Abstract
This study investigated the influence of energy supplementation with or without the addition of lipids on microbial production, microbial synthesis efficiency and nitrogen balance. Eight fistulated steers were used with accessible rumens and kept in individual stalls. Their diets consisted of corn silage; corn silage + concentrate; corn silage + concentrate with addition of lipids in the form of soybean oil; and corn silage + concentrate with addition of lipids in the form of soybean grains. Estimates of microbial protein synthesis were obtained based on the urinary excretion of purine derivatives. The concentrations of ammonia in the rumen were determined immediately at 2, 4, 6 and 8 hours after feeding. The diets with concentrate increased (P<0.05) the microbial protein synthesis and the efficiency of the synthesis and nitrogen balance without a difference between the lipid sources (P>0.05). Concentrated diets presented higher concentrations of urea nitrogen in the serum and urinary urea excretion (P<0.05), but there was no difference between the lipid sources (P>0.05). Energy supplementation, with or without lipid addition, can be used as a strategy to increase the synthesis of the microbial protein in the cattle fed corn silage.
Highlights
The rumen is an important component of the digestive tract of ruminants, inhabited by a dense and varied population of microorganisms, whose importance is in degrading organic matter, producing mainly volatile fatty acids, methane, carbon dioxide and microbial protein
Evaluate the production CPmic in wide feed conditions becomes essential to identify and correct the factors that affect it, improvement the use of the nitrogen present in fodder and sources of rumen undegradable protein (RUP), since the requirements of metabolizable protein of ruminants are met by the intestinal absorption of CPmic and RUP
Considering the importance of CPmic for protein nutrition of ruminants, as well as the interest in adding lipid sources to the diet, this study aimed to evaluate the influence of energy supplementation and lipid addition to the supplement on microbial production and efficiency of microbial synthesis (Emic), estimated on the basis of urinary excretion of purine derivatives (PD), nitrogen balance (NB), levels of ruminal ammonia (N-NH3) and serum Nurea (NUS) and urinary excretion of urea (UEU) in confined cattle whether or not supplemented with different lipid sources, in the form of milled soybeans or soybean oil
Summary
The rumen is an important component of the digestive tract of ruminants, inhabited by a dense and varied population of microorganisms, whose importance is in degrading organic matter, producing mainly volatile fatty acids, methane, carbon dioxide and microbial protein. There are sequestration and turnover of microorganisms in the rumen, a large proportion of the microorganisms leaves the rumen and is digested in the posterior gastrointestinal tract, supplying about 50 to 80% of the daily requirements of ruminants amino acids from the absorbed microbial protein (CPmic) in the small intestine (SNIFFEN; ROBINSON, 1987; FIRKINS; YU; MORRISON, 2007). Evaluate the production CPmic in wide feed conditions becomes essential to identify and correct the factors that affect it, improvement the use of the nitrogen present in fodder and sources of rumen undegradable protein (RUP), since the requirements of metabolizable protein of ruminants are met by the intestinal absorption of CPmic and RUP. RUP requirements are calculated as the total protein requirement minus the CPmic amount reaching the duodenum (NRC, 1996)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
