Holcombe D J, Roland D A, Harms R H
Poult Sci. 1975 Mar;54(2):552-61. doi: 10.3382/ps.0540552.
Two experiments were conducted in which 270 hens received a choice of diets offered in two plastic cups. The treatments consisted of hens fed diets containing 3.0% calcium (Ca) in both cups, 6.0% Ca vs. 0.7% Ca, or 3.0% Ca vs. 0.7% Ca. Young hens exhibited the ability to discriminate between high and low levels of Ca. They greatly increased their consumption of the 3.0% Ca over the 0.7% Ca diet. Old birds showed an immediate marked aversion to the 6.0% Ca diet. They did not increase their consumption of the 3.0% Ca over the 0.7% Ca diet as did young hens. Reversing the position of the diets after the young hens' initial adjustment resulted in a reversal of the hens' positional preference for the feed. The birds tended to eat more of the higher calcium diet in the early morning and late afternoon, the times of greatest Ca need or anticipated need. This indicated that the young hens regulated their calcium intake according to metabolic need. Young hens in the regulating groups maintained egg production and egg weight, but not specific gravity of eggs nor serum calcium, at levels comparable to controls.
进行了两项实验，270只母鸡可在两个塑料杯中选择所提供的日粮。处理方式包括两个杯中都给母鸡喂食含钙3.0%的日粮、含钙6.0%的日粮与含钙0.7%的日粮对比，或含钙3.0%的日粮与含钙0.7%的日粮对比。年轻母鸡表现出区分高钙和低钙水平的能力。与含钙0.7%的日粮相比，它们大大增加了对含钙3.0%日粮的摄入量。老母鸡对含钙6.0%的日粮立即表现出明显的厌恶。它们不像年轻母鸡那样，与含钙0.7%的日粮相比增加对含钙3.0%日粮的摄入量。在年轻母鸡最初适应后颠倒日粮的位置，导致母鸡对饲料的位置偏好发生逆转。这些鸡在清晨和傍晚，即对钙需求最大或预期需求最大的时候，往往会吃更多含钙量高的日粮。这表明年轻母鸡根据代谢需求调节它们的钙摄入量。调节组中的年轻母鸡维持产蛋量和蛋重，但鸡蛋的比重和血清钙水平与对照组相当。
