Effects of lighting schedule during incubation of broiler chicken embryos on leg bone development at hatch and related physiological characteristics

Carla W. van der Pol*, Inge A.M. Van Roovert-Reijrink, Sander W.S. Gussekloo, Sander Kranenbarg, Karen M. Leon-Kloosterziel, Margaretha H. van Eijk-Priester, Michal Zeman, Bas Kemp, Henry van den Brand

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Providing a broiler chicken embryo with a lighting schedule during incubation may stimulate leg bone development. Bone development may be stimulated through melatonin, a hormone released in darkness that stimulates bone development, or increased activity in embryos exposed to a light-dark rhythm. Aim was to investigate lighting conditions during incubation and leg bone development in broiler embryos, and to reveal the involved mechanisms. Embryos were incubated under continuous cool white 500 lux LED light (24L), continuous darkness (24D), or 16h of light, followed by 8h of darkness (16L:8D) from the start of incubation until hatching. Embryonic bone development largely takes place through cartilage formation (of which collagen is an important component) and ossification. Expression of genes involved in cartilage formation (col1α2, col2α1, and col10α1) and ossification (spp1, sparc, bglap, and alpl) in the tibia on embryonic day (ED)13, ED17, and at hatching were measured through qPCR. Femur and tibia dimensions were determined at hatch. Plasma growth hormone and corticosterone and pineal melatonin concentrations were determined every 4h between ED18.75 and ED19.5. Embryonic heart rate was measured twice daily from ED12 till ED19 as a reflection of activity. No difference between lighting treatments on gene expression was found. 24D resulted in higher femur length and higher femur and tibia weight, width, and depth at hatch than 16L:8D. 24D furthermore resulted in higher femur length and width and tibia depth than 24L. Embryonic heart rate was higher for 24D and 16L:8D in both its light and dark period than for 24L, suggesting that 24L embryos may have been less active. Melatonin and growth hormone showed different release patterns between treatments, but the biological significance was hard to interpret. To conclude, 24D resulted in larger leg bones at hatch than light during incubation, but the underlying pathways were not clear from present data.

Original languageEnglish
Article numbere0221083
JournalPLoS ONE
Volume14
Issue number8
DOIs
Publication statusPublished - 15 Aug 2019

Fingerprint Dive into the research topics of 'Effects of lighting schedule during incubation of broiler chicken embryos on leg bone development at hatch and related physiological characteristics'. Together they form a unique fingerprint.

Cite this