Preparation Of Soybean Meal Extracts Complex And Its Effects On Broilers

Soybean meal extracts complex (SMEC) extracted from soybean meal by usingmicrowave-assisted optimizing process is a new feed additive consisted with soybeanisoflavones, soybean oligosaccharides, soybean saponins, soybean polypeptides and otherbiological active substances. In this study, four experiments were conducted to investigate thepreparation conditions of SMEC and the effects of SMEC on broilers. The objective of thisstudy was to explore the function and mechanism of SMEC, clarify the optimum adding level inthe diet, and provide a theoretical basis for scientific utilization in productive practice.Experiment1: This experiment was carried out to study the optimum process of SMECpreparation. Applying the column chromatography principle and microwave-assisted ethanolextraction method, according to the results of single factor trial focusing on the yield of soybeanisoflavone, five factors including ethanol concentration, dropping speed of solvent, solid toliquid ratio, extracting temperature and extracting time were investigated. The L16(45)orthogonal test was adopted to determine the optimum extraction process of SMEC. Resultsshowed that the optimum processes condition of SMEC extraction was85%ethanol,75mL/mindropping speed of solvent, solid to liquid ratio of1:8, temperature of60℃and extracting timeof1h. Results of qualitative and quantitative analysis showed that SMEC is consisted with0.928%of soybean isoflavones,71.33%of soybean oligosaccharides (42.6%of Sucrose,22.6%of raffinose and6.13%of stachyose),7.2%of soybean saponins,6.2%of soybeanpolypeptides and14.342%of carriers.Experiment2: The experiment was carried out to study the effects of SMEC on productionperformance and serum biochemical index of broilers. Six hundred healthy Avian chicken of1day old were randomly allocated into5treatments,4replicates per treatment,30birds perreplicate (half male and half female).The trial diets were added with250mg/kg,500mg/kg,750mg/kg and1000mg/kg SMEC respectively in basal diet as the control. The results showed asfollows. SMEC had significant effects on average daily gain, average daily feed intake, feedconversion ratio, slaughter performance, meat quality, apparent metabolic rate of crude proteinand ether extract (P<0.05).500mg/kg SMEC caused the best effects on improving growthperformance, slaughter performance, meat quality and apparent metabolic rate of nutrients.When additive amount of SMEC was over to750mg/kg, daily gain and slaughter rate presenteddecreasing tendency (P>0.05). In addition, the results also showed that there was sex differencein effect of SMEC on growth performance, male significantly better than female(P<0.05). Also, SMEC could significantly improve contents of immunoglobulin in the serum and high-densitylipoprotein cholesterol and reduce uric acid, blood ammonia, triglyceride, cholesterol andlow-density lipoprotein cholesterol levels. Among them,500~750mg/kg treatment did better.The appropriate SMEC level was500mg/kg according to the test results.Experiment3: The experiment was conducted to study the effects of SMEC on antioxidantindex, immune index, hormone index, IFN-γ and IL-2mRNA expression in spleen tissue. Theresults showed that, in21d and49d, the broilers’ thymus index of500mg/kg treatmentincreased17.16%and16.85%(P<0.05) respectively, and the bursal index increased12.45%and18.46%(P<0.05) compared to the control. SMEC could enhance serum immunoglobulinlevel to different extent, in which500mg/kg,750mg/kg and1000mg/kg treatmentssignificantly increased serum IgA, IgG and IgM compared to the control (P<0.05), andsupplementation of750mg/kg enhanced the immune effect best. SMEC could remarkablyimprove the peripheral blood T lymphocyte CD3+,CD4+content and CD4+/CD8+ratio. SMECdecreased the serum ACTH and COR concentration with a dose-dependent relation as quadraticcurve significantly (P<0.05), among which500~750mg/kg treatments were lower relatively.SMEC could increase IL-2mRNA and IFN-γ mRNA expression in spleen tissue, raise thelevel of cellular immunity and non-specific immune function. Under the condition of thisexperiment, supplementation with750mg/kg could obviously increase the IL-2and IFN-γmRNA expression.Experiment4: The experiment was conducted to study the effects of SMEC on intestinaldigestive enzyme activity, intestinal mucosal morphology and intestinal flora of broilers. Theresults showed that SMEC could obviously improve the intestinal digestive enzyme activity.Activities of proteolytic enzyme in750mg/kg treatment was the highest among all the trialgroups, with50.61%(P<0.05) higher than the control, and500mg/kg treatment observed withthe highest enzyme activity of total protein hydrolase (P<0.05), in which39.69%higher thanthe control as well.500mg/kg and750mg/kg of SMEC could improve the microvilli of thesmall intestine remarkably. SMEC could also improve intestinal microvilli, in which500mg/kgand750mg/kg treatments significantly increased the height of villus and height/crypt depth ofvillus. SMEC showed the positive effects on regulating the intestinal micro-ecologicalenvironment, in which750mg/kg treatment remarkably reduced the number of E.coli andincreased the amount of Lactobacillus and bifidobacterium.In conclusion, comprehensively considering all testing indexes of this study,500～750mg/kg of SMEC was suggested as the optimal supplementation level in broiler’s corn-soybeanmeal diet.