The effects of feeding with synbiotic (Pediococcus acidilactici and fructooligosaccharide) enriched adult Artemia on skin mucus immune responses, stress resistance, intestinal microbiota and performance of angelfish (Pterophyllum scalare).

The aim of this study was to evaluate the effects of feeding on synbiotic (Pediococcus acidilactici and fructooligosaccharide) enriched adult Artemia franciscana on skin mucus immune responses, stress resistance, intestinal microbiota and growth performance of angelfish (Pterophyllum scalare). Three hundred and sixty fish with initial weight 3.2 ± 0.13 g were randomly divided into twelve aquaria (50 L) assigned to four groups in triplicates. Fish were fed for 7 weeks with dietary treatments, including treatment 1: feeding adult Artemia without enrichment (control group), treatment 2: feeding adult Artemia enriched with lyophilised probiotic P. acidilactici (700 mg L(-1)), 3: feeding adult Artemia enriched with prebiotic fructooligosaccharide (FOS) (100 mg L(-1)), group 4: feeding adult Artemia enriched with synbiotic (P. acidilactici (700 mg L(-1)) + FOS (100 mg L(-1))). Skin mucus immune responses (lysozyme activity, total Immunoglobulin and protease), stress resistance against environmental stress (acute decrease of temperature and increase salinity), intestinal microbiota as well as growth indices were measured at the end of feeding trial. Artemia enriched with synbiotic significantly improved growth performance compared to other treatments (P < 0.05). The highest weight gain and specific growth rate (SGR) was observed in synbiotic fed fish (P < 0.05). Compared to the other treatments, the population of lactic acid bacteria was significantly higher in the intestinal microbiota of fish fed synbiotic supplemented diet (P < 0.05). In the environmental stress challenge test, the maximum resistance to abrupt decrease of temperature (17 °C) or elevation of salinity (12 g per liter) was observed in the synbiotic treatment. Also, the total immunoglobulin and lysozyme activity level of skin mucus was significantly elevated in fish fed Artemia enriched with synbiotic (P < 0.05). These results revealed that feeding angelfish with synbiotic enriched Artemia was more effective than singular enrichment with probiotics or prebiotics.