Effect of various levels of imbalance between energy and nitrogen release in the rumen on microbial protein synthesis and nitrogen metabolism in growing double-muscled Belgian Blue bulls fed a corn silage-based diet

• Published in: Journal of animal science Vol. 84; no. 4; pp. 877 - 885
• Main Authors: Valkeners, D, Théwis, A, Amant, S, Beckers, Y
• Format: Journal Article Web Resource
• Language: English
• Published: Savoy, IL American Society of Animal Science 01.04.2006; Am Soc Animal Sci
• Subjects: ammonium nitrogen; Anatomie (cytologie, histologie, embryologie...) & physiologie; Anatomy (cytology, histology, embryology...) & physiology; Animal Nutritional Physiological Phenomena; Animal production & animal husbandry; Animal productions; Animals; Azote; beef cattle; Belgian Blue; Biological and medical sciences; blood chemistry; bulls; Cattle - classification; Cattle - metabolism; Crosses, Genetic; Deséquilibre; Diet - veterinary; digestibility; Digestion; diurnal variation; double muscling; duodenum; Duodenum - metabolism; Energy; Energy Metabolism; Equilibre azoté; Fermentation; Fermentation ruminale; Fundamental and applied biological sciences. Psychology; Imbalance; Life sciences; Male; microbial activity; microbial protein synthesis; Nitrogen; Nitrogen - metabolism; Nitrogen balance; nutrient balance; nutrient retention; Productions animales & zootechnie; Protein Biosynthesis; Rumen - microbiology; Rumen fermentation; rumen microorganisms; Ruminantia; Sciences du vivant; Silage; Terrestrial animal productions; Time Factors; urea; Urea - blood; Vertebrates; Zea mays; rumen fermentation; imbalance; Digestive system; Blue; Corn; Rumen; Nitrogen; Fermentation; Metabolism; Nitrogen balance; Energy; Diet; Silage; Protein synthesis; Cereal; Release
• ISSN: 0021-8812; 1525-3163; 1525-3163
• DOI: 10.2527/2006.844877x

Seven double-muscled Belgian Blue bulls (initial BW: 341 ± 21 kg) with cannulas in the rumen and proximal duodenum were used in an incomplete replicated Latin square. The study examined the effect of imbalance between energy and N in the rumen on microbial protein synthesis and N metabolism by giving the same diet according to 3 different feeding patterns. The feed ingredients of the diet were separated into 2 groups supplying the same amount of fermentable OM (FOM) but characterized by different levels of ruminally degradable N (RDN). The first group primarily provided energy for the ruminal microbes (12.5 g of RDN/kg of FOM), whereas the second provided greater N (33.3 g of RDN/kg of FOM). These 2 groups were fed to the bulls in different combinations with the aim of creating 3 levels of imbalance (0, 20, and 40 g/ kg of DM) between energy and N supplies in the rumen. Imbalance was measured by the variation of the degradable protein balance (OEB value in the Dutch system) of the diet between the 2 meals each a day. Diurnal variations in ruminal NH₃-N concentrations and plasma urea concentrations were greatly influenced by the feeding patterns of the diet. Introduction of imbalance affected neither microbial N flow at the duodenum (P = 0.97) nor efficiency of growth (P = 0.54). The feeding patterns of the diet had no negative impact on NDF degradation in the rumen (P = 0.33). Nitrogen retention was not affected by imbalance (P = 0.74) and reached 49.7, 52.0, and 51.3 g/d, respectively for 0, 20, and 40 g of OEB/kg of DM imbalance. It seems that introduction of an imbalance between energy and N supplies for the ruminal microbes by altering the feeding pattern of the same diet does not negatively influence the microbial activity in the rumen nor N retention of the animal. Nitrogen recycling in the rumen plays a major role in regulating the amount of ruminally available N and allows a continuous synchronization of N and energy-yielding substrates for the microorganisms in the rumen. Therefore, imbalance between dietary energy and N created over a 24-h interval was not detrimental to rumen microbial growth for the animal as long as the level of imbalance did not exceed 40 g of OEB/kg of DM. Thus, these feeding patterns of the diet can be used under practical feeding conditions with minimal impact on the performance of ruminant animals for meat production.