Effects of nitrate and fumarate in tree leaves-based diets on nutrient utilization, rumen fermentation, microbial protein supply and blood profiles in sheep

Abstract

This experiment was conducted to study the effects of nitrate and fumarate on nutrient utilization, rumen fermentation and blood biochemical profile in sheep fed on tree leaves-based diet. Thirty two matured male Chokla breed of sheep (2–3 years old and 46.9±0.95 kg average body weight) were equally distributed in a randomized block design in four groups with similar average age and mean body weight. All groups were fed diets containing roughage and concentrate in a 70:30 ratio. Control group (C) was fed with cenchrus (Cenchrus ciliaris) straw as an only roughage source, whereas other three groups (T1, T2 and T3) were fed with cenchrus straw, ardu (Ailanthus excelsa) leaves and khejri (Prosopis cineraria) leaves (50:25:25) as roughage sources. Animals in the T1 group were not supplemented with any feed additive; whereas, animals in the T2 and T3 groups were added with 2% potassium nitrate of the concentrate mixture and 2% fumarate of the dry matter (DM) intake, respectively. There were no effects (P>0.10) of any treatments on DM intake, BW change or nutrient utilization. N retention increased in treatment groups compared with control due to greater amount of N intake. Concentrations of glucose, haemoglobin, albumin, blood urea nitrogen and creatinine, and different blood enzyme concentrations were not affected (P>0.10) by any treatments, but concentrations of total protein, globulin and cholesterol in blood were higher for T1 and T3 than for C and T2 treatments. Microbial N supply in terms of digestible OM intake or digestible OM retained in the rumen did not differ among treatments. Total amylase and carboxymethyl cellulase concentrations were similar among the groups. However, total xylanase activity increased in T3 group than other groups. A reduction in average propionate concentration (P=0.020) was observed for the T2 treatment in comparison with the C and T1 groups. Concentrations of ammonia N, total N and trichloroacetate-perceptible N were lower in control than other treatments, but concentrations of soluble N were not affected (P>0.05) by any treatments. In conclusion, fumarate (2% of DM) may be included in the diet of sheep fed with ardu–khejri leaves without affecting nutrient utilization and rumen fermentation, whereas ardu–khejri leaves diet containing nitrate (0.6% of DM) may affect rumen fermentation.