Study Of Enzymatic Reaction Conditions Of Evaluating The Available Phosphorus Of Plant-origin Feedstuffs For Growing Pig With Bionic Digestion

The objective of this study was to research the rule of dissolution and dialysis of plant feedstuffsphosphorus and enzymatic reaction conditions, include pH of simulated gastric fluid, intestinal digestiveenzyme and digestive time of gastric phase and intestine phase. Provided basis for evaluating theefficient of plant feedstuffs phosphorus in growth pigs with the enzyme methods based on SimulativeDigestion System.In the first part, we investigated to study the rule of dissolution and dialysis of three plantfeedstuffs phosphorus in order to provide reference for the establishment of bionic digestive operatinginstruction of evaluating the efficient of plant feedstuffs phosphorus in growth pigs. A6×6（pH×time）completely random design which included six pH treatments (2,3,4,5,6,7)and six time treatments(2h,4h,6h,8h,10h,12h) was adopted. Corn, soybean meal and wheat bran were used for research and thecontent of inorganic phosphorus and total phosphorus in dialysis fluid were determined. The resultsshowed that1)the rule of total phosphorus dialysis of plant feedstuffs accorded with the rule of totalphosphorus dissolution in other research, therefore, dialysis could be used for researching solubility ofplant feedstuffs total phosphorus;2)the effect of alkalinity or acidity of the simulative condition onsolubility of plant feedstuffs total phosphorus was significant, and the total phosphorus dialysance ofcorn, soybean meal and wheat bran were beyond80%,70%and90%in pH6～7, respectively;3) thedialysis tube with14000D could not divide the inorganic phosphorus and organic phosphorus.In the second part,we investigated to the variational rules of simulated gastric fluid pH when fivefeedstuffs and two simply mixed feeds were digested in order to research the relationship between invivo and in vitro gastric fluid pH. Provided basis for setting the pH of simulative gastric fluid. Fivefeedstuffs (corn, soybean meal, wheat bran, wheat and barley) and two simply mixed feeds（corn:soybean meal8:2; wheat:barley:soybean meal4:4:2) were digested in pH2simulative gastricfluid. The pH of three reduplicates in every group were determined at0.5h,1h,2h,3h. The resultsshowed that plant feedstuffs could significantly affect the buffer capacity of pH2hydrochloric acidbuffer; within one hour, the variational trend of in vitro gastric fluid accorded with in vivo.The third and fourth parts were investigated to research the effect of four small intestinaldigestive enzymes and digestive time of gastric phase and small intestinal phase on in vitro digestibilityof plant feedstuffs in order to provid basis for simulative small intestine fluid and optimal digestivetime. The experiments were carried out on SDS-Ⅰand corn, soybean meal and wheat bran were used astrial materials. A single factor completely random design was adopted for experiment three; accordingto digestive enzyme categories in simulative intestinal fluid, the treatments were divided into no enzymegroup and four enzyme groups into which Trypsin, Chymotrypsin, Amylase and Lipase were added inturn. Two single factor completely random designs were adopted for experiment four. Digestive time ofgastric phase:0.5h、0.75h、1h、1.25h、1.5h; digestive time of small intestinal phase:1h、2h、3h、4h、5h、6h. The results showed that1) Trypsin, Chymotrypsin, Amylase and Lipase could significantly（P<0.05） affect the in vitro digestibility of plant feedstuffs phosphorus and were used for simulating small intestinal fluid.2) considering the variational rules of in vitro digestibility of corn, soybean mealand wheat bran with digestive time and residence time of chyme in gastrointestinal tract, the digestivetime of gastric phase and small intestinal phase were determined for1h an5h.