Effect of Aloysia triphylla essential oil on the productive performance and digestive tract histology of juvenile Apistogramma cacatuoides

The objective of this study was to evaluate different concentrations of Aloysia triphylla essential oil (ATEO) on the productive performance of juvenile Apistogramma cacatuoides, as well as on liver morphology and intestinal villi morphometry. The experiment followed a completely randomized design with four treatments (0, 3, 6, or 9 g of ATEO per kg of feed), each with four replicates. A total of 80 juvenile A. cacatuoides (average weight of 28.4 ± 14.5 mg) was fed twice daily over a period of 45 days. At the end of the experimental period, final survival rates were determined, and the fish were measured to assess zootechnical performance. Additionally, eight juveniles per treatment were processed histologically to evaluate liver and intestinal tissues. The results showed that the use of ATEO in the feed did not result in statistically significant differences in growth or survival. However, juveniles that received feed containing 6 and 9 g*kg-1 of ATEO exhibited higher averages in the intestinal morphometry parameters evaluated, with no liver damage. These findings highlight the potential of ATEO in the production of this species. Further studies with extended periods of administration and elevated oil concentrations are recommended, as well as research to evaluate its immunostimulant effects on fish.