空怀期云南半细毛羊磷需要量

Phosphorus Requirement for Yunnan Semi-Fine Wool Sheep during Non-Pregnancy

本试验旨在研究饲粮磷水平对空怀期云南半细毛羊生长性能、磷消化代谢及血清生化指标的影响,以确定空怀期云南半细毛羊磷需要量。选择50只体况良好、体重相近且年龄一致的经产2胎空怀期云南半细毛羊,按体重随机分为5组,每组10只,每只羊为1个重复,分别饲喂磷水平为0.19%、0.32%、0.45%、0.56%和0.64%的试验饲粮,饲粮其他营养水平保持一致。试验期共44 d,其中预试期14 d,正试期30 d。在正试期第12天从各组中选取5只母羊进行为期5 d的消化代谢试验。结果表明:1)0.19%和0.32%磷水平组平均净增重和平均日增重显著高于0.45%和0.64%磷水平组(P<0.05),而前者料重比显著低于后者(P<0.05);干物质采食量以0.19%磷水平组最高,显著高于0.45%、0.56%和0.64%磷水平组(P<0.05),而与0.32%磷水平组差异不显著(P>0.05)。2)随着饲粮磷水平升高,空怀期母羊进食磷、粪磷、尿磷、排泄磷、可消化磷和沉积磷显著或极显著提高(P<0.05或P<0.01);而磷表观消化率和磷利用率呈先降低后升高的趋势,0.19%、0.56%和0.64%磷水平组间磷利用率差异不显著(P>0.05)。3)随着饲粮磷水平升高,空怀期云南半细毛羊的血清磷含量、碱性磷酸酶(ALP)活性呈上升趋势,血清降钙素(CT)和瘦素(LEP)含量呈先升高后下降趋势;0.32%磷水平组血清羟脯胺酸(HYP)含量显著高于0.45%和0.56%磷水平组(P<0.05);饲粮磷水平对血清钙、甲状旁腺激素(PTH)和骨钙素(BGP)含量的影响则不显著(P>0.05)。4)进食磷(x)与沉积磷(y_(3))的线性回归方程为y_(3)=0.3091 x-0.0254(R^(2)=0.8934)。综上所述,饲粮磷水平在0.19%~0.32%时有利于空怀期云南半细毛羊的生长,减少磷的排泄量和沉积量,空怀期云南半细毛羊磷维持需要量为0.0822 g/(kg W^(0.75)·d),总磷需要量为0.21~0.33 g/(kg W^(0.75)·d)。

This study was conducted to evaluate the effects of dietary phosphorus(P)level on growth performance,P digestion and metabolism,and serum biochemical indices of Yunnan semi-fine wool sheep during non-pregnancy,and to determine the P requirement for Yunnan semi-fine wool sheep during non-pregnancy.A total of fifty healthy non-pregnant Yunnan semi-fine wool sheep with the similar age and body weight were randomly divided into 5 groups,and each group had 10 replicates containing 1 ewe per replicate.The P level of experiment diets for the 5 groups were 0.19%,0.32%,0.45%,0.56%and 0.64%,respectively,and other nutrient levels were consistent.The experiment lasted for 44 d,including 14 d of pretrial period and 30 d of experimental period.On the 12th day of the experimental period,five ewes were randomly selected from each group and fed individually in cage for digestion and metabolism experiment of 5 d.The results showed as follows:1)the average net gain and average daily gain in 0.19%and 0.32%P level groups were significantly higher than those in 0.45%and 0.64%P level groups(P<0.05),however,the feed/gain in 0.19%and 0.32%P level groups was significantly lower than that in 0.45%and 0.64%P level groups(P<0.05).The highest dry matter intake was observed in 0.19%P level group,which was significantly higher than that in 0.45%,0.56%and 0.64%P level groups(P<0.05),but there was no significant different between 0.19%and 0.32%P level groups(P>0.05).2)P intake,fecal P,urine P,P excretion,digestible P and P retention were significantly or extremely significantly increased with the dietary P level increasing(P<0.05).P apparent digestibility and P utilization were decreased firstly and then increased with the dietary P level increasing.No significant differences were found in P utilization among 0.19%,0.56%and 0.64%P level groups(P>0.05).3)Serum P content and alkaline phosphatase(ALP)activities were increased with the dietary P level increasing.Serum calcitonin(CT)and leptin(LEP)contents were increased firstly and then decreased with the dietary P level increasing.Serum hydroxyproline(HYP)content in 0.32%P level group was significantly higher than that in 0.45%and 0.56%P level groups(P<0.05).Dietary P level had no significant effects on serum calcium(Ca),parathyroid hormone(PTH)and osteocalcin(BGP)contents(P>0.05).4)The correlation between P intake(x)and P retention(y_(3))was showed in the linear regression equation,y_(3)=0.3091 x-0.0254(R^(2)=0.8934).According to above findings,when the dietary P level is 0.19%to 0.32%,it is beneficial to maintain the growth and decrease the excretion and deposition of P.Maintenance P requirement of Yunnan semi-fine wool sheep during non-pregnancy is 0.0822 g/(kg W^(0.75)·d),and the total P requirement is 0.21 to 0.33 g/(kg W^(0.75)·d).