Evidence of enteritis, hepatic steatosis and jaundice in juvenile pirarucu (Arapaima gigas) fed high levels of soybean meal

This study evaluated the effects of replacing dietary fishmeal with increasing levels of soybean meal (0, 15, 30, 45 and 60% corresponding to 0, 11, 22, 33 and 44% inclusion in the formulated diet) on the intestine and liver histomorphology of juvenile pirarucu Arapaima gigas (233 +/- 12 g; mean +/- SD) fed for 120 days. At the end of the feeding trial, fish fed diets with higher soybean levels (45 and 60%) presented clinical signs such as appetite loss, cachexia and jaundice. In addition, fish fed on 45% and 60% soybean meal had histomorphological alterations in the middle and posterior portions of the intestinal mucosa (enteritis) and high liver lipid deposition (steatosis). Therefore, 45% or 60% of soybean meal is not recommended; however, a replacement of fishmeal by soybean meal of up to 30% (22% inclusion) can be used in diets to feed juvenile pirarucu for long periods.