McKee J S, Harrison P C
Department of Animal Sciences, University of Illinois at Urbana-Champaign 61801, USA.
Poult Sci. 1995 Nov;74(11):1772-85. doi: 10.3382/ps.0741772.
An experiment was conducted to determine whether ascorbic acid (AA) increases resistance of female Hubbard x Hubbard broiler chicks to multiple concurrent stressors. Stressors imposed from 10 to 17 d posthatch included 2 x 2 x 2 factorial combinations of beak trimming [(B), sham-operated or beak-trimmed and cauterized], coccidiosis [(C), gavage with 0 or 3 x 10(5) sporulated Eimeria tenella oocysts], and heat stress [(H), 28 vs 33 C]. A starter diet was supplemented with AA to provide 0, 150, or 300 ppm (milligrams per kilogram). This resulted in a 2 x 2 x 2 x 3 factorial design with two six-chick replicates of each of the 24 treatment combinations. Data were analyzed using ANOVA and a level of 95% significance. Ascorbic acid increased feed intake and lowered plasma corticosterone and heterophil:lymphocyte ratios. Heat depressed weight gain and feed intake and elevated heterophil:lymphocyte ratios. Heat and AA interacted to improve weight gain and feed intake and lower heterophil:lymphocyte ratios. Coccidiosis depressed weight gain, feed efficiency, and heterophil:lymphocyte ratios. Coccidiosis and AA interacted to increase feed intake and lower plasma corticosterone and heterophil: lymphocyte ratios. Beak trimming increase heterophil:lymphocyte ratios. Beak trimming and AA interacted to increase feed intake and lower heterophil: lymphocyte ratios. Weight gain and feed efficiency decreased whereas heterophil:lymphocyte ratios increased linearly in unsupplemented birds as a function of stressor "order" (the number of stressors imposed simultaneously) indicating an additive effect of systematically increasing the number of stressors. No changes in feed efficiency or heterophil:lymphocyte ratios were detected as a function of stressor order when AA was provided. Ascorbic acid reduced the slope of the regression equation describing the relationship between weight gain and stressor order. It was concluded that AA, particularly at 150 ppm, enhanced performance of broiler chicks exposed to multiple concurrent environmental stressors.
进行了一项实验，以确定抗坏血酸（AA）是否能增强哈伯德×哈伯德雌性肉鸡雏鸡对多种并发应激源的抵抗力。孵化后10至17天施加的应激源包括喙修剪（[B]，假手术或喙修剪并烧灼）、球虫病（[C]，灌胃0或3×10⁵个孢子化的柔嫩艾美耳球虫卵囊）和热应激（[H]，28℃与33℃）的2×2×2析因组合。在起始日粮中添加AA，使其含量达到0、150或300 ppm（毫克/千克）。这产生了一个2×2×2×3析因设计，24种处理组合中的每一种都有两个每组6只鸡的重复。使用方差分析和95%的显著水平对数据进行分析。抗坏血酸增加了采食量，降低了血浆皮质酮和嗜异性粒细胞：淋巴细胞比率。热应激降低了体重增加和采食量，并提高了嗜异性粒细胞：淋巴细胞比率。热应激和AA相互作用，改善了体重增加和采食量，并降低了嗜异性粒细胞：淋巴细胞比率。球虫病降低了体重增加、饲料效率和嗜异性粒细胞：淋巴细胞比率。球虫病和AA相互作用，增加了采食量，降低了血浆皮质酮和嗜异性粒细胞：淋巴细胞比率。喙修剪提高了嗜异性粒细胞：淋巴细胞比率。喙修剪和AA相互作用，增加了采食量，降低了嗜异性粒细胞：淋巴细胞比率。在未添加AA的鸡中，体重增加和饲料效率下降，而嗜异性粒细胞：淋巴细胞比率随着应激源“顺序”（同时施加的应激源数量）呈线性增加，表明系统增加应激源数量具有累加效应。当提供AA时，未检测到饲料效率或嗜异性粒细胞：淋巴细胞比率随应激源顺序的变化。抗坏血酸降低了描述体重增加与应激源顺序之间关系的回归方程的斜率。得出的结论是，AA，特别是150 ppm时，可提高暴露于多种并发环境应激源的肉鸡雏鸡的性能。
