Nutrient Requirements and Feed Formulation | Animal Husbandry & Veterinary Science Optional for UPSC PDF Download

Nutrient Requirements and Feed Formulation

• Composition of Feedstuff: Before calculating poultry rations, it is essential to know the exact composition of the feed ingredients being used. This information is crucial for formulating balanced diets. While some Indian studies have addressed this, reliance is primarily on reports from the N.R.C.
• Nature of Poultry Feed: Not all feed is suitable for poultry. Some feeds, such as rye, may not be preferred by poultry or could have toxic properties. Fibrous feeds can dilute high-energy feed and cause crop impaction. Certain feeds like dark sorghum or castor seed may contain harmful substances that affect poultry health. Careful consideration is needed when selecting and processing feeds.
• Cost and Availability of Feed: Choosing readily available and cost-effective feeds is crucial to keeping the production costs of eggs in check. Opting for expensive or hard-to-find feeds can significantly increase the overall cost of egg production.
• Nutrient Requirements: The nutrient needs of poultry vary depending on their type and age. These requirements are detailed in reports from the N.R.C. in the U.S.A. and the Indian Standards Institute. Different nutrient compositions are recommended for starting, growing, and laying chickens to ensure their optimal health and productivity.

Nutrient Requirements and Body Finish in Poultry

Nutrient Requirements Calculation: 
(i) Calculation methods for nutrient requirements:

• Amount of nutrients needed per kilogram of diet
• Amount of nutrients required for 1000 kilocalories of metabolizable energy

Body Finish in Broilers: 

(i) To achieve body finish in broilers:

• Increase the fat content of the carcass to around 4% at 6 weeks of age
• Feed a high-energy ration of 3400 kcal/kg diet
• Reduce the protein diet slightly

Energy Requirements in Poultry:

• Egg type birds like White Leghorns require about 300 to 320 kcal energy per day

Factors affecting energy consumption:

• Seasonal variations: birds may need more energy in winter to maintain body temperature
• Sex differences: cocks may require slightly more energy due to larger body size

• Energy requirements for broiler breeds range from 400 to 450 kcal/day, depending on body size
• Efficient egg production: energy intake should be restricted to 420 kcal/day

Energy content in rations:

• Low-energy ration with 2600 to 2750 kcal/kg for controlling energy intake
• Specific energy content for small breeds like White Leghorn: 3000 to 3100 kcal/kg of feed

Mineral Requirements for Chickens: 

• Ration for chickens should contain adequate quantities of calcium, phosphate, sodium, chlorine, and manganese.
• A severe deficiency or imbalance of calcium and phosphorus can lead to rickets in growing chicks.
• Chick ration should ideally contain about 1% calcium and 0.8% phosphorus.
• Grower diet should contain 1.3% calcium and 0.6% phosphorus.
• Diets for layers must have sufficient calcium for shell formation.
• High-energy diets with low intake levels should contain about 3.8% calcium.
• Low-energy diets, consumed in larger amounts, should contain around 3% calcium.

Importance of Sodium and Chlorine:

• A deficiency of sodium and chlorine may reduce appetite, leading to decreased growth rate or egg production.
• Most diets include around 0.5% salt to prevent deficiencies.
• However, the salt level should not exceed 1% to avoid excessive water intake and wet feces production.

Manganese Deficiency and Bone Development:

• Manganese deficiency in birds can lead to abnormal bone development.
• This abnormality can cause tendon slippage in growing birds at the hock joint.
• Adding a small amount of manganese to the ration is common practice to prevent this issue.
• High levels of calcium in the ration can reduce the availability of manganese.

Vitamin Requirements for Growing Birds

• Vitamin A:
  • Vitamin A is crucial for growth and disease resistance, particularly in combating respiratory diseases.
  • Fowls can convert carotene from green plants and yellow maize into vitamin A, but most rations are supplemented with vitamin A preparation or fish liver oil.
• Vitamin D:
  • Vitamin D3 is essential for the utilization of calcium and phosphorus for bone formation.
  • While fowls can produce vitamin D through sunlight exposure, indoor-reared birds require synthetic vitamin D or fish liver oil in their diets.
• Vitamin E:
  • Vitamin E is usually present in sufficient quantities in commonly used feed, but under certain conditions, it can be destroyed, leading to diseases like 'crazy chick disease'.
• Vitamin B:
  • Most B vitamins are found in adequate amounts in cereals used in rearing rations.
  • Deficiencies in some B vitamins can result in slow growth and poor feather development, requiring synthetic forms or dried yeast as supplements, especially for young chicks.
  • Low hatchability of eggs post-incubation is linked to vitamin B deficiency, prompting the supplementation of breeding fowl diets with B vitamins, particularly riboflavin.

Choline, Methionine, Folic Acid, and B12 Interrelationship

• Vitamin B12 and folic acid are crucial for the metabolism of choline in transferring methyl groups. When the concentration of folic acid is high, the requirement for choline increases significantly.
• The level of methionine is also vital for choline to function as a methyl donor, and the relationship is mutual. Methionine's availability can impact choline's effectiveness in donating methyl groups.
• Choline can help conserve methionine, thereby sparing the need for additional methionine intake.

Enhancing Pigmentation in Poultry and Eggs

The Significance of Pigmentation:

• The challenge of achieving adequate pigmentation in poultry and eggs has grown in recent years due to modern chicken-raising methods that rely on high-energy, low-fiber diets lacking in yellow pigments essential for natural skin or yolk color.

Principal Pigment- Carotenoid Lutein:

• Carotenoid lutein, also known as xanthophyll, plays a key role in pigmentation of skin, body fat, and egg yolk.

Sources of Xanthophyll:

• Yellow corn is a common source of xanthophyll in poultry feeds, but its content may be insufficient for optimal pigmentation.
• Alternative feedstuffs like corn, milo, or barley, which are low in xanthophyll, might need supplementation with additional xanthophyll sources.
• Algae meal and orange oil by-products from the citrus industry are rich in xanthophyll and can enhance pigmentation properties.
• Other sources such as soybean, pyrethrum plant waste, and retinyldene cyanoacetic acid can also contribute to improving yolk color.

Enhancing Yolk Color:

• Adding retinyldene cyanoacetic acid salts or esters to feed can lead to significant enhancement in yolk color.
• For example, mixing finely powdered retinyldene cyanoacetic acid methylester with feed has shown to visibly improve yolk color in eggs.

Prevention of Mycotoxicosis in Poultry:

• Poultry hemorrhagic syndrome is characterized by bleeding in the legs, thighs, and other organs, along with digestive changes in the liver and kidneys, leading to death rates ranging from 0 to 50 percent and morbidity rates up to 90 percent.
• Mycotoxicosis in poultry is caused by a fungus that develops on stored food grains.
• To address mycotoxicosis, the toxic effects of feed can be mitigated by treating cereal feed with certain chemicals such as 2-bromo-5-nitrothiazole, 2-chloro-5-nitro-pyridine, or 8-hydroxy-quinoline.
• If a batch of feed is affected by toxins, it can be salvaged by diluting the toxins with toxin-free feed and reducing the toxic levels to within acceptable sublethal limits.

Feed Formulation for Poultry

• Utilization of Computers in Feed Formulation

  In developed countries, computers are extensively used to formulate least-cost poultry rations through linear programming.

• Feed Formulation Procedure

  1. Determine the type of ration and its purpose, considering factors like whether it's a complete ration or a supplement. Check appropriate columns in requirement tables for energy and protein levels.

  2. Create a 'Premix' by adding trace elements, vitamins, and other necessary additives in small quantities. This forms the first addition to the feed formula.

• Additives and Supplements

  Include additives like common salt, berseem or lucerne meal, and animal protein sources such as fishmeal and bonemeal.

• Protein Calculation

  Calculate the percentage of crude protein contributed by the ingredients added so far to balance the ration adequately.

• Method of Feeding Poultry

  Various feeding methods include Whole Grain Feeding, Grain and Mash Method, and All Mash Method, each with its advantages and disadvantages.

• Pellet Feeding

  Pellet feeding involves pelleting the dry mash under high pressure, resulting in hard cylindrical pellets that are more efficiently consumed by poultry.