Circadian disruption and divergent microbiota acquisition under extended photoperiod regimens in chicken

Abstract

The gut microbiota is crucial for metabolic homeostasis, immunity, growth and overall health, and it is recognized that early-life microbiota acquisition is a pivotal event for later-life health. Recent studies show that gut microbiota diversity and functional activity are synchronized with the host circadian rhythms in healthy individuals, and circadian disruption elicits dysbiosis in mammalian models. However, no studies have determined the associations between circadian disruption in early life, microbiota colonization, and the consequences for microbiota structure in birds. Chickens, as a major source of protein around the world, are one of the most important agricultural species, and their gut and metabolic health are significant concerns. The poultry industry routinely employs extended photoperiods (>18 h light) as a management tool, and their impacts on the chicken circadian, its role in gut microbiota acquisition in early life (first 3 weeks of life), and consequences for later life microbiota structure remain unknown. In this study, the objectives were to (a) characterize circadian activity under two different light regimes in layer chicken (12/12 h′ Light/Dark (LD) and 23/1 h LD), (b) characterize gut microbiota acquisition and composition in the first 4 weeks of life, (c) determine if gut microbiota oscillate in synchrony with the host circadian rhythm, and (d) to determine if fecal microbiota is representative of cecal microbiota in early life. Expression of clock genes (clock, bmal1, and per2) was assayed, and fecal and cecal microbiotas were characterized using 16S rRNA gene amplicon analyses from birds raised under two photoperiod treatments. Chickens raised under 12/12 LD photoperiods exhibited rhythmic clock gene activity, which was absent in birds raised under the extended (23/1 LD) photoperiod. There was differential microbiota acquisition under different photoperiod regimes in newly hatched chicks. Gut microbiota members showed a similar oscillating pattern as the host, but this association was not as strong as found in mammals. Finally, the fecal microbiota was found to be not representative of cecal microbiota membership and structure in young birds. This is one of the first studies to demonstrate the use of photoperiods to modulate microbiota acquisition in newly hatched chicks, and show their potential as a tool to promote the colonization of beneficial microorganisms.

The Role of Housing Environment and Dietary Protein Source on the Gut Microbiota of Chicken

“…Light intensity and natural photoperiods may reinforce unique microbiota communities, some of which may also oscillate in synchrony with the host biological rhythms [67,68]. These phenomena have been well documented in mouse studies, and we recently demonstrated that photoperiods influence both microbiota diversity and structure in Hy-line Brown layers [69]. Taken together, the synergistic contribution of cage-free environments is likely to have a more significant contribution to poultry gut microbiota and health than the impact of the soil and litter differences when compared to caged environments.…”

Molecular mechanism underlying the effect of illumination time on the growth performance of broilers via changes in the intestinal bacterial community

“…During the growth of newly hatched chicks, different light regimes cause changes in the circadian rhythm of the clock gene, which in turn changes the structure of intestinal microbes. However, it is unclear how the light cycle affects broiler gut microbiota during fattening (Hieke, Hubert & Athrey, 2019 Bacterial community structure affects insulin synthesis…”

Cloacal swabs are unreliable sources for estimating lower gastro-intestinal tract microbiota in chicken

“…Fecal samples show qualitative similarities with quantitative differences compared to GIT [27,54]. Hieke et al [14] also showed fecal samples are not representative of cecal communities in young layer-type chicken.…”

“…Because of this, there is a great emphasis on improving poultry health and performance [2][3][4][5]. Notably, the role of gut microbiota in improving performance [6][7][8], welfare [9], and health [4,[10][11][12][13][14], is a topic of intense interest. The gut microbiota is studied intensively in broilers; an NCBI PubMed Central search for "Poultry Gut Microbiota" yielded 2586 research articles within the last five years.…”