饲料中添加植酸酶对草鱼生长、体组成及各组织磷含量的影响

Effect of phytase on growth, body composition and phosphorus content in tissues of juvenile grass carp(Ctenopharyngodon idellus) fed plant protein based diet

摘要:

选用初重为（39.68±3.05） g的草鱼(Ctenopharyngodon idellus)幼鱼作为试验对象，在全植物蛋白基础饲料中添加植酸酶，设5种不同的植酸酶添加水平（500 U/kg、750 U/kg、1 000 U/kg、1 250 U/kg、2 500 U/kg），另设2个对照组，对照组1：全植物蛋白基础饲料中只添加1.5%的无机磷；对照组2：全植物蛋白基础饲料不添加植酸酶和无机磷，通过60 d的试验，探讨和研究植酸酶对草鱼生长、体组成及各组织磷含量的影响。结果表明，对照组1鱼体的特定生长率最大，饲料系数显著低于其它各组（P<0.05）；与对照组2相比较，全植物蛋白饲料中添加植酸酶后，当植酸酶添加水平大于1 000 U/kg时，草鱼的饲料系数显著降低、蛋白质效率得到显著提高；植酸酶对草鱼的形体指标没有显著影响；当植酸酶添加水平大于1 000 U/kg时鱼体粗脂肪含量有所降低；当植酸酶添加水平为1 000 U/kg时，其肌肉粗脂肪含量显著提高；添加植酸酶后鱼体、肌肉和脊椎骨中的磷含量有一定提高，且当植酸酶添加水平为1 250 U/kg时，肌肉和脊椎骨中的磷含量显著提高。结果表明，当植酸酶添加水平在1 000 U/kg～1250 U/kg时，与对照组2相比较，全植物蛋白饲料中添加植酸酶可提高草鱼的特定生长率和蛋白质效率、降低饲料系数，并显著提高草鱼磷的积累。若欲减少无机磷添加量，建议植酸酶添加水平为1 000 U/kg～1 250 U/kg。

Abstract:

An 8week laboratory trial was designed to study the effect of phytase on growth, body composition and phosphorus content in tissues of juvenile grass carp (〖WTBX〗C. idellus〖WTBZ〗) fed plant protein based diet. Seven trial diets were formulated to feed fish (with mean initial body weight of 39.68±3.05 g) that were divided into 5 experimental groups and 2 control groups. Five triplicate experimental groups were supplemented with five different levels of phytase (500 U/kg, 750 U/kg, 1 000 U/kg, 1 250 U/kg, 2 500 U/kg). The positive control group was supplemented with 1.5% monobasic calcium phosphate; and the negative control group was not supplemented with phytase and monobasic calcium phosphate. Through 60 d experiment,the effects of phytase were examind on growth, body composition and phosphorus content in tissues of juvenile grass carp(C. idellus)fed plant protein based diet.The results showed that，the feed conversion rate (FCR) was significantly lower, whereas protein efficiency ratio (PER) and specific growth rate (SGR) were significantly higher than those of other groups (P<0.05), when only monobasic calcium phosphate was supplemented. Compared with negative control group，after added phytase in diet, when the supplemented level of phytase was higher than 1 000 U/kg, the FCR of experimental group 3 (1 000 U/kg) was significantly lower than that of negative control group (P<0.05)，and PER was significantly higher than that of negative control group (P<0.05); The phytase has no effcets on the HSI, VSI, and CF of fish; the content of crude fat decreased in body, when the phytase content was higher than 1000U/kg, when the supplemented level of phytase content was 1 000 U/kg, the crude fat in muscle was significantly improved; The phosphorus content was enhanced to some degree in body, muscle and spine after added phytase, and when the content was 1 250 U/kg, the phosphorus content were significantly improved in muscle and spine. The result indicated that, when the supplemented level of phytase was 1 000 U/kg-1 250 U/kg, the SGR, PER and phosphorus content of grass carp were enhanced, and FCR was improved compared with negative control group. If you want to reduce the supplemented level of monobasic calcium phosphate, the suitable supplemented level of phytase was 1 000 U/kg-1 250 U/kg.