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

PLoS One. 2022 Feb 4;17(2):e0263507. doi: 10.1371/journal.pone.0263507. eCollection 2022.

Abstract

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%.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Feed / analysis
  • Animal Nutritional Physiological Phenomena
  • Animals
  • Antioxidants / metabolism
  • Diet
  • Dietary Proteins / metabolism*
  • Dietary Supplements / analysis
  • Fishes
  • Immune System
  • Lipase / chemistry
  • Muramidase / metabolism*
  • Nutritional Requirements
  • Oxidative Stress*
  • Superoxide Dismutase / metabolism*
  • Trypsin / chemistry

Substances

  • Antioxidants
  • Dietary Proteins
  • Superoxide Dismutase
  • Lipase
  • Muramidase
  • Trypsin

Grants and funding

This work was financially supported by the National R & D Supporting Program (2015BAD25B01), Fund of the State Key Laboratory of Freshwater Ecology and Biotechnology and the earmarked fund for China Agriculture Research System (CARS-45), and the Shandong Provincial Agricultural Seed Engineering Project (No. 2017LZN003). The contribution of programs are as follows: The National R & D Supporting Program (2015BAD25B01) played a role in study design, the Fund of the State Key Laboratory of Freshwater Ecology and Biotechnology and the earmarked fund for China Agriculture Research System (CARS-45) played a role in data collection and analysis, and the Shandong Provincial Agricultural Seed Engineering Project (No. 2017LZN003) played a role in experiment conduction and data analysis.