Growth and Muscle Quality of Grass Carp (Ctenopharyngodon idella) in In-Pond Raceway Aquaculture and Traditional Pond Culture

In-pond raceway aquaculture (IPRA) is the rational prescription for water eutrophication and improves the pond environment, enhancing production and the quality of fish. This experiment explored the growth performances and muscle quality of grass carp with stocking densities of 32 tail/m³ and 0.07 tail/m² in IPRA and traditional pond culture (TPC), respectively. The hepatosomatic index, visceral mass ratio, and correction factor were statistically similar in IPRA compared to TPC. While the weight gain rate (p < 0.001) and the content of crude lipid (p < 0.05) in the flesh of grass carp were observed to be statistically promising in IPRA, the pH and water holding capacity, as well as hardness and chewiness, in grass carp muscle were not significantly different between the two culture systems. However, the 2-MIB concentration in the muscle was observed to increase continuously for the complete culture period in IPRA. The abundance of Proteobacteria was found to be higher in TPC (p < 0.05), while the richness of Planctomycetes was superior in IPRA (p < 0.05). Despite the high stocking density, the off-flavor in IPRA-produced grass carp had less of an impact on the flesh aesthetic quality compared to TPC. Considering all these facts, the results of this study show that grass carp with a better muscle quality can be produced from IPRA.