Metabolic and physiological responses to intraperitoneal injection of chromium oxide in hyperglycaemic Nile tilapia juveniles

This study evaluated the effect of chromium oxide (Cr2O3) on the metabolic and physiological variables of hyperglycaemic Nile tilapia (Oreochormis niloticus) juveniles. The experimental design comprised two treatments (glucose and glucose + Cr2O3) and four different times (30, 60, 120 and 240 min), with 7 fish per group. Fish received glucose at 1 g kg body weight(-1), injected intraperitoneally. For the glucose + Cr2O3 treatment, 40 mM Cr2O3, equivalent to a dose of 6.07 mg kg body weight(-1), was co-injected. At different times, the presence of Cr2O3 reduced plasma total cholesterol and triglycerides, as well as hepatic glycogen levels and haemoglobin values. In both treatments, blood glucose, plasma total cholesterol and triglycerides levels, and the activities of intestinal amylase and protease enzymes were time-dependent, showing a reduction at 240 min after initial glucose exposure, but haemoglobin values decreased most at 30 and 240 min than at 60 and 120 min. In fish not exposed to Cr2O3, hepatic glycogen, and plasma total protein and amino acids levels were highest at 30 min while in fish treated with Cr2O3, plasma albumin levels were higher at 240 min than at 120 min. In conclusion, Cr2O3 improved the metabolic responses and improves nutritional and physiological status of Nile tilapia.