Abstract

Simple SummaryLow-protein diets are widely used in goose production, but they could also lead to excessive fat deposition due to more starch content and energy imbalance. This study aimed to investigate whether adjusting the starch: fat ratio in the low-protein diet could maintain normal glucose and lipid metabolism in geese. A total of 360 male geese received diets containing two crude protein levels (14.5% and 16.5%) and three SFRs (SFR20:1, SFR11:1, and SFR5:1). A lower SFR increased body fat deposition, Liver cholesterol accumulation, and reduced liver glycogen stores. Dietary protein level mainly influenced Liver AMPK-related enzyme activities, whereas SFR exerted a stronger effect on Liver glucose and lipid metabolism as well as muscle fatty acid composition. In particular, an SFR of 11:1 better maintained the unsaturated fatty acid profile of breast muscle than an SFR of 5:1. Overall, improving the energy structure of low-protein diets, especially by avoiding an excessively low SFR, might benefit glucose and lipid metabolism and help maintain meat lipid quality in geese.This study examined the effects of dietary crude protein (CP) level and starch: fat ratio (SFR) on glucose and lipid metabolism in geese. A total of 360 male Jiangnan White geese were allocated to a 3 × 2 factorial arrangement with two CP levels (14.5% and 16.5%) and three SFRs (SFR20:1, SFR11:1, and SFR5:1) from 28 to 63 days of age. Under the low-protein condition, Both the SFR11:1and SFR5:1group enhanced body weight of geese at 63 d, but SFR5:1increased subcutaneous and abdominal fat deposition. Dietary SFR changed liver cholesterol metabolism and glycogen content, while CP levels mainly affected the activity of enzymes related to liver glucose and lipid metabolism: 14.5% CP increased AMPK and ACC activity, but decreased FAS, CS and G6PC activity. Both CP level and SFR altered muscle fatty acid composition, but the effect of SFR was usually more significant. An SFR of 11:1 was beneficial f