肉用雏鸡在采食条件下卵黄囊内营养素的转移和耗用

NUTRIENT TRANSFER IN YOLK SAC OF FEEDING CHICK

以４６２只刚出壳的星杂（ｓｔａｒｂｒｏ）商品代雏鸡分成５组。１，２，３和５组饲喂代谢能２．９３兆卡／千克和蛋白质２３．８％的基础日粮，并分别依次含有赖氨酸和蛋氨酸是１．１３％和０．３６％；１．１３％和０．４６％；１．２２％和０．５１％；１．４２和０．５８％。另一组为绝食组。所有５组雏鸡相继在１２、５８，１０６、１３０时龄窒死，并按时龄测定全屠体和卵黄囊的重量、含水量、燃烧值（能量）、蛋白质和氨基酸。在１２～５８时龄将近两天的时间内，采食组每只雏鸡只增重２克左右，但绝食组则损失体重５．６克。这说明对刚出壳的雏鸡尽早布料的重要性。采食组雏鸡在１２～１３０时龄全期内日增重约７克。在１２～５８时龄内采食组（以第Ⅱ组为例）卵黄囊内的燃烧值、蛋白质、赖氨酸和蛋氨酸含重分别减少１９千卡、１．１克、８０毫克和３６毫克，而同期内的全屠体则相应只减少８千卡、０．２克、３０毫克和１０毫克。这些数值说明，即便在采食条件下雏鸡需要的燃烧值１１千卡，蛋白质０．９克，赖氨酸５０毫克，蛋氨酸２６毫克也完全由卵黄囊提供。在５８～１０６时龄阶段内全屠体燃烧值、蛋白质、赖氨酸和蛋氨酸含量分别增加１６千卡、１．２克、８０毫克和１０毫克，而同期卵黄?

Four hundred and sixty-two newly-hatched commercial Starbro broilers were dividedinto 5 groups.Group 1,2,3 and 5 were fed on the basal diet containing ME 2.98 Mcal/kg and CP 23.8%, the level of Lys and Met were 1.13%,0.36%;1.13%,0.46%;1.22%,0.51%;1.42%,0.58%respectively. The other group was fasted. Chickens ofeach group were kiIled by anaesthesia at the age of 12, 58, 106, and 130 hours.Wei-ght,water content,energy(heat value),CP and amino acids were determined on thebasis of whole body and yolk sac respectively.During the period of 12～58 hours old,the fed groups gained about 2g/cbick ,andthe fasted group lost 5. 6g/chick.It suggested the importance of providing the newly ha-tched chicks with feeds as early as possible,The ADG 0f feeding groups was about7gthrough the whole period.The content of energy (heat value),CP, Lys and Met in yolk sac (for examplegroup2) decreased by 19 Kcal,1.1g,80mg and 36mg respectively from the age of 12to 58 hours,the corresponding indexes ofwhole body decreased only by 8 Kcal,0.2g,30mg and 10mg.These data showed the requirement of energy(heat vale),CP, Lysand Met,which、vere 11 Kcal,0.9g,50mg and 26mg,was completely come from yolkasc, Duringthe period 58～106 hours-old,the content of energy(heat value),CP,Lysand Met ii1cresed by 16 Kcal,1.2g,80mg and 10mg respectively on the basis of wholebody, but the corrsponding parameters of yolk sac decreased by 4 Kcal,0.5g,30mgand19mg. These data showed the nutrient sources of chicks had been exchanged from yolk sac to diet .In group 5(Lys 1.42%, Met 0.58%in diet), the content of Lys and Met inyolk sac did not decreased as other feeding groups during the period of 106～130 hoursold, but increased 7mg and 2mg respectively.It suggested the malabsorption of yolk sac.Parameters after 130 hour had not been determined because the yolk sac was too smallto get enough samples.