Effects of jackbean seed meal on the intestinal mucosa of juvenile Heterobranchus longifilis

Abstract

Juvenile Heterobranchus longifilis were fed diets that were isonitrogenous (CP 30%) and isocaloric (ME 2900 Kcal/kg) comprising the control diet without jackbean seed meal (JBSM) and those containing raw and 60 min boiled JBSM at different inclusion levels. At the conclusion of the 56 days feeding study, histological examination of the intestinal mucosa of H. longifilis indicated that those fed the control diet remained normal. However, progressive damage to the epithelial mucosa of H. logifilis intestines was observed with increasing dietary level of JBSM. While fish fed diets with 10% fishmeal substituted by raw JBSM showed minor degeneration of the intestinal mucosa, those fed with 100% fishmeal substituted by raw JBSM showed severe damage. Boiling JBSM however moderated the adverse effect of high dietary JBSM since fish fed diet with 80% fishmeal substituted by boiled JBSM showed only early signs of mucosal degeneration. The findings suggest that boiled JBSM could be used to substantially replace fishmeal in fish diets with no negative effect on fish intestinal mucosa. This development impacts positively on fish production by reducing the cost of fish feed given the comparatively lower cost of JBSM with respect to fishmeal