Kemin Industries, Des Moines, IA, USA.
Southern Poultry Research, Athens, GA, USA.
Poult Sci. 2018 Oct 1;97(10):3494-3500. doi: 10.3382/ps/pey227.
This study determined the effect of a dried algae product containing beta-1,3-glucan on broiler performance and immunity during an Eimeria challenge. Heterotrophically grown Euglena gracilis, which contained ∼55% beta-1,3-glucan, was dried and milled for inclusion into a non-medicated starter diet. Two experiments were conducted to evaluate dietary treatments containing 0, 50, 100, 150, and 200 g/ton dried algae. In both experiments, male broilers were orally challenged on day 14 with a coccidial inoculum consisting of E. acervulina, E. maxima, and E. tenella. Fecal matter was collected 120-144 hours post-exposure to determine relative amounts of oocyte shedding and birds were sacrificed on day 20 for lesion scoring. Broiler performance was assessed on a weekly basis. In the first experiment, birds receiving dried algae at 50 and 200 g/ton showed a significant improvement in FCR compared to the infected control during the challenge period (days 14-20). In the second experiment, the dried algae treatment had no significant effect on FCR, but lesion scores were significantly reduced in the groups receiving 50, 150, and 200 g/ton dried algae relative to the infected control. In both experiments, the dried algae treatment did not significantly impact mortality or oocyte shedding. In the second experiment, staining of intestinal samples with fluorescently tagged antibodies demonstrated that dried algae at 100 g/ton increased the number of intestinal macrophages compared to the infected control. A significant and dose-dependent increase in intestinal MHC-II+ expression was also observed for birds fed dried algae, with an 8-fold increase observed in the 200 g/ton group relative to the infected control. Similarly, increased total immune cell density (measured by the mean fluorescence intensity of CD45+ cells) was also observed at 150 and 200 g/ton. Overall, these data suggest that dried algae rich in beta-1,3-glucan can help improve gut immunity and host protection, thereby reducing morbidity associated with coccidiosis.
本研究旨在确定一种含有β-1,3-葡聚糖的干藻产品对受艾美耳球虫攻毒的肉鸡生产性能和免疫力的影响。通过异养培养小球藻（Euglena gracilis），得到了含有约 55%β-1,3-葡聚糖的干藻，并将其干燥和粉碎，以添加到非药物性的起始日粮中。进行了两项实验来评估含有 0、50、100、150 和 200 克/吨干藻的日粮处理。在两项实验中，雄性肉鸡在第 14 天通过口服接种包含柔嫩艾美耳球虫（E. acervulina）、巨型艾美耳球虫（E. maxima）和毒害艾美耳球虫（E. tenella）的球虫接种物进行攻毒。攻毒后 120-144 小时收集粪便，以确定卵囊排出量；第 20 天处死肉鸡，进行病变评分。每周评估肉鸡的生产性能。在第一项实验中，与感染对照组相比，在攻毒期（第 14-20 天），摄入 50 和 200 克/吨干藻的肉鸡的饲料转化率（FCR）显著提高。在第二项实验中，干藻处理对 FCR 没有显著影响，但与感染对照组相比，摄入 50、150 和 200 克/吨干藻的肉鸡的病变评分显著降低。在两项实验中，干藻处理均未显著影响死亡率或卵囊排出量。在第二项实验中，用荧光标记的抗体对肠组织样本进行染色表明，与感染对照组相比，100 克/吨的干藻增加了肠道巨噬细胞的数量。摄入干藻的肉鸡肠道 MHC-II+表达也呈现出显著的剂量依赖性增加，与感染对照组相比，200 克/吨组的增加了 8 倍。同样，在 150 和 200 克/吨组也观察到总免疫细胞密度（通过 CD45+细胞的平均荧光强度测量）增加。总体而言，这些数据表明，富含β-1,3-葡聚糖的干藻可有助于改善肠道免疫和宿主保护，从而降低与球虫病相关的发病率。
