SELENIUM SOURCES AND SELENIUM LEVELS ON GROWTH PERFORMANCE AND MUSCLE QUALITY OF JUVENILE HYBRID CULTER “XIANFENG NO. 1”

To investigate the effects of sodium selenite and selenium yeast supplementation on growth performance and muscle quality of juvenile hybrid culter “Xianfeng No. 1” (Erythroculter ilishaeformis × Ancherythroculter nigrocauda), a basal diet (C0) was supplemented with 0.3, 0.6, and 1.2 mg/kg selenium from sodium selenite (groups S1, S2, S3) or selenium yeast (groups Y1, Y2, Y3). A total of 420 juvenile hybrid F₁ initial body weight: (59.62±0.53) g were randomly allocated into seven groups (three replicates per group) and fed experimental diets for 8 weeks. The results showed that the sodium selenite group S3 (1.2 mg/kg) and selenium yeast group Y2 (0.6 mg/kg) achieved the highest weight gain rate (WGR) and specific growth rate (SGR). Y2 exhibited significantly higher final body weight, WGR, and SGR compared to the control (C0) and S2 groups (P<0.05). Selenium yeast significantly enhanced muscle selenium deposition (P<0.05), with Y2showing the highest crude protein content (20.00%). Neither selenium source affected crude fat content (P>0.05). Muscle elasticity, cohesiveness, and resilience increased with selenium levels (P<0.05). Selenium yeast groups demonstrated superior hardness, adhesiveness, and gumminess (P<0.05), while Y2 and Y3 exhibited higher chewiness than sodium selenite groups (P<0.05). Serum aspartate aminotransferase (AST) in S3 and Y2, and alkaline phosphatase (ALP) in Y2 were significantly lower than that in C0 (P<0.05). Total cholesterol (T-CHO) decreased in S3, Y1, Y2, and Y3 compared to C0 (P<0.05). No significant differences in muscle amino acids were observed between selenium sources, though Y2showed a higher EAA/TAA than C0, S2, and Y3 (P<0.05). Y2 exhibited significantly elevated n-3 PUFA content (P<0.05), while Y1 exhibited higher n-6 PUFA levels (P<0.05). In conclusion, under the experimental conditions of this study, with growth performance and muscle quality as evaluation criteria, it is recommended to add 0.6 mg/kg selenium yeast to the feed of hybrid F₁ feed.