Comparative analysis of growth, nutrition and serum biochemical indexes of Scylla paramamosain under different feeding conditions in saline-alkali pond

In order to explore the effects of feeding different diets on pond water quality, growth, nutritional quality and serum biochemical indexes of Scylla paramamosain in saline-alkali water pond, this experiment was set up with three biological bait groups and one artificial compound feed group, namely, Mactra chinenesis, Synechogobius hasta and Trachypenaeus curvirostris. Three replicates were set in each group, and the experimental period was 4 months. The changes of pond water quality in each group were analyzed, and the growth, nutrition and serum biochemical indexes of crabs in each group were compared by One-Way ANOVA. The results show the following. The differences of water temperature, salinity and pH in each group were small, but the differences of dissolved oxygen, ammonia nitrogen and nitrite nitrogen were large. Among them, dissolved oxygen in the S. hasta group decreased from 11.5 to 9.2 mg/L, while ammonia nitrogen and nitrite nitrogen increased from 0.44 mg/L and 0.022 mg/L at the beginning of culture to 0.89 mg/L and 0.050 mg/L at the end of culture, respectively. The crab weight (334 g), weight gain rate (332.7%) and specific growth rate (0.076%/d) were significantly higher in the M. chinenesis group than in the other groups. The survival rate of artificial compound feed group was the highest, reaching 66.67%. The fatness (0.221 g/cm³) in the group of S. hasta was significantly higher than that in other groups. The content of valine, methionine, isoleucine and phenylalanine in the essential amino acids of crab muscles and the total hepatopancreas taste-presenting amino acids and total fresh taste amino acids in the M. chinenesis group were the highest among all groups. The contents of threonine, leucine, lysine and histidine in the essential amino acids of hepatopancreas in the artificial diet group were the highest among the three groups. The total amount of savory amino acids and umami amino acids in muscle of T. curvirostris group were the highest among all groups. The contents of saturated fatty acids, polyunsaturated fatty acids and fatty acids in muscle and hepatopancreas were the highest in the M. chinenesis group. The total protein content in the M. chinenesis group was significantly higher than that in other groups. The total cholesterol in the S. hasta group was significantly higher than that in other groups. The aspartate aminotransferase, triglyceride and glucose in the artificial compound feed group were significantly higher than those in other groups. Correlation analysis showed that there was a significant positive correlation between the routine nutrients of biological diets such as M. chinenesis and the growth indexes of S. paramamosain. The results of the study showed that the M. chinenesis group had significant advantages in growth, nutrition and serum protein indexes, which could be used as palatable diet for breeding S. paramamosain in saline-alkali ponds. This study provides data reference for the cultivation and popularization of S. paramamosain in saline-alkali water ponds in northern China.