Effects Of β-mannanase On Production Performance Of Weaned Piglets And Studying On Mechanism

Early-weaned piglets(28d age)are useed as animal model to determine the effect of beta mannanase on performance,immunity,intestinal microecology of weaned piglets and discuss mechanism;to provide a scientific basis for utilizing and Appropriate dosage in weaned piglets'diets.The first experiment:Seventy-two 28-d-old weaned Duroc×Landrace×Yorkshire piglets were divided into four groups with three replicates,each of which including 6 piglets,in a randomized block design(male:female=1:1)to study the effect of beta mannanase on the performance,digestability of nutrients,intestinal digestive enzymes activity,economic efficencies and determine the optimal level of beta mannanase on the early weaned piglets..the frist group(control group),the second,third and fourth group were fed with corn-soybean meal basal diet adding beta mannanase in 0%,0.025%,0.05%and 0.1%level.The whole experimental period was 4 weeks.The main results:Adding the optimal level of beta mannanase in dietary of weaned piglets.1.Dietary beta mannanase can increase the average daily gain group and the average daily feed intake,decrease the feed-meat ratio and the diarrhea frequencies compared with control group in the different degree(p＜0.05).2.The cost of diets may be reduced by 2-7%,promoting economical efficiencies.3.The dietary beta mannanase can increase digestability of nutrient except Ca,P(p＜0.05).4.The dietary beta mannanase can increase remarkably intestinal Parenzyme and Amylase activities(p＜0.05).but had no significant effect on Lypase.5.The experimental group3(0.05%beta mannanase)was optimum in the way of improving performance.The second experiment:On the basis of the first experiment' optimum.150 28-d-old weaned DurocxLandrace×Yorkshire pigs were divided into five groups with one-way random design,each group including 3 replicates(10 pigs per replicates)to determine the effective energy of 0.05%beta mannanase in weaned pigs' diet.The first group was the control group,fed with corn-soybean basal diet.The group2 and group3,combination 0.05%beta mannanase with antibiotics,were fed with the basal diet decreased 80kal/kg and 100kal/kg energy respectively.The group4 and The group5 were fed with the basal diet decreased 80kal/kg and 100kal/kg energy respectively,and alone 0.05%beta mannanase.The whole experimental period was 4 weeks.The experimental results showed that:1.0.05%beta mannanase can instead 80-100kal/kg energy in the corn-soybean meal diet of weaned piglets.2.Beta mannanase and antibiotics may promote each other.The third experiment:At the start,the first weekend,the second weekend,the third weekend and the fourth weekend of the first experiment,preparing serum for biochemical parameters,the SFD antibody and TLR to study the effect of beta mannanase on serum biochemical parameters and immunity,discuss mechanism of beta mannanase on performance of weaned piglets.The experiment showed:the optimal level of beta mannanase in dietary of weaned piglet's diets.1.Beta mannanase can advance serum T₄ and IGF-1(p＜0.05),had no significant effect on serum T₃.so beta mannanase can promote performance of weaned piglets to some extent.2.Beta mannanase can advance serum SOD,GSH-PX,T-AOC activities remarkably(P＜0.05),decrease serum MDA,promoting antioxidant capacity.3.Beta mannanase can advance serum IgG,IgA and the SFD antibody of piglets(p＜0.05),had no significant effect on serum IgM,promoting humoral immunity of weaned piglets to some extent.4.Beta mannanase have no impact on serum GPT and GOT,decrease serum LDH,CK activities(p＜0.05),slowing weaning stress of piglets to some extent.5.Beta mannanase can advance serum TLR(p＜0.05),promoting Cellular immune function of weaned piglets to some extent.6.Beta mannanase can advance serum AKP antivities,GLU,TP,ALB(p＜0.05), promoting protein deposition of weaned piglets,and had no sifinificant effect on serum BUN.7.Beta mannanase had no sifinificant effect on serum lipids level.but beta mannanase can regulate Lipid metabolism,Speed up digestion and absorption of fat, reduce deposition of cholesterol in the different degree. The fourth experiment:12 piglets(1 pig each replicate randomly)were slaughtered at the end of first experiment,the corresponding intestines were removed to study the effect of beta mannanase on intestinal flora and intestinal Morphology.The experiment showed that:Adding the optimal level of beta mannanase in dietary of weaned piglets.1.Beta mannanase can increase the quatities of benefical flora,reduce the quatities of harmful flora in the different degree(p＞0.05).2.Beta mannanase can decrease intestinal pH(p＜0.05).3.Beta mannanase can increase remarkably Villous height of Duodenum,Jejunum,decrease crypt depth of Duodenum,Jejunum(p＜0.05);had no significant effect on Villous height and crypt depth of Ileum(p＞0.05).4.Considering effects of beta-mannanase on intestinal flora and Morphology of weaned piglets,0.05%beta mannanase is the best. The fifth experiment:Collecting 50g fresh faecel of each replicate randomly selected at the first experimental 14d and 28d and mixturing,storing at-20℃.and extracting total DNA→PCR→DGGE to study the effect of beta mannanase on diversity intestinal flora of weaned piglets.The experiment showed that:Adding the optimal level of beta mannanase in dietary of weaned piglets.1.Beta mannanase can increase remarkably DGGE bands and H'of weaned piglets faecal samples in earlier period(P＜0.05),had no significant effects on DGGE bands and H' in later period(P＞0.05).2.Beta mannanase can slow reducing of intestinal microbial kinds and quatities caused by weaning press.In the conclusion,the different dosage of beta mannanase added in the feed of weaned piglets can improve ADG and AFI,decrease F/G and diarrhea in the different degree;0.05%beta mannanase group is the best in the way of improving performance of weaned piglets;Improving of the production performance was gained by effect of beta mannanase on intestinal microecology,blood physiological and biochemical index and immunity.