肉鸡玉米型日粮添加高剂量植酸酶对其养分利用的影响

Effects of high dose phytase on nutrient utilization of broilers fed with maize-based diet

文章旨在研究肉鸡饲粮中植酸酶水平从1000 FTU/kg(行业推荐水平)提高到2500 FTU/kg(超剂量水平)对肉鸡养分回肠表观消化率系数和氮平衡校正表观代谢能值的影响。试验选择360只1日龄雄性肉仔鸡,随机分为3组,每组4个重复,每个重复30只肉鸡。试验1~14 d饲喂基础日粮(前期料),在15~21 d期间饲喂3种日粮,即正对照日粮(不含植酸酶)、负对照日粮(1000 FTU/kg植酸酶),植酸酶组日粮(2500 FTU/kg植酸酶)。负对照组日粮除钙和非植酸磷含量降低1.80 g/kg和1.50 g/kg外,其余营养指标均与正对照组日粮相同。结果显示,正对照组日粮的总能和粗蛋白质回肠表观消化系数显著高于负对照组(P <0.05)。正对照组日粮中淀粉、钙、磷的回肠表观消化系数与负对照组日粮无显著差异(P> 0.05)。正对照组日粮的氮校正表观代谢能显著低于负对照组日粮(13.34 MJ/kg和14.46 MJ/kg,P <0.05)。负对照组日粮中植酸酶水平从1000 FTU/kg升高至2500 FTU/kg,导致总能和粗蛋白质回肠表观消化系数分别升高2.5%和7.1%(P <0.05),且磷有显著升高的趋势(10.4%,P=0.08)。此外,负对照组日粮中植酸酶水平从1000 FTU/kg升高至2500 FTU/kg时对淀粉回肠表观消化系数和日粮的氮校正表观代谢能值无显著影响(P> 0.05)。综上所述,日粮超剂量植酸酶水平(≥2500 FTU/kg)在改善玉米能量、蛋白质和磷在回肠消化率的效率要优于肉鸡行业推荐水平。

The purpose of this study was to study the effect of dietary phytase level in broilers on coefficient of apparent ileal digestibility(CAID)of nutrient and apparent metabolic energy value of nitrogen balance correction from 1000 FTU/kg (recommended level in the industry)to 2500 FTU/kg(overdose level). A total of 360 male broilers of 1 d-old were randomly divided into 3 treatment groups with 4 replicates in each group and 30 broilers in each repeat. In the experiment,the basic diet (prophase feed)was fed on day 1~14,and three diets were fed during period 15~21,namely,the positive control die(t without phytase),the negative control diet(1000 FTU/kg phytase),and the phytase group diet(2500 FTU/kg phytase).Except for the decreasing of 1.80 g/kg of calcium and 1.50 g/kg of phosphorus phytate,the other nutritional indicators were the same as the positive control group. The results showed that the CAID of total energy and crude protein in the positive control group were significantly higher than that in the negative control group(P < 0.05). The CAID of starch,calcium and phosphorus in the positive control diet were not significantly different from that in the negative control diet(P > 0.05). The nitrogen corrected apparent energy of the positive control diet was significantly lower than that of the negative control diet(13.34 MJ/ kg and 14.46 MJ/kg,P < 0.05). Phytase levels in the negative control diet increased from 1000 to 2500 FTU/kg,resulting in an increase in CAID of total energy and crude protein by 2.5% and 7.1%,respectively(P < 0.05),and a significant increase in phosphorus(10.4%,P=0.08). In addition,when the phytase level in the negative control diet increased from 1000 to 2500 FTU/kg,there was no significant effect on the CAID of starch ileum and the nitrogen correction apparent metabolic energy value in the diet(P > 0.05). In summary,dietary overdose phytase level(≥ 2500 FTU/kg)was more effective in improving CAID of energy,protein and phosphorus in corn than recommended levels in broiler diets.