Recent advances in Feed additives in Poultry Nutrition
A.K. Panda, S.V. Rama Rao and M.V.L.N. Raju
In the modern feeding practices, feed additives are assuming a position of prime importance in poultry nutrition. Feed additives not only stimulate growth and feed efficiency but the health of the birds can also be improved. Probiotics, Enzymes, Amino acid supplements and highly available minerals are all relatively new additions to the armory of the poultry nutritionist and have a very positive effect on nutrient utilization when used with appropriate feed ingredients,
Probiotics are defined as live microbial feed supplements, which beneficially affects the host animal by improving its intestinal balances. The term probiotic originates from Greek words meaning for life and contrasted with the term antibiotic, which means against life. Nearly all the Probiotics available in the market contain Lactobacilli and / or Streptococci and a few contain bifid bacteria, yeast and fungi also. The microbial sp. used in the probiotic preparations include:
Lactobacillus acidophilus, L. bulgaricus, L. planatarum, L. casei. Streptococcus faecium. S. lactis, S. thermophilus, S. diacetilactus, Bifidobacterium bifidum, Aspergillus oryzae and Saccharomyces cerevisiae. There are several commercial probiotic products available in the market and some are as follows; Parabolas, biovet, protein, lacto sac and yeasacc etc. These products are either non viable and freeze dried or viable and microencapsulated which proliferate and establish in large numbers in the gastrointestinal tract particularly in the small intestines.
The use of live micro organisms popularly known as "Probiotics" in two poultry feeds is gaining popularity in the recent years and a large number of such preparations have been launched by different commercial organizations. To achieve high level of economic efficiency poultry are raised under intensive production system in densely populated colonies or flocks during which they are succumbed to various kinds of stresses, which adversely affect their productive performances. The dietary use of probiotic is gaining momentum to counteract the stresses because of their beneficial effects on live weight gain, feed conversion efficiency and reduced mortality in broilers and egg production and feed conversion in layers.
Enzymes are biological catalysts, which brings about biochemical reactions without themselves undergoing any change. Enzymes are protein in nature and composed of amino acid arranged in a sequence. Enzyme activity is dependent on the substrate in a random manner or at a very specific site on the substrate. Enzymes are not living organism but they are the products of living organism such as bacteria, yeast, fungi and plant tissue. Commercial enzymes used as feed supplements do not contain a single enzyme but rather they are preparations of a variety of enzymes. A large numbers of multienzyme preparations have been launched by different commercial organizations. Some of the most common preparations available in the market are Novozyme Sp-243 containing
beta glucanase, cellulose, pectinase and amylase; Selfeed containing protease, amylase, cellulase, lipase and pectinase; Nutrizyme containing cellulase, B- glucosidase, hemicelluloses, pectinase, protease and amylase. Poultry do not produce enzymes like cellulase, hemicelluloses and B- glucanase which are required for the digestion of cell wall component of plant material. About 85-90%of poultry feed consists of plant materials which contain large amount of dietary fibers. The most promising results with enzymes are in diets with wheat or barley as the main grain, because they both have non-starch polysaccharides (NSP) in the cell walls and the anti nutritional activity canto some extent be eliminated by enzymes. The beneficial effect of enzymes in barley, oat, wheat and rye in diets is based on the hydrolysis of the viscous non-starch polysaccharides. By carefully selecting the enzyme from the wide range of enzymes commercially available, improvement in the performance can be obtained in the poultry. An increased use of feed enzymes is expected not only from the aspect of economic gain but also from the environmental point of view as enzymes enhances nutrient utilization, there by reducing the manure out put and reducing nutrient excretion particularly excess phosphorus, nitrogen, copper and zinc.
Commercial amino acids
The amino acids of particular interest to poultry nutrition are L-lysine, DL-methionine, L-threonine and L-tryptophan. The use of commercial amino acid in diet formulation of poultry allows formulations to approximate more closely to an ideal amino acid balance, thereby reducing dietary nitrogen concentrations with corresponding reductions in amino acid catabolism and nitrogen pollution. It also allows flexibility in feed formulation and more consistent prediction of amino acid availability from the diet. Thus provides a consistent performance in a similar way to that obtained with commercial feed enzymes. Analogues of the amino acids can also be produced such as methionine hydroxyls analogue, which have a lower efficacy but have the advantage of being available in a liquid form giving more uniform distribution in the feed.
Highly available minerals
Highly available trace minerals such as chelates or proteinates can replace those inorganic sources currently use to meet the nutrient requirements of poultry. Due to the higher bio availability the use of organic elements allows the reduction in total nutrient content in the diet. The trace element selenium when provided as Seyeast can have specific effects on the metabolism and therefore help to increase, the health status of the bird. The copper lysine complex, chelated iron and zinc proteinates are further examples of the application of organic trace elements with a beneficial effect on the health.
ConclusionThe beneficial effects on health status, growth performance as well as nutrient utilization are mainly the reasons, why feed additives are widely used. While feed enzymes and amino acids are catching commercial application, the probiotic area is ata much less advanced stage. Hence a more effort is needed to have a greater impact on poultry production.