Bolden S L, Jensen L S
Poult Sci. 1985 May;64(5):937-46. doi: 10.3382/ps.0640937.
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.
在两项2×3析因设计实验中，给单冠白来航蛋鸡（SCWL）分别饲喂玉米-大豆（CS）日粮或含有5%鱼粉、5%苜蓿粉和5%圆酵母的日粮（FAY），在实验1中钙含量分别为2.0%、2.75%或3.5%，在实验2中钙含量分别为2.5%、3.5%或4.5%。实验持续时间分别为6周和8周。低钙日粮在两项实验中均导致能量利用效率降低，在实验2中显著提高了能量消耗。肝脏脂质和体重不受日粮钙水平影响，两项研究均观察到产蛋量和蛋壳质量下降。在实验1中，日粮钙降低会使血浆雌二醇和胫骨骨灰显著降低，但在实验2中未观察到这种情况。在实验1中，日粮钙降低使蛋重显著增加。在两项试验中，血浆钙均不受日粮钙的影响。在两项实验中，饲喂FAY导致的肝脏脂质显著低于饲喂CS，血浆雌二醇也呈现类似但不显著的趋势。在实验1中，饲喂FAY的母鸡胫骨骨灰和蛋壳抗压强度显著更高。在实验2中，饲喂含3.5%钙的FAY日粮的母鸡血浆总钙较低，蛋壳比例高于饲喂含3.5%钙的CS日粮的母鸡。在采食量、体重或产蛋量方面，CS和FAY之间未观察到差异。这些研究表明，与饲喂简单的CS日粮相比，给蛋鸡饲喂更复杂的日粮可能会改变钙代谢，并在钙水平处于临界值时提高蛋壳质量。
