Cachama negra (C. macropomum) is one of the most important aquaculture species in South America. In recent years, the use of feed additives based on natural products has been highlighted for their positive effects on aquatic organisms, particularly in modulating the immune response and promoting better growth performance. This underscores the potential of these additives in the diet of economically important aquaculture fish. In this study, we investigated the growth performance of cachama negra fed with additive feed containing 3% powdered extracts of garlic (Allium sativum), mint (Mentha piperita), and oregano (Origanum vulgare).
A total of 220 juvenile cachama negra with an average weight of (18.2 g ± 3.2 g) were allocated in 20 tanks with a randomized design containing 4 treatments and 5 replicates. The experimental diets consisted of commercial feed with inclusion of commercial powder extract (30 g/kg of feed) of each plant used. For each treatment, 10 kg of commercial feed were finely ground, and 300 g of extract were added to the mass at the respective inclusion level of the treatments (3%), except in the control diet. The ready-made feeds were provided twice a day (4% of the biomass), and the parameters evaluated were relative growth rate (RGR), feed conversion rate (FCR) and weight gain (WG) at intervals of 20, 40 and 60 days of feeding.
The results after 20 and 40 days of supplementation indicated no statistical difference compared to the control. However, after 60 days of feeding, we observed that feed conversion rate (FCR) was significantly lower in the group of fish fed a diet containing oregano, when compared to the control (p < 0.05). Therefore, our results highlight the use of oregano extract as a feed additive, as it directly improves the feed conversion of fish, positively impacting the production of cachama negra.