Pereskia aculeata (Ora-pro-nobis) as an alternative protein source and metabolic modulator: Effects on growth, metabolism, and antioxidant status in tilapia

This study aimed to evaluate the inclusion of ora-pro-nobis (OPN) flour in tilapia diets (0%, 5%, 10%, and 15%) and its influence on zootechnical performance, digestive processes, metabolism, antioxidant status, and meat proximate composition. The 5% inclusion level improved zootechnical parameters compared to the control. Moreover, the activities of the digestive enzymes chymotrypsin, trypsin, lipase, amylase, and maltase increased with OPN supplementation. The fillet proximate composition showed higher protein content across all supplemented groups, along with an increase in lipid content in the 5% group. The fatty acid profile of the fillets revealed a predominance of unsaturated fatty acids, with a dose-dependent increase in polyunsaturated fatty acids (PUFAs) at 5%, 10%, and 15%, and an increase in long-chain PUFAs observed in the 5% and 10% groups. Blood biochemical parameters (glucose, cholesterol, triglycerides, albumin, ALT, AST, alkaline phosphatase, lactate dehydrogenase, total proteins, and urea) were not affected by OPN supplementation. However, higher inclusion levels (10% and 15%) increased in the hepatic activities of AST, ALT, glutamate dehydrogenase (GLDH), and fatty acid synthase (FAS), while decreasing the activities of hexokinase (HK), phosphofructokinase-1 (PFK), and glucose-6-phosphate-dehydrogenase (G6PDH). No changes were observed in the hepatic activities of citrate synthase (CS), malate dehydrogenase (MDH), NADH dehydrogenase, or β-hydroxyacyl-CoA dehydrogenase (HOAD). Under transport stress challenge, all experimental groups showed improved survival rates, with no changes in hepatic catalase and glutathione reductase (GR) activity nor in lipid peroxidation levels. However, there were reductions in glutathione peroxidase (GPx) activity and glutathione (GSH) content. The observed effects on performance, metabolism, and stress resistance highlight the potential of OPN as a modulator of metabolic and antioxidant status in fish. These findings suggest that OPN flour can be a valuable supplement for tilapia diets when used at inclusion levels below 10%.