Abstract: 【Objective】 The purpose of this experiment was to explore the application effect of earthworm hydrolysate in Muscovy duck healthy culture under high temperature environment.【Method】 A total of 360 healthy Muscovy ducks were randomly divided into 3 groups (6 replicates per each group,20 ducks per replicate).The Muscovy ducks in control group were fed the basal diet,and in test groups were fed with basal diet that supplemented with 1.5% and 2.5% earthworm hydrolysate,respectively.The test period was 55 days.The growth performance,heat shock protein 70 (HSP70) mRNA expression,hormone levels (triiodothyronine,tetraiodothyronine,corticosterone,cortisol) in serum,intestinal morphological parameters (villi height,crypt depth,villi width,villi height/crypt depth ratio and surface area of villi) and intestinal barrier-related parameters (diamine oxidase,D-lactate,lipopolysaccharide) of Muscovy ducks were measured.【Result】 Under high temperature environment,compared with the control group,① 1.5% and 2.5% earthworm hydrolysate boosted the average daily gain (ADG) of Muscovy ducks at 21-42 and 16-70 d (P＜0.01),decreased the feed conversation ratio(F/G) at 21-42 d (P＜0.05),and reduced the F/G at 16-70 d (P＜0.01).2.5% earthworm hydrolysate markedly decreased the F/G of Muscovy ducks at 42-70 d (P＜0.05).②1.5% and 2.5% earthworm hydrolysate decreased the mRNA level of HSP70 in Muscovy ducks at 42 and 70 days old (P＜0.01).③At 42 days old,1.5% earthworm hydrolysate increased the level of cortisol in Muscovy ducks (P＜0.01),and 2.5% earthworm hydrolysate decreased the levels of triiodothyronine (P＜0.05) and tetraiodothyronine (P＜0.01),and increased the level of corticosterone (P＜0.05) in Muscovy ducks.At 70 days old,1.5% earthworm solution decreased the level of corticosterone (P＜0.01),2.5% earthworm hydrolysate decreased the levels of triiodothyronine and cortisol (P＜0.05),and increased the level of tetraiodothyronine (P＜0.01) in Muscovy ducks.④1.5% earthworm hydrolysate increased the intestinal thickness and intraepithelial lymphocyte of Muscovy ducks (P＜0.01),2.5% earthworm hydrolysate increased the villi length and intestinal thickness of Muscovy ducks (P＜0.01).⑤At 42 days old,1.5% and 2.5% earthworm hydrolysate increased the activity of diamine oxidase in Muscovy ducks (P＜0.01).At 70 days old,1.5% earthworm hydrolysate decreased the serum level of LPS in Muscovy ducks (P＜0.01),and 2.5% earthworm hydrolysate decreased the activity of diamine oxidase,the levels of D-lactate and LPS in serum of Muscovy ducks (P＜0.01).【Conclusion】 Dietary earthworm hydrolysate could improve the growth performance of Muscovy ducks,increase the ability to resist heat stress.It could be used for healthy breeding of Muscovy ducks under high temperature environment.

Key words: earthworm hydrolysate; high temperature; growth performance; heat stress index; hormone; intestinal function