The Comparative Value of Five Calcium Sources for Laying Hens

Abstract

1961. Analysis of carotenoids in corn grain. J. Agric. Fd. Chem. 9: 132-135. Reiser, R., 1950. The metabolism of polyunsaturated fatty acids in growing chicks. J. Nutr. 42: 325-336. Salmon, R. E., and J. B. O'Neil, 1973a. The effect of the level and source and a change of source of dietary fat on the fatty acid composition of the depot fat and the thigh and breast meat of turkeys as related to age. Poultry Sci. 52: 302-314.ABSTRACT Supplemental calcium sources for Red x Rock sex-linked females were studied. Each of six treatments involved seven replicates of 24 birds or a total of 168 birds per treatment. Beginning at 33 weeks of age, the supplemental calcium in the diets was supplied by 1) granular limestone, 2) aragonite, 3) oyster shell, 4) clam shell, 5) egg shell and 6) egg shell with ration modification to utilize the protein in the egg shell meal.There were statistically significant supplemental calcium source differences among treatment means in overall hen-day but not in overall hen-housed egg production or in feed efficiency, livability, body weight, egg weight, or egg shell thickness at any age sampled. Haugh unit values for the group receiving aragonite as the supplemental calcium source were significantly greater than for the groups receiving clam shells or limestone at 56 weeks of age but at the other ages sampled, no significant treatment differences existed. ABSTRACTSerotonin (5-hydroxytryptamine) injected 8 hours before the expected time of ovulation effectively blocked ovulation (90%). When serotonin was administered for 10 days, the ovarian weight, number follicles, adrenal weights, and ovulation rate were significantly changed (P £ .05). Serotonin or reserpine treatment induced premature oviposition if the egg was in the genital tract. It was suggested from this study that there is stimulation for ovulation at 8 hour before ovulation which can be inhibited by serotonin.

Use of Particulate Limestone or Oyster Shell in the Dietary Regimen of White Leghorn Hens

“…In the former experiment, the strain of hen used was known to produce eggs of good shell quality, whereas, the strain used in the latter experienced shell quality problems especially toward the end of the laying cycle. Both Miller and Sunde (1975) and Muir et al (1976) found that particulate size had little effect on egg shell quality. Roland et al (1974), Muir et al (1975), and Roland (1981) concluded that particulate size had no effect on shell quality if the diet contained sufficient calcium to allow the hens to consume a minimum of 3.75 g calcium per day for young birds and 4.75 g/day for older hens.…”

Eggshell Quality as Influenced by Sodium Bicarbonate, Calcium Source, and Photoperiod

“…This hypothesis has been used to explain the improvement in eggshell quality when oyster shell replaces finely ground limestone (Scott et al, 1971). However, Muir et al (1976) and concluded that particle size had no effect on shell quality if the diet contained sufficient Ca. Mongin (1978) reported that two hydrogen ions are generated for each molecule of CaC0 3 synthesized in the shell gland, resulting in an acidosis increase until the 22nd hr after ovulation (Mongin, 1970).…”

Effects of Dietary Calcium Sources and Particle Size on Laying Hen Performance

“…Muir et al (1976) conducted an experiment using aragonite and concluded there were no significant differences among aragonite, limestone, or oyster shell in egg weight or egg shell thickness.…”