Dietary Machilus thunbergii Supplementation Influences Growth Performance and Physiological Responses in Penaeus vannamei

초록

This study aimed to investigate the effects of dietary supplementation with Machilus thunbergii (MT), a natural coastal plant resource, on the growth performance, feed utilization, innate immune response, antioxidant status, and resistance to Vibrio parahaemolyticus causing acute hepatopancreatic necrosis disease (AHPND) of Penaeus vannamei. Experimental diets containing 0.0%, 0.5%, and 1.0% MT extract powder (designated as MT0.0, MT0.5, and MT1.0, respectively) were formulated. After the 5-week feeding trial, shrimp fed the MT0.5 diet showed significantly higher final body weight, weight gain, and protein efficiency ratio, along with a lower feed conversion ratio, than shrimp fed the MT0.0 diet. The activities of lysozyme, superoxide dismutase, and glutathione peroxidase, along with the expression of crustin and penaeidin-3a, were significantly higher in shrimp fed the MT0.5 diet, suggesting modulation of innate immune and antioxidant responses. During the AHPND challenge test, no significant differences in final survival were observed among the dietary treatments; however, shrimp fed the MT1.0 diet showed a tendency toward higher survival. Histopathological analysis also indicated partial restoration of hepatopancreatic tissue structure in the MT0.5 and MT1.0 groups at 150 h post-infection. To our knowledge, limited information is available regarding the dietary application of MT in shrimp aquaculture. The present findings suggest that MT supplementation may influence growth performance, immune responses, and antioxidant status of P. vannamei, suggesting its potential application as a phytogenic feed additive.

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