Effect of Different Levels of Potato on Nutrient Digestibility, Fibrolytic Enzyme and Ruminal Characteristics in Dalagh Ewes

This study was performed to investigate the effect of different levels of potato in the diet on ruminal parameters, nutrient digestibility and rumen liquor cellulolytic enzymes including microcrystalline-cellulase and carboxymethyl-cellulase in different parts of rumen liquor (particulate material (PM), extra cellular (EC) or cellular. Twelve Dalagh ewes were used in this experiment in a completely randomized design with 3 treatments and 4 replicates. Experimental treatments included 1) control treatment (no potatoes) 2) 7.5% potato treatment 3) 15% potato treatment based on dietary dry matter. The diets were similar in protein and energy. The results of this study showed that the difference in pH of rumen liquor between treatments (6.02-6.4) was statistically significant (p=0.0003). Among the experimental treatments, the highest amount of rumen ammonia nitrogen was observe in the control treatment (14.93) and the lowest in the treatment containing 15% potato (10.23) and the difference was statistically significant (p= 0.0001).The number of protozoa in the control treatments was the lowest and the potato treatment 7.5% the highest .This difference was significant between control treatment and treatments containing 7.5 and 15% potatoes (p=0.023). The DDM, CP, OM, NDF digestibility of diet in three rations did differ significantly (p =0.0001). Among the activities of carboxymethyl-cellulase and microcrystalline-cellulase enzymes in the cellular, EC, PM and total fraction (all 3 sections), the highest and lowest values were observed in control and 15% potato treatments, respectively. There was a significant difference between the three treatment (p<0.0001). According to the results mentioned, potato can be used up to 15% of the diet of ewes without any adverse effect.