Assessment of organosomatic indices and histopathological changes in vital organs of <i>Clarias gariepinus</i> juveniles fed graded levels of boiled sunflower (<i>Helianthus annuus</i>) seed meal

Abstract

This study investigated the effects of substituting boiled sunflower seed meal (BSSM) for soybean meal (SBM) on the organosomatic indices and histopathological changes in the liver, kidney and intestine of Clarias gariepinus juveniles for fifteen weeks. BSSM was substituted for SBM at 0, 20, 40, 60, 80 and 100% in formulating six isonitrogenous (40% crude protein) and isocaloric (4651.5 Kcal/kg) diets. Diets were fed twice daily to triplicate groups of 360 C. gariepinus juveniles inside eighteen rectangular tanks (20 fish per tank). The result showed that hepatosomatic index (HSI) was significantly highest (3.11%) in the fish fed 0% BSSM diet and lowest (0.87%) in those fed 100% BSSM inclusion. HSI values progressively decreased with increasing inclusion level of BSSM. Kidney-somatic index (KSI) was highest (0.74%) in fish fed 20% BSSM inclusion and least (0.32%) in those fed 100% inclusion. Intestino-somatic index (ISI) was superior (3.82%) in fish fed 100% BSSM inclusion and least (3.16%) in those fed 40%. The liver, kidney and intestine of fish fed 0 and 20% BSSM inclusions showed no visible signs of damage. However, fish fed higher BSSM inclusions (>20%) revealed extensive hepatic degeneration, periportal congestions and severe diffuse cytoplasmic vacuolations of hepatocytes. Kidney tubules of fish fed higher BSSM inclusions exhibited diffuse interstitial congestions, diffuse swelling, epithelial vacuolations and degeneration as well as necrosis. Intestinal changes in fish fed higher BSSM inclusions included reduced sub-mucosal width, markedly stunted villi, moderate erosion of villi's epithelia, hyperplastic villi, necrosis of enterocytes and inflammatory cells in villi's lamina propria. Inclusion of boiled sunflower seed meal beyond 20% in C. gariepinus' diet could cause adverse histological alterations.

Keywords: Clarias gariepinus, Sunflower seed meal, Histopathology, Hepatosomatic index, Anti-nutrients