The development of the gastrointestinal tract in broilers : effects of access to feed, water and probiotics in the hatcher

Sammanfattning: The study was performed at the research facility of SLU outside Uppsala, where the gastrointestinal tract development and production performance was evaluated in broilers without contra with access to feed, water and probiotics in the hatcher. After hatch, 450 chickens of Ross 308 were divided into five treatments. One treatment was not provided feed and water at hatch, one was provided with feed and water and the three remaining had probiotic addition of different characters. At arrival to the research facility, chickens of the unfed treatment, chickens of the fed treatment and one treatment with probiotic addition were split in two subgroups, where one of the two groups where provided one of the probiotics the first three days at the research facility. The remaining two treatments were not split nor supplemented with probiotics. Throughout the study data was collected in weights of chickens, feed and gastrointestinal organs. The two treatments without feed and water at hatch had lower weights up to 18 days of age compared to the majority of treatments with feed and water, although unfed chickens at hatch without probiotic supplementation in the research facility had compensated in weight the last day of the study. Unfed chickens at hatch with probiotic supplementation at the research facility were not able to compensate in weight until the end of the study. Differences in organ weights, feed conversion ratio, feed intake and chicken weights (after 18 days of age) were not exclusively linked to chickens of unfed treatments at hatch. Moreover, probiotic supplementation did not result in improved growth but was rather contributing to the opposite in three treatments. Goblet cells in the duodenum were ocularly studied in a light microscope of intestinal incisions. It appeared as if chickens in treatments with probiotic addition had a higher cell density compared to treatments without probiotic addition in two-day-old chickens. In addition, goblet cell sizes in two-day-old chickens seemed to be linked to unfed chickens at hatch, with smaller goblet cells in the duodenum than chickens in fed treatments at hatch. Unfed chickens without probiotic supplementation appeared most profitable and least time consuming from this study, however, more studies are required.