ruminal fermentation, microbial protein synthesis and nitrogen balance in sheep fed pistachio by-product silage

This study was conducted to evaluate the effect of feeding several levels of pistachio by-product silage (pbs) on feed intake, nitrogen metabolism, protozoa population and purine derivative excretion in sheep. the isoenergetic and isonitrogenous diets were: 1) control (without pbs), 2) 7% pbs, 3) 14% pbs, and 4) 21% pbs. eight rams (40±2.5 kg live weight) were used in a replicated latin square design with four diets and four periods of 35 days each. feeding 14% of pbs enhanced significantly (p<0.05) dry matter intake, nitrogen intake and nitrogen retention in sheep. purine derivative excretion and microbial protein synthesis increased (p<0.05) when diets contained pbs. ruminal ph increased and holotrich protozoa population decreased linearly with increasing levels of pbs in the diets (p<0.05). by increasing pbs in the experimental diets, total protozoa population and entodinium sp. changed quadratically (p<0.05). the results showed that pbs up to 14% can be used as a dietary ingredient for sheep, especially when conventional feeds are in short supply.