Nutrient Requirements of Poultry/Chickens

The requirement for any nutrient may be defined as the amount of that nutrient that must be supplied in the diet to meet the needs of the normal healthy animal, given an otherwise completely adequate diet in an environment compatible with good health.

Such a level of nutrient must be capable of meeting the requirements for maintenance optimum growth, and reproductive potential of the animal.

Simply defined, the nutrient requirement is the amount of a given nutrient required by the animal to maximize performance but not necessarily maximize profit. Maximum performance may however occur at different nutrient levels depending on the response criteria being considered, e.g. a specified rate of growth, or a stated level of production.

Chickens on traditional free range poultry farmThe nutrient levels or requirements are expressed in the amount of nutrients per kilogram of air dry feed (i.e. feed as fed) or in terms of percentages on a fed basis (air dry basis). It should be emphasized that the recommendations are merely guidelines and circumstances on individual farms may require adjustments.

Nutrient Requirements of Poultry/Chickens

This topic will be discussed under the following five sub-headings: Energy requirements, Protein requirements, Mineral requirements, Vitamin requirements, and Water requirements.

1. Energy Requirements

The largest single dietary need of an animal is a source of energy. Energy is required for all processes of life. Without energy birds cannot move, eat, digest, grow, maintain body temperature, and, in the case of layers produce eggs.

The requirements for energy cannot be stated as precisely as the requirements for protein, amino acids, minerals, and vitamins. This is because good growth and egg production can be achieved with a wide range of energy levels. Most chickens can adjust feed intake to obtain the necessary energy required for optimum performance.

Chicks aged day-old to 4–6 weeks are however not able to adjust feed intake to diet energy variations and thus tend to consume slightly more energy as the energy level of the diet increases. Not all energy eaten by the chicks is used.

The energy that is used is called metabolizable energy (ME) and is measured in terms of kilocalories or kilojoules. Another energy is rejected in feces.

The energy levels recommended for broiler chickens (3000 kcal/kg diet) are lower than those (3200, 2900, and 2900 kcal/kg diet respectively) recommended or assumed for temperate zones of America.

The reasons for these observations are obvious. At high temperatures, heat losses and basal metabolic rates are generally lower than those at lower temperatures. This means that at high temperatures the energy is used more for reproductive and productive purposes and less for non-productive purposes.

It is not therefore surprising that the energy requirements of poultry reared in the hotter tropical environment are lower.

2. Protein Requirements

The protein requirement is one of the most important criteria upon which any feed formula is based and if it is to be specified, the dietary energy level must be specified because it is essential to maintain the proper ratio of protein to energy in poultry diets.

Protein needs for maintenance are relatively low, and therefore the requirement depends primarily on the amounts needed for productive purposes.

To properly meet the protein requirements, the essential amino acids must be supplied in the proper amounts; and the total level of nitrogen in the diet must be high enough and in the proper form to permit the synthesis of the non-essential amino acids.

Once the minimum amount of protein required to support the maximum growth rate or egg production is supplied, additional protein is oxidized for energy.

The crude protein required in a layers diet has been reported to vary from 15 to 18 percent which is lower than the requirement for pullet chicks (20%) and broilers (20-23%) since protein sources are expensive components of a ration, it is not economical to feed excess protein to animals.

For this reason, protein levels in diets for poultry are usually stated in precise terms to be closer to the minimum requirements than other nutrients. The recommended protein levels decrease
as the chickens get older.

Under normal circumstances, birds eat more as they grow older. Therefore the total protein consumed increases as the birds get older and presumably increases in weight.

However, the protein consumed per unit weight either reduces or remains constant. The amino acid levels are expressed as percentages of the diets and decrease as the recommended protein level decreases.

Read More: Types of Pig Feeds and When to Feed Each

3. Mineral Requirements of Poultry

Minerals are the basic elements required for skeletal tissue development and maintenance. Special mention must be made of the recommended levels of calcium and phosphorus, particularly for “layers”, because of the roles these two minerals play in egg formation.

The levels of calcium and total phosphorus recommended for commercial layers (for table egg production) and breeders (for hatching chicks) are respectively 3.5% and 0.85%. The requirements for these minerals appear to be higher for warm climates than cold climates.

As a general rule, a level of 4-4.5% calcium and 1-1.1% total phosphorus should be provided at all times for birds reared in the tropics. In practice, 0.30–0.50% common salt or sodium chloride would take care of the requirements for sodium and chloride by all classes of poultry.

All other macros – minerals are provided in ample amounts by the usual natural ingredients used in formulating poultry feeds. The microelements are often included in most commercial premixes.

The amount of a microelement is sometimes expressed in parts per million (ppm) or milligrams per kilogram of diet. In practice, about double the amount of premixes added to chicken diets should be used in turkey diets.

4. Vitamin Requirements

Vitamins are organic compounds required in extremely small quantities but essential for normal growth, health, and productivity.

Unlike protein, vitamins are usually supplied to poultry feeds more than their minimum requirements. However, if only minimum levels are provided, variations of expected feed consumption must be considered, and very high energy rations must be more liberally supplied with vitamins than low energy rations.

Requirements are expressed in international units (I.U) which are the same as United States Pharmacopoeia units (U.S.P. Most requirements for poultry are precisely known, particularly for those vitamins likely to be deficient in practical rations. Rations for young starting chicks and starting broilers are usually very liberally supplied with supplemental vitamins.

Dietary vitamin premix inclusion is at the rate of 2.0–2.5 kg/tons of feed.

There are 13 vitamins listed as required by the chickens. The vitamins are classified as fat-soluble vitamins (A, D, E, and K) and water-soluble vitamins (the B-complex vitamins and vitamins C).

5. Water Requirements

The quantities of water required by one hundred layers are about or over 24 litres per day or about one–quarter of a litre per bird per day. Normally, poultry consumes about 2 -3 parts of water for every part of feed on a weight basis (i.e. 2 to 3 kg water per kg consumed feed).

Depending on the age, the turkey should be provided with about two to five times the amount of water recommended for pullets.

During hot weather, consumption of water may rise to about 4-5 times the intake of feed. This has been suggested as being responsible for inadequate feed intake in the tropics.

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