果胶和木聚糖对中华绒螯蟹生长性能和消化生理的影响

Effects of Pectin and Xylan on Growth Performance and Digestive Physiology of Chinese Mitten Crab(Eriocheir sinensis)

为了揭示植物性饲料中非淀粉多糖(NSPs)对中华绒螯蟹(Eriocheir sinensis)的潜在抗营养作用,本试验研究了果胶和木聚糖对中华绒螯蟹生长性能和消化生理的影响。将果胶、酶解果胶、麦麸(木聚糖源)、酶解麦麸分别以8%、8%、30%和30%的比例添加到饲料中制成试验饲料,饲养初始体重为(5.9±0.4)g的中华绒螯蟹8周,每种饲料3个重复,每个重复50只,过量投饲。消化率试验采用初始体重为(42.0±5.1)g中华绒螯蟹进行,每种饲料3个重复,每个重复15只。结果显示:各组中华绒螯蟹的生长性能差异均不显著(P>0.05)。果胶组血清胆固醇(CHO)、高密度脂蛋白(HDL)和低密度脂蛋白(LDL)含量显著低于酶解果胶组、木聚糖组和酶解木聚糖组(P<0.05),后三者间差异不显著(P>0.05)。果胶组肝胰腺胰蛋白酶活性显著低于酶解果胶组(P<0.05);木聚糖组和酶解木聚糖组肝胰腺胰蛋白酶活性差异不显著(P>0.05),但均显著高于酶解果胶组(P<0.05)。木聚糖组肝胰腺淀粉酶活性显著低于酶解木聚糖组(P<0.05)。中华绒螯蟹对饲料中干物质、蛋白质和脂肪的表观消化率均呈现果胶组<酶解果胶组<木聚糖组<酶解木聚糖组的态势,果胶组干物质和脂肪的表观消化率显著低于酶解果胶组(P<0.05),木聚糖组蛋白质和脂肪的表观消化率显著低于酶解木聚糖组(P<0.05)。各组中华绒螯蟹肠道上皮均覆盖围食膜,未见各组中华绒螯蟹在围食膜厚度、皱襞宽度和皱襞高度上有明显不同。由此得出,果胶和木聚糖会降低中华绒螯蟹对营养物质的消化率,但不影响其肠道形态;果胶和木聚糖对中华绒螯蟹的抗营养作用强度不同,总体上表现为果胶的抗营养作用大于木聚糖。

To reveal the potential anti-nutritional effects of non-starch polysaccharides （NSPs） in plant feed ingredients, the effects of pectin and xylan on growth performance and digestive physiology of Chinese mitten crab （ Eriocheir sinensis） were studied. The pectin, enzymatic hydrolysis pectin, wheat bran （ xylan source） and enzymatic hydrolysis wheat bran were supplied into the experimental diets at 8%, 8%, 30% and 30%, respectively. Chinese mitten crab with an initial body weight of （5.9±0.4） g were over-fed experimental diets for eight weeks. Each experimental diet had 3 replicates with 50 crabs. Chinese mitten crab with an initial body weight of （42.0±2.1） g were used to digestion rate experiments. Each experimental diet had 3 replicates with 15 crabs. The results showed that no significant difference in growth performance of Chinese mitten crab was detected among groups （P 〉 0.05 ）. The contents of serum cholesterol （CHO）, high density lipoprotein （HDL） and low density lipoprotein （LDL） of crabs fed the diet containing pectin were significantly lower than that of crabs fed the diets containing enzymatic hydrolysis pectin, xylan and enzymatic hydrolysis xylan （ P〈 0.05）, and no significant differences were observed among the latter three groups （P〉0.05）. Hepatopancreas trypsin activity of crabs fed the diet containing pectin was significantly lower than that of crabs fed the diet containing enzymatic hydrolysis pectin （P〈0.05） ; no significant difference was detected between crabs fed the di- ets containing xylan and enzymatic hydrolysis xylan （P〉0.05） , but both of them were significantly higher than of crabs fed the diet containing enzymatic hydrolysis pectin （P〈0.05）. Hepatopancreas amylase activity in xylan group was significantly lower than that in enzymatic hydrolysis xylan group （P〈0.05）. The apparent digestibility of dry matter, protein and lipid could be described as pectin grouP 〈 enzymatic hydrolysis pectin grouP〈xylan grouP〈 enzymatic hydrolysis xylan group. The apparent digestibility of dry matter and lipid in pectin group was significantly lower than that in enzymatic hydrolysis pectin （P〈0.05）, and the apparent digestibility of protein and lipid in xylan group was significantly lower than that in enzymatic hydrolysis xylan group （P〈0.05）. The intestinal mucosa of crab was covered by peritrophic membrane （PE）, and no difference was observed in the thichness of PE, the width or height of fold among groups. In conclusion, pectin and xylan can reduce nutrient apparent digestibility, but no impact on intestinal morphology of Chinese mitten crab; pectin and xylan show different intensity of anti-nutritional effects on Chinese mitten crab, and on the whole they demonst pectin higher than xylan.