Study On Digestive Enzyme Activities Of Sciaenops Ocellatus And Digestibility Coefficients On Feedstuff In Vitro

The Sciaenops ocellatus weight from 300g to 350g were used in the experiment . The whole digest tract was divided into stomach, hepatopancreas, pylorus, foregut and hindgut. Protease, amylase and lipase activities were measured and three digestive enzyme activities were detected in different pH values. The results showed that protease activity of different digestive organ and tissues was in the sequence of stomach > poregut> pylorus> hindgut> hepatopancreas, the protease activities were 284.99±24.84, 91.45±4.57, 81.90±2.90, 78.41±1.79, 6.73±2.53 (U/g); The protease activity of hepatopancreas was very low in comparison with other parts. The protease activity in stomach was significantly higher than those in the other tissues (P<0.05), and there were no significant differences among poregut, pylorus and hindgut (P>0.05). Amylase activity was in the sequence of hepatopancreas > poregut> pylorus> hindgut>stomach, the amylase activities were 113.26±8.07,55.64±3.93,40.40±2.25,36.84±1.15,17.06±0.56 (U/g). Lipase activity was in the sequence of hepatopancreas > poregut> hindgut> pylorus>stomach, the lipase activities were 6.01±0.18, 4.65±0.51, 4.15±0.11, 4.06±0.24, 1.16±0.12 (U/g) , respectively. Amylase and lipase activities in hepatopancreas were significantly higher than those in other tissues (P<0.05).The optimal pH values for protease, amylase and lipase were also tested. The results showed that the optimal pH value for protease activity in stomach was 1.4-2.2 in the range from pH1.0-5.0; the optimum pH for amylase and lipase in stomach were 6.0, 4.8 respectively in the range from pH4.0-6.4 . In the range from pH6.4-9.0, the optimal pH values for protease in pylorus, foregut, hindgut and hepatopancreas were 7.0, 7.0-7.4, 7.4, 8.2; for amylase were 7.2-8.2, 7.4, 8.2-8.6, 7.8-8.2; for lipase were 7.0, 7.0, 7.0 ,7.4; respectively.A two-step enzymatic method of pepsin-pancreatin was used to evaluate the digestibility of dry matter and protein of nine feedstuff (New Zealand red fish meal, New Zealand white fish meal, Protein powder of blood powder, meat and bone meal, soybean meal, corn gluten meal, expander soybean, rapeseed meal and kelp meal ). The in vitro crude protein and dry matter digestibility of ingredients using commercial enzymes and Sciaenops ocellatus crude enzyme. The results showed, the two enzyme system gave significant correlated with each other. The dry matter digestibility were significant correlate on (r=0.832, p=0.005, n=9) between commercial enzymes and crude enzyme, so did the protein digestibility (r=0.823, p=0.006, n=9).