文献类型： 外文期刊

第一作者： Zhao, Jianfei

作者： Zhao, Jianfei;Cao, Shanchuan;Yin, Heng;Xue, Pengcheng;Liu, Jingbo;Zhai, Hengxiao;Zhai, Hengxiao;Chen, Liang;Zhang, Hongfu

作者机构：

关键词： growing pigs; inositol; phosphorus; phytase; super-dosing

期刊名称：JOURNAL OF ANIMAL SCIENCE （ 影响因子：2.9； 五年影响因子：3.3 ）

ISSN： 0021-8812

年卷期： 2025 年 103 卷

页码：

收录情况： SCI

摘要： This study investigated the effects of super-dosing phytase (up to 3,000 phytase units/kg-FTU/kg) and supplementary dietary inositol (2 g/kg) on phosphorus (P) digestibility and retention (experiment 1), and the growth performance (experiment 2) of growing pigs fed either P-deficient or P-adequate diets. In experiment 1, a total of 96 Duroc x Landrace x Yorkshire barrows [initial body weight (BW) = 37.2 +/- 0.4 kg] were housed individually in 32 stainless steel metabolism cages. The barrows were blocked by BW and randomly allocated to 8 treatment groups, using a randomized complete block design. Experiment 1 was conducted in 3 runs to complete 12 replicate pigs per group. Total feces and urine were collected to determine the digestibility and retention of P. In experiment 2, a total of 2,496 Duroc x Landrace x Yorkshire pigs (initial BW = 24.6 +/- 0.3 kg) were blocked by BW and sex and randomly allocated to 8 treatment groups, using a randomized complete block design with 12 replicates of 26 pigs per pen, per group. The treatment setup was the same across both experiments. The 8 experimental treatments comprised 2 total P levels (deficient, total P = 0.45% and adequate, total P = 0.60%). Within each P level, 4 diets were fed: control (without added phytase), control plus inositol (2 g/kg), control plus phytase (500 FTU/kg), and control plus phytase (3,000 FTU/kg). Phytase supplementation significantly enhanced P digestibility and retention across both P levels. Phytase supplementation at 500 and 3,000 FTU/kg improved P digestibility from 50.3% to 74.4% and 81.3%, respectively, in P-deficient diets, and from 59.2% to 73.5% and 78.0%, respectively, in P-adequate diets. Similarly, P retention increased from 36.6% to 62.6% and 69.6% in P-deficient diets and from 46.0% to 61.6% and 66.3% in P-adequate diets. In addition, phytase supplementation significantly improved the growth performance of pigs, resulting in increased final BW, average daily gain, and gain-to-feed ratio over the 42 d experimental period. Supplementary dietary inositol alone had no observable impact on P metabolism or growth performance. The interaction between dietary P level and phytase supplementation suggested that the optimal benefit of phytase supplementation may depend on the baseline dietary P content. These results suggested that phytase super-dosing enhanced P digestibility and utilization, reduced P excretion, and optimized growth performance in P-deficient diets. These benefits were mainly driven by the digestible P released by phytase, rather than the presence of inositol. The positive effect of super-dosing phytase in pig diets was driven by improved phosphorus digestibility and utilization rather than inositol release. The impact on growth performance can be limited when the dietary P level is adequate. Supplementing pig diets with high levels of the enzyme phytase significantly improves phosphorus (P) utilization and growth performance, offering both environmental and economic advantages. High phytase doses (3,000 FTU/kg) increased pigs' ability to digest and retain dietary P, resulting in improved weight gain and feed efficiency. Supplemental inositol alone did not enhance pig growth or P retention. Phytase super-dosing increased the growth performance of growing pigs by improving nutrient availability, thus reducing feed costs, while inositol supplementation provided minimal additional benefits.

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