Enzymes Role and impact in poultry

Dr. Yogesh Paharia

B.V.Sc , M.V.Sc ( Nutrition )

The biggest single expense in any system of poultry production is feed accounting for up to 70% of total cost per bird. Poultry naturally produces enzymes to assist the digestion of feed nutrients. However, they are doing not have enzyme to interrupt down fiber completely and wish exogenous enzymes in feed to assist digestion. Enzymes are biological catalyst composed of amino acids with vitamins and minerals. They bring about b i o c h e m i c a l r e a c t i o n s w i t h o u t themselves undergoing any change. Feeding enzymes to poultry is one of the major nutritional advances in the last fifty years. It is the culmination of something that nutritionists realized for a long time but until 1980's it remained beyond their reach. Indeed, the theory of feed enzymes i s s i m p l e . P l a n t s c o n t a i n s o m e compounds that either the animal cannot digest or which hinder its gastrointestinal system, actually because the animal cannot produce the required enzyme to degrade them. Nutritionists can help the animal by identifying these indigestible compounds and feeding an appropriate enzyme. These enzymes come from microorganisms that are carefully selected for the task and grown under controlled conditions (Wallis, 1996). Exogenous enzymes hydrolyze non-starch polysaccharides (NSPs) which could be potentially employed by the animal, increasing the usage of feed energy. Moreover, the releasing of cell content occurs, becoming available to enzymatic digestion, therefore increasing the digestibility of all nutrients. Phytase, in its turn, hydrolyzes phytate that's found in every ingredient from vegetal source. Phytate is a polianionic molecule with potential to chelate nutrients positively charged (Na , Mg , K , Ca and Zn , among + ++ + ++ ++ others), characterizing its antinutriotional property, which compromises utilization of protein, energy, calcium and trace-minerals (Selle and Ravindran, 2007). Consecutively, phosphorus and other elements become available for metabolism and animal (Roland, 2006). Hence, this review aims to present the economic and environmental impacts of enzymes utilization in poultry diets. Economic impacts: Economic benefits from exogenous enzymes utilization on poultry nutrition is said to feeding costs reduction, allowing the flexibleness on diets formulation and / or a far better performance, as well as better litter quality and birds' health, which, thus, will influence on total production costs. Flexibilization of low cost diets formulation: Availability and variety of grains in India are great, which permits the total or partial inclusion and/or substitution of certain ingredients by others with reduced prices, mainly during the time between harvests. However, such ingredients also named alternatives present some restrictions as for their use in poultry diets formulation, due to the presence of anti-nutritional factors that impair performance and consequently, result in low uniformity and profitability at the end of production. The possibility of using enzymes in reformulated diets must be evaluated, in which the enzyme nutritional matrix is to be considered during diets formulation, allowing a greater reduction on feeding costs, since enzymes contribute with 50 to 75 kcal of ME, 0.1% of Ca and 0.1% of obtainable P by kilogram of ration (Wyatt and Bedford, 1998). Economic and Environmental Impact of Using Exogenous Enzymes on Poultry Feeding recommend the utilization of enzymatic complexes in extruded soybean on broiler chicks diets, verified that diets using wheat as main ingredient thanks to the feeding costs reduction, r e a c h e d t h r o u g h t h e g r e a t e r

metabolizable energy (+6%) and amino acids (+10%) availability. Likewise, phytase utilization represents a potential economy, since by turning the phytic p h o s p h o r u s a v a i l a b l e , m a k e s unnecessary inorganic phosphorus supplementation, resulting in reduced diet formulation cost. Studies performed by Plumstead et al. (2008) Higher nutrient digestibility and better p o u l t r y p e r f o r m a n c e : N u t r i e n t digestibility can be improved with exogenous enzymes supplementation. According to Rutherfurd et al. (2002) phytase addition improves minerals retention and amino acids, fat and litter moisture lower incidence of wounds in older carbohydrates digestibility. Kocher et al. (2003) verified an increase of AME of corn and soybean based diets for b r o i l e r s w i t h a c o m b i n e d supplementation of pectinase, protease and amylase only when basal diets presented low protein and energy. Yu and Chung (2004) verified that the addition of appropriate levels of "- amylase, glucanase and xylanase in diets with 3% of ME reduction for broiler chickens resulted in similar performance to the obtained with the control diet. These data demonstrate the real efficiency given to birds fed exogenous enzymes in their diets, in order to rebound directly on production costs reduction, due to make possible to reduce energetic and proteic levels of these enzymes inclusion. Improvement on litter quality: NSPs increase diets'