Effect of dietary protein levels on the growth, enzyme activity, and immunological status of Culter mongolicus fingerlings

• Published in: PloS one Vol. 17; no. 2; p. e0263507
• Main Authors: Qian, Jing, Xiao, Lingjun, Feng, Kai, Li, Wei, Liao, Chuansong, Zhang, Tanglin, Liu, Jiashou
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 04.02.2022; Public Library of Science (PLoS)
• Subjects: Animal Feed - analysis; Animal Nutritional Physiological Phenomena; Animals; Antioxidants - metabolism; Biology and Life Sciences; Biotechnology; Commercial fishing; Culter mongolicus; Diet; Dietary Proteins - metabolism; Dietary Supplements - analysis; Ecology and Environmental Sciences; Engineering; Enzymatic activity; Enzyme activity; Enzymes; Fish; Fisheries; Fishes; Fishes, Fresh-water; Fishing; Food and nutrition; Freshwater ecology; Growth; Growth rate; Health aspects; Immune System; Immunology; Laboratories; Lipase - chemistry; Lipids; Lysozyme; Malondialdehyde; Medicine and Health Sciences; Muramidase - metabolism; Nutrients; Nutritional aspects; Nutritional Requirements; Oxidative Stress; Proteins; Proteins in human nutrition; Superoxide dismutase; Superoxide Dismutase - metabolism; Trypsin; Trypsin - chemistry; Water pollution; China; Beijing China; Hubei China
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0263507

A 65-day growth trial was conducted to investigate the dietary protein requirements for Culter mongolicus fingerlings. Isolipidic and isoenergetic diets were formulated with five dietary protein levels (32%, 37%, 42%, 47%, and 52%). Each diet was assigned to triplicate groups of 70 C. mongolicus fingerlings (0.99±0.08 g). The results indicated that weight gain and specific growth rate (SGR) increased with increasing dietary protein levels up to 47%. The activities of intestinal trypsin and lipase were the lowest in the 32% protein and 52% protein groups, while amylase activity reduced markedly in the 47% protein group. These results suggest that different dietary protein levels may cause different transformations of nutrients. The activities of superoxide dismutase (SOD) and lysozyme were not affected by varying dietary protein levels, except for those in the 32% protein group. In contrast, the content of malondialdehyde (MDA) increased with increasing dietary protein levels and reaching a maximum in the 52% protein group, suggesting that MDA accumulation depends on the protein concentration and the potential oxidative stress. Taken together, based on the broken-line analysis of SGR, we recommended the optimum dietary protein for C. mongolicus fingerlings to be 48.97%~49.31%.