Effects of dietary sodium chloride on growth and muscle quality of Ctenopharyngodon idella

To investigate the effects of adding sodium chloride (NaCl) to diets on the growth performance and flesh quality of Ctenopharyngodon idella, five diets were prepared with NaCl addition at 0 (control diet), 10, 20, 30, 40 g/kg and fed to C. idella with an initial body weight of (12.26±0.03) g. After 60 days of feeding, 10 and 20 g/kg NaCl groups showed the similar growth to the control, while 30 and 40 g/kg NaCl groups had lower weight gain and higher feed conversion ratio than the control. No significant differences were observed in flesh proximate composition except ash among all the groups, and the ash content increased with the increasing NaCl level. The water-holding capacity was significantly decreased by the supplementation of NaCl except in thawing loss of 10 g/kg NaCl group. The addition of 10 and 20 g/kg NaCl increased the total free amino acids contents, but the supplementation of 20, 30, 40 g/kg NaCl significantly decreased the contents of free Glu and Asp in flesh. Dietary NaCl decreased the flesh hardness and the supplementation of 30 and 40 g/kg NaCl decreased the flesh chewiness, but there was no significant difference in elasticity and resilience among all the groups. In intestinal histology, the villus height and the villus width of 30 and 40 g/kg NaCl groups were significantly lower than those of the control, and the supplementation of NaCl significantly increased the muscular thickness. In conclusion, the supplementation of NaCl (10-40 g/kg) in diet did not improve the growth performance and flesh quality of C. idella.