Effect of hatching system and prophylactic antibiotic use on serum levels of intestinal health biomarker diamine oxidase in broilers at an early age

To overcome some of the disadvantages of conventional hatcheries, a new concept is being explored in the broiler industry: on-farm hatching. In on-farm hatching systems, broiler eggs are transported to the broiler house on day 18 of incubation. On-farm hatched chicks hatch in a low dust environment, are immediately exposed to light, and have instant access to nutrients and water. Previous studies reported that on-farm hatching systems provide birds with an improved intestinal health and a lower feed conversion rate; resulting in a reduced use of antibiotics. Although it is generally agreed that the intestinal health of on-farm hatched chicks is better, the causative factors remain largely unknown. To explore the effect of hatching system on intestinal development, a full factorial in vivo experiment was designed, taking into account commercial age (minus two days, D-1, D1 and D2) and hatching condition (hatchery-born, hatchery-born with Spectoliphen 100 (SL) treatment, and on-farm hatched using the NestBorn-system) as factors. To assess intestinal development, diamine oxidase (DAO) serum levels were measured. DAO, a highly active intracellular enzyme that is synthesised mainly by the intestinal mucosal cells, is generally used as an indicator for intestinal maturation and intestinal permeability (IP) in mammals and birds. Analysis of serum samples showed that serum DAO levels in hatchery-born chicks were significantly lower compared to their on-farm hatched counterparts on all four days, suggesting that the intestinal development in the latter took place earlier. However, the long-term effect was not explored in this study. An additional comparison between the hatching systems was made, not according to commercial age, but in reference to time of access to feed. In this comparison, no differences between the two groups were observed. Interestingly, in the hatchery-born chicks, no compensatory development of the intestines took place within the time span of this experiment. The effect of SL during the first days on intestinal development and IP of chicks remains poorly understood and requires further investigation.