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The sparing effect of phytase in plant‐protein‐based diets with decreasing supplementation of dietary NaH 2 PO 4 for juvenile yellow catfish P elteobagrus fulvidraco
Author(s) -
Cheng Niancheng,
Chen Pei,
Lei Wen,
Feng Meihui,
Wang Chunfang
Publication year - 2016
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/are.12845
Subject(s) - phytase , catfish , biology , zoology , feed conversion ratio , juvenile , dry matter , fish <actinopterygii> , body weight , biochemistry , enzyme , fishery , ecology , endocrinology
An 8‐week feeding trial was conducted to evaluate the sparing effect of dietary phytase on decreasing supplement of dietary sodium dihydrogen phosphate (NaH 2 PO 4 ) in the diets of juvenile yellow catfish P elteobagrus fulvidraco . Seven diets were formulated: one reference group that contained only 2% NaH 2 PO 4 ; one control group that consisted of neither NaH 2 PO 4 nor phytase; and five treatment groups supplemented with 1000 IU kg −1 phytase and 2%, 1.5%, 1%, 0.5%, 0% concentrations of NaH 2 PO 4 . Thus, dietary NaH 2 PO 4 was substituted with phytase at ratios of 0%, 25%, 50%, 75% and 100% respectively. Triplicate tanks were each filled with 50 juvenile fish (3.5 ± 0.1 g), which were fed one of the seven experimental diets. Substituting phytase for NaH 2 PO 4 didn't diminish the growth performance, protein, dry matter, lipid and ash deposit and protein retention in the whole body and reduced feed conversion ratio compared to the reference diet. Moreover, phytase substitution at level of 0–50% enhanced P, Mg and Ca deposit. However, weigh gain had a tendendy of decreasing with increasing substituted level. Phytase substituted level exceeding 75% decreased serum P concentration compared to the control group. Apparent digestibility of P peaked when 1000 IU kg −1 phytase substituted 50% NaH 2 PO 4 . Phytase also increased apparent digestibility of protein. The improvement of digestibility of protein and P resulted in the decrease in N load by 25% and P load by 31% to environment. Therefore, 50% dietary NaH 2 PO 4 can be substituted by 1000 IU kg −1 feed phytase for juvenile yellow catfish.