麦麸、细菌性植酸酶和柠檬酸对肉鸡提高钙、磷和蛋白质利用的影响

以23%粗蛋白（CP）的玉米豆粕日粮为正对照,以添加了15%麦麸（提供内源性植酸酶）的低营养玉米豆粕日粮（21%CP）为负对照,研究内源性及细菌性植酸酶和柠檬酸在低营养肉鸡日粮中对肉鸡生长的作用.实验结果表明：所有组的胫骨灰分差异不显著（P＞0.05）.添加细菌性植酸酶或柠檬酸的日增重（ADG）、肉料比（G/F）和钙利用率与正常营养水平组差异不显著（P＞0.05）,但粪磷排泄量和蛋白质的利用率显著低于正对照组（P＜0.05）,磷的利用率极显著高于正对照组（P＜0.01）.已添加内源性植酸酶组除ADG、G/F和CP利用率低于正对照组外,其它的差异不显著（P＞0.05）.三者同时添加（第5组）的粪磷排泄量降低了1.4%（P＜0.05）;钙的利用率极显著地高于其它4个组（P＜0.01）,最大提高了7.2%;G/F与第1组相当,增高3.9%;在蛋白利用率上也显著地高于其它3个组,高出2.3个百分点（P＜0.05）.可以看出内源性及外源性植酸酶和柠檬酸在肉鸡的生长方面能起到补充或协同的作用.

Effect of Wheat Middlings,Microbial Phytase,and Citric Acid on Phytate-phosphorus,Calcium and Protein Utilization of Broilers

A corn-soybean meal diet containing 23% crude protein(CP) was used as the positive control(CSB)(or Diet 1),and another corn-soybean meal diet containing 21% CP and 15% wheat middlings was used as negative control(WM)(or Diet 2).Through comparison and analysis for effects of citric acid,intrinsic phytase and microbial phytase in the low-nutrient chick diets,the results showed five treatments had similar effects on Tibia ash(%)(mg)(P>0.05).Under the supplementation of bacterial phytase or citric acid,The daily body weight gains(ADG),Gain:feed(G:F)ratio and Calcium(Ca) utilization were similar to that of the standard-nutrient CSB diet(Diet 1)(P>0.05).Fecal P and CP utilization were lower than(P<0.05) that of Diet 1.But P utilization was significantly higher than(P<0.01) that of Diet 1.However the ADG,G/G and CP utilization produced by supplementation of intrinsic phytase were lower than that of Diet 1,but other aspects were similar to that produced by Diet 1(P>0.05).In Diet 5,intrinsic phytase,bacterial phytase and citric acid were added to the dietary,which produced a 1.4% decrease fecal P(P<0.05),a 7.2% increase Ca utilization that was significantly higher than(P<0.01) that of other 4 Diets,a 3.9% increase G/F that was similar to that of Diet 1,and a 2.3% increase CP utilization that was higher than(P<0.05) that of other 3 Diets.In summary,results of this study indicated that citric acid,intrinsic phytase and bacterial phytase might have some additive or synergistic effects for broilers.