the effect of feeding ensiled alfalfa with different levels of waste date on rumen protozoal population, microbial protein synthesis and blood parameters in kermani sheep

introduction ensiling is less dependent to weather condition and farmers are trying to ensile forages for preserving them for livestock feeding. ensiling legumes because of their buffering capacity and high moisture content are difficult. also, ensiling alfalfa will lose up to %85 of its nitrogen content as non-protein nitrogen. adding some additives like carbohydrate sources will improve alfalfa silage quality and its physical characteristics. there are some agricultural byproducts which can be used in animal feeding. waste date is being produced annually in iran and it can be used as carbohydrate source during alfalfa ensiling. this experiment was conducted to investigate ensiling alfalfa with different levels of waste date and its feeding effect on rumen protozoa population, microbial protein synthesis and blood parameters in kermani sheep. materials and method eight rams (47 ± 2 kg bw) were used in a 2×2 change over design experiment. each experimental period was conducted for 21 days (16 days for adaptation and days for sampling). for ensiling, fresh alfalfa with different levels of waste date (0, 5, 10 and %15) were mixed together and ensiled in 100 l containers for 45 days. after opening chemical compositions of silages such as dry matter, crude protein, ammonia nitrogen, crude fat, organic matter, ash, ndf, adf and ph were determined according to standard methods. then, it was used %30% of diet in experimental diets as: 1) control diet (alfalfa silage without waste date); 2) alfalfa silage with 5% waste date; 3) alfalfa silage with 10% waste date and 4) alfalfa silage with 15% waste date. treatment diets were mixed and fed as a tmr at 0800 and 1700 h. amount of the tmr offered was recorded, and treatment diets were sampled daily for the last 5 d of each period. orts were weighed, recorded, and sampled according to the same procedures followed for the treatment diets. urine samples were acidified during collection to a ph <3.0 by addition of 2 m sulfuric acid. aliquots were diluted 1:10 with distilled water, stored frozen at −20°c, and later analyzed for n, allantoin and uric acid. the amount of microbial purines absorbed was calculated from purine derivative excretion. a blood sample (about 10 ml) was collected from a jugular vein into tubes containing 12 mg of edta, and plasma was separated by centrifugation at 500 × g for 10 min and stored at −20°c until analysis of plasma glucose, protein, triglyceride, cholesterol, urea n and creatinine. statistical analysis was performed using the glm procedure of sas software. data were analyzed using the model yijk = μ + ti + pj + ck + εijk . treatments means were statistically compared by the new multiple range test of duncan. results and discussion the results of this experiment showed that total protozoal population and all of holotrish, cellulolytic and entodinium species in rumen fluid were increased linearly by increasing the level of waste date during ensiling alfalfa. also, the nitrogen and microbial protein, cholesterol level, blood glucose and blood urea nitrogen were significantly different and triglyceride was tended to be significant. higher amount of easily fermentable carbohydrates in waste date might increase propionate in rumen fluid and therefore increases blood glucose level in animals which fed diet containing alfalfa silage plus %15 waste date. the highest blood urea nitrogen was achieved in control diet and it might be due to lower fermentable carbohydrate, higher rumen ph and lower efficiency of microbial protein synthesis. protozoa populations tended to be increased linearly with increasing level of waste date in the diets (p<0.05) which might be due to higher dry matter intake. nitrogen intake, urine excretion of n, and nitrogen retention were affected by treatments. with regards to n utilization, n excretion and n retention should reflect differences in n metabolism, because n retention was the most important index of the protein nutrition status of ruminants. the microbial n supply calculated from purine derivative excretion were from 44.23 to 53.29 g of n/d. the efficiency of rumen microbial protein synthesis was increased as level of waste date increased during ensiling which might be due to higher level of rapidly fermentable carbohydrates in diets containing higher level of waste date. by increasing soluble carbohydrates microbes are able to access energy more efficiently and therefore rumen microbes will be able to utilize protein of diet more efficiently. conclusion in conclusion, using %15 of waste date during ensiling alfalfa improved nitrogen retention and increased microbial protein synthesis.