RESUMEN
Five experiments were conducted to determine the influence of potassium iodide (KI) on serum calcium in the laying hen. Serum calcium was significantly increased when hens were fed a diet containing 5000 p.p.m. I as KI. This occurred even though feed consumption, egg production and size of ovary and oviduct were significantly decreased. In some hens fed KI, serum calcium was increased to as high as 70 mg. %, a 163% increase. Most of the increase was in the form of non-diffusible calcium. Hens fed a diet containing 0.05% calcium had significantly reduced serum calcium values. When these calcium-deficient hens were fed 5000 p.p.m. I as KI, a significant increase in serum calcium occurred within 3 days and within 7 days their average serum calcium value was significantly greater than that of hens fed a diet containing 3.00% calcium. A combination of KI plus estradiol was significantly more effective in increasing serum calcium than was either compound alone. Although these data gave no indication as to the mechanism of action of KI on serum calcium they do offer a new model in which to study calcium metabolism in the laying hen.
Asunto(s)
Calcio/sangre , Pollos/sangre , Yoduro de Potasio/farmacología , Animales , Calcio de la Dieta/metabolismo , Estradiol/farmacología , FemeninoRESUMEN
Experiments were conducted to determine the effect of cropectomy on the total amount and calcium content of ingesta in the digestive tract of the laying hen at night, as well as to determine if any abnormal physiological changes had occurred in the cropectomized hens. Treatments were cropectomized, sham operated and unoperated control hens. The gizzards from cropectomized hens contained about twice as much feed at 7:30 p.m. as that of the controls. The gizzard weight, without contents, was also significantly heavier in cropectomized hens than that of the controls. At 7:30 p.m. total contents of the digestive system of cropectomized and control hens were 15.94 gm. versus 24.07 gm., respectively. The control birds also had 2.71 times more total calcium in the digestive system at 7:30 p.m. than the cropectomized birds. The contents of the small intestine of cropectomized birds had 17% more calcium at 7:30 p.m. than did that of the controls. However, by 5:30 a.m. the contents of the small intestine of the control birds had 3.17 times more calcium than did that of the cropectomized birds. No differences were found between treatments or between time periods in relation to tibia breaking strength, calcium content of tibia or percent tibia ash. The degree of dietary calcium deficiency at night appears to be greater with cropectomized hens, even though the gizzard compensates, in part, for the loss in storage capacity of the crop. It is hypothesized from these data that the crop is an important and necessary organ in the laying hen for supplying nutrients throughout the night when the hen is not consuming feed.
Asunto(s)
Pollos/metabolismo , Buche de las Aves/metabolismo , Sistema Digestivo/metabolismo , Tibia/metabolismo , Alimentación Animal/análisis , Animales , Calcio/metabolismo , Ciego/metabolismo , Buche de las Aves/cirugía , Femenino , Absorción Intestinal , Intestino Grueso/metabolismo , Intestino Delgado/metabolismo , Proventrículo/metabolismo , TiempoRESUMEN
Two-hundred and fifty Babcock B-300 pullets (18 weeks of age) were either cropectomized, sham-operated or used as unoperated controls in two experiments. Although feed consumption was slightly less in cropectomized birds than in control birds, the pattern of feed consumption in relation to time of day remained unchanged. Egg production and body weight of cropectomized birds were significantly lower than that of control or sham birds. Egg weight was not affected by cropectomy or the sham operation. Cropectomy had no influence on the pattern of serum calcium or on egg specific gravity in relation to time of day; however, serum calcium and egg specific gravity was consistently lower at each time interval measured throughout the day or night when compared to that of controls. The adverse effect of cropectomy on specific gravity of eggs and serum calcium indicated that the crop is an important organ in the laying hen. The crop appeared to serve as a storage depot for feed providing the bird with nutrients necessary for optimal shell quality during periods on non-consumption.