低钙磷日粮中添加耐热植酸酶对仔猪钙磷利用的影响

Effects of supplementation of heat-stable phytase in diet with lower calcium and phosphorus contents on utilization of calcium and phosphorus in pig

60头杜长大仔猪(9.8±0.1)kg随机分为2个处理,每个处理3个重复,每个重复10头,对照组饲喂含钙0.62%、磷0.49%的基础日粮,试验组饲喂在基础日粮中添加500U/g植酸酶的日粮。试验期为4周,进行饲养试验。在饲养试验结束时分别从各组每个重复栏中选择1头接近其组平均体重的仔猪进行屠宰,取出其掌骨测定相关指标。另外,选取4头体重相似的生长猪(31±0.6)kg按2×2交叉设计进行消化代谢试验,测定两种试验日粮的相关养分利用率。结果表明:(1)植酸酶组仔猪的鲜掌骨重、脱脂干骨重、脱脂干骨灰分含量、脱脂干骨钙含量和脱脂干骨磷含量分别较对照组提高了9%(P<0.05)、7%、2%、7%(P<0.05)和6%(P<0.05);(2)植酸酶日粮的粗蛋白质表观消化率和表观消化能与对照组差异均不显著(P>0.05),但其钙和磷的表观消化率、钙和磷的存留率均显著高于对照组(P<0.05),分别提高了20%、11%、12%和12%。耐热植酸酶在低钙磷日粮中的添加可促进仔猪对钙磷的利用,从而促进仔猪骨骼发育。

To study the feeding effects of a heat-stable phytase expressed by a gene-engineered yeast on the utilization of calcium（Ca）and phosphorus（P）in pigs,a feeding experiment and a digestion and metabolism trial were carried out using two experimental diets.The two diets were isonitrogenous and isocaloric （20.0 %, 13.39 MJ/kg）with the same Ca （0.62 %）,P （0.49 %）and Ca/P ratio （1.26）.In feeding experiment,60 piglets （9.8±0.1）kg were randomly assigned to 2 groups with 3 replicates of 10 piglets each,the control group was fed with the basal diet,whereas the treatment was fed with phytase diet（PD） which was the basal diet supplemented with phytase of 5000 U/g at 100 g/t.The feeding experiment lasted for 4 weeks.At the end of the feeding experiment,one piglet was selected from each replication of each treatment group and slaughtered for chemical analysis of piglet metacarpus.In the digestion and metabolism trial,4 male pigs （31±0.6）kg were used in a 2×2 reversal experimental design with each pig receiving both diets.The digestibilities of nutrients in the two diet was determined.The results of those 2 experiments showed that： （1）the fresh weight of metacarpus,dry weight,and percentage of ash,Ca and P of defatted metacarpus of the PD group were higher than those of the control group by 9 %（P〈 0.05）,7 % ,2 %,7 %（P 〈 0.05）and 6 %（P 〈 0.05）,respectively; （2）the apparent digestibility of crude protein and apparent digestible energy of PD were not different from those of control group respectively,but the apparent digestibility of Ca and P,and retention of Ca and P were significatly higher than those of control group by 20 %, 11%, 12 % and 12 % ,respectively.The heat-stable phytase supplemented in low-phosphorus and low-calcium diet could improve the utilization of Ca and P and eventually promote the bone growth.