Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada, T6G 2P5.
Poult Sci. 2010 Jan;89(1):82-7. doi: 10.3382/ps.2009-00284.
By the time of hatching, the residual yolk sac (RYS) should be completely internalized into the body cavity of the chick via the navel and the navel should be closed (healed). After hatching, the RYS contents are used for general growth and development including growth of the small intestine. This research examined the relationship between the presence of navel buttons (an unhealed navel covered with a scab) and the RYS weight and intestinal villi height of broiler chicks from 0 to 5 d posthatching. Hatching eggs containing live embryos were collected at 18, 19, and 20 d of incubation (n = 5/d). At 21 d of incubation, chicks with healed navels (H) and chicks with navel buttons smaller than 3 mm in diameter (B) were obtained (n = 30/group). The BW and RYS of embryos (n = 5/d) and chicks (n = 5/treatment per day) were weighed. Samples of the small intestine (duodenum and ileum) were processed for histological evaluation to measure villi height. The trial was replicated in time 4 wk after the first collection using eggs and chicks from the same flock. Data were analyzed using SAS PROC MIXED (P < or = 0.05). No significant differences in BW were observed between H and B chicks. Average RYS weight and percentage RYS were greater in B than in H chicks. The interaction of age and navel condition significantly influenced both duodenal and ileal villi heights. On most of the days, duodenal and ileal villi were shorter in B than in H chicks. The presence of small navel buttons at hatching is indicative of impaired absorption of the RYS content and decreased intestinal villi growth. Further research on the relationship between navel buttons, intestinal physiology, and yolk sac infections is advised.
出雏时，残余卵黄囊（RYS）应通过脐带完全内化到雏鸡的体腔中，脐带应闭合（愈合）。出雏后，RYS 内容物用于一般生长和发育，包括小肠的生长。本研究检查了脐扣（未愈合的脐部覆盖着痂）的存在与肉鸡雏鸡从出雏到 5 日龄的 RYS 重量和肠绒毛高度之间的关系。在孵化 18、19 和 20 天收集含有活胚胎的孵化蛋（n = 5/天）。在孵化 21 天，获得了脐带愈合的雏鸡（H）和直径小于 3 毫米的脐扣雏鸡（B）（n = 30/组）。称重胚胎（n = 5/天）和雏鸡（n = 5/天/处理）的 BW 和 RYS。处理后从小肠（十二指肠和回肠）取样进行组织学评估以测量绒毛高度。在第一次收集后 4 周，使用来自同一批的蛋和雏鸡重复该试验。使用 SAS PROC MIXED（P < or = 0.05）分析数据。H 和 B 雏鸡之间的 BW 没有差异。B 雏鸡的 RYS 重量和 RYS 百分比大于 H 雏鸡。年龄和脐条件的相互作用显著影响十二指肠和回肠绒毛高度。在大多数日子里，B 雏鸡的十二指肠和回肠绒毛比 H 雏鸡短。出雏时存在小脐扣表明 RYS 内容物的吸收受损，并且肠绒毛生长减少。建议进一步研究脐扣、肠道生理学和卵黄囊感染之间的关系。
