Effect Of Compound Nondigest Enzymes Preparations On The Endogenous Digest Enzyme Activity Change Rule And Its Carry-Over Effets In Cherry Valley Ducks

To provide a scientific evidence for further exploration of the mechanism and reasonable application of compound enzyme in poultry nutrition, this study evaluated the influence of compound enzymes on the endogenous digestive enzyme activity and its carry-over effects in cherry valley ducks. Three sections were included in this research:In the first part, an experiment was designed to study the effect of compound nondigest enzymes preparations on performance, nutrients apparent metabolizability and its carry-over effects.360healthy ducklings of1-day-old were randomly allocated into3groups, and each group had4replicates with30ducks per replicate. The whole was divided into prophase (1-14d) and mid-phase (15-42d). Performance of d14and42ducks were determined.Another6ducks from each group were used for metabolic test in six metabolic cages respectively, which conducted at the d14,21and28. There were4days in pre-test and next3days to collect excreta. The ducks in control group fed basal diet without enzyme, while Group2fed basal diet with100mg/kg compound enzyme. The ducks in Group3fed the basal diet with enzyme until14d, then fed the basal diet to the end of test. The compound enzyme contained xylanasc10000U/g, mannanase18000U/g, glucanase3000U/g and cellulase36000U/g. The results showed:1) compared with Group1, the average weight of Group2and Group3increased7.56%(P<0.05) and4.63%(P>0.05) respectively at14d. Prophase daily body gain in Group2and Group3were significantly higher than Group1(P<0.05). Prophase feed to gain ratio decreased by22.91%and17.07%(P<0.05) in Group2and3in comparison to Group1. Anaphase daily gain in Group1and3was significantly lower than that in Group2(P<0.05). Feed to gain ratio during the whole period of Group2was lower than Group1and3by7.83%(P<0.05) and2.75%(P>0.05);2) Along with age, apparent metabolizability of energy in Group1increased gradually, while increased firstly and then decreased in Group2and3. Apparent metabolizability of crude protein decreased as age increasing in all groups. Compared with group1, apparent metabolizability of crude protein in Group2and3increased by8.08%(P<0.05) and2.88%(P>0.05) at14-16d, and by10.11%and3.29%(P>0.05) at21-23d. Ether extract apparent metabolizability firstly increased and then decreased in all groups with aging. Ether extract apparent metabolizability in Group2and3was significantly higher than Group1at14-16d, while that in Group3was higher than Group1and2significantly at28-30d (P<0.05). Along with aging, crude fiber apparent metabolizability of all groups increased firstly and then decreased. Crude fiber apparent digestibility in Group2was higher by45.99%(P=0.097) and57.92%(P=0.059) than that in Group1and3at28-30d.In the second part, the experiment was to study the effects of compound nondigest enzymes on the endogenous digestive enzyme activity and its carry-over effects in cherry valley ducks. Birds were suffered from the same proposal of former experimental. Activities of digestive enzyme in pancreas and intestinal chym of ducks in Group1and2were determined at d7、14、21、28and42,while that were determined at21、28and42d in Group3. The results showed:1) Trypsinase activity of ducks in Group2was extremely significantly higher than that in Group1at d7,21and42(P<0.01), and significantly higher at28d (P<0.05).At21d, Trypsinase activity of ducks in Group3was enhanced extremely significantly compared with that in Group1(P<0.01), and was extremely significantly higher than Group1and2(P<0.01) at28d, while was extremely lower than Group2(P<0.01) but no difference with Group1at42d. Amylopsin activity of ducks in Group2was extremely significantly higher than that in Group1(P<0.01) at d7and42, while improved significantly (P<0.05) at28d. Amylopsin activity of ducks in Group3was greatly significantly lower than that in Group2(P<0.01) but no difference compared with that in Group1(P>0.05) at d28and42. Pancreatic lipase activity in Group2was extremely significantly higher than that in Group1at d7and21(P<0.01). Pancreatic lipase activity in Group3was no difference compared with Group2but extremely significantly higher than that in Group1(P<0.01) at21d, while significantly lower compared with Group2(P<0.05) but no difference compared with Group1(P>0.05) at28d;2) There was no significantly difference in all parts of intestine among all groups at any time points (P>0.05). The change trend of protease activity in intestinal contents of ducks showed increased first and then decreased with aging in Group1and2. The amylase activity in intestinal contents of ducks enhanced firstly then degraded finally enhanced with aging in Group1and2. The amylase activity in duodenum of14d ducks and jejunum of7d ducks in Group2was greatly significantly higher than that in Group1(P<0.01). The amylase activity in duodenum ducks in Group3significantly lower than that in Group2at21d (P<0.05), however, there seemed a increasing trend compared with Group1(P>0.05). Along with aging, lipase activity in content of duodenum and ileum of ducks in Group1and2increased first and then dropped and increased at last, while that of jejunum decreased first and then increased. Compared with Group1, lipase activity in duodenum of42d ducks, in jejunum of28d ducks and ileum of d14,21and28ducks in Group2was increased significantly(P<0.05) and that in jejunum content enhance greatly significantly at7d.Lipase activity of duodenum content of ducks in Group3was significantly higher than that in group1in duodenum at28d(P<0.05), and was significantly higher than that in Group1at28d and group2at42d in jejunum(P<0.05), while was significantly lower than that in Group2in ileum at d21and28(P<0.05);3) The changing trend of sucrase activity in jejunum mucosa of ducks in Group1and2was increased with aging. Compared with Group1,sucrase activity in jejunum mucosa of ducks in Group3was significantly lower at28d(P<0.05). With aging, sucrase activity in jejunum mucosa of ducks in Group1increased firstly and then decreased slightly and increased last. In Group2while increased firstly then decreased slightly and increased subsequently, peaked at28d, and decreased finally. Sucrase activity in jejunum mucosa of ducks in Group2was significantly higher than that in group1and3at28d.In the third part, effects of nondigest enzyme compound on the expression of pancreatic enzyme mRNA in ducks and its carry-over effects was investigated. Birds were suffered from the same proposal of former experimental.Expression of pancreatic digestive enzyme was determined at d21,28and42among all groups.The results showed that:1) The expression of amylopsin increased with age among all treatment groups. Expression of amylopsin of ducks in Group2was higher than that in Group1by66.21%,33.76%and27.61%(P>0.05) at d21,28and42respectively;2) The expression of trypsinogen decreased as age among all groups. Compared with group1, expression of trypsinogen in group2and3enhanced by32.91%and17.57%at21d, by10.14%and48.95%at42d, while dropped by4.58and16.54%at28d(p>0.05).