Aquaculture is crucial for global food and nutrition security but relies on unsustainable inputs like fishmeal and soybean meal. Global fishmeal production is declining due to overexploitation and climate change impacts, while soybean meal faces food-feed competition, making the cost of these commodities increasingly high. Insect meals, especially from black soldier fly larvae, provide a sustainable alternative with high protein content and low environmental impact. T his study investigated the effects of BSF meal on growth, feed utilization , and intestinal health of mirror carp (Cyprinus carpio) juveniles.
An 8-week feeding trial was conducted with C. carpio (initial body weight: 6.44 ± 0.05 g) in tanks (13 L, each) in a Recirculatory Aquaculture System (RAS). Three isonitrogenous and isolipidic diets were prepared based on the known nutritional requirement of carp to contain 0 % (Control: BSF0), 20 % (BSF20), and 40 % (BSF40) defatted black soldier fly larvae (BSF) meal (Table 1). The fish were divided into 3 groups of 20 juvenile fish in triplicate tanks and were fed the diets at 4 % biomass. After the trial, final body weight (FBW), weight gain (WG), specific growth rate (SGR), and protein efficiency ratio were improved while feed conversion ratio (FCR) was lowered significantly with increasing BSF meal in the diet compared with the control diet (Table 2) .
Ongoing analyses include investigation of fish carcass composition, chitinase enzyme activity, intestinal histology applying both light and electron microscopy, expression of immune-related genes, and intestinal microbiota. These analyses aim to provide deeper insights into the effect of BSF meal on the fish.
This study, therefore, suggests that BSF meal can be used as an alternative protein source in the diets of C. carpio juveniles to promote growth performance and feed utilization.