Effect on metabolites produced by actinomycetes on in vitro digestibility and ruminal fermentation

Abstract

Actinomycetes are microorganisms that able to productive active compounds employed as antifungal agents, immunosuppressants, anticarcinogenic, antibacterial, and among them a nigericin, valinomycin and the dynactin have done similar to the ionophore monensin. Our hypothesis is that these active metabolites produced by actinomycetes are similar to monensin for rumen fermentation and improved dry matter digestibility of diets for dairy cows. The aim of this study is to evaluate the effect of nigericin, valinomycin and dynactin on in vitro digestibility of dry matter, pH of rumen fluid, concentration of short chain fatty acids and gas production. For experimental purpose, 100 mL of ruminal liquid by two Holstein cows will be gather. They will fed with control diet of corn silage and concentrate based on soybean meal, urea, corn meal and mineral - vitamin supplement. Doses of metabolities and monensin will be utilized and insert to the rumen fluid for in vitro fermentation in artificial rumen (DAISY®ANKOM-ll). The active metabolites are obtained by micro extraction of isolated actinomycetes growing in eucalyptus and mangrove (Eucal and AMC). From these extracts will be done mass spectrometry to chemical characterization of metabolites. The study will be completely randomized factorial sampling design with 5 treatments (5 x 5), control, monensin, nigericin, valinomycin and dynactin in inclusion levels (0, 2, 4, 6 and 8 mM). The response variables will be: pH, gas, short chain fatty acids and ammonia nitrogen production and in vitro digestibility of dry matter, crude protein and neutral detergent insoluble fiber. The results of in vitro ruminal fermentation will be evaluated as repeated measures by the MIXED of SAS (2001) procedure. Thus, it is expected that this study will develop new alternatives of ionophores monensin compared, which would allow improved ruminal fermentation of dairy cows. (AU)