Four Luxi beef cattle (400±10 kg) fitted with ruminal, duodenal and ileal cannulas were used in a 4×4 Latin square to assess the effects of soybean small peptide (SSP) infusion on rumen fermentation, diet digestion and flow of nutrient in the gastrointestinal tract. The ruminal infusion of SSP was 0 (control), 100, 200 and 300 g/d. Ruminal SSP infusion linearly (p<0.01) and quadratically (p<0.01) increased microbial protein synthesis and rumen ammonia-N concentration. Concentrations of total volatile fatty acid were linearly increased (p = 0.029) by infusion SSP. Rumen samples were obtained for analysis of microbial ecology by real-time PCR. Populations of rumen Butyrivibrio fibrisolvens, Streptococcus bovis, Ciliate protozoa, Ruminococcus flavefaciens, and Prevotella ruminicola were expressed as a proportion of total Rumen bacterial 16S ribosomal deoxyribonucleic acid (rDNA). Butyrivibrio fibrisolvens populations which related to total bacterial 16S rDNA were increased (p<0.05), while Streptococcus bovis populations were linearly (p = 0.049) and quadratically (p = 0.020) decreased by infusion of SSP. Apparent rumen digestibility of DM and NDF were (Q, p<0.05; L, p<0.05) increased with infusion SSP. Total tract digestion of DM, OM and NDF were linearly (p<0.01) and quadratically (p<0.01) increased by infusing SSP. The flow of total amino acids (AA), essential amino acids (EAA) and individual amino acids were linearly (p<0.01) and quadratically (p<0.01) increased with infusion SSP. The digestibility of Lysine was quadratically (p = 0.033) increased and apparent degradability of Arginine was linearly (p = 0.032) and quadratically (p = 0.042) increased with infusion SSP. The results indicated that infusion SSP could improve nutrient digestion, ruminal fermentation and AA availability.

ABSTRACT:The objective of the present study was to investigate how feeding a diet containing a type of purified starch entirely produced from normal or high amylose maize grains would affect rumen fermentation and blood profile in goats. Twenty rumen-cannulated growing goats were assigned equally to one of two dietary treatments according to a randomized controlled trial design and fed two total mixed rations with similar ingredients and chemical composition except for the types of purified maize starch. One type was the high amylose starch (HAS), and the other was the normal amylose starch (NAS). Compared to goats fed the NAS diet, goats fed the HAS diet had significantly higher ruminal pH (P = 0.00), molar proportions of acetate (P = 0.00), butyrate (P = 0.01) and isobutyrate (P = 0.00), acetate to propionate ratio (P = 0.00), plasma concentrations of glucose (P = 0.02) and C-reactive protein (P = 0.03), and plasma levels of insulin (P = 0.03) and gastrin (P = 0.04), but had significantly lower ruminal concentrations of lactate (P = 0.04) and total volatile fatty acids (P = 0.04), propionate molar percentage (P = 0.00), whole blood ammonia concentration (P = 0.02), plasma concentrations of urea nitrogen (P = 0.00) and creatinine (P = 0.02), plasma levels of glucagon (P = 0.02) and motilin (P = 0.04), and plasma activities of glutamic-oxaloacetic transaminase (P = 0.02) and creatine kinase (P = 0.03). In addition, the HAS diet in comparison to the NAS diet tended to raise whole blood hematocrit (P = 0.08), plasma concentrations of albumin (P = 0.09), branched-chain amino acids (P = 0.09), valine (P = 0.09), phenylalanine (P = 0.08) and proline (P = 0.07), plasma levels of growth hormone (P = 0.06) and interleukin-2 (P = 0.07), and plasma α-amylase (P = 0.05) activity in goats. In conclusion, results showed that feeding goats the HAS diet instead of the NAS diet had multiple beneficial effects.