Vol. 5, Issue 6, Part A (2020)

Author(s): Diriba Taye and Monenus Etefa

Abstract: The use of exogenous enzymes in animal nutrition dates back to the mid-1920s, however, nowadays the development of interdisciplinary sciences exploiting molecular methods create new opportunities and deliver new tools to assess effectiveness of their utilization. The proper use of exogenous enzymes in animal nutrition allows obtaining maximum benefit from their action not only for the animals, but also for the environment. The strategies of exogenous enzymes utilization in nutrition of high yielding ruminant animals are intended to be published in this special issue. Effectiveness of enzymes in animal nutrition depends on (i) type, (ii) source, (iii) level of supplemented enzymes, as well as (iv) the type of diet fed, (v) animal health and (vi) animal productivity. In most tropical countries, the ruminant feed is based on fibrous resources with a cell wall content between 40 and 70% of dry matter, of which less than 50% is quickly digested, which generates high excretion of nutrients to the environment and low productivity in their production systems. Recently, forage cell wall digestibility has undergone significant improvements through exogenous enzyme technology. In terms of enzyme technology, the two most popular enzyme complexes are those of the cellulase and hemicellulose families, generally known to be multicomponent enzymes that when added to forage could possibly assist in the preservation of forages, especially silage. Enzymes can be applied to straw in their pure form or through inoculation with appropriate cell wall degrading microbes. There are many bacterial sources of enzymes. However, in general, Bacillus subtilis, Lactobacillus acidophilus, L. plantarum, and Streptococcus faecium, spp. are the source of bacterial enzymes. Fungal enzymes generally come from Aspergillus oryzae, Trichoderma reesei, and Saccharomyces cerevisiae species.