Use of mealworms (Tenebrio molitor) larvae meal in Nile tilapia (Oreochromis niloticus) diets

In this study, the effects of using Tenebrio molitor larva meal (%0-TM0, %50-TM50, %75-TM75 and %100-TM100) at different rates in the feeding of Nile tilapia (Oreochromis niloticus) fry on growth performance, feed conversion ratios, biochemical and fatty acid composition and digestive enzymes were investigated. Fish with an average weight of 3.57±0.02 g were fed with the prepared experimental diets for 12 weeks. The highest average live weight was obtained in the TM75 group (21.94±0.35 g). The best feed conversion ratio and specific growth rate were determined in the TM75 group (1.21±0.02 and 2.60±0.01g/day) (p<0.05). HSI and VSI values did not differ between the groups (p>0.05). In biochemical analyses, the moisture content of the TM0 group was found to be the highest (p<0.05), the protein content decreased depending on the TM content, and the crude fat and ash ratios did not change. The fatty acid composition of the fish reflected the feed content; SFA ratio was found to be low and PUFA ratio was found to be high in TM containing groups. Especially EPA, DHA, arachidonic and linoleic acid levels were higher in TM groups. In amino acid analysis, TAA, TEAA and TNEAA values were determined to be higher in TM0 and TM100 groups and significantly lower in TM50 and TM75. In digestive enzyme analyses, alpha-amylase activity increased as TM ratio increased, lipase in TM75 group, pepsin in TM50 group and trypsin activity in TM0-TM100 groups were found to be at the highest values. In conclusion, the use of Tenebrio molitor larva meal instead of fish meal up to 75% in Nile tilapia diets did not have any negative effects on growth and digestion. KEYWORDS: Nile tilapia (Oreochromis niloticus), mealworm, growth, enzyme activities