不同水溶性的果胶和木聚糖对中华绒螯蟹生长及饲料利用性的影响

为了探究非淀粉多糖(NSPs)对中华绒螯蟹生长和饲料利用性的影响及其作用机制,以水溶性果胶(SP)、水不溶性果胶(ISP)、水溶性木聚糖(SX)和水不溶性木聚糖(ISX)为材料,按照12%的比例添加到饲料中饲养初质量(1.6±0.7)g的河蟹13周。分析测定了饲料粘性及各组河蟹特定生长率、饲料系数、营养物质和能量保留率、体成分、血清胆固醇、甘油三脂、肝胰腺脂肪酶和淀粉酶活性等指标。结果显示,4种饲料的粘性差异较大,SP组最高,ISP组其次,ISX组最低。各组河蟹的特定生长率、体成分和消化酶活性差异不显著(P0.05)。SP组饲料系数高于ISP组和SX组(P0.05),ISX组饲料系数与其他各组差异不显著(P0.05)。SP组的蛋白、脂肪和能量保留率低于ISP组(P0.05),而SX组的蛋白保留率高于ISX组(P0.05),且ISP和SX组间差异不显著(P0.05);NSP的溶解性不影响血清总胆固醇水平(P0.05),但ISP组低于SX组和ISX组(P0.05)。上述研究结果提示,实验NSPs影响河蟹对饲料营养物质的利用,其影响机制可能与粘性有关而与溶解性无关,粘性过高或过低都会降低河蟹对饲料的利用;NSPs可能影响河蟹胆汁酸的重吸收但不影响河蟹对饲料脂肪的利用。

Effect of pectin and xylan with different solubility on growth and feed utilization of Chinese mitten crab, Eriocheir sinensis

In order to explore the effect and action mechanism of non-starch polysaccharides (NSPs) on growth and feed utilization of Chinese mitten crab, Eriocheir sinensis. Soluble pectin (SP), insoluble pectin (ISP), soluble xylan (SX) and insoluble xylan (ISX) were included in test diets at 12% and were fed juvenile Chinese mitten crab, whose initial body weight was (1.6±0.7) g, for 13 weeks. Diet viscosity, special growth rate, feed conversion ratio, energy and nutrients retention, body composition, serum cholesterol and triglyceride, activity of lipase, amylase in hepatopancreas were measured. The results showed that dietary viscosity varied greatly, with diet containing SP the highest, followed by diet containing ISP, and diet containing ISX the lowest. No significant difference was observed in special growth rate, body composition and digestive enzyme activity among groups (P > 0.05). Feed conversion ratio of group SP was higher than of group ISP and group SX (P < 0.05) while no significant difference was detected between group ISX and other groups (P > 0.05). Retention of protein, lipid and energy of group SP was lower than that of group ISP (P < 0.05), however, protein retention of group SX was higher than group ISX (P < 0.05) and no significant difference was detected between group ISP and group SX. No significant difference was observed in serum cholesterol between soluble and insoluble NSPs (P > 0.05). However, it was lower in group ISP than in group SX and ISX (P < 0.05). These results suggested that tested NSPs influence the nutrients utilization of Chinese mitten crab, which might attribute to their viscosity but not the solubility. Both high and low viscosity of diet would reduce feed utilization. NSPs might decrease the resorption of bile acid but not lipid utilization.