Crude glycerin in feed for Colossoma macropomum fish: evaluation of histopathological effects on the liver and kidney

The present study aimed to verify whether the use of crude glycerin in the diet of juvenile Colossoma macropomum could promote histopathological changes in the liver and kidneys. 150 juveniles were used, divided into 15 tanks of 1000 liters (five treatments and three repetitions, n = 10). Five different diets with inclusion of crude glycerin (0%; 7.5%; 10%; 12.5%; 15%) were used in exchange for soybean oil and partial replacement of corn bran. The animals were fed to satiation for 60 days. After this period, liver and kidney samples from each group were submitted to histological processing and histopathological analysis. The semi-quantitative method was used to assess the lesions: calculation of Mean Alteration Values (MVA), which assess the occurrence of the lesion, and the Histopathological Alterations Index (HAI), which allows assessing the severity of the lesions. The results indicated significant non-harmful effects, but adaptive responses to the diet. In conclusion, the inclusion of up to 15% crude glycerin can be used without causing significant liver and kidney changes in C. macropomum juveniles.