Increasing industrialization or production of large amounts of fructose (FRU) consumed in syrup, foods, and vegetables culminates a food chain problem including aquatic toxicity. Thus, this study investigated the potential modulatory role of L-arginine (L-ARG) supplementation, a protein biosynthesis amino acid, during FRU feeding in juvenile African catfish (JAC). Using standard methods of probit analyses, fresh FRU solution was prepared 24 hours a day and introduced to the aquaria containing dechlorinated tap water (pH 6.7-7.1). Oral acute toxicity of FRU was done by the adding 0, 0.5, 1.3, 5, 10 and 15 g of FRU per liter of water to each of the fish groups (n = 10) respectively daily for 96 hours. Signs of toxicity, behavioral changes, food consumption, movement abnormality, and morphological changes were recorded. The lethal dosage was calculated by studying the mortality rate in each pond for 24, 48, 72, and 96 hours respectively. Also, 108 JACs (average weight, 25.4±7.1) were exposed to sublethal (14 days) FRU alone (1/12th and 1/2th lethal concentration, LD50 = 1156.11 mg/kg after 96 hours) or with divided doses of L-ARG (0.05 and 0.2 mg) and assessed for fasting blood glucose, biochemical parameters, insulin level, GLUT-4 level, weight and histology of gills, liver and heart respectively.
FRU (0.1 and 0.5 g) administrations in the JAC diet showed elevated (p< 0.05-0.01) serum blood glucose levels (BGLs) (110.28 mg/dL - 147.09 mg/dL versus control (94.1 mg/dL), 1.2 - 1.6 folds), aspartate aminotransferase (266.27 - 297.07 IU/L versus control 147.53 IU/L, 2 folds), and total cholesterol (1.17 - 1.69 IU/L versus 1.09 IU/L, 1.1 - 1.6 folds) levels. This was accompanied by increased insulin (41.53 - 59.48 ng/mL versus control 34.74 ng/mL) and decreased GLUT-4 protein (0.118 - 0.510 ng/mL versus control 0.175 ng/mL) levels in the JAC groups. Also, FRU-fed JAC demonstrated elevated malondialdehyde plus lowered antioxidants reduced glutathione levels as well as activities of superoxide dismutase and catalase. FRU intoxication increased gill (1.23 - 1.72 versus control 1.15 g) and liver (1.32 - 1.38 g versus control 1.03 g) weights and also decreased the body weight (2 folds). The addition of L-ARG improved antioxidants status and lowered hyperinsulinemia. However, L-ARG supplementations appear to modulate the changes observed in BGLs, liver biomarkers, lipids, GLUT-4 protein as well as necrotic damage of the gill. Bioaccumulation of FRU in the fish may contribute to metabolic disorders including type-2 diabetes symptoms and other cardiovascular risk factors which may require public health intervention. Although, a high FRU level can cause damage to aquatic life, however, L-ARG supplementations prove to be beneficial via modulation of the antioxidant defense system and biochemical parameters. Thus, both short-term and long-term tests are essential to evaluate the toxicity of sugar effluents to aquatic organisms using the One Health approach in order to ascertain the production of healthy fish for healthy people.