Abstract
In order to elucidate the total fate of dietary Ca in the laying hen, 2 experiments were conducted.
Single Comb White Leghorn hens older than 60 weeks and in 100% egg production were fed 105g diet/hen/day containing 3.32% Ca. After 4 days of Ca balance test, in experiment I, 39.8μCi of 45CaCl2 were ingested at 2 hrs after ovulation. Three hens each were killed at 4, 8, 12, 16, 24 and 48 hrs after ingestion. The absorbed 45 Ca reached 66.40% of dose by 12 hrs. The recovery % of 45 Ca and the specific activity in the end, medullary and cor-tical bone in the femur reached a maximum between 12 and 16 hrs. Though the recovery % of 45Ca in the first and second egg shell were 39.54% and 4.05% of dose, respectively.
In experiment II, 39.8μCi of 45 Ca was injected intravenously at 3.5 hrs after ovulation.ISHIBASHI et al: Time Course of Distribution of Single Dose Oral or Intravenous 45 Ca 81Three hens each were killed at 1, 2 and 4 hrs after injection. About 2% of 45 Ca of dose was recovered in the digestive tract 2 hrs after injection. The recovery % of 45 Ca in the end, medullary and cortical bone in the femur decreased with time, but the specific activity in the medullary and end bone decreased from 1 to 2 hrs and increased from 2 to 4 hrs after injection. The recovery % of 45 Ca and the specific activity in the egg shell increased with time, but those in the blood decreased with time. From these data it was suggested that not only the medullary Ca but also the end and cortical Ca trurned over rapidly.AcknowledgementsThe authors are grateful to Dr. P. GRIMINGER of Rutgers University for his reading of the manuscript and to Kyowa Hakko Co., Ltd, and Takeda Feed Supplement Co., Ltd, for generously supplying crystalline amino acids and vitamin-mineral premixes.
