| Digestive enzyme was a kind of erzymes that secreted by digestive gland and digestive organ,and it played an important role at digesting food. The research of denomination, distribution andactivity of digestive enzyme was significant. Because ecological environment was destrotedseriously, the number of Lenok declined in china, it faced the danger of extinction. To protect thisrare species, some institutions artificially acclimated Lenk. They use artificial diet instead of naturediet, and have gained some advancement. In this study, the distribution and activity of protease,amylase and lipase was determinated in wild acute snout, blunt snout Lenok of Mudanjiang andWusulijiang population, wild young fish of Mudanjiang population and artificial breeded F1 ofWusulijiang population. The result was:Digestive enzymes activities distribution different in digestive organ. Protease, amylase andlipase activities were higher in stomach; lipase and protease activities were higher and amylaseactivities were weaker in pyloric caeca; lipase and amylase activities were higher, proteaseactivities were weaker in intestinal tract. All show that the digestion and absorption of proteinconcentrated in stomach; intestine tract, stomach and pyloric caeca were the main organ that digestscarbohydrate; the digestion and absorption of fat concentrated in stomach and intestinal tract.Digestive enzymes activities in digestive organ different among population, digestive organand different parts of the intestinal tract. Among different population, protease, amylase and lipaseof adult fish were no significant difference in digestive organ (P＞0.05); the lipase activity of wildyoung fish of Mudanjiang population was significantly higher than adult fish of Mudanjiangpopulation in pyloric caeca (P＞0.05), this indicate that the digestive ability of young fish washigher than adult fish; The lipase activity of artificial breeded F1 of Wusulijiang population wassignificantly higher than adult fish of Wusulijiang population in esophageal (P＜0.05); Theamylase activity ofself-producted F1 of Wusulijiang population were significantly higher than wildacute snout of Wusulijiang population in stomach, pyloric caeca, esophagus and intestinal tract (P＜0.05). It may be result from self-producted population chronically adapt to artificial diets.The protease activity order of wild adult fish of different population were foregut＞hindgut＞midgut in intestinal tract, the protease activity of foregut was significantly higher than midgut (P＜0.05); the protease activity order of wild young fish of Mudanjiang population was foregut＞midgut＞hindgut in intestinal tract, the protease activity of foregut was significantly higher thanhindgut (P＜0.05). The amylase activity of artificial breeded F1 of Wusulijiang population inforegut was significantly higher than midgut and hindgut in intestinal tract (P＜0.01), the amylaseactivity order was foregut＞midgut＞hindgut; amylase activity of other population in intestinal was uniform distribution, and no significant difference (P＞0.05). The lipase activity order of wildacute snout of Wusulijiang population was hindgut＞midgut＞foregut, the lipase activity ofhindgut was significantly higher than midgut and foregut (P＜0.05); The lipase activity order ofwild blunt snout of Wusulijiang population was foregut＞hindgut＞midgut, and the lipase activityof foregut was significantly higher than hindgut (P＜0.01), in intestinal tract, the lipase activity ofwild acute snout, blunt snou, young fish of Mudanjiang population and artificial breeded F1 ofWusulijiang population was uniform distribution, and no significant difference(P＞0.05).The protease activity order in digestive organ was pyloric caeca＞esophagus＞stomach＞intestinal tract in wild blunt snout, artificial breeded F1 of Wusulijiang population, wild acute snout,blunt snout, young fish of Mudanjiang population. The protease activity in pyloric caeca wassignificantly higher than intestinal tract (P＜0.05). The protease activity order was stomach＞pyloric caeca＞esophagus＞intestinal tract in wild acute snout of Wusulijiang population, proteaseactivity in stomach was significantly higher than intestinal tract, esophagus (P＜0.05) and pyloriccaeca (P＜0.01). In wild blunt snout of Wusulijiang population and wild acute snout, young fish ofMudanjiang population, the amylase activity in digestive organ have no significant difference (P＞0.05), the amylase activity order in digestive organ was stomach＞intestinal tract＞esophagus＞pyloric caeca, amylase activity order of artificial breeded F1 of Wusulijiang population in digestiveorgan was stomach＞pyloric caeca＞intestinal tract＞esophagus. In wild acute snout, bluntsnout, self-producted F1 of Wusulijiang population and wild blunt snout of Mudanjiang population,the lipase activity in digestive organ have no significant difference (P＞0.05).The optimum pH value of pepsin activity was 2.6, the optimum pH value of erepsin activitywas 10.2～10.4 in different population.The result show, among four different wild populations, neither acute snout nor blunt snouthas significant difference in the activity of digestive enzymes. This show, morphologicaldifferences of snout have no direct influence on various digestive enzyme activity; but betweenadult fish and young fish, wild population and artificial breeded population, part of digestiveenzyme activity have significant difference, this show the digestive ability of young fishsignificantly higher than adult fish; artificial breeded population digestive ability significantlyhigher than wild population, this may be result from young fish adapt to rapid growth and artificialbreeding populations adapt to high-energy feed. |
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