Effects of three kinds of different protein-to-fat ratio ingredi-ents on growth, slaughter performance and fat deposition of Small-Tail Han lambs

Abstract

Abstract This study aimed to investigate the effect of three kinds of different protein-to-fat ratio ingredients on growth, slaughter performance and meat quality of Small-tail Han lambs. For this, 45 Small-tailed Han lambs (♂)(BW = 34.00 ± 2.5 kg, age = 120 ± 9 d) were randomly assigned to three treatment: (1) PF5 group, (2) PF10 group and (3) PF20 group, each treatment consisted of fifteen repeats. The ratio of protein and fat in three ingredients were the PF5 (CP:EE = 50:5 ), PF10 (CP:EE = 50:10), and PF20 (CP:EE = 50:20 ). This experiment lasted for 65 days, with feed intake recorded daily, and animals being weighed on days 0, 30, and 65. At the end of the experiment, eight lambs from each group were slaughtered, slaughter performance and meat quality were subsequently determined. The results showed that the PF10 group had the highest average daily weight gain (370.15 g) (P < 0.05). Fore-gastric weights (1216.88 g) of the PF10 group were significantly highest the other groups (P < 0.05). There was no significant difference in the proportion of fat weight to body weight in different parts, which was basically at the same level (P > 0.05). Feed conversion rate of the PF10 group was also the best. Furthermore, the PF10 group had a high carcass weight and slaughter rate and there were few differences between the other groups in terms of dry matter intake, meat quality, organ weight, and fat deposition (P > 0.05). In conclusion, a protein-fat ratio of raw materials of 50:10 is the best ratio, which can more conducive to enhancing the growth and development of small-tail Han lambs.