– Reducing the use of fishmeal (FM) in shrimp feed means significant savings in the amount of FM
consumed globally and subsequently reducing production costs and environmental impacts. Insect meal (IM) is
one of the protein sources to replace FM in aquafeeds. In this regard, this study was conducted with the aim of
investigating the effect of replacing FM with mealworm (MW, Tenebrio molitor) on the growth performance,
haemolymph biochemical responses, and innate immunity of Litopenaeus vannamei. Shrimps with a mean
weight of 7.41 ± 0.13 gram were cultured in 300-liter fiberglass tanks (with a useful drainage volume of 200
liters) with a density of 20 shrimp per tank over a period of 60 days. Dietary treatments, including the control
treatment (no mealworm; T0), 15% (T15), 30% (T30), 60% (T60), and 100% (T100) level of replacing FM with
mealworm (MW), each with three replications, were investigated in the form of a randomized design. The
results of this study showed a significant difference in body weight gain (BWG), feed efficiency (FE), feed
conversion ratio (FCR), and hepatopancreas index (HPI) among the treatments (P < 0.05). With the increase of
the replacement of FM with MW up to 30%, BWG, FE, and HPI were significantly increased then reduced. The
levels of cholesterol (Chol), triglycerides (Tg), and glucose (Glu) showed a decreasing trend with increasing
replacement of FM with MW and revealed a significant difference with the control treatment at high levels of
replacement (P < 0.05). Besides, the results showed that replacing FM with MW had a significant effect on the
activities of superoxidase dismutase (SOD), phenol oxidase (PO), lysozyme (LZM), acid phosphatase (ACP),
alkaline phosphatase (ALP) and the total count of hemocytes (THC) in the practical diets compared to the
control group (P < 0.05). Overall, the findings suggest that MW is a promising alternative protein source for
L. vannamei, as it enhances both growth performance and the immune system. The study recommends the use of
MW in the diet of farmed species in the aquaculture industry, given its lack of adverse impacts on growth
performance and its potential to reduce environmental consequences resulting from its production. The results
also underscore the importance of exploring alternative protein sources to reduce dependence on FM and
enhance sustainability in the aquaculture industry.