| Summary: | 碩士 === 國立屏東科技大學 === 水產養殖系所 === 104 === The probiotic effects of Bacillus subtilis E20-supplemented diets (control (without probiotics), 108, 109, and 1010 cfu g-1, respectively designated C, E108, E109, and E1010) fed to the grouper, Epinephelus moara, for 56 days were evaluated by tracking the growth performance, non-specific immune responses, and disease resistance against Vibrio alginolyticus. No significant differences in survival of fish were found among groups during the experiment. Growth enhancement was recorded in group E109 after 56 days of probiotic feeding, but the percentage of weight gain and feed efficiency of fish in group E1010 were significantly lower than those of fish in group E109 despite them not significantly differing from the controls. After 56 days of feeding, compositions of the dorsal muscle did not significantly differ among groups. For the pathogen challenge test, grouper fed the E109 and E1010 diets containing B. subtilis had significantly lower cumulative mortalities compared to those of fish fed the C and E108 diets. The lower cumulative mortalities of grouper in groups E109 and E1010 after being injected with the potential pathogen, V. alginolyticus, might have been due to increased respiratory bursts and lysozyme activity despite there being no significant change in SOD activity or phagocytic activity recorded after 56 days of probiotic feeding. Therefore, the diet containing 109 cfu g-1 of B. subtilis E20 is recommended to improve E. moara growth and health status.
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