Effects Of Dietary Supplementation Of Chitosanoligosaccharide And Xylo-oligosaccharide On Growth Performance, Body Composition,biochemistry Of Serum And Non-specific Immunity Of Juvenile Turbot(scophthalmus Maximus)

PART 1 A 2×3 two-factorial experiment was conducted to evaluate the effects of COS and XOS on growth, feed utilization and body composition of juvenile turbot,with initial body weight(15.46±0.06)g. The feeding trail lasted for 60 days.Totally 9 diets(T1、T2、T3、T4、T5、T6、T7、T8、T9)were formulated to provide graded levels of COS(0.0%, 0.5%, 1.0%) and XOS(0.0%, 0.5%, 1.0%),one of which was fed to a triplicate group of juvenile turbot in a flow-through water system.Results showed that: 1) weight gain ratio(WGR), specific growth ratio(SGR),protein efficiency ratio(PER) increased(P<0.05) and feed conversation ratio(FCR)decreased significantly(P<0.05) with the supplemantary of COS and XOS in diets.Compared with the control group, weight gain rate(WGR) increased by 18.75%, the relative weight gain rate increased significantly, the specific growth rate(SGR)increased by 10.92%, protein efficiency ratio(PER) increased by 20.91%, the feed coefficient ratio(FCR) was reduced by 17.78% in the group of A0.5B1.0. 2)Adding COS alone can significantly reduce the hepatosmatic index(HIS) and muscle crude fat content(P<0.05), significantly improve viscerosomatic index(VIS), condition factor(CF) and muscle protein content(P<0.05). 3)Adding XOS and COS in the diet has the significantly effects on WGR, SGR, PER, FCR, muscle protein and lipid(P<0.05), whereas body composition and muscle ash have no significantly effect(P>0.05). The interaction of COS and XOS were significantly on SGR, WGR,whole body lipid and ash, muscle lipid and protein(P<0.05). Above the results, the addition of XOS and COS not only can significantly improve the effect of turbot larval growth perfomance, improve feed utilization, but also can significantly improve muscle protein content, decrease crude fat content. In this experiment, With weightgain rate as the evaluation index, it is recommended that adding 0.5% COS and 1.0%XOS in the diet at the same time can achieve the best effect of growth.PART 2 A 60 days feeding trail in a flow through system was conducted to detemine the effects of COS(0.0%,0.5%,1.0%) and XOS(0.0%,0.5%,1.0%) on serum biochemistry index and the activity of digestive enzyme of turbot. Results showed that: 1) Triglyceride(TG), total cholesterol(TCHO), Alanine transaminase(ALT), Aspartate transaminase(AST) were decreased with compare to the control group. Adding COS alone can reduced the TG significantly(P<0.05). 2)The XOS can improve the intestinal lipase significantly(P<0.05). The moderate amount of COS and XOS can significantly improve the intestinal amylase content(P<0.05), but high amount reduced intestinal lipase content instead. 3)The interaction of COS and XOS were significantly on TG, HDL-cholesterol(HDL-C), total protein(TP), Amylase and lipase of intestinal(P<0.05). Therefore we can draw that COS and XOS were cooperate to use can reduce turbot larvae in serum lipid levels, improve the intestinal digestive enzyme activity.PART 3 A 60 days feeding trail in a flow through system was conducted to detemine the effects of COS(0.0%,0.5%,1.0%) and XOS(0.0%,0.5%,1.0%) on non-specific immune and premunition of turbot.Results showed that:1)The activity of Lysozyme(LZM) was increased significantly(P<0.05),whereas reduced the activity of alkaline phosphatase(AKP) and superoxide dismutase(SOD) with the supplement of XOS and COS in the diet.2)The challenge experiment showed that fish fed diet A0.5B0,A1.0BO,A1.0B0.5 presented lower cumulative mortality rate than the control group(P<0.05) and higher imune protectiveratio(23%) compare with the control group afer 48 hours.In conclusion,Adding COS and XOS in moderate can improve immunity and premunition of turbot.