Dietary probiotics and prebiotics improved food acceptability, growth performance, haematology and immunological parameters and disease resistance against Aeromonas hydrophila in snakehead (Channa striata) fingerlings

This study was carried out to investigate the effects of commercially available probiotics and prebiotics on growth performances, haematological and immune response and disease resistance in Channa striata fingerlings against the pathogenic bacteria Aeromonas hydrophila. Fish were fed six different diets up to 12 weeks containing single dosage of Lactobacillus acidophilus at 1 g kg− 1 feed (1010 cfu), yeast 1%, β-glucan 0.1%, Galacto-oligosaccharide (GOS) 1% and Mannan oligosaccharide (MOS) 0.2% and control without any supplement. The fish were challenged intraperitoneally with 1 × 107 cfu ml− 1 of A. hydrophila. Feeding the fish L. acidophilus, yeast and β-glucan significantly increased weight gain, protein efficiency ratio (PER) and feed conversion ratio (FCR). Feeding of supplemented diets to fish led to reduced mortalities after challenging with A. hydrophila. The haematological and immunological parameters were assayed both in pre-challenged and post-challenged groups. There was a significant improvement in red blood corpuscles (RBCs), white blood corpuscles (WBCs), pack cell volume (PCV), haemoglobin (Hb%) concentration, erythrocyte sedimentation rate (ESR) and serum protein content in treated groups over the control. Immunoglobulin level showed an increased trend but it was much higher in challenged fish. There was a significant increase in lysozyme activity and further significant increase in the levels of serum lysozyme occurred in fish induced with A. hydrophila. In conclusion, the L. acidophilus, yeast and β-glucan added at a designated dose in the diet improves growth and stimulates the immunity and makes C. striata more resistant to infection by A. hydrophila.