STUDIES ON GROWTH AND IMMUNE RESPONSES IN Pangasianodon hypophthalmus FED WITH BIOTIC SUPPLEMENTS.

Health awareness, rising income, and demographic pressure have led to a demand for food fish. The intensification of farming practices for higher production has increased the likelihood of disease occurrence in aquaculture. Available limited government-approved antibiotics and chemotherapeutics for disease treatments are more often marginally effective and may cause an adverse impact on the consumer and/or culture environment. Alternative biocontrol measures are warranted to avoid the global multi-billion-dollar loss to the aquaculture industry. Dietary probiotics and prebiotics are considered as novel functional ingredients that can influence the host's microbiota, significantly affecting the health and general well-being of the host

Forty-five days feeding trial was conducted to investigate the effect of probiotic bacteria (Lactobacillus acidophilus) and commercially available biotic supplements (FOS, β-glucan and mixed prebiotic) on growth performance, haematological response and disease resistance in Pangasianodon hypothalamus. To evaluate the in vivo synergism, fish were fed seven different diets in triplicates containing L. acidophilus at 1×10⁶CFU/g of feed (A), L. acidophilus in combination with mix prebiotic (MP) (A+MP), Fructo-oligosaccharide (FOS) 1%, Fructo-oligosaccharide in combination with L. acidophilus (FOS+A), β-glucan (0.1%) (BG), β-glucan in combination with L. acidophilus (BG+A) and a control diet without any biotic supplement. Following the feeding trial, the growth of the fish, measured by weight gain%, FCR, SGR and PER in the biotic supplement fed group appeared to be different from that of the control. In addition, there was a significant improvement in red blood corpuscles, total immunoglobulin and serum lysozyme in the biotic supplemented groups over the control and the immune system of fish was stimulated to resist the infection by A. hydrophila. Based on the results, it was concluded that L. acidophilus, FOS and β-glucan added at a designated dose in the diet improves growth of P. hypophthalmus and evoke immunostimulatory effects and protects against A. hydrophila infection.