Interaction between barley grain processing and source of dietary protein on nutrients digestibility, rumen pH and ammonia concentration in sheep

摘要

The effects of barley grain processing (whole vs. cracked) combined with two different protein sources (urea vs. soybean meal) on nutrients digestibility, rumen pH and ammonia concentration in sheep were investigated. Four permanently rumen fistulated Mehraban sheep were allocated in a 4×4 Latin square design. Four different experimental diets were used: 1) whole barley grain with urea (WB-U), 2) cracked barley grain with urea (CB-U), 3) whole barley grain with soybean meal (WB-S), and 4) cracked barley grain with soybean meal (CB-S). The study lasted 56 days which consisted of four 14-day experimental periods. The results showed that DM, OM and CP digestibility were not affected by treatments. However, digestibility of neutral detergent fiber (NDF) was affected by treatments with the highest fiber digestibility obtained for soybean fed animals. Although, average rumen pH was not different among treatments, determined pH on 2 h after feeding differed among treatments (P & 0.05). The results for rumen ammonia concentration was clarified that urea supplemented diets increased ammonia concentration compared to soybean meal fed diets. The rumen ammonia concentration for treatments WB-U and CB-U increased dramatically for both 2 and 3 h after feeding. The results of the present study showed that supplementation of sheep diet with soybean meal has significant effect on fiber digestion compared to urea supplementation and the increased ammonia concentration which was caused by urea supplementation may not be a valuable factor affecting nutrients digestibility in sheep nutrition.