1f:T4e2,Yellow mealworm (Tenebrio molitor) larvae are a potential alternative animal protein source for sustainable aquaculture. However, reports on the successful complete substitution of fish meal with yellow mealworm larvae in an aquaculture diet have been limited. In this study, we conducted a feeding trial with red seabream (Pagrus major) being fed diets with partial or complete replacement of fish meal with yellow mealworm larvae defatted with a hexane⁻ethanol solution. Feed intake in red seabream increased in accordance with yellow mealworm larvae inclusion, and diets including 65% defatted mealworm larvae (complete replacement of fish meal) showed significant growth promotion. The addition of the oil fraction from mealworm larvae to diets resulted in growth reduction, despite meeting the nutritional requirements of red seabream. Moreover, the survival rate of red seabreams fed diets with partial replacement of fish meal with mealworm larvae was significantly higher in a challenge test with pathogenic Edwardsiella tarda bacteria. The present study demonstrated that yellow mealworm larvae are not merely an alternative animal protein, but have potential as functional feed ingredients for aquaculture production.20:T54f,Insect meals are good candidates to replace fishmeal as new protein sources in aquafeeds. This study evaluated the effects of fishmeal replacement with different dietary inclusion levels of a partially defatted Tenebrio molitor (L.) larva meal (TM) on rainbow trout (Oncorhynchus mykiss Walbaum) growth, diet digestibility, and hepatic intermediary metabolism. A 154-day growth trial was performed with 252 rainbow trout (78.3 ± 6.24 g) randomly divided into twelve tanks and fed four experimental diets containing increasing levels of TM: 0% (TM0), 25% (TM25), 50% (TM50), and 100% (TM100) of fishmeal substitution, corresponding to TM dietary inclusion levels of 0%, 5%, 10%, and 20%, respectively. A digestibility trial was performed feeding 180 rainbow trout (94.6 ± 7.31 g) with the experimental diets used in the growth trial. The growth parameters were not affected by TM dietary inclusion. Regarding the evaluated apparent digestibility coefficients (ADC), only the ADC of crude protein was affected, showing the following trend: TM0 = TM25 > TM50 > TM100. The activities of key hepatic amino acid catabolic and lipogenic enzymes were not affected by the dietary composition. The results suggest that a partially defatted TM could totally replace fishmeal in commercial rainbow trout diets without negative effects on fish performance.

	Year	Citations

References