DIFFERENT CULTURE MODES ON GROWTH, SERUM BIOCHEMICAL INDEXES AND MUSCLE NUTRIENT OF YOUNG SALMO TRUTTA

To explore the diversified culture mode of Salmon trutta, a study was conducted to compare the growth performance, serum biochemical indexes, and muscle nutrient composition between recirculating water and open water culture modes with an initial body mass of juvenile S. trutta (100.05±1.12) g for 180d. The results showed that weight gain rate, fatness, liver body index, specific growth rate, and feed conversion rate were significantly higher in open flow water mode than in recirculating water mode (P<0.05), but there was no significant difference in survival rate between them (P >0.05). Meanwhile, complement C4, total protein, and growth hormone were significantly lower in the circulating water mode than in the open running water mode (P<0.05), but the opposite was true for lysozyme, ghrelin, and glutamate (P<0.05), while complement C3, alkaline phosphatase, acid phosphatase, and globulin were not significantly different between the two modes (P>0.05). In addition, the crude protein and crude fat contents of the main muscle nutrients were higher in the open running water mode than in the circulating water mode, the amino acid composition was not significantly different between the two (P>0.05), and the fatty acid contents of oleic acid, α-linolenic acid, C20﹕1, C20﹕2, and MUFA were significantly lower than in the open running water (P<0.05), while the contents of EPA+DHA, SAFA, and PUFA were significantly different (P<0.05). Furthermore, mineral magnesium content was significantly higher in the recycled water model than in the open running water model (P<0.05), calcium content was the opposite (P<0.05), and the differences in zinc, iron, and selenium content were not significant (P>0.05). In conclusion, the circulating water culture mode of S. trutta in Tibet can make full use of the abundant local solar and geothermal resources or rely on the greenhouse for water temperature control, while further optimizing the micro-ecological purification capacity of the water body to make its growth conditions more similar to the open water culture environment, thus improving the efficiency of S. trutta culture and ensuring the nutritional quality.