تأثیر سطح خوراک مصرفی بر قابلیت هضم، تعادل نیتروژن و میزان سنتز پروتئین میکروبی در گوسفند

     An experiment was conducted to determine the effects of different levels of feed intake at 70%, 85% and 100% of the voluntary feed intake on digestibility and rumen microbial protein synthesis. For this purpose, six male lambs (42±1.5 kg BW) were used in a replicated Latin square design (replicated in three periods that were 21 days each). A twenty five days period was assigned as adaptation period before start of the experiment to determine animals’ voluntary feed intake. Then in experimental period the potential of urinary purine derivatives as a predictive index of microbial protein supply was determined. The data were analyzed using SAS statistical software. The results showed that by decreasing the level of feed intake, the amounts of allantoin, total purine derivations excretion, microbial protein synthesis in the rumen, nitrogen balance and PDC index were decreased (P<0.05). However, apparent digestibility of dry matter and organic matter were increased (P<0.05). In conclusion, it is suggested that during feed resource shortage or low quality of forage in pasture, by increasing the level of feed intake, microbial protein synthesis and animal performance improvement can be achieved.