Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada.
Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA.
Poult Sci. 2022 Oct;101(10):101957. doi: 10.1016/j.psj.2022.101957. Epub 2022 May 8.
The effect of commercial selection by poultry breeders on the growth, efficiency, and sexual maturity of broiler breeders was studied using 2 University of Alberta Meat Control strains unselected since 1957 and 1978 (AMC-1957 and AMC-1978, respectively) and 2 strains originating from the University of Arkansas; 1995 Random-bred (1995RB) and 2015 Random-bred (2015RB). A study with a 4 × 2 factorial arrangement was conducted with the 4 strains fed at either ad libitum, or restricted levels to achieve a current commercial breeder target BW profile. Growth rate, feed intake, feed efficiency, age at sexual maturity, carcass components, and body conformation were measured. To assess reproductive development, birds were assigned to 2 fates: dissected at photostimulation or dissected after the second oviposition. At 22.4 wk of age, the restricted-fed AMC-1957, AMC-1978, 1995RB, and 2015RB reached 100, 61, 46, and 38% of their ad libitum-fed counterparts' BW, respectively. During the rearing phase, the amount of feed needed to maintain restricted-fed birds on the target BW was 99.4, 57, 29.5, and 24.9% of their ad libitum-fed counterparts for AMC-1957, AMC-1978, 1995RB, and 2015RB, respectively. Feed restricted birds in the 2015RB had lower heat production relative to the AMC-1957 and AMC-1978, which shows that modern strains utilized feed more efficiently compared to the antique strains. This might be related to the increasing severity of feed restriction of broiler breeders over the past 60 years. Relative to AMC-1957 and AMC-1978 strains, the 1995RB and 2015RB strains had heavier breast muscle and lower fat pad weight. Although the pubertal threshold for age and BW have increased over the last 6 decades, changes in selection programs for feed efficiency have resulted in broiler breeders that prioritize nutrient allocation to growth and breast development rather than adipose storage. As a result, feed restricted modern broiler breeders may have marginally sufficient fat resources to support reproduction.
研究了商业选择对肉鸡繁殖者生长、效率和性成熟的影响，使用了自 1957 年和 1978 年以来未经过选择的 2 个阿尔伯塔大学肉类控制品系（分别为 AMC-1957 和 AMC-1978）和 2 个来自阿肯色大学的品系；1995 年随机繁殖（1995RB）和 2015 年随机繁殖（2015RB）。进行了一项具有 4×2 析因设计的研究，用 4 个品系自由采食或限制采食，以达到当前商业繁殖者目标 BW 模式。测量生长速度、饲料摄入量、饲料效率、性成熟年龄、胴体成分和身体结构。为了评估繁殖发育，将鸟类分为 2 种命运：在光刺激时解剖或在第二次产卵后解剖。在 22.4 周龄时，限制饲养的 AMC-1957、AMC-1978、1995RB 和 2015RB 分别达到了自由采食对应品系 BW 的 100%、61%、46%和 38%。在育雏阶段，为了使限制饲养的鸟类保持目标 BW，需要的饲料量分别为自由采食对应品系的 99.4%、57%、29.5%和 24.9%，对于 AMC-1957、AMC-1978、1995RB 和 2015RB 分别如此。与 AMC-1957 和 AMC-1978 相比，2015RB 限制饲养的鸟类产热量较低，这表明现代品系与古老品系相比，饲料利用率更高。这可能与过去 60 年来肉鸡繁殖者饲料限制的日益严重有关。与 AMC-1957 和 AMC-1978 品系相比，1995RB 和 2015RB 品系的胸肌较重，脂肪垫重量较低。尽管过去 60 年来，性成熟的年龄和 BW 阈值有所增加，但饲料效率选择方案的变化导致肉鸡繁殖者优先将营养分配给生长和乳房发育，而不是脂肪储存。因此，受限制的现代肉鸡繁殖者可能只有微薄的脂肪资源来支持繁殖。
