Life Science Journal 2015;12(2s) http://www.lifesciencesite.com 23 Use of Exogenous Enzyme in Animal Feed Ana I. Mireles-Arriaga 1 , Enrique Espinosa-Ayala 2 , Pedro A. Hernández-García 2 , Ofelia Márquez-Molina 2 * 1. Universidad Autónoma del Estado de México, Facultad de Medicina Veterinaria y Zootecnia, El Cerrillo Piedras Blancas, Toluca, Estado de México C.P. 50090, México 2. Universidad Autónoma del Estado de México, Centro Universitario UAEM Amecameca, Carretera Amecameca- Ayapango K.M. 2.5. Amecameca, Estado de México C.P. 56900, México ofeliammolina@yahoo.com Abstract: The constant population increase and the continued need for feed of animal have originated rise in demand for livestock products and continuous research on the use of additives for growth. In last years, the addition of exogenous enzymes has become a good solution for improving animal performance, and it is most widely studied and reported disciplines in animal science showing rapid growth worldwide in the industry. Nowadays, consumer and producers increase knowledge concern to the use of secure growth promoters and antibiotics in livestock production attend these reasons; many researchers have been investigated the use of exogenous enzymes in ruminant and non-ruminant animal production. The aim of this paper is to review about exogenous enzymes add and their use on different animal livestock species in most recent years. [Ana I. Mireles-Arriaga, Enrique Espinosa-Ayala, Pedro A. Hernández-García, Ofelia Márquez-Molina. Use of Exogenous Enzyme in Animal Feed. Life Sci J 2015;12(2s):23-32]. (ISSN:1097-8135). http://www.lifesciencesite.com . 4 Keywords: Animal feed, enzyme, nutrition The intensive and rapid grow on world population are caused on increased demands of animal origin. Meat and meat end-products consumption (including beef, pork, goat, mutton and poultry) has increased gradually, by almost 60% between 1990 and 2009; from 175,665 thousand to 278,863 thousand tons, driven in part by a growing world population (Henchion et al., 2014). The need of methods for animal rapid growth has been derived in investigation for an increase the livestock production with the human food safety and animal welfare requirements. On this topic, animal nutritional researchers are in constant investment about improvements breeding strategies, based on improvement genomics (Rothschild and Plastow, 2014), or applied growth promoters, as well as the possible alternative strategies for their use in livestock feeding; nevertheless, the use of chemical substances like β-agonist whose increase lean meat to fat ratio and improve feed conversion efficiency it is actually illegal since the 90´s decade (Cayetano et al., 2013; Johnson et al., 2014). For these reasons, many researchers were investigated the use of other additives for improving efficiency on animal livestock (Cedillo et al., 2014; Gado et al., 2014; Salem et al., 2014; Zhao and Kim, 2015), natural antioxidants (Rossi et al., 2014) and exogenous enzymes (Salem et al., 2013, 2015; Valdes et al., 2015). The popular attention on the use of exogenous enzyme it is due to their capacity to increase the efficiency of digestion by help break down anti-nutritional factors (e.g. fiber, phytate and non-starch polysaccharide (NSP)) (Adeola and Cowieson, 2011; Alsersy et al., 2015), or do improve the digestibility of many ingredients, which remains low because of a lack of the enzymes needed for breaking down the complex cell wall structure that encapsulates nutrients presents in plant based feed. The use of dietary exogenous enzymes on livestock production could be a promising strategy for improve animal digestibility and feed efficiency; however, many articles have been published every year in enzyme and animal nutrition disciplines, with counterpoised results, reveled new challenges, and opportunities for this topic research. The purpose of this review article summarizes current research regarding exogenous enzymes and their use on different animal livestock species for a show a general understanding on this topic. Types of Enzymes Utilized in Animal Feed Since the late 1980, feed enzymes have played a major part in helping to improve the efficiency of livestock products. The use of exogenous enzymes, specifically non-starch polysaccharidase and phytase, is almost ubiquitous in poultry and common place in pigs feeds because the inclusion of feed of plant origins, which compounds with low digestibility, considered anti nutritional factors such as NSP (Schedle et al., 2012) and phytic acid (Abudabos, 2012). However, recently many researchers have directed their work on other species like ruminants, actually exists many types of enzymes utilized in animal feed; most popular are