Effect of different levels of lucerne (Medigo sativa) in diet on rumen fermentation and energy metabolism of ewes

A study was conducted to examine the effect of different levels of dietary lucerne (Medigo sativa) on rumen fermentation and energy metabolism in ewes. Four groups of ewes (6 in each) were fed experimental ration, containing nutrients as per NRC (2001). The concentrate in ration of groups T¹⁰⁰, T²⁰⁰ and T⁴⁰⁰ was replaced by lucerne hay to provide saponin at the rate of 100, 200 and 400 mg/kg body weight, respectively. Ruminal pH, protozoal count, volatile fatty acid production and ammonia nitrogen concentration were determined on 0, 3, 7, 14 and 28 days of experiment. There was no significant difference among the groups for pH, total volatile fatty acid, acetate, propionate and butyrate per cent. The total protozoa in strained rumen liquor on 0 day in the treatments T⁰⁰, T¹⁰⁰, T²⁰⁰, and T⁴⁰⁰ were 2.79, 2.75, 2.80 and 2.67x10⁶/ml respectively. On 3, 7, 14 and 28 day of saponin feeding, there was significant (P<0.05) reduction in protozoal population. The ammonia nitrogen in treatments T²⁰⁰ and T⁴⁰⁰ were significantly (P<0.05) lower than the control group on 3, 7, 14 and 28 day of saponin feeding. Methane emission was measured in respiration chamber for 48 h in continuation. Daily methane emission in T⁰⁰, T²⁰⁰, T²⁰⁰, and T⁴⁰⁰ were 10.52, 9.92, 9.84 and 8.14 l/d, respectively. Compared to T00 group, reduction in daily methane production due to saponin feeding were 5.70, 6.46 and 22.62% in T¹⁰⁰, T²⁰⁰, and T⁴⁰⁰, respectively. Loss of methane energy as per cent of (digestible energy was 8.49, 7.63, 7.37 and 6.48%, respectively for treatments T¹⁰⁰, T²⁰⁰, and T⁴⁰⁰. From the study, it can be concluded that lucerne saponin significantly reduced the methane production and total protozoal count in rumen liquor. It can significantly increase the nitrogen retention along with the efficiency of energy utilization in sheep.