The influence of dietary supplementation of cinnamaldehyde and thymol on the growth performance, immunity and antioxidant status of monosex Nile tilapia fingerlings (Oreochromis niloticus)

This study investigated the effects of two essential oils (Eos), cinnamaldehyde and thymol on the growth performance, antioxidant status of the meat and the immunity of Nile tilapia fingerlings, Oreochromis niloticus . A total of 375 O. niloticus (10.2 ± 0.06 g) were randomly assigned to 5 dietary treatments (3 replicates for each). Diet 1 was the control with no additives. Diets 2 and 3 were supplemented with 1 and 2 ml cinnamaldehyde /kg diet (CINN1 or CINN2), respectively. While diets 4 and 5 were supplemented with 1 and 2 ml thymol /kg diet (THYM1 or THYM2), respectively. Fish feeding was done by hand until satiation 3 times daily for 75 days. The results showed that dietary supplementation with 1 ml thymol/ kg diet increased the growth performance significantly than other groups. Dietary supplementation with cinnamaldehyde or thymol significantly reduced (P ≤ 0.05) the malondialdehyde (MDA) formation and increased glutathione reductase (GR) in the muscle, and increased lysozyme activity, IgM, IgG levels and catalase activity in the serum thus improved the antioxidant protective capacities and the immune status of the fish. Furthermore, thymol supplementation can stimulate more growth and immune responses than cinnamaldehyde as essential oils in Nile tilapia nutrition.