植酸酶对中华绒螯蟹幼蟹生长、消化性能及物质利用率的影响

为探讨植酸酶对中华绒螯蟹(Eriocheir sinensis)幼蟹生长、消化性能及物质利用率的影响, 设计了6种配合饲料, 以不含植酸和植酸酶的组别为对照组(C), 在含有10 g/kg植酸的饲料中, 分别加入0、500、1000、1500 U/kg的植酸酶, 分别记为P0、P500、P1000、P1500和P2000。投喂初始体重为(4.34±0.05) g的幼蟹, 56d后称重并取样分析。结果发现: P0幼蟹增重率、特定生长率、蛋白质效率低于对照组, 饲料系数则高于对照组(P<0.05); 幼蟹增重率、特定生长率、蛋白质效率随着饲料中植酸酶含量的增加而升高, 在P2000达到最高, 且该组的饲料系数最低(P<0.05); P1500和P2000全蟹体磷含量显著高于P0 (P<0.05); 在P2000中, 幼蟹肝胰腺中胰蛋白酶、淀粉酶以及肠道胰蛋白酶活力达到最高(P<0.05); 中华绒螯蟹蛋白质消化率和磷透析率随着饲料中植酸酶含量的增加而逐渐升高, 其中P2000显著高于P0(P<0.05), 与对照组无显著差异(P>0.05); P2000幼蟹的氮、磷保留率最高(P<0.05)。以上结果表明, 在含有植酸的饲料中添加2000 U/kg的植酸酶, 能够显著提高幼蟹的生长和胰蛋白酶活力, 进而提高幼蟹对蛋白质的利用率, 降低饲料系数。此外, 植酸酶的添加也能有效提高幼蟹体磷含量和氮/磷保留率。

EFFECTS OF PHYTASE ON GROWTH,DIGESTION AND NUTRIENT UTILIZATION OF JUVENILE CHINESE MITTEN CRABS (ERIOCHEIR SINENSIS)

To investigate the effects of phytase on the growth, digestibility and nutrient utilization of juvenile Chinese mitten crab Eriocheir sinensis, six diets were designed that included the control group with no phytic acid (C) and phytase and five experimental groups with 10 g/kg of phytic acid and 0, 500, 1000, 1500 or 2000 U/kg phytase that were named as P0, P500, P1000, P1500 and P2000, respectively. Juvenile crabs with an initial body weight of (4.33±0.05) g were fed with these diets for 56 days. The results showed that the weight gain rate, specific growth rate and protein efficiency of the juvenile crabs in P0 group were lower than those of the C group, and the feed coefficient was higher than that of the C group (P<0.05). The weight gain rate, specific growth rate and protein efficiency of juvenile crab increased with the increased phytase with the highest one in P2000 that had the lowest feed coefficient (P<0.05). Phosphorus content of whole crabs of P1500 and P2000 was significantly higher than that of P0 (P<0.05). P2000 had the highest trypsin activity, amylase activity in the hepatopancreas and trypsin activity in the intestine of juvenile crabs (P<0.05). The protein digestibility and phosphorus dialysis rate of Eriocheir sinensis increased gradually with the increased phytase. P2000 had the highest nitrogen and phosphorus retention rates (P<0.05). These results indicated that 2000 U/kg phytase in the diet can significantly increase the growth, protein utilization rate and trypsin activity, and reduce the feed coefficient of juvenile crabs fed the diets containing phytic acid, and promote nitrogen/phosphorus deposition rate of juvenile crabs.