The effect of marginal levels of calcium, fish meal, torula yeast and alfalfa meal on feed intake, hepatic lipid accumulation, plasma estradiol, and egg shell quality among laying hens.
In two 2 X 3 factorial-design experiments, Single Comb White Leghorn (SCWL) laying hens were fed either a corn-soy (CS) diet or one containing 5% each of fish meal, alfalfa meal, and torula yeast (FAY), each with 2.0, 2.75, or 3.5% calcium in Experiment 1 and 2.5, 3.5, or 4.5% in Experiment 2. Duration of the experiments were 6 and 8 weeks, respectively. Low dietary calcium resulted in decreased efficiency of energy utilization in both experiments and significantly elevated energy consumption in Experiment 2. Liver lipids and body weight were unaffected by dietary calcium level, and declines in both egg production and shell quality were observed in both studies. In Experiment 1, overall plasma estradiol and tibial bone ash were significantly reduced with lowered dietary calcium, but this was not observed in Experiment 2. Egg weight was significantly increased by decreased dietary calcium in Experiment 1. Plasma calcium was not affected by dietary calcium in either trial. Feeding FAY resulted in significantly lower liver lipid than feeding CS in both experiments, and similar but nonsignificant trends were realized for plasma estradiol. Tibial bone ash and egg-breaking strength were significantly higher for hens fed FAY in Experiment 1. In Experiment 2, plasma total calcium was lower and the percent shell was higher in hens fed FAY with 3.5% calcium than in hens fed CS with 3.5% calcium. No differences were observed between CS and FAY in feed consumption, body weight, or egg production. These studies indicate that feeding a more complex diet to laying hens may change calcium metabolism and improve shell quality at marginal levels of calcium compared with feeding a simplified CS diet.
D000821:Animal Feed; D000818:Animals; D001835:Body Weight; D002136:Calcium, Dietary / Q000008:administration & dosage; D002645:Chickens / Q000378:metabolism*; D003454:Cryptococcus; D004528:Egg Shell; D002149:Energy Intake; D004958:Estradiol / Q000097:blood*; D005260:Female; D005396:Fish Products; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism*; D000455:Medicago sativa; D010058:Oviposition
D002136:Calcium, Dietary; D004958:Estradiol