Histopathological analysis of Colossoma macropomum liver, treated with bioproducts used by controlling parasites

Possible histological changes in the liver of Colossoma macropomum Cuvier, 1816 (tambaqui) generated by the use of products incorporated into the diet as a control method of Neoechinorhynchus buttnerae Golvan, 1956 were evaluated. 1036 juveniles tambaqui with 77±3.0g of average weight were used, maintained in 28 polyethylene tanks of 1000L, with constant aeration and water recirculation system, using UV filter. The experimental units (30 fish per experimental unit) were distributed into four treatments, with seven replicates. The products, incorporated in fish oil, were added to the feed, according to the treatments: control group with commercial feed (Nutrizon Karino 36% GW) (A); extract of garlic (B); organic acids (C) and extract of garlic + organic acids (D). A parasitic and histopathological evaluation was performed at time zero (T0). During the experiment, two samples were collected, with an interval of five weeks, evaluating 15 fish per experimental unit. At the end, 63 liver samples for histological analysis were collected. The evaluated animals presented the expected growth for the species. 87.2% of efficacy was obtained with the association extract of garlic + organic acids. Hepatic morphological lesions compatible with toxicological processes were not observed, indicating a low toxicity for tested concentrations.