rather than artificial intervention, making it an important traditional practice in fish farming. The bundhs also serve as nurseries where the newly hatched fry can grow in a relatively protected environment before being transferred to larger rearing ponds.

Milk is an emulsion of fat and lactose produced by dairy animals and serves as a highly nutritious food source. Milk contains various enzymes which are destroyed during pasteurization, a heat treatment process used to eliminate harmful microorganisms. Milk is a rich source of vitamins A, B₁, and B₂, though it is deficient in vitamin C, which is why supplementary sources of this vitamin are necessary in the diet. Due to its comprehensive nutritional composition including proteins, fats, carbohydrates, minerals like calcium and phosphorus, and essential vitamins, milk serves as a complete food for infants and supports growth and development throughout life. Various dairy products are processed and manufactured from milk, including yoghurt, cheese, butter, ice cream, condensed milk, curd, and milk powder. These products not only extend the shelf life of milk but also provide diverse options for consumption and add significant value to the raw milk. The production of these diverse dairy products has made dairy farming a highly attractive and economically viable agricultural enterprise, contributing substantially to rural economies and providing employment to millions of people involved in dairy production, processing, and marketing.

• Feed on zooplankton and phytoplanktons decaying weeds debris and other aquatic plants.
• They can survive in turbid water with slightly higher temperatures.
• Can tolerate O 2 variations in water.
• Can be transported from one place to another easily.
• They are highly nutritive and palatable.

• To improve the quality of fish seed by the artificial method of fertilization is developed.
• The gonadotrophin (FSH+ LH) secreted by the pituitary gland influences the maturation of gonads and spawning in fishes.
• The pituitary gland is removed from a healthy mature fish.
• The pituitary extract is prepared by homogenizing in 0.3% saline and centrifuged for 15 minutes at 8000rpm.
• The supernatant is injected at the base of the caudal fin.
• Male and Female fishes start to releasing gametes and are fertilized.

Game breeds are special poultry breeds that have been selectively bred and used since ancient times for specific purposes, particularly for the sport of cockfighting. The Aseel is a prominent example of a game breed that is highly valued for its fighting qualities and meat production. The Aseel breed is typically white or black in colour and is found in all states of India. The hens of this breed are not good egg layers, but they possess excellent brooding and incubation abilities, making them valuable for hatching eggs of other breeds. Aseel is renowned for its exceptional pugnacity, which refers to its aggressive and combative nature, along with its high stamina and majestic gait that gives it a distinctive appearance. The breed is particularly noted for its dogged fighting qualities, meaning its persistent and determined nature in combat situations. Although the Aseel breed is poor in productivity in terms of egg production, it compensates with superior meat qualities, producing high-quality meat that is valued in the market. The breed's combination of fighting ability, meat quality, and brooding capacity has made it an important breed in Indian poultry farming despite its lower egg-laying capacity.

• Macrobrachium rosenbergii is seen in rivers fields and low – saline estuaries.
• For fertilization, one pair of prawn are kept in a separate tank.
• After mating the eggs are laid.
• Temperature 24°C – 30°C and PH 7-8 should be maintained in the hatching tank.
• The hatched larvae are supplied with artificial feed.
• Young ones 5cm length can be reared in fresh or slightly brackish water ponds and harvesting of prawns can be done twice a year.

Poultry farming offers several significant benefits, making it a valuable sector in animal husbandry. Firstly, it does not require a substantial initial capital investment for the construction of housing and maintenance, making it accessible to a wider range of entrepreneurs. Secondly, it does not necessitate large tracts of land, as poultry can be raised in relatively confined spaces. Thirdly, poultry farming ensures a high return on investment within a remarkably short period, as birds grow quickly and start producing eggs relatively soon. Furthermore, it provides a source of fresh, nutritious food, including meat and eggs, which have a huge global demand due to their health benefits and versatility. Lastly, poultry farming creates numerous employment opportunities, contributing to the economic well-being of individuals and communities.

Cultivable fishes can be broadly categorized into several types based on their origin and habitat. Indigenous or native freshwater fishes are those naturally found in the region's freshwater bodies. Major Indian carps like Catla, Rohu (Labeo rohita), and Mrigala (Cirrhinus mrigala) are prime examples. Saltwater fishes that have been acclimatized for freshwater cultivation also form an important group; examples include Chanos and Mullets. Exotic fishes are those imported from other countries for aquaculture purposes, with the Common Carp being a widely introduced species. Carps, in general, possess several advantageous characteristics for cultivation. They are omnivorous and feed on a variety of food sources including zooplanktons, phytoplanktons, decaying weeds, and debris, effectively utilizing available resources. They exhibit resilience, capable of surviving in turbid water conditions and tolerating slight increases in temperature. Furthermore, carps can withstand variations in dissolved oxygen levels in the water. Their ability to be transported from one location to another without significant mortality is also a key advantage for aquaculture. Finally, carp species are highly nutritious and palatable, making them popular choices for consumption.

To culture fish, one should have an idea about different stages of fish culture such as topographic situation quality source physical-chemical and biological factors of water.
Stages of fish farming:
Breeding Pond:
The first step in fish culture is the breeding of fishes therefore for proper breeding special types of ponds are prepared called breeding ponds. These ponds are prepared near the rivers of natural water resources.
a) Natural breeding:
These bundhs are constructed in large low-lying areas that can accommodate a large quantity of rainwater.
b) Induced breeding:
* This involves the removal of ova and sperm from female and male by artificial mechanical process and the eggs are fertilized.
* The fertilized eggs are removed from the spawning place and kept in hatching hapas. Fish seeds: The fish seed is collected from breeding ponds and transferred to the hatching pits.
3. Hatching Pit:
The fertilized eggs are kept in hatching pits. The hatching pits should be nearer to the breeding grounds should be smaller in size with good quality water.
There are two types of hatching pits:
* Hatcheries: These are small-sized ponds in which unfertilized eggs are transferred and hatching happens.
* Hatching hapas: These are rectangular trough-shaped tanks made up of mosquito net cloth supported by bamboo poles and fixed in the river.
4. Nursery Pond:
The newly hatched fries are transported from the hatching happa to nursery ponds where they grow into fingerlings.
5. Rearing Pond:
This pond is long and narrow and this pond should be free from toxicants and predators. The fingerlings are transferred to the stocking ponds.
6. Stocking Ponds:
* This pond should be devoid of weeds and predatory fishes.
* Proper organic manuring should be done to the production with cow dung.
7. Harvesting:
* Well-grown fishes are taken out for marketing is harvesting.
* Small-sized fishes are again released into the stocking ponds for further growth.
* The harvested fishes are preserved and then marketed.

a. Composite fish farming, also known as polyculture, is an aquaculture technique where several selected fish species, belonging to different ecological niches within the same pond, are stocked together in appropriate proportions. This method aims to maximize the utilization of available resources and enhance overall fish production. b. The significance of composite fish farming lies in several key advantages. It ensures that all available niches within the pond are fully utilized, as different species feed on different food sources and occupy different water layers. This reduces competition for food and space among the cultured fish. Furthermore, the selected compatible species do not harm each other, leading to a more stable and productive ecosystem. c. The fishes commonly cultured through composite fish farming in India include Indian major carps like Catla Catla (which feeds in the surface layer), Labeo rohita (which feeds in the middle zone), and Cirrhinus mrigala (which feeds at the bottom). Exotic carps like Common Carp and Silver Carp are also often included in polyculture systems.

1. Fishes form a rich source of protein food the sardines, mackerel tuna herrings have high amino acid concentrations.
2. These fishes have histidine and omega fatty acids.
3. Minerals such as calcium magnesium phosphorus potassium and copper and present.
a) Fish Oil:
* It is an important fish product it is derived from fish liver and from the fish body.
* This is rich in vitamin A and O and iodine.
* It is used in the manufacture of laundry soap paints and cosmetics.
b) Fish Meal:
* It is prepared from fish waste after extracting oil from the fish.
* These dried wastes are used to prepare food for pigs, poultry, and cattle.
* The wastes obtained during the preparation of fish meals are used as manure.
c) Ising glass:
* It is high-grade collagen produced from the dried air bladder of catfish and carps.
* It is used for clarification of wine beer and vinegar.

a) Pearl Culture:
* Pearl is a white shining globular concretion found within the shell of an oyster.
* In India, it was cultured for the first time in 1973 at Thoothukudi.
* High-quality pearls are obtained from Genus Pinctada that can be cultured in the salinity range of 30 ppt in racks raft and long-line method.
* The pearl oysters inhabit the ridges of rocks or dead coral forming the best quality pearl.
b) Pearl Formation:
* When a foreign particle accidentally enters into the space between the mantle and shell of the oysters it adheres to the mantle.
* The mantle epithelium encloses its likes sac and starts to secrete concentric layers of nacre around it as a defensive mechanism.
* The repeated layers of calcium carbonate make the hard and glossy pearl that are separated and graded.

Oysters are caught by a special type of cages.
* This cage is dipped into a sand cement mixture providing a rough surface to the cages and are suspended at a depth of 6 meters.
2. Rearing of oysters:
* The collected oysters are placed into the culture cages for a period of 10 – 20 days.
* These cages are protected from enemies like octopus, Eel, and devil fishes.
3. Insertion of the nucleus:
a) Fitness of oysters for operation:
The selected oysters for the insertion of the nucleus should be healthy and strong enough to overcome the stress during operation.
b) Preparation of graft tissues:
* The piece of tissue which is inserted inside the mantle is called “graft” tissue.
* It is essential to keep the outer surface in contact with the inserted nucleus as nacre secreting cells are found only on the outer surface.
c) Preparation of nucleus:
* Any small particle may function as a nucleus to initiate pearl formation.
* If it is calcareous the deposition of nacre was found to be more on the calcareous nucleus.
d) Insertion of the nucleus:
For the insertion of the nucleus, oysters are fixed in a desk clamp and mantle folds are smoothly touched to expose the foot followed by an incision into the epithelium of the foot and the nucleus is inserted.
e) Post Operation Care:
* Nucleated oysters are placed into cages and suspended into 2-3 metres of depth for 6-7 days.
* These periods are known as the “Recovery Period”.
* These oysters are kept for 3-6 years undisturbed.
f) Harvesting of Pearl:
After the completion of 3 years, pearl oysters are harvested. It is usually done from December to February.
g) Clearing of Pearls:
After taking out the pearls from the oyster’s shell. They are washed properly cleared with the soap solution.

Inbreeding is a form of selective breeding where mating is restricted between animals of the same breed that are closely related, typically for four to six generations. The primary merit of inbreeding is that it increases homozygosity, leading to the fixation of desirable traits and the development of pure breeds. It also has the advantage of exposing deleterious recessive genes that might be present in the population, allowing them to be identified and eliminated. However, continuous inbreeding has significant demerits. It can lead to a reduction in fertility and overall vigor, a phenomenon known as inbreeding depression. This depression is characterized by decreased growth rate, reduced disease resistance, and lower reproductive performance. To avoid or mitigate inbreeding depression, a practice called outbreeding is employed, where selected animals from the inbred line are mated with superior, but unrelated, animals of the same breed. This introduces new genetic variation and revitalizes the population.

Dairying is the comprehensive process of production, processing, and marketing of milk and its various products. It represents an important agricultural enterprise that involves multiple interconnected operations. The dairy operation encompasses several key components including the proper maintenance and care of dairy cattle to ensure their health and productivity, the collection of milk from the animals through hygienic practices, the processing of raw milk into various forms to ensure safety and extend shelf life, and the production of various by-products and value-added products derived from milk. Proper maintenance of cattle involves providing adequate nutrition, healthcare, housing, and breeding management to maximize milk production and animal welfare. The collection process requires adherence to strict hygiene standards to maintain milk quality and prevent contamination. Processing includes pasteurization, standardization, and other treatments to make milk safe for consumption. The by-products and processed items include yoghurt, cheese, butter, ghee, ice cream, milk powder, and other dairy products that add significant value to the raw milk and cater to diverse consumer preferences and market demands.

1. Out Crossing:
It is the breeding between unrelated animals of the same breed but having no common ancestry.
Out Cross: This method is suitable for breeding animals that are below average in productivity.
2. Crossbreeding:
* Breeding between a superior male of one breed with a superior female of another breed.
* The cross-breed progeny has superior traits. This is called hybrid vigour or heterosis.
3. Interspecific hybridization:
* Mating between male and female of two different species.
* The progeny obtained from such crosses are different from their parents.
* Mule is produced by the crosses between a male donkey and a female horse.

MOET:
* This method is applied when the success rate of crossing is low even after artificial insemination.
* In this method, the follicle-stimulating hormone is administered to cows for inducing follicular maturation and superovulation.
* Instead of one egg per cycle, 6-8 eggs can be produced.
* The eggs are carefully recovered non-surgically from the genetic mother and fertilized artificially.
* The embryos at the 8 – 32 celled stage are recovered and transferred to a surrogate mother.
* This technology can be applied to cattle sheep and buffaloes.
* It can produce high milk-yielding females and high-quality meat-yielding bulls in a short time.

a) Dairying:
* It is the production and marketing of milk and its products.
* The dairy operation consists of maintenance of cattle the collection, processing of the milk, and its by-products.
* These are 26 well-defined breeds of cattle and 6 breeds of buffaloes in India.
b) Classification of Cattle
* Dairy breeds: They are high milk yielder with extended lactation, (eg) Sindhi, Jersey Sahiwal
* Drought breed: Bullocks are good for draught purposes, (eg) Kangeyam Malvi.
* Dual-purpose breeds: Cows are meant for yielding more milk and bullocks are used for better drought purposes (eg) Ongole Hariana.
c) Uses of dairy product:
1. Milk: Milk is a rich source of vitamin A, B2, B and deficient in Vitamin C.
Dairy products such as yoghurt cheese butter ice cream condensed milk powder are produced from milk.
2. Meat: Meat is rich in protein and also contains minerals like iron zinc vitamins and selenium.
3. Land Management: Grazing of live stocks sometimes used as a way to control weeds.
4. Manure: Manure can be spread on agriculture fields to increase crop yields.

1. Egg layers: These are farmed mainly for the production of eggs.
Leghorn:
* It is originated in Italy. They are small compact with a single comb.
* They mature early and begin to lay eggs at the age of 5 or 6 months.
Chittagong:
* They are good egg layers and are delicious.
* They are found in West Bengal.
2. Selection of eggs for hatching:
Eggs should be fertile medium-sized dark brown shelled and freshly laid eggs are preferred for rearing.
3. Incubation and hatching:
* The maintenance of newly laid eggs in optimum condition till hatching is called incubation.
* The fully developed chick emerges out of egg after an incubation period of 21 – 22 days.
* There are two types of incubation namely natural incubation and artificial incubation.
* In the Natural incubation method, only a limited number of eggs can be incubated by a mother hen.
* In artificial incubation, more eggs can be incubated.
4. Brooding:
* Caring and management of young chicks for 4 – 6 weeks immediately after hatching is called brooding.
* They are natural and artificial brooding. The housing of Poultry:
* To protect the poultry from the sun.
* Rain and predators it is necessary to provide housing to poultry.
* A poultry house should be moisture-proof rat-proof and it should be easily cleanable and durable.
5. Poultry feeding:
The diet of chicks should contain an adequate amount of water carbohydrates proteins fats vitamins and minerals.
Poultry Products:
* The main products of poultry farmings are eggs and meat.
* The primary aim of poultry farming is to obtain eggs.
C. Poultry by-products:
* The feathers: They are used for making pillows and quilts.
* Droppings: The droppings are rich in nitrogen potash and phosphates.
* The by-products of poultry are used as good sources of nutrients for meat-producing animals and poultry.
* These by-products supply proteins fats Vitamins and minerals.
Poultry diseases: Ranikhet coccidiosis Fowl Pox is a common poultry disease.
Merits:
* They can adapt themselves to all types of environmental conditions.
* And for the breed for feed efficiency.
* Growth rate and resistance to diseases.
* They are exhibited in poultry shows they are calm friendly and can be maintained as pets.

Types:
* Organic method
* Yarding method
* Battery cage method
* Furnished cage method.
Stages involved in rearing:
1. Selection of the best layer.
* An active intelligent-looking bird with a bright comb not obese should be selected.
* They are golden or light yellow coloured.
2. Broiler type:
* White Plymouthrock is a fast-growing breed and soft quality meat.
* They have white plumage throughout the body. This is an American breed. It is a fast-growing breed.
3. Dual Purpose breed:
It is known for its massive body having heavy bones. Well feathered and Peacomb is one of the important breed characters.
4. Game breeds:
Aseel:
* The hens are not good egg layers but are good in the incubation of eggs.
* Aseel is noted for its pugnacity high stamina majestic gait.
* This breed is well known for its meat qualities.
5. Ornamental breeds:
Silkie:
* They are reared as pets and for egg production and meat.
* The chicken has a fluffy plumage which is said to feel like silk and satin.
* It has black skin and bones blue ear lobes and five toes on each foot.

(a) Poultry production, particularly egg-laying, is significantly influenced by the photoperiod, which refers to the duration of light exposure. Light plays a crucial role in stimulating the secretion of important hormones like Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH) from the pituitary gland. These hormones are essential for reproductive functions, including ovulation and egg production. The optimal wavelength of light required for this stimulation is generally between 400 and 700 nm. A decrease in the photoperiod, meaning shorter days or less light exposure, can negatively impact egg production by disrupting the hormonal balance and reproductive cycle of the hens. Therefore, managing the photoperiod is a key aspect of modern poultry farming to ensure consistent and high egg yields. (b) Polyculture, or the practice of raising multiple fish species together in a single pond, is of great importance in aquaculture. This mixed farming approach is termed composite fish farming. Its significance stems from several factors: Firstly, it leads to the full utilization of all available ecological niches within the pond, as different species have varying feeding habits and habitat preferences, consuming different food sources and occupying different water strata. Secondly, the selected species are compatible and do not harm each other, creating a harmonious environment. Thirdly, due to their different ecological requirements and feeding habits, there is minimal or no competition among the different fish species for food and space, which maximizes the overall productivity of the pond.