Evaluation Of Nutritional Value And Prediction Of Available Nutrients Of Extruded Soybeans In Weaned Pigs

Soybean is an important dietary protein source with high protein content and balanced amino acids composition.But soybean contains anti-nutritional factors direct use will cause nutrient absorption impaired.Extrusion can reduce or remove anti-nutritional factors in soybean,promote nutrient digestion and absorption and animal performance.Therefore,it is of great significance to accurately evaluate the nutrition and value variation of the available nutrients of extruded soybean in weaned pigs for its efficient utilization in weaned pigs diets and to improve the feed material database.In this study,amino acid content,ileal amino acid digestibility of 7 extruded soybeans and total intestinal nutrient digestibility and available energy of 8 extruded soybeans were determined by two weaned pigs experiments.The prediction equations of digestible energy(DE),metabolizable energy(ME)and standardized ileal digestibility(SID)of amino acids for extruded soybean were established.The extruded soybeans used in the experiment were all from different manufacturers.Experiment 1 Determination of ileum amino acid digestibility of different extruded soybeans and its effect on health of weaned pigsThe amino acids composition,ileal amino acid digestibility,the comparative effects of 7extruded soybeans and soybean meal on the health of weaned pigs were evaluated.Nine DLY weanling barrows with a T-cannula in the distal ileum(initial BW:15.33±0.72 kg)were selected.Nine diets(including 1 nitrogen-free diet,1 soybean meal diet and 7 extruded soybean diets)were randomly distributed to nine pigs in a 9×6 incomplete Latin square design.The experiment lasted for 6 periods,with each trial period consisting of 5 days recovery period,4 days adaptation period and 3 days formal period.The results are shown below.(1)The contents of CP and 17 amino acids except methionine had little difference(CV<10%),and the content of methionine was CV>10%.Mycotoxin and anti-nutritional factors were significantly different(CV>10%),and deoxynivalenol(DON)content was the most different(CV=45.20%).(2)The apparent ileal digestibility(AID)and SID of CP and amino acids of extruded soybeans were significantly different(P<0.05).The AID of CP and major limiting amino acids was CP 60.39%-81.47%,Lys 72.86%-87.77%,Met 74.94%-89.10%,Thr61.50%-81.72%,Trp 65.50%-83.94%,and SID of CP and major limiting amino acids was CP64.16%-84.77%,Lys 74.89%-89.67%,Met 77.95%-92.11%,Thr 65.65%-85.45%,and Trp82.20%-104.52%,respectively.(3)The correlation analysis of the SID of CP and amino acids in extruded soybean with mycotoxin and anti-nutritional factors showed that the contents of mycotoxin and anti-nutritional factors could seriously affect the SID of CP and amino acids of extruded soybean,especially DON and krypsin ihhibitor(KTI),which were significantly negatively correlated with the SID of CP and amino acids of extruded soybean(P<0.05).(4)Different extruded soybeans had significant effects on intestinal integrity(serum DAO)and antioxidant capacity(CAT,T-SOD,GSH-Px activity)of weaned pigs(P<0.05).Compared with soybean meal,extruded soybeans could significantly reduce DAO(P<0.05)and significantly increase CAT,T-SOD,GSH-Px(P<0.05).The effects of different extruded soybeans on immune function indexes(IL-2,IL-4,IL-8,IL-10,IFN-γ,TNF-α,Ig G,Ig M)of weaned pigs were significantly different(P<0.05).Compared with soybean meal group,extruded soybeans could significantly reduce the levels of IL-2,IL-8,IFN-γ,TNF-αof weaned pigs(P<0.05),and could significantly increase the levels of IL-4 and IL-10(P<0.05).The correlation analysis of the SID of CP and amino acids with immune indices of weaned pigs showed that IL-2 and IL-8 were negatively correlated with SID(P<0.05).(5)The prediction equation of the SID of limiting amino acid and nutrient composition of extruded soybean was established.SID Lys(%)=-24.18+15.35×Glu content(%)(R~2=0.81),SID Met(%)=7.69+51.51×Phe content(%)-17.40×Tyr content(%)(R~2=0.74),SID Thr(%)=1.61+60.05×Val content(%)-18.84×Pro content(%)(R~2=0.73),SID Trp(%)=-9.19+58.18×Val content(%)(R~2=0.69).Experiment 2 Determination of total intestinal nutrient apparent digestibility and effective energy value of different extruded soybeansThe total intestinal nutrient apparent digestibility and available energy of extruded soybean were evaluated by total fecal collection method and nested algorithm,and the prediction equations of DE and ME and nutrient composition of extruded soybean were established by regression analysis.Nine healthy DLY castrated male weaned pigs with body weight of 11.14±1.46 kg was randomly assigned to nine different diets(a corn-based diet and 8 extruded soybean diets)according to a 9×6 incomplete Latin square design.The experiment consisted of 6 periods,each consisting of 4 days of pre-feeding period and 5 days of formal period.The results are shown below.(1)The nutrient contents of extruded soybeans varied greatly,and the CV of CF,NDF,ADF and Ca contents was more than 10%.GE of 8 extruded soybeans varied from 20.52 to22.20 MJ/Kg,with an average of 21.18 MJ/Kg.(2)The variation ranges of total intestinal nutrient apparent digestibility of nutrient content for different extruded soybeans were DM 88.44%-89.39%,EE 80.96%-88.58%,CF79.6%-83.65%,Ash 69.56%-90.42%,Ca 41.58%-68.51%,P 55.11%-77.48%.The total intestinal nutrient apparent digestibility of EE,Ash and P of extruded soybeans was significantly different(P<0.05),respectively.(3)There were significant differences in apparent total tract digestibility of GE and DE,ME among extruded soybeans(P<0.05).The variation range of DE and ME was 18.81-19.80MJ/kg and 18.12-19.15 MJ/kg.(4)The prediction equation of DE,ME with nutrient composition of extruded soybean was established.DE(MJ/kg)=4.24+0.49×CP content(%)-0.12×CF content(%)(R~2=0.80);ME(MJ/kg)=-2.07+1.07×DE(MJ/kg)(R~2=0.77).In conclusion,the nutrient content of different extruded soybeans had little difference,but the content of mycotoxin and anti-nutritional factors had great difference,and the nutrient apparent digestibility,ileal amino acid digestibility and available energy value were significantly different.The available energy and amino acid digestibility of extruded soybean could be predicted by the chemical composition of extruded soybean.Weaned pigs fed extruded soybean can improve antioxidant capacity,reduce intestinal damage and regulate immune function.