The effects of stocking density on some blood and serum biochemical indices of goldfish Carassius auratus

In this study, the effect of stocking density on some hematological (Red and white blood cells) and serum biochemical parameters (Glucose, triglycerides, cholesterol, total protein, inorganic phosphorus, calcium and magnesium, enzymes alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase and cortisol) of Carassius auratus was investigated. Fish with average weight 200±18 g were stocked randomly into 6 tank with triplicate in two treatments for a 30-day period and were submitted to different stocking densities: low density (T1, 10 kg/m3) and high density (T2, 45 kg/m3). At the end of the trial, Fish from each group were selected and their blood was collected and the following parameters were analyzed. Fish held at high density showed significant higher levels of cortisol, glucose and alkaline phosphatase (23±0.4 ng/dl, 52±3.2 mg/dl and 93.2±8.1U/L, respectively) compared with those held at low density (36±0.9 ng/dl, 83±5.2 mg/dl and 61.2±6.3U/L, respectively), while the levels of triglycerides significantly decreased with increasing density (P