高直链淀粉/支链淀粉比在低蛋白日粮中促进鹅生长性能和胸肌蛋白质沉积

Abstract

This experiment was conducted to investigate the effects of different dietary protein levels and amylose to amylopectin (AM/AP) ratios on the growth performance and muscle development of geese. A total of 240 healthy male Jiangnan White geese (body weight [BW] 2124.8 ± 91.4 g, 35-d-old) were randomly assigned to 4 groups, with 6 replicates per group and 10 birds per replicate. The 2 × 2 factorial design included two protein levels (16% and 14%) and two AM/AP ratios (0.34 and 0.44). The 4 groups were: control group, normal protein (16%) with normal AM/AP ratio (0.34) (NPNR); normal protein (16%) with high AM/AP ratio (0.44) (NPHR); low protein (14%) with normal AM/AP ratio (0.34) (LPNR); and low protein (14%) with high AM/AP ratio (0.44) (LPHR). The results showed that compared with normal protein diet, low protein diet increased average daily feed intake (ADFI; P = 0.008). Increasing the AM/AP ratio increased BW of geese at 56 d ( P = 0.003), improved average daily weight gain (ADG; P = 0.003) and decreased feed-to-gain ratio (F/G; P = 0.009). Increasing the AM/AP ratio led to an increase in crude protein content in the breast muscle ( P = 0.015), also enriched the amino acids composition in the liver and muscles, specifically elevated the Lys content in the liver ( P = 0.004) and leg muscle ( P = 0.031), and Glu, Leu, Lys, and Pro content in breast muscles ( P < 0.05). Both a low protein diet and a high AM/AP ratio increased short-term breast muscle protein deposition. High AM/AP ratio diets accelerated the protein fractional synthesis rate ( P = 0.036) and fractional growth rate ( P = 0.002) in breast muscles. Antagonistic interactions between AMPK and mTOR pathways were observed. Compared with the control group, the LPHR group showed down-regulation of AMPKα1 mRNA ( P = 0.020) and up-regulation of mTOR mRNA in the breast muscle ( P = 0.047). High AM/AP ratio in the diets induced hypertrophy and thickening of leg muscle fibers. In conclusion, i