These are the CBSE class 9 biology notes on chapter Improvement in food resources
covered in this page are
Poultry is the rearing of domesticated fowl (chicken), ducks, geese, turkey and some varieties of pigeon for their meat and eggs. The specialized meat-producing poultry birds are called broilers
while egg-laying poultry birds are called layers.
The tremendous rise in the availability of poultry products is called Silver Revolution.
Assel, Burosa, Chattisgarh and kadaknath
White leghorn, Black Minorca, Rhode island red and Light Sussex
It is done by cross-breeding indigenous breeds with exotic breeds. The improved varieties are developed for the following desirable traits:
- To improve the quality and quantity of chicks.
- To develop breeds with low maintenance requirements.
- To develop dwarf broiler parents for commercial chick production.
- To develop varieties which have tolerance to high temperature (summer adaptation capacity)
Egg and broiler production:
Hens raised for egg production are called layers
. Young birds are vaccinated. Their food should be rich in vitamins, minerals and macronutrients. They start laying eggs at the age of 5 months. The average egg production period in commercial layers is 500 days.
Broilers are quick growing birds which are raised for 6-8 weeks. They attain the weight of 700g to 1.5kg. Their food is rich in vitamin A and K.
- Shelter for poultry birds should be clean, well-illuminated and well-ventilated.
- Birds of different ages should be housed separately.
- Temperature in their living place should be kept between 34˚C to 38˚C.
Diseases and pests of poultry birds:
Poultry birds suffer from number of diseases caused by virus (Bird flue disease), bacteria (Tuberculosis, Cholera diseases), fungi (Aspergillosis), parasites as well as nutritional deficiencies.
- By providing proper housing, cleanliness, sanitation and rich diet.
- By timely vaccination against infectious diseases.
Fish is a cheap source of animal protein for our food. Fish liver oil is rich in vitamin A and D.
Basically fisheries are of two types:
- Fin fishery includes capturing, management and exploitation of cartilaginous and bony fishes.
- Shell fishery includes capturing, management and exploitation of crustaceans (prawns, crabs) and mollusks (oysters, mussels etc.).
Depending up on the mode of obtaining fish, fisheries are of two types:
- Capture fishing: The fish is caught from water, both marine and inland.
- Culture fishing: it is cultivating, rearing and harvesting of fish. Culture fishery is also called fish farming or pisciculture and aquaculture.
- Our marine fishery resources include 7500kms coast line an extensive deep sea.
- Popular marine fish varieties include Pomphret, Mackerel, Tuna, Sardines, Bombay Duck, Eel, Salmon and Hilsa.
- Marine fishes are caught by:
(1) Traditional methods: These include fishing nets and gear operated fishing vessels.
(2) Modern methods: These include use of ecosounders and satellite to locate fish shoals.
Culture of marine fin fishes, shell fishes and sea weeds is called mariculture.
- Inland fisheries deal with freshwater (like in rivers, canals, reservoirs and lagoons) and brakish water fisheries.
- Inland fishery is of two types- capture fishery and culture fishery.
Composite fish culture:
- Intensive fish farming can be done in composite fish culture system. Both local and imported fish species are used in such systems.
- In such a system, a combination of five or six fish species is used in a single fishpond. These species are selected so that they do not compete for food among them having different types of food habits.
- As Catlas are surface feeders, Rohu feeds in the middle zone of the pond, Mrigal and Common Carps are bottom feeders and Grass Carps feed on the aquatic weeds.
- Composite culture is highly advantageous as:
- These fishes do not compete for food.
- The food available in all the part of the pond is used.
- Six different types of fishes are reared together.
- It gives very high yield.
Increase in the production of fish, shellfish, prawns, crabs and shrimps through culture fishery has brought a revolution. This revolution in fish food is called Blue Revolution.
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