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Impaired intestinal villi growth in broiler chicks with unhealed navels
L T Kawalilak1, A M Ulmer Franco, G M Fasenko
1Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada, T6G 2P5.
Insights
Navel buttons in newly hatched chicks indicate incomplete residual yolk sac absorption and reduced intestinal development. This impacts overall chick health and growth potential.
Area of Science:
- Poultry Science
- Animal Physiology
- Histology
Background:
- Complete internalization of the residual yolk sac (RYS) and navel healing are critical at hatching for chick development.
- The RYS provides essential nutrients for growth, including the development of the small intestine.
Purpose of the Study:
- To investigate the relationship between the presence of navel buttons (unhealed navels) and RYS weight and intestinal villi height in broiler chicks posthatching.
- To assess the impact of navel condition on early chick growth and intestinal development.
Main Methods:
- Broiler hatching eggs were collected at 18-20 days of incubation.
- Chicks were categorized at 21 days of incubation into healed (H) and navel button (B) groups.
- Body weight (BW), RYS weight, and small intestinal villi height (duodenum and ileum) were measured from 0 to 5 days posthatching.
Main Results:
- No significant difference in BW was found between healed and navel button chicks.
- Chicks with navel buttons had significantly greater RYS weight and percentage RYS compared to healed chicks.
- Duodenal and ileal villi heights were generally shorter in chicks with navel buttons than in healed chicks.
Conclusions:
- The presence of navel buttons at hatching suggests impaired RYS absorption and reduced intestinal villi growth.
- Navel condition is a critical indicator of early chick health and digestive system development.
- Further research is recommended to explore the links between navel buttons, intestinal physiology, and potential yolk sac infections.
Abstract:
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.
