The Effects Of Mannanoligosaccharide (MOS) On Intestinal Microflora And Immune Function Of Juvenile Jian Carp (Cyprinus Carpio Var.Jian)

The effect of different dietary MOS levels on growth performance, intestine growth .intestinal microflora and immune function of juvenile Jian carp were studied. 945 juvenile Jian carps with initial body weight 8.47g + 0.04g were randomly allocated to 7 experimental groups with 3 replicate, feeding semi-purified diets containing MOS 0, 90,180, 270, 360, 450 and 619mg/kg respectively for 70 days.The results showed that there were great significant or significant differences inweight gain, SGR, feed conversion efficiency, intestine weight, intestine length,intestine weight/ body weight, intestine length/body length, proximal and distalintestinal folds's height, spleen weight, spleen weight/body weight, blood hematocytecounts, phagocytic activity of the leucocytes, serum lyso/.ymc activity ,scrum antibodylevel at 17d and survival rate after vaccination against Aeromonas hydrophila(p<0.05 or 0.01), but were not significant differences in survival rate,feed intake, headkidney weight, head kidney weight/body weight, post kidney weight, post kidneyweight/body weight, hepatopancreas weight, hepatopancrvas weight/body weight,blood leukocyte counts among exprimental groups (p>0.05) . Bacteriological analysisresults showed that the intestinal Bifidobacteriiun and lactobaciUiis counts increasedwith Escherichia coli counts decreaseing great significantly as dietary MOSincreasing from 0 to 270mg/kg(p<0.01). There were significant correlations betweensome two indices, such as SCR and feed intake/weight gain (r= - 0.9540, P<0.05), feedintake/weight gain and intestine weight or intestine length or height of proximalintestinal folds or distal intestinal folds (r,=-0.9700, P<0.01; r2=-0.9440, P<0.01;r3=-0.8690, P<0.05; r4=-0.9210, P<0.01). The significant correlations also existedbetween some two indices, such as the survival rate at I7d after vaccination andspleen weight or blood hematocyte counts or phagocytic activity of the leucocytes orserum lysozyme activity or serum antibody level at 17d after vaccination (r1=+0.8966,p<0.01; r2=+0.7960, p<0.05; r3=+0.8200, p<0.05; r4=+0.7440, p<0.05; r5=+0.9340,p<0.01) . There was significant quadraticly relationship between weight gain or feedintake/weight gain and the levels of dietary MOS (R21=0.410,p<0.01: R22=0.495,p<0.01) . The best weight gain and feed conversion efficiency of 8-37g juvenile JianCarp(cyprinus carpio Var.Jian) were achieved as feeding diet containing MOS 378 and374mg/kg.In summary, MOS can promote growth rate of juvenile Jian carps by optimizing intestinal microflora and increasing intestine growth. MOS also increased resisting diseases s ability of juvenile Jian carps with promoting spleen growth and increasing non-specific as well as specific immune ability . The optimal level of MOS for 8-37g juvenile Jian Carp(cyprinus carpio Var.Jiati) was 378mg/kg.