Fish meal replacement with poultry byproduct and black soldier fly larvae proteins: effects on growth, flesh quality, bioactivity, and physiological responses of Nile tilapia

The demand for fishmeal is increasing, but its supply is stagnating or even declining. There is an urgent need to find an eco-friendly and cost-effective alternative protein source. This study evaluated poultry by-product and insect meal as alternatives to fishmeal for the health performance and bioactivity of Nile tilapia. A Nile tilapia fry was divided into four groups with three replicates (No = 168). The first group was fed a basal diet containing 20% fishmeal (T FM ). The second, third, and fourth groups received a basal diet where the fishmeal was substituted with poultry by-product meal (T PM ), insect meal from Hermetia illucens (T IM ), and a mixture of poultry by-product and insect meal (T MIX ), respectively. The overall growth performance data indicated that T FM and T IM significantly achieved the highest growth rates and feed utilization ( P < 0.05). The T IM diet significantly exhibited the highest total phenolic content, and both T IM and T FM showed superior antioxidant activity in fish muscle. There were no abnormal hematological or serum biochemical parameters observed in Nile tilapia fed insect meal and/or poultry by-product. The fish fillet samples from all groups were microbiologically safe for human consumption. Fish fed T IM displayed the lowest levels of TNF-α and the highest levels of IL-10 ( P < 0.05). All the groups exhibited normal architecture of the internal organs. The significantly highest recorded absorption surface area was found in both T FM and T IM diets ( P < 0.05). The NF-κB immunostaining showed no significant changes among experimental groups ( P > 0.05). Based on this study, it can be suggested that the insect meal can be a sustainable and cost-effective substitute for conventional fishmeal in aquaculture feed formulations.