Dietary Thymol Supplementation to Improve Growth in Common Carp (Cyprinus carpio) and Tambaqui (Colossoma macropomum)
Common carp (Cyprinus carpio) and tambaqui (Colossoma macropomum) are the fish that are commonly farmed in Indonesia. The advancement of improved feeding practices is crucial for the sustainable production of both common carp and tambaqui, leading to better growth performance. This research was conducted to enhance growth performance and improve feed utilization efficiency by using thymol as a feed additive. For common carp, thymol was supplemented at a dose of 0, 0.1, 0.2, 0.4, or 0.8 g/kg commercial feed. While thymol was added to the tambaqui feed formulation at doses of 0.0, 0.2, 0.4, or 0.6 g/kg. Common carp with an initial weight of 3.23±0.00 g were reared in net enclosures for 60 days, while tambaqui weighing 8.22±0.01 g were kept in aquariums for 70 days. The study found that supplementing carp feed with 0.4 g/kg thymol led to the highest growth performance. Meanwhile, feeding tambaqui with thymol at 0.6 g/ kg resulted in significant improvements in growth-related parameters compared to other treatments, including final total biomass, final average weight, protein efficiency ratio, specific growth rate, and antioxidant status. In conclusion, the optimal thymol supplementation levels were found to be 0.4 g/kg for carp and 0.6 g/kg for tambaqui.