Effects of single or mixed dietary supplementation of inulin or mannan-oligosaccharide (MOS) on growth, feed utilization, fatty acid profiles, gut morphology, and hematology in Nile tilapia fry

Abstract

The present study was designed to investigate the effect of supplementation of inulin and mannan-oligosaccharides (MOS), single or combined, on the growth performance, feed utilization, hematology, fatty acid profiles, and intestinal morphology of Chamo strain Nile  tilapia Oreochromis niloticus (L.) fry. Nile tilapia fry (initial weight 1.37 ± 0.116 g) were fed four diets supplemented with prebiotics at 0 g  of prebiotic/kg of fish feed (Diet-T1), 5 g kg^-1 inulin-supplemented diet (Diet-T2), 6 g kg^-1 MOSsupplemented diet (Diet-T3), or a  combination of 2.5 g kg^-1 inulin and 3 g kg-1 MOS (Diet-T4). Each diet was randomly assigned to three aquaria and handfed 6% of their  body weight divided into three portions daily. Fish fed 6 g kg1 of MOS had higher weight gain, Daily Growth Rate (DGR), Specific Growth  Rate (SGR) and Feed Conversion Ratio (FCR) although the effect was not significant (p>0.05). Fish fed Diet-T3 and Diet-T4 had the highest content of polyunsaturated fatty acids (PUFAs). Fish fed Diet-T3 and Diet-T4 had significantly higher villi length in the proximal and middle  portion of the intestine compared to other feeding groups. There was also significant difference (p<0.05) recorded in villus width  in fish fed Diet-T3 and other feeding groups. Fish fed Diet-T3 also showed significantly higher goblet number at proximal and middle  portion of the intestine. RBC, HCT, HGB neutrophil and monocyte levels were higher in the 6 g MOS kg-1 fed fish. MCHC, platelets, and  eosinophil levels were higher in fish fed 5 g kg^-1 inulin supplemented diet. In conclusion, dietary supplementation of MOS could confer  benefits on growth performance, fatty acid profiles, haematology, and intestinal morphology of Chamo strain Nile tilapia.