Analysis of the growth performances, muscle quality, blood biochemistry and antioxidant status of Micropterus salmoides farmed in in-pond raceway systems versus usual-pond systems

Abstract In-pond raceway system (IPRS) was introduced to China as a sustainable pond farming approach since 2012 that effectively reduces pollution and facilitates management. To assess how IPRS affect the growth and quality of the farmed fish Micropterus salmoides , various rearing parameters were compared to the usual-pond system (UPS). The growth performances, muscle nutritional quality, serum biochemical indexes, antioxidant enzymatic activities and genes expression were analyzed in Micropterus salmoides with body weight of (8.25 ± 0.51) g reared in IPRS versus usual-pond system(UPS) at stocking densities of 37,500 ind./ha with triplication for 240 days. The final body weight of M. salmoides reared in IPRS and UPS was 482.52 ± 22.53 g and 539.51 ± 34.91 g. Survival rates were higher, despite lower weight gain, in IPRS compared to UPS, with no significant differences in specific growth rate or the food conversion ratio. The hepatosomatic index, viscerosomatic index, and lipid content in liver was lower in IPTS compared to URS. Crude fat and crude protein content significantly differed in muscle. EAA/TAA and EAA/NEAA in the muscle was higher in fish reared in IPRS compared to UPS. Saturated fatty acids in the muscle was lower in fish reared in IPRS compared to UPS. IPRS fish had lower percentages of monounsaturated fatty acids and polyunsaturated fatty acids, including EPA and DHA, than in IPRS.Total protein content was higher in the serum of IPRS fish. Total cholesterol and triglyceride content were lower in IPRS fish. Total bilirubin content and alanine aminotransferase activity was lower in IPRS fish. Glutathione peroxidase activity was higher, while malondialdehyde content was lower, in the liver of IPRS fish. Superoxide dismutase and catalase activity did not differ between the two conditions. mRNA expression of gpx and hsp70 was significantly up-regulated in IPRS compared to UPS. The result show, compared to UPS, IPRS can improve the survival rates, nutritional quality of fish muscle, and liver biological functioning and antioxidant ability of the target fish.