关键词: 生长猪, 褪黑激素, 生产性能, 养分消化率

Abstract: To test the effects of oral melatonin on performance and feed nutrients apparent digestibility, 15 (Landrace×Yorkshire) pigs (initial body weight 35 kg approximately) were employed and allotted into 3 groups, and each group had 5 replicates of 1 pig. Two groups were fed with diets containing high level [3.0 mg/(kg·d)] or low level [1.5 mg/(kg·d)] of melatonin respectively and one group as the control were fed with diet containing no melatonin. The results show that high level MT reduces the average daily gain (ADG) and feed intake (ADFI) of pigs by 11.31% (P<0.01) and 13.63% (P<0.01) respectively, and the feed to gain ratio (F/G) also reduces (P>0.1) compared with the control. The ADG and ADFI of pigs in low level MT group are similar to the control, but the feed to gain ratio (F/G) reduces significantly by 5.85% (P<0.05). Two levels of MT have no significant influences on apparent digestibility of feed gross energy and total organic nutrients for pigs, but the apparent digestibility of crude fat (CEE) is reduces by 6.19% (P<0.05) and 5.27% (P=0.056) for high and low level MT respectively compared with the control. Apparent digestibility of crude protein (CP) is reduces in high level MT group, but improves in low level MT group, and it is significantly different between high level and low level MT groups.

Key words: growing pigs, melatonin, performance, nutrients digestibility