Effects of pond culture and lake culture on fish quality of Megalobrama amblycephala "Huahai No.1"

In order to explore the quality differences of the new variety "Huahai No.1" Megalobrama amblycephala cultured in different modes, this study took "Huahai No.1" M. amblycephala with different culture modes (pond culture and lake culture) as the research object; their appearance and texture were determined by colorimeter and texture analyzer, and their nutritional characteristics and flavor compounds were determined by ultra performance liquid chromatography (UPLC) or gas chromatography-mass spectrometry (GC-MS). The results showed that the brightness, whitenes as well as the springiness, chewiness and resilience of flesh in M. amblycephala cultured in lake mode were significantly higher than those of those cultured in pond mode, and the muscle moisture content of the lake group was higher and the crude fat content was lower. The EAA/TAA and EAA/NEAA ratios of fish in pond group and lake group were 0.41, 0.82 and 0.38, 0.72, respectively, which were in line with the ideal essential amino acid composition recommended by FAO/WHO. Although the index of essential amino acids in the pond group were higher than that in the lake group, only lysine content in the essential amino acids as significantly higher than that in the lake group, while the contents of non-essential amino acids and semi-essential amino acids of fish in the lake group were 1.05 times and 1.01 times that in the pond group, respectively. The total fatty acid content in the lake group decreased by 21.09%, and the proportion of polyunsaturated fatty acids increased by 4.00%, among which EPA and DHA content were 14.20 times and 7.51 times those in the pond group, and the nutrition of the fish in the lake group was more balanced. The TAV values of glutamic acid and alanine in pond group were greater than 1, while that of lysine in lake group was greater than 1, but the total proportion of fresh and sweet amino acids in fish in lake group was higher, and the total proportion of bitter amino acids was lower, and the contents of umami-presenting AMP and IMP in lake group were 1.24 times and 1.54 times those in pond group, while Hx and HxR in bitter taste were only 62.74% and 44.53% of those in pond group. Combined with sensory evaluation, the interaction of flavor substances made the lake group fish fresh and sweet, and the content and ROAV value of volatile compounds such as (Z)-cis-4-hepten-1-al and 1- hexanol which negatively affect the odor in fish meat of lake group were lower, and the odor quality was better. In sensory evaluation, the scores of texture, color, taste and smell were significantly higher in lake group, which was consistent with the above results. The above results indicate that the material quality, nutritional quality and flavor quality of M. amblycephala in the lake culture mode are better than those in the pond culture mode, which can be promoted as a better culture mode.This study provides a theoretical basis for selecting the appropriate culture mode to improve the muscle quality of "Huahai No.1" M. amblycephala.