Inclusion of essential oil from ginger in the diet improves physiological parameters of tambaqui juveniles (Colossoma macropomum)

The aim of this study was to investigate the effect of essential oil of ginger (Zingiber officinale) (EOZO) on the growth performance and hematological, biochemical and histological parameters of tambaqui (Colossoma macropomum) juveniles. The fish were randomly distributed in 20 tanks (15 fish per tank), in five treatments containing different concentrations of EOZO (0.0 (control); 0.50; 1.0; 1.5; and 2.0 mL kg diet-1) for 60 days. The main chemical compounds were zingiberene (31.8%), sesquiphellandrene (13.0%) and ar-curcumene (12.4%). The addition of EOZO to the diet did not improve growth performance. Treatments with the highest levels of EOZO reduced plasma albumin, alanine aminotransferase and aspartate aminotransferase levels and increased leukocytes, hemoglobin and thrombocytes, blood glucose and plasma cholesterol levels. The control group had high villus height, epithelial thickness and goblet cell number in the intestinal villi. Hepatocyte area and the number of hepatocytes with necrosis were higher in fish supplemented with the highest levels of EOZO. To sum up, it seems that the addition of 0.5 mL EOZO kg diet- 1 can improve some physiological parameters (leukocytes, hemoglobin and thrombocytes, and plasma ALT and AST levels) without causing liver damage or negatively affecting the intestinal villi of tambaqui juveniles.