The Utilization of Mixed Silage Composed of Pennisetum giganteum and Rice Straw as an Alternative to Maize Silage in Fattening Lambs

This experiment evaluated the application effects of the dietary substitution of maize silage with mixed silage prepared with Pennisetum giganteum and rice straw on fattening lambs. Forty-eight male Hu lambs with similar body weights and ages were randomly divided into four groups. The maize silage in the diet was replaced with Pennisetum giganteum and rice straw mixed silage in proportions of 0 (CON), 25% (PR1), 50% (PR2) and 75% (PR3). The average daily gain of the PR3 group was lower (p < 0.05) than that of the other groups. The highest substitution level increased (p < 0.05) ruminal ammonia nitrogen concentration and acetate-to-propionate ratio in lambs compared with the CON and PR1 groups. Moreover, dry matter and neutral detergent fiber digestibility in PR3 lambs were lower (p < 0.05) than in PR1 lambs. Compared with the CON group, the concentrations of serum catalase and total antioxidant capacity were increased (p < 0.05) in the PR2 and PR3 groups. Overall, the dietary substitution of maize silage with Pennisetum giganteum and rice straw mixed silage at a 50% level did not show a negative influence on growth performance of fattening lambs but displayed positive effects on their fiber digestibility and antioxidative capacity.