Effect of N-methyl-aspartate and Betaine on Growth Perfor-mance and Correlation Between Growth Hormo

<正> Ninety finishing pigs were selected to study the effect of N-methyl-aspartate and betaine on the internal growth hormone level in the serum and the correlation between the growth hormone level, growth performance and carcass characteristic of finishing pig. The study showed that the two matters could improve pig growth and carcass composition significantly. The correlation analyses indicated that the growth hormone and IGF-I have a positive correlation with the growth rate. Carcass lean ratio, longissimus dorsi area, serum free fatty acid and lipase activity have a negative correlation with the feed conversion ratio, carcass fat ratio and urine nitrogen. But the growth hormone is more effective than IGF-I (P<0.01). The results implicated that both the two matters may act through growth hormone axis (growth hormone - IGF-I) to manipulate pig growth.