Effect of phytase on phosphorous balance in 20-kg barrows fed low or adequate phosphorous diets

• 作者: Michael J.Azain Michael R.Bedford Robert Dove Tsung Cheng Tsai
• 来源期刊: 动物营养:英文版
• 学科: 农学
• 关键词: Phosphorous PHYTASE Bone Calcium DIGESTIBILITY Tissue
• 年，卷（期）: dwyyywb_2020,（1）
• 页码范围: 9-15
• 页数: 7页
• 分类号: S828.5

摘要

The effects of phytase on phosphorus(P)digestibility are well established.However,there are few studies that report P balance,particularly when phytase is used in diets that have adequate or deficient P.The main objective of the study was to determine the effect of dietary P levels and exogenous phytase on P balance in growing pigs.The first part of the experiment was a 14-d metabolism study conducted with 80 barrows(initial body weight 18.5±0.5 kg)with a 2 x 5 factorial arrangement of treatments and main effects of available P(0.13%available P,low P[Low-P]diet;0.35%available P,adequate P[Adeq-P]diet)and phytase(0,250,500,2,500,and 12,500 U/kg).A portion of the pigs(n=24)fed the Low-P diet,with0,500,2,500,12,500 U/kg phytase,and those fed the Adeq-P diet,with 0 and 12,500 U/kg phytase,remained on test diets for another 4 d,and tissues were collected for determination of bone characteristics and tissue P concentration.There was a P×phytase interaction for P retention that was accounted for by a lack of re sponse to phytase in pigs fed the Adeq-P diet.Retention of P was greater with incremental levels of phytase in pigs fed Low-P diets as compared to those fed Adeq-P diets(P level x phytase,P<0.01),but calcium(Ca)retention was greater in pigs fed Adeq-P diets(P level x phytase P<0.01).Apparent total tract digestibility(ATTD)of P was improved by phytase(P<0.001)and was greater in pigs fed Adeq-P diets as compared to those fed Low-P diets(P=0.006).Metatarsal bone ash(quadratic,P=0.01)and strength(linear,P=0.03)was increased by phytase addition to the Low-P diets.There were no phytase or dietary P effects on P concentrations of the heart,kidney,liver,muscle,and spleen.These results suggest that as compared to the effects in an Adeq-P diet,adding phytase to a Low-P diet was more effective at reducing the P and Ca excretion and restoring average daily gain(ADG).The P released by phytase is absorbed and contributes to improved bone growth,greater rates of tissue accretion,and increased body weight,but does not change t