幼龄鸡卵黄囊中^3H—VA的吸收代谢及其利用的研究

THE METABOLISM AND UTILIZATION OF ~3H-VITAMIN A IN YOLK SAC OF BROILER CHICKENS

选用出壳后１２时龄的ＡＡ肉雏１４５只，采用放射性同位素＾Ｈ示踪方法，分别进行了饲养试验，屠补试验和代射试验研究表明，在全价日粮和无ＶＡ纯日粮条件下，雏鸡卵黄囊中的内源性３＾Ｈ－ＶＡ在体内发挥持续时间分别为２１天和１４天。卵黄囊（内源）３＾Ｈ－ＶＡ在鸡肠道中的吸收代谢，与饲料（外源）中营养物质相比，有着独自的特点。卵黄囊中内源３＾Ｈ－ＶＡ在雏鸡肠料中外源ＶＡ之间存在有动态交换关系。

The vitamin A labelled by 3H and 145 newly hatched Arbor Acres broiler chickens were used to study the metabolism and utilization of vitamin A in yolk sac. Following results were found. 1. The continuing time for utilization of 3H-vitamin A in yolk sac under the balance diet and the vitamin A free purified diet was 3 weeks and 2 weeks respectively. 2. The metabolic way of 3H-vitamin A in yolk sac was the same as that of dietary vitamin A. Firstly, the 3H-vitamin A in yolk sac was sent into the small intestine, then it was transported adversely to the stomach through the intestine. It was digested and absorbed along the small intestine. There was an exchange relationship between the vitamin A in yolk sac and that in diet. 3. The main part of vitamin A and other whole nutrients in yolk sac were utilized by chicken in 12-84 hours since their birth. Its mean utilization speed per day for yolk sac vitamin A and other whole nutrients under the balance diet and the vitamin A free purified diet were 14.64%, 14.90%, 12.43%, 14.51% respectively. 4. The total utilization rates of yolk sac vitamin A during the first week of age under the balance diet and the vitamin A free purified diet were 86.77% and 91.70% respectively. However, for the dietary vitamin A it was 80.3%.