Effect of partial and complete replacement of soybean with discarded cashew nut (Anacardium occidentale L) on liver and stomach histology of Clarias gariepinus (Burchell, 1822)

Abstract

The need for replacement of highly priced soybean meal (SM) in fish diets with unconventional plant materials has become imperative for the sustainability of aquaculture production. This study addressed the effect of replacing SM with discarded cashew nut meal (DCNM) on the liver and stomach histology in African catfish (Clarias gariepinus). Total 90 juveniles (24.83 ± 1.52 g) were fed DCNM based diets, inclusion level of 0, 50% and 100%. Fish were fed twice daily (8:00 a.m.–4:00 p.m.) at 5% body weight for 56 days. The histology of liver and the stomach were assessed. Histo-morphological changes of the liver tissue were moderate at 100% DCNM fed fish compared to 50% DCNM and control (0 DCNM). Photomicrograph of stomach of 50% DCNM fed fish showed normal histo-morphological features, while moderate to severe histological distortions were observed in the stomach of 100% DCNM fed fish. The findings of the present study showed that partial (50%) replacement of SM with DCNM had no adverse nutritional consequence while total (100%) replacement of SM with DCNM in the diet of C. gariepinus resulted to moderate histological distortions of the liver and stomach. Keywords: African catfish, Discarded cashew nut meal, Alternative protein source, Histology, Liver, Stomach