Effects of different culture salinities on the growth and muscle quality of grass carp (Ctenopharyngodon idellus)

Grass carp (Ctenopharyngodon idellus) is an economically important farmed fish. This experiment was conducted to study the effects of different culture salinities on the growth and muscle quality of grass carp. We found that salinity of 0 to 5 had no significant effect on the growth of grass carp, but it significantly decreased at salinities above 5. Compared to salinity 0, the protein content of serum was significantly higher at salinities of 3 and 5. However, all serum biochemical compound measured, except glucose and total protein, decreased significantly at salinity 9. Muscle textural properties of grass carp were significantly higher at salinities of 3 and 5 than at 0, 7, and 9. Salinities of 0 to 3 had no significant effect on muscle nutrition of grass carp, but this parameter tended to decrease at salinities above 7. Salinities of 3 and 5 significantly favored muscle growth and expression of collagen-related genes, whereas the opposite was true for salinities of 7 and 9. These results indicated that grass carp grew normally at salinities of 3 and 5, with some improvement in muscle quality, whereas salinities of 7 and 9 had a negative effect on growth and quality. Therefore, appropriate salinity levels can help to improve the muscle quality of grass carp without affecting their growth.This study explored the effects of different culture salinities on the growth and muscle quality of grass carp, suggesting that moderate salinity improves muscle quality and collagen content, while higher salinity impairs both growth and muscle quality.Grass carp is an important economic fish with the highest production in the world. In recent years, the issue of quality improvement of grass carp has received more attention. On the other hand, as the climate warms and the salinized area increases, the use of salt-water resources has become an important issue. This experiment was conducted to study the effects of different culture salinities on the growth and muscle quality of grass carp. The results suggested salinity of 3 and 5 could enhance the muscle quality of grass carp without affecting the growth, especially with higher collagen content, expression of collagen-related genes, and sweet amino acids in muscle compared with salinity 0. However, salinity 7 and 9 inhibited the growth of grass carp and negatively affected muscle quality. This study suggested that a slight increase in aquaculture salinity can improve the muscle quality of grass carp without affecting the growth, which provided data basis and theoretical support for the healthy aquaculture of grass carp and utilization of saline water.