饲粮锌水平对肉鸡组织锌含量的影响

以肉仔鸡(9～27日龄)为试验动物,采用大豆分离蛋白、蔗糖、玉米淀粉及去皮去胚玉米为主的半纯合饲粮,锌水平为10.5 mg/kg,在此基础上,分别添加20,40,60及80 mg/kg 锌,观察饲粮锌水平对肉仔鸡生长发育和组织锌含量的影响。18天的试验结果表明,低锌组(10 mg/kg)除肝脏较重外(P<0.05),其它组织器官发育及体增重均不受饲粮锌水平的影响。促使全鸡及血液锌含量明显增加的饲粮锌水平分别为30及50 mg/kg(P<0.05)。当饲粮锌水平从10 mg/kg 增至30 mg/kg 时,胰脏、肝脏和胫骨锌含量分别增加63%、92%及63%;随着锌水平的继续增加,肝脏及胫骨的锌含量增加的幅度较小,二者(y)与饲粮锌水平(x)呈指数曲线变化,y 肝=61.54e~(-8.67/x)(r=0.95,P<0.01);y 胫骨=53.19e~(-6.92/x)(r=0.88,P<0.01);胰脏锌含量与饲粮锌水平呈正向变化,直线相关:y=37.97±0.34x,(r=0.78,P<0.01)和幂曲线相关:y=18.81x~(0.284),(r=0.82,P<0.01)。胰脏沉积锌的能力远大于肝脏和胫骨。根据上述结果认为,胰、肝和胫骨锌是评价饲料锌效价的良好指标。

STUDIES ON CORRELATION BETWEEN DIETARY ZINC LEVELS AND ZINC BIOAVAILABILITY FOR BROILERS

Female broilers were fed on basal diet with 10 ppm Zn or the basal diet plus 20,40,60 and 80 ppm Zinc of Zn sulphate,respectively.from 9 to 27 days old.Zn concentrations in tissues were determined and the determinants of Zn bioavailability to broilers were discuseed according to the correlation of dietary Zn levels with criteria measured. The growth rate and tissue development of broilers were not significantly affected by the dietary Zn levels except the fresh weight of liver of broilers fed 10ppm Zn diet(P<0.05).When Zn contents in diets were 30 or 50 ppm,Zn concentrations in the whole body or blood were higher than those of the control(P<0.05).When dietary Zn contents were increased from 10 to 30 ppm.,the Zn concentrations rose sharply to 63,92 and 63%(20,24 and 18 ppm).Zn concen- trations in pancreas raised to a great degree and to a some degree in liver and to a slight de- gree in tibia with Zn levels in diets were increased to 90 ppm.There was a approximate corre- lation of index function between dietary Zn levels(X)and liver or tibia Zn(Y)(turn to page 55) (Continned from page 49) liver:Y'=61.54e 8.67/x,r=0.95(P<0.01); tibia:y=53.19e 6.92/x,r=0.88(P<0.01). There was a correlation of power function between dietary Zn levels(X)and pancreas Zn contents(Y),Y=18.81X~(0.284)(P<0.01),the linear regression equation was Y=37.79+0.34X,r=0.79 (P<0.01).According to the correlation between dietary Zn levels and Zn contents in tissues it was suggested that pancreas,liver and tibia Zn contents could be a good determinants of Zn bioavailability for broilers.