Abstract
Monoterpenoids are interesting hydrocarbons typically found in essential oils and have a significant role in medicinal and biological purposes. The goal of this study was to investigate the effects of two monoterpenoids, carvacrol (CAR) and menthol (MEN), supplemented with Moringa oleifera leaf meal (MOLM) based diets on growth parameters, digestibility and body composition of Nile tilapia (Oreochromis niloticus). Alongside the basal diet (control-T1), nine experimental diets supplemented with categorized levels of CAR and MEN at 200, 300 and 400 mg/kg individually and their mixtures (MIX) (1:1) (CAR-T2, 200; T3, 300; T4, 400 mg/kg, MEN-T5, 200; T6, 300; T7, 400 mg/kg and MIX- (1:1) T8, 200; T9, 300; T10, 400 mg/kg) were fed to the fingerlings (6.55 ± 0.03 g) for the period of 60 days. Monoterpenoids supplementation led to significantly (p<0.05) better growth, feed utilization and nutrient digestibility in comparison to the control group. The highest growth, feed efficiency and nutrient digestibility were noticed in fishes fed with a diet supplemented with 200 mg/kg MIX. Interestingly, fishes fed with diets containing monoterpenoids had significantly higher levels of protein and ash, but with lower lipid in comparison to the control group. Conclusively, the dietary supplements like CAR and MEN improved the health status of Nile tilapia when given either individually or in a mixture,. Specifically, the MIX at 200 mg/kg was the optimal supplementation for the fishes.