Effects of dietary supplementation of oligosaccharides on growth performance, gut health and immune response of hybrid catfish (Pangasianodon gigas x Pangasianodon hypophthalmus)

The effects of dietary supplementation of various oligosaccharide types on growth performance, gut health and immune response were investigated in hybrid catfish (Pangasianodon gigas x Pangasianodon hypophthalmus). The fish (5.50 +/- 0.04 g initial body weight) were fed for 10 weeks with fish meal-soybean meal-based diets containing 0.6% of xylooligosaccharide (XOS), galactooligosaccharide (GOS), fructooligosaccharide (FOS) or mannanoligosaccharide (MOS), while the control diet was not supplemented. At the end of experiment, growth performance was similar across the five dietary treatments, but some improvements in feed utilization parameters were mainly observed in fish fed with the MOS diet, followed by the diet containing FOS. The preferred treatment improved gut health, as indicated by the activities of digestive enzymes and microvillus length. Positive responses in protein synthesis capacity and protein turnover rate as well as amount of native myosin and actin were also observed, while the carcass proximate composition did not differ across the five dietary treatments. Improved immunological response and survival rate after challenge with Edwardsiella ictaluri was achieved in fish fed with the preferred oligosaccharide type. Overall, these findings indicate that a MOS supplemented diet can improve growth performance, gut health and immune response in juvenile hybrid catfish. This prebiotic could be applied by supplementation in practical diets for this hybrid fish.