Dietary full-fat Stinkbug ( Encosternum delegorguei ) meal effects on growth performance, blood chemistry, liver and intestinal histology of juvenile Mozambique tilapia ( Oreochromis mossambicus )

The main objective in this study was to evaluate full-fat Stinkbug as an alternative protein source in the diet of Oreochromis mossambicus. Five diets were formulated to partially replace fishmeal at 0, 10, 30, 50, and 70% levels and were denoted as D1, D2, D3, D4, and D5, respectively. The diets were formulated to be isonitrogenous, isocaloric, and isolipidic. Each diet was fed to triplicate groups of fish for 8 weeks. All growth performance indices declined with an increase in Stinkbug meal inclusion. The specific growth rate declined from 2.16% in the control to 1.28% in D5 (P < 0.05). The thermal-unit growth coefficient declined from 1.30 in the control to 0.72 in diet D5 (P < 0.05). The protein efficiency ratio declined from 2.95 in the control to 1.66 in D5 (P < 0.05). However, organosomatic indices did not differ across the fish diets. The aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities did not differ significantly (P > 0.05) across diets D1 to D4. No histological alterations were evident in the liver and intestine across diets. It was therefore concluded that Stinkbug meal may partially replace fishmeal at 30% replacement level in the diet of O. mossambicus without adverse effects on growth performance and nutrient utilisation indices.