Effects of grain level on lamb performance, ruminal metabolism and leptin mRNA expression in perirenal adipose tissue
2017
Hernández, Pedro A. | Mendoza, Germán D. | Castro, A. | Lara, A. | Plata, F. X. | Martinez, J. A. | Ferraro, S.
The effects of four different grain composition diets of finishing lambs on lamb performance, dry matter (DM) digestibility, rumen fermentation and leptin mRNA expression were evaluated. Thirty-two Pelibuey lambs (25.35 ± 4.73 kg bodyweight) were used in a completely randomised experiment in which lambs were fed diets that contained 30%, 45%, 60% or 75% grain (DM basis). The results indicated that increasing the grain level improved the average daily weight gain, hot carcass weight, DM digestibility and feed conversion linearly (P < 0.01); however, feed intake was not affected. Ruminal pH decreased linearly as the grain content was increased (P < 0.01). Ruminal propionate concentration increased and acetate concentration declined with increased grain content (P < 0.01). Leptin mRNA expression in perirenal adipose tissue increased linearly (P < 0.05) as grain content increased. Based on these results, we conclude that increasing grain level in the diets of finishing feedlot lambs improved weight gain and feed efficiency; however, because weight gain and feed efficiency were similar at the higher grain levels, our data suggest including 60% grain in lamb finishing rations.
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