Impact of Spirulina platensis Supplementation on Growth, Health, and Antioxidant Defence in Giant Gourami (Osphronemus goramy)

A 90-day trial investigated the effects of dietary Spirulina platensis (SP) supplementation on growth performance, haematology, serum biochemistry, digestive enzymes, and hepatic antioxidants in giant gourami (Osphronemus goramy). Fish (6.96 ± 0.011 g) were distributed into six treatments with 3 replicates each (15 fish per replicate) across 18, 60 L aquaria. Six isonitrogenous diets with 0% (control), 1% (SP1), 2% (SP2), 3% (SP3), 4% (SP4), and 5% (SP5) SP were provided ad libitum twice daily. Results showed dose-dependent improvements in final weight, weight gain, weight gain rate, protein efficiency ratio, and specific growth rate, with the highest values at 5% SP (P<0.05). Feed conversion ratio decreased with higher SP, indicating enhanced efficiency. Body indices increased significantly with higher SP (P<0.05). Haematological parameters, including WBC (white blood cells), HB (hemoglobin), HCT (hematocrit), monocyte %, and neutrophil %, improved with increasing SP significantly (P<0.05). Serum biochemistry showed markedly reduced cholesterol and triglycerides concentration, and increased total protein, albumin, and globulin levels with higher SP (p<0.05). Intestinal amylase and lipase activities increased significantly with SP (p<0.05), while protease remained consistent. Hepatic antioxidants revealed decreased MDA (malondialdehyde) and increased SOD (Superoxide dismutase) with higher SP (P<0.05). Carcass analysis showed increased protein, fibre, and fat content, and decreased ash and carbohydrates with higher SP. These findings suggest that 5% SP enhances growth, biochemical parameters, haematology, digestive, and antioxidant mechanisms in O. goramy, supporting its potential as a dietary supplement in aquaculture.