Effects Of Dietary Supplementation Of Oligosaccharides And Probiotics On Growth Performance, Digestion, Absorption, Immunity And Antioxidant Function Of Blunt Snout Bream (Megalobrama Amblycephala)

This study was conducted to determine the effects of dietary supplementation of several feed additives on growth performance, digestion, absorption, immunity and antioxidant function of blunt snout bream, in order to provide theoretical basis for the development of efficient and environmentally friendly aquaculture feed additive, which included four series:Series 1 Effects of dietary supplementation of xylooligosaccharide (XOS)、 bacillus subtilis (BS) on growth performance, intestinal digestive enzymes activities and apparent digestibility of blunt snout bream(Megalobrama amblycephala) yearlingsA feeding experiment was conducted to evaluate the effects of dietary supplementation of xylooligosaccharide(XOS)、bacillus subtilis(BS) on growth performance, intestinal digestive enzymes activities and apparent digestibility of blunt snout bream (megalobrama amblycephala) yearlings.120 healthy blunt snout bream with an average initial weight of (30±0.52) g were randomly divided into 4 groups, group 1 was control group fed basic feed, groups 2,3 and 4 were experimental groups which were fed basic feed added with 0.01% xylooligosaccharide,0.01% bacillus subtilis,0.01% xylooligosaccharide+0.01% bacillus subtilis, respectively. The feeding trial was carried out in indoor facilities with water recycling system for 60 days. The results showed that the weight gain ratio of all the experimental groups were higher that of the control group. The weight gain ratio of group 4 which was the highest was 24% higher than that of the control group and the difference was significantly (P<0.05). The activities of the protease、lipase and amylase in the intestine of all the experimental groups were higher than that of the control group to various degree, among which group 4 was the highest. The apparent digestibility of dry matter in all the experimental groups were significantly higher than that of the control group (P<0.05), the apparent digestibility of crude protein in group 4 was significantly higher than that of the control group. The results showed that dietary supplementation of xylooligosaccharide and bacillus subtilis improved the growth performance, intestinal digestive enzymes activities and apparent digestibility of blunt snout bream(megalobrama amblycephala) yearlingsSeries 2 Effects of dietary supplementation of xylooligosaccharide (XOS)、 bacillus subtilis (BS) on immunity and antioxidant function of blunt snout bream(Megalobrama amblycephala) yearlingsThe conceptual design of raising was the same as that of the first experiment. The activities of lysozyme(LZM) in the serum of all the experimental groups was significantly higher than that of the control group (P<0.05), the activities of ACH50 in the serum of all the experimental groups was higher than that of the control group, the difference between group 4 and the control group was significantly (P<0.05). The activities of AKP in the serum of all the experimental groups was also higher than that of the control group to various degree, among which group 3 was the highest and the difference was significantly (P<0.05). The activities of ACP in the serum of all the experimental groups was also higher than that of the control group, however, the difference between the experimental groups and the control group was not significantly. The volume of SOD and CAT in the hepatopancreas of the experimental groups were higher than that of the control group to some degree and the volume of MDA in the hepatopancreas of the experimental groups decreased, these mean the body of the fish had less oxidation and stress. The results indicated that dietary supplementation of XOS、BS could enhance the immunity and antioxidant function of blunt snout bream(megalobrama amblycephala).Series 3 Effects of dietary supplementation of fructooligosaccharide (FOS) on growth performance, Biometric parameters and body composition of blunt snout bream(Megalobrama amblycephala) fingerlingsA feeding trial was conducted to investigate the effects of dietary fructooligosaccharide (FOS) on growth performance, body composition and Biometric parameters of fingerling Megalobrama amblycephala. A total of 1200 fish (1.42±0.01 g) were fed diets containing graded levels of FOS (0,0.5,1,2,4 and 8 g kg-1 diet) for 8 weeks.The weight gain, specific growth rate (SGR) and survival rate were all improved in dietary supplementation of FOS fed fish and the feed conversion ratio (FCR) of all the experimental groups were lower than that of the control group, and the difference between 4,8 g kg-1 diet group and the control group was significantly (P<0.05). The difference with dressout percentage, hepatosomatic index, viscerosomatic index and condition factor between all the FOS fed groups and the control group was not significantly (P>0.05). Increasing FOS levels resulted in both higher whole-body lipid and lower moisture contents, whereas ash and protein contents showed no significant differences among all the treatments. The results showed that dietary supplementation of FOS enhances growth performance, change the whole-body lipid and moisture contents.Series 4 Effects of dietary supplementation of fructooligosaccharide (FOS) on intestinal enzymes activities and intestinal histology of blunt snout bream(Megalobrama amblycephala) fingerlingsThe conceptual design of raising was the same as that of the third experiment. Intestinal amylase, protease, Na+,K+-ATPase, alkaline phosphatase, y-glutamyl transpeptidase and creatine kinase activities all increased with dietary FOS levels up to 4 g kg-1 (P<0.05), while the difference of intestinal lipase activities between dietary FOS groups and the control group was not significantly (P>0.05). Transmission electron microscopy analysis indicated that microvilli length in the mid-intestine was significantly increased with increased dietary FOS levels (P<0.05). In conclusion, dietary supplementation of FOS could confer benefits on intestinal digestive and absorptive ability, histology of fingerling Megalobrama amblycephala.