Effects Of Methionine On Intestinal Microflora, Digestive Enzyme And Immune Function Of Juvenile Jian Carp(Cyprinus Carpio Var.Jian)

The experiments was conducted to study the effect of methionine on intestinal microflora, digestionfunction and immune function of juvenile Jian Carp (Cyprinus carpio Var. Jian). In trial, 1320 juvenileJian carps with initial body weight 9.90g±0.02g were randomly allocated to 8 experimental groups with3 replicate, feeding semi-purified diets containing methionine 0.60, 0.80, 1.00, 1.20, 1.40, 1.60,1.80, 2.00% respectively for 60 days. After 60d, a challenge trial was conducted by injection ofAeromonas Hydrophila (AH) for 17 day.The results showed that methionine level great significantly or significant affected weight gain, feedintake , feed conversion ratio, SGR and the significant correlation existed between weight gain and feedintake , feed conversion ratio, SGR (r₁=+0.8840,P＜0.01: r₂=-0.9030,P＜0.01; r₃=+0.9980, P＜0.01);Thepath-analysis results indicated that there were significant direct effects of feed intake, feed efficiency onweight gain (path coefficient P_0.1=+0.4658, P_0.2=+0.6021;decision coefficient d_0.1=0.2126,d_0.2=0.3625). Methionine level significantly or significant affected the weight of liver and pancreas,intestine weight, intestine length, Bacillus acidi-lactici, Bacillus coli,Aeromonas diastatic,γ-Glutamytransferase and creatine kinase and the significant correlation existed between weight gainand Bacillus acidi-lactici, Bacillus coli, Bacterium coli,Aeromonas diastatic,γ-Glutamytransferase andcreatine kinase (r₁=+0.8540, P＜0.01; r₂=+0.8710, P＜0.01; r₃=-0.9260, P＜0.01; r₄=-0.9510,P＜0.01; r₅=+0.9560, P＜0.01; r₆=+0.8700, P＜0.01), the significant correlation existed between feedconversion ratio and Bacillus acidi-lactici, Bacillus coli, Bacterium coli,Aeromonas diastatic,γ-Glutamytransferase and creatine kinase (r₁=-0.7980, P＜0.05; r₂=-0.9110, P＜0.01; r₃=+0.8190,P＜0.05; r₄=+0.8160, P＜0.05: r₅=-0.9270, P＜0.01; r₆=-0.7560, P＜0.05); The path-analysis resultsindicated that there were significant direct effects of Bacillus acidi-lactici, Bacillus coli, Bacteriumcoli,Aeromonas diastatic on weight gain (path coefficient P_0.1=+0.4677,P_0.2=+0.1747,P_0.3=+0.1456,,P_0.4=-0.6087;decision coefficient d_0.1=0.2187, d_0.2=0.0305,d_0.3=0.0212, d_0.4=0.3705).Methionine level significantly or significant affected head kidney weight, hind kidney weight,spleen weight ,lysozyme,agglutinant, addiment C3, addiment C4 and serum total iron binding capacity, the significant correlationexisted between survival rate after vaccination against Aeromonas and lysozyme, agglutinant, addimentC3 and total iron binding capacity (r₁=+0.8590, P＜0.01; r₂=+0.7800, P＜0.05; r₃=+0.7610, P＜0.05;r₄=+0.8220, P＜0.05); The path-analysis results indicated that there were significant direct effects ofagglutinant, addiment C3 on spleen weight (path coefficient P_0.1=+0.5315,P_0.2=+0.4425; decisioncoefficient d_0.1=0.2825, d_0.2=0.2202).In summary, methionine can influence the balance of intestinal microflora by promotingthe growth of beneficial bacterium and depressing the growth of baneful bacterium;methionine can promote the digestion of carbohydrate and advance absorption bypromoting the activity of membrane protein and the enzyme of producing ATP; methioninecan promote the ability of recognition, adhesion, bacteriostasis and sterilization. In a dietfor 9.90-39.58 juvenile Jian carps with a total protein level of 35% and Cys level of0.28%, Jian carps appeared best growth performance, the growth of helpful microflora, digestivefunction, ingestive function, immune function as feeding the diets containing methionine3.34g/100gCP或1.17%, 3.46g/100gCP-3.74 g/100gCP或1.21-1.31% 3.06g/100gCP或1.07%, 3.43g/100gCP或1.20% and 3.34g/100gCP-3.54 g/100gCP或1.17-1.24%respectively.