AUTHOR=Yang Xuanyi , Zhao Xumin , Wang Guanghui , Dong Xiaohui , Yang Qihui , Liu Hongyu , Zhang Shuang , Tan Beiping , Chi Shuyan 

TITLE=Improvement of hybrid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) by enzyme-digested poultry by-product: Growth performance, amino acid and peptide transport capacity, and intestinal morphology

JOURNAL=Frontiers in Nutrition

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.955734

DOI=10.3389/fnut.2022.955734

ISSN=2296-861X

ABSTRACT=<sec><title>Background</title><p>At present, fish meal (FM) resources are in short supply, and competition for food between humans and animals is becoming increasingly critical. Finding non-grain protein sources that can replace FM is the key to solving the rapid development of aquaculture.</p></sec><sec><title>Methods</title><p>Seven trial diets were prepared with 0 g/kg (EP0), 30 g/kg (EP3), 60 g/kg (EP6), 90 g/kg (EP9), 120 g/kg (EP12), 150 g/kg (EP15), and 180 g/kg (EP18) of enzyme-digested poultry by-product meal (EPBM) by replacing of FM. A total of 630 hybrid groupers (<italic>Epinephelus fuscoguttatus</italic> ♀ × <italic>E. lanceolatus</italic> ♂) were equally portioned into 21 tanks. At 8:00 and 16:00 each day, groupers were fed until they were full for a cumulative period of 8 weeks.</p></sec><sec><title>Results</title><p>The results showed that 30 g/kg of EPBM significantly increased the rates of weight gain and special growth (<italic>P</italic> &lt; 0.05). Significantly higher activities of serum glutamic pyruvic transaminase, glutamic oxaloacetic transaminase, catalase, and superoxide dismutase were observed in the EP3 group (<italic>P</italic> &lt; 0.05). The categories and numbers of the top 10 dominant bacteria in the phylum and genus levels were not significantly influenced by feed (<italic>P</italic> &gt; 0.05). In the proximal intestine and distal intestine, there were significantly higher expressions of <italic>SNAT3, LAAT1, CAT2</italic>, and <italic>CAT1</italic> in the EP3 group compared with the EP0 group (<italic>P</italic> &lt; 0.05). In the EP3 group, the expressions of <italic>PepT1, LAAT1, B<sup>0, +</sup>AT</italic>, and <italic>CAT2</italic> were significantly increased in MI than those in all other groups (except the EP0 group, <italic>P</italic> &lt; 0.05).</p></sec><sec><title>Conclusion</title><p>When FM was replaced by 30 g/kg of EPBM, growth performance, antioxidant capacity, and the ability to transport amino acids and peptides of hybrid grouper were significantly improved.</p></sec>