Farmer M, Roland D A, Eckman M K
Poult Sci. 1983 Mar;62(3):465-71. doi: 10.3382/ps.0620465.
Experiments were conducted to determine the influence of time of dietary calcium intake on eggshell quality in broiler breeder hens. In Experiment 1, 60 hens were randomly divided among three treatment groups. The control group received 155 g feed (3.1% calcium) per day at 0800 hr whereas the morning- (a.m.) and evening-fed (p.m.) treatments received a .42% calcium diet (155 g/bird) and were intubated with 4.2 g calcium at 0800 or 1600 hr, respectively. Egg weight, shell weight, and specific gravity were determined at 3-day intervals for 15 days. In Experiment 2, 150 breeder hens were randomly divided among two treatment groups. They were fed 122 g per hen during a 2.5-hr feeding time at 0700 to 0930 or 1530 to 1800 hr. Eggs were collected for egg weight, shell weight, and specific gravity determinations. At the end of the 5th week, 10 hens from each treatment group were sacrificed at various times throughout a 24-hr period and the contents of each segment of the GI tract and feces were analyzed for moisture, dry matter, and calcium. In Experiment 3, two commercial broiler-breeder houses with 5,000 hens each were used. They were fed 132 g/hen per day at 0530 hr daily with water provided ad lib. The feeding time of one house was moved forward by 2 or 2.5 hr per day until the feeding time was 1600 hr. Eggs were collected for 2 weeks following pretreatment data and values determined for specific gravity. Eggs were also candled at 7 days incubation to determine embryonic mortality and fertility. Hens intubated at 0800 hr with their daily supply of calcium did not maintain shell quality equivalent to controls (Experiment 1). However, hens intubated at 1600 hr had no difficulty maintaining shell quality. Hens fed at 1530 hr had significantly better shell quality during all weeks tested compared to hens fed at 0700 hr (Experiment 2). The p.m.-fed hens had 66.9% more calcium available at 1800 hr (2.07 vs. 1.24 g) compared to a.m.-fed hens. Hens fed at 1600 hr in the commercial houses (Experiment 3) had significantly better eggshell quality (specific gravity) than hens fed at 0530 hr. There was no significant difference in percent embryonic mortality or percent fertility when eggs were candled after 7 days of incubation. It was concluded that p.m.-fed hens had significantly more calcium available during the stages of eggshell calcification. The result was significantly better eggshell quality.
开展了实验以确定肉种鸡日粮钙摄入时间对蛋壳质量的影响。在实验1中，60只母鸡被随机分为三个处理组。对照组在08:00时每天接受155克饲料（钙含量3.1%），而上午组和下午组接受钙含量0.42%的日粮（155克/只），并分别在08:00或16:00时通过插管给予4.2克钙。每隔3天测定蛋重、蛋壳重量和比重，持续15天。在实验2中，150只种鸡被随机分为两个处理组。它们在07:00至09:30或15:30至18:00的2.5小时喂食时间内，每只母鸡喂食122克。收集鸡蛋以测定蛋重、蛋壳重量和比重。在第5周结束时，每个处理组的10只母鸡在24小时内的不同时间点被宰杀，对胃肠道各段内容物和粪便进行水分、干物质和钙分析。在实验3中，使用了两个商业肉种鸡舍，每个鸡舍有5000只母鸡。它们每天在05:30时每只母鸡喂食132克，并自由饮水。其中一个鸡舍的喂食时间每天提前2或2.5小时，直到喂食时间为16:00。在预处理数据后收集鸡蛋2周，并测定比重值。在孵化7天时还对鸡蛋进行照蛋，以确定胚胎死亡率和受精率。在08:00时通过插管给予每日所需钙的母鸡，其蛋壳质量无法维持在与对照组相当的水平（实验1）。然而，在16:00时插管的母鸡在维持蛋壳质量方面没有困难。与在07:00时喂食的母鸡相比，在15:30时喂食的母鸡在所有测试周内的蛋壳质量明显更好（实验2）。下午喂食的母鸡在18:00时可利用的钙比上午喂食的母鸡多66.9%（2.07克对1.24克）。在商业鸡舍中于16:00时喂食的母鸡（实验3）的蛋壳质量（比重）明显优于在05:30时喂食的母鸡。孵化7天后照蛋时，胚胎死亡率百分比或受精率百分比没有显著差异。得出的结论是，下午喂食的母鸡在蛋壳钙化阶段可利用的钙明显更多。结果是蛋壳质量明显更好。
