Dietary Lactobacillus acidophilus modulated skin mucus protein profile, immune and appetite genes expression in gold fish ( Carassius auratus gibelio )

The objective of the present study was to investigate the effect of dietary Lactobacillus acidophilus on skin mucus protein pattern, immune and appetite related genes expression as well as growth performance in gold fish (Carassius auratus gibelio). Three hundred healthy gold fish (2.5 ± 0.05) juveniles were randomly distributed in 12 glass aquariums (400-L; 25 fish per aquaria) and fed experimental diets contain different levels of L. acidophilus (0, 1.5 × 108, 3 × 108 and 6 × 108) for 8 weeks. SDS-PAGE analysis of skin mucus protein profile at the end of the feeding trial revealed differences in protein profile of probiotic fed fish and control group; even three new bands were observed in L. acidophilus treated groups. Furthermore, fish fed 6 × 108 CFU g-1 supplemented diet showed up-regulation of both TNF-1α and TNF-2α gene expression (P < 0.05). Evaluation of appetite related gene expression showed down-regulation of ghrelin in probiotic fed fish compared those of control treatment (P < 0.05). However, administration of different levels of L. acidophilus had no significant effects on growth performance (P > 0.05). These results demonstrated that while no beneficial effects on growth performance, dietary L. acidophilus affects immune and appetite related genes expression as well as skin mucus protein profile.