Abstract
Earthworm has a variety of molecular biological characteristic, for example, growth promotion, antioxidant, and anti-bacteria. Thus, we decomposed earthworm by earthworm's own protease for preparing of earthworm hydrolysate. Muscovy ducks were fed with basal diet that formulated to contain 1.5% and 2.5% earthworm hydrolysate. Then, we investigated the influences of earthworm hydrolysate on growth performance in Muscovy ducks by performance terminology and measurement for poultry (NY/T 823-2020). The morphology of duodenum and number of intraepithelial lymphocytes were tested by HE staining and immunohistochemical method. Serum biochemical parameters and antioxidant capacity were also determined. High-throughput sequencing technology can sequence 16S rDNA of cecal contents from experimental Muscovy ducks. Results showed that 1.5% earthworm hydrolysate increased ADG (16-70 days old), ALB, HDL-C, T-AOC, CAT, SOD, GSH-PX, villi length, intestine thickness and surface area of villi (P < 0.05 or P < 0.01), and reduced FCR (16-70 days old), UREA, CRE, LDL-C, MDA (P < 0.05 or P < 0.01). Meanwhile, 2.5% improved ADG (16-70 days old), abdominal fat yield, breast muscle yield, heart index, spleen index, ALP, UA, T-AOC, CAT, SOD, GSH-PX, villi length, crypt depth, intestine thickness, surface area of villi, the percentage of intraepithelial lymphocytes (P < 0.05 or P < 0.01), and decreased FCR (42-70 days old and 16-70 days old), UREA, UA, MDA (P < 0.05 or P < 0.01). The sequencing results of gut flora demonstrated that earthworm hydrolysate improved variety of the gut flora in the V4 area of ducks immensely. In a word, our results provide the foundation for preliminary researching the potential principles of earthworm hydrolysate in promoting production performance, adjusting antioxidant function and intestinal functions in the Muscovy duck industry.