Effects of dietary supplementation with immunogen® on the growth, hematology and gut microbiota of fingerling common carp Cyprinus carpio (Linnaeus)

Abstract

We studied the effects of the proprietary prebiotic Immunogen® on the growth, hematology and gut microbiota of common carp fingerlings. A basal diet was formulated using common feed ingredients and supplemented with Immunogen® at concentrations of 0, 5, 10, 20 and 40 g kg-1, each of which was tested experimentally on replicated groups of fish. The trials ran for 8 weeks. Common carp fingerlings with an initial weight of 4.82 ± 0.05 g were randomly distributed among the experimental tanks at a stocking density of 25 fish per tank. The experimental diets were provided thrice per day; on each occasion the fingerlings were given a weight of feed that amounted to 4% of fish biomass. At the end of the experimental period, we determined the growth performance, feed conversion ratio, hematological parameters, body composition and gut micro-flora parameters of the test fish. Inclusion of 5 g kg-1Immunogen® in the diet significantly improved growth performance and feed utilization in comparison with controls. However, the whole-body composition of the fish was not significantly influenced by prebiotic inclusion. Inclusion of 5 g kg-1 Immunogen® significantly increased the total bacterial and Lactobacillus counts in fish intestines, but these bacterial parameters were significantly negatively impacted by higher concentrations of the prebiotic. Red blood cells counts were increased by prebiotic dietary supplementation at concentrations of 5 and 10 g kg-1 prebiotic. Glucose and cholesterol levels were elevated by administration of Immunogen®. Thus, dietary supplementation with 5 g kg-1 Immunogen® improved fingerling common carp growth performance and feed utilization, and beneficially influenced the gut microflora.