盐度对瘤背石磺(Onchidium struma)消化酶活性的影响

为探讨盐度对瘤背石磺(Onchidium struma)不同消化器官蛋白酶、淀粉酶和纤维素酶活性的影响,试验选用1 200只个体均一的瘤背石磺[初均重(16.82±2.14)g]随机分成5组,分别置于不同盐度梯度(5、15、25、35和45)下饲养,期间用海泥与螺旋藻粉(m∶m=5∶1)拌饲投喂。每组设置3个重复,每个重复80只,饲养30 d后测定消化道不同器官蛋白酶、淀粉酶和纤维素酶活性。试验结果显示:1)各消化酶在幽门胃、贲门胃、肝胰腺和肠中均有分布,但各消化器官之间酶活性差异显著(P<0.05)。不同消化器官中蛋白酶活性由大到小依次为幽门胃[(91.46±0.57)U/g]、肝胰腺[(72.63±0.59)U/g]、肠[(44.78±0.66)U/g]和贲门胃[(40.12±0.45)U/g];淀粉酶活性由大到小依次为肝胰腺[(87.11±1.31)U/mg]、幽门胃[(45.72±1.06)U/mg]、肠[(26.52±1.05)U/mg]和贲门胃[(23.68±0.82)U/mg];纤维素酶活性以肝胰腺[(2.02±0.01)U/mg]最高,其次是肠[(1.01±0.01)U/mg],最低的是幽门胃[(0.53±0.01)U/mg]。2)盐度对各种消化酶活性的影响差异显著(P<0.05)。除肝胰腺中的蛋白酶以外,幽门胃、贲门胃、肝胰腺和肠中各消化酶活性随盐度升高均呈先上升后下降的趋势,且淀粉酶和纤维素酶分别在盐度15和25时活性最高,盐度45时活性最低。试验结果表明,低盐度(盐度5～25)对各消化器官消化酶活性均具有激活作用;其中,盐度15～25时消化酶活性最高,有利于瘤背石磺对饵料的消化吸收;而当盐度高于25时,则会抑制消化酶活性。

Effects of Salinity on Digestive Enzyme Activities of Onchidium struma

The objective of this study was to evaluate the effects of salinity on the activities of protease,amylase and cellulose in the different digestive organs of Onchidium struma.One thousand and two hundred individuals with an initial average body weight of(16.82±2.14) g were randomly divided into 5 groups with 3 replicates per group and 80 individuals per replicate.The Onchidium struma were raised 30 days under different salinities(5,15,25,35 and 45),fed with sea mud mixed with spirulina powder(m∶m=5∶1),and the activities of protease,amylase and cellulose in different digestive organs were measured.The results showed as follows: 1) digestive enzymes were distributed in the pyloric stomach,cardiac stomach,hepatopancreas and intestine,while the digestive enzyme activities among these organs were significantly different(P<0.05).The descending order of protease activity of different digestive organs was pyloric stomach [(91.46±0.57) U/g],hepatopancreas [(72.63±0.59) U/g],intestine [(44.78±0.66) U/g] and cardiac stomach [(40.12±0.45) U/g],while the amylase activity of hepatopancreas was the highest [(87.11±1.31) U/mg],followed by pyloric stomach [(45.72±1.06) U/mg],intestine [(26.52±1.05) U/mg] and cardiac stomach [(23.68±0.82) U/mg],and the hepatopancreas also owned the highest cellulose activity [(2.02±0.01) U/mg],followed by the intestine [(1.01±0.01) U/mg],and the pyloric stomach [(0.53±0.01) U/mg] was the lowest.2) Salinity had a significant influence on the digestive enzyme activity(P<0.05).The activities of the digestive enzymes of all digestive organs had a trend of decreasing after an initial increase with the salinity rising except the protease activity of hepatopancreas.The activities of amylase and cellulose were the highest at salinity 15 and 25,respectively,and were the lowest at salinity 45.The results indicate that low salinity(salinity 5 to 25) can increase the three digestive enzyme activities in the digestive organs of Onchidium struma;digestive enzyme activity is the highest at salinity 15 to 25,which will be beneficial to the digestion and absorption.However,the digestive enzyme activities may be inhibited when salinity is above 25.