Singular and combined effects of dietary mannan oligosaccharide and Lactobacillus plantarum on some growth indices and hematological parameters of Caspian trout, Salmo trutta caspius (Kessler, 1877)

The present study was conducted to examine singlular and combined effects of manan oligosacharid (MOS) and L. plantarum supplements on growth indices and hematological parameters of Caspian trout (Salmo trutta caspius Kessler, 1877). Caspian trout fingerlings (~ 10 g) were fed with a control diet (basal diet) or supplemented diets as follows: 1) the basal diet + 4g kg−1 IMOS, 2) the basal diet + -8×108 CFU/g-1  L. plantarum)  and 3) a synbiotic diets (the basal diet + 8×108 CFU/g-1  L.plantarum + 4g kg−1IMOS) for 8 weeks. At the end of this trial, the results of the MOS supplemented and synbiotic diet showed significant increase in feed conversion ratio (FCR), weight gain (WG), feed intake (FI), protein efficiency ratio (PER), specific growth ratio (SGR) and daily growth index (DGI) compared with fish fed the control diet (p<0.05). The highest FCR and FI were observed in the control group. In the case of condition factor, the singlular and combined diets showed no significant differences (p>0.05). The results of blood indices among all treatments revealed significant differences of the number of red blood cells (RBC) compared to the control group (p<0.05). The highest and lowest number of RBC was found in L. plantarum diet and control group, respectively. The number of white blood cells (WBC) showed no significant differences with control group (p>0.05). The results demonstrated that the MOS-supplemented diet and the combined diets containing MOS and L. plantarum improved the growth performance in Caspian trout fingerlings.