Inclusion of concentrate and growth promoters' additives in sheep diets on intake, digestibility, degradability, ruminal variables and nitrogen balance

This study evaluated the inclusion of concentrate and monensin, salinomycin and flavomycin in sheep diets on intake, digestibility, in situ degradability, ruminal variables and nitrogen balance. Five sheep in a latin square received the treatments: HAY (hay only), CONT (hay + concentrate), MON (hay + concentrate + monensin), SALI (hay + concentrate + salinomycin), and FLAV (hay + concentrate + flavomycin). Hay was offered ad libitum, concentrate, 20 g kg(-1) of body weight (BW), and additives, 0.75 mg kg(-1) of BW. The treatments with the concentrate (CONT, MON, SALI and FLAV) showed increased (P <= 0.05) on intake, digestibility, total VFA, propionate and butyrate proportions, N-NH3, and nitrogen balance, and decreased (P <= 0.05) DM and NDF degradability, acetate proportion, acetate:propionate ratio, and rumen pH compared to the HAY. The comparison between the outcome effects from additives with the CONT showed that the acetate proportion and acetate:propionate ratio was only reduced by MON (P <= 0.05). MON and SALI increased (P <= 0.05) the propionate proportion. The proportion of butyrate was increased with the inclusion of FLAV and reduced with MON 8and SALI. Only MON reduced the production of N-NH3 (P <= 0.05). Other variables showed no effects from additives (P>0.05) in relation to the CONT. The inclusion of the concentrate in sheep diets caused alterations on intake, digestibility, ruminal variables (VFA, pH, and N-NH3) and nitrogen balance. However, the additives only altered the ruminal variables (VFA and N-NH3) and the greatest effects were observed with MON.