Adjusting phosphate feeding regimen according to daily rhythm increases eggshell quality via enhancing medullary bone remodeling in laying hens

Jiakun Yan; Jiajie Wang; Jie Chen; Hao Shi; Xujie Liao; Chong Pan; Yanli Liu; Xin Yang; Zhouzheng Ren; Xiaojun Yang

doi:10.1186/s40104-023-00829-0

Adjusting phosphate feeding regimen according to daily rhythm increases eggshell quality via enhancing medullary bone remodeling in laying hens

J Anim Sci Biotechnol. 2023 Mar 10;14(1):17. doi: 10.1186/s40104-023-00829-0.

Authors

Jiakun Yan¹, Jiajie Wang¹, Jie Chen¹, Hao Shi¹, Xujie Liao¹, Chong Pan¹, Yanli Liu¹, Xin Yang¹, Zhouzheng Ren², Xiaojun Yang³

Affiliations

¹ College of Animal Science and Technology, Northwest A&F University, Yangling, 712100, Shaanxi, China.
² College of Animal Science and Technology, Northwest A&F University, Yangling, 712100, Shaanxi, China. poultryren@nwafu.edu.cn.
³ College of Animal Science and Technology, Northwest A&F University, Yangling, 712100, Shaanxi, China. yangxj@nwsuaf.edu.cn.

Abstract

Background: Body phosphorus metabolism exhibits a circadian rhythm over the 24-h daily cycle. The egg laying behavior makes laying hens a very special model for investigating phosphorus circadian rhythms. There is lack of information about the impact of adjusting phosphate feeding regimen according to daily rhythm on the phosphorus homeostasis and bone remodeling of laying hens.

Methods and results: Two experiments were conducted. In Exp. 1, Hy-Line Brown laying hens (n = 45) were sampled according the oviposition cycle (at 0, 6, 12, and 18 h post-oviposition, and at the next oviposition, respectively; n = 9 at each time point). Diurnal rhythms of body calcium/phosphorus ingestions and excretions, serum calcium/phosphorus levels, oviduct uterus calcium transporter expressions, and medullary bone (MB) remodeling were illustrated. In Exp. 2, two diets with different phosphorus levels (0.32% and 0.14% non-phytate phosphorus (NPP), respectively) were alternately presented to the laying hens. Briefly, four phosphorus feeding regimens in total (each included 6 replicates of 5 hens): (1) fed 0.32% NPP at both 09:00 and 17:00; (2) fed 0.32% NPP at 09:00 and 0.14% NPP at 17:00; (3) fed 0.14% NPP at 09:00 and 0.32% NPP at 17:00; (4) fed 0.14% NPP at both 09:00 and 17:00. As a result, the regimen fed 0.14% NPP at 09:00 and 0.32% NPP at 17:00, which was designed to strengthen intrinsic phosphate circadian rhythms according to the findings in Exp. 1, enhanced (P < 0.05) MB remodeling (indicated by histological images, serum markers and bone mineralization gene expressions), elevated (P < 0.05) oviduct uterus calcium transportation (indicated by transient receptor potential vanilloid 6 protein expression), and subsequently increased (P < 0.05) eggshell thickness, eggshell strength, egg specific gravity and eggshell index in laying hens.

Conclusions: These results underscore the importance of manipulating the sequence of daily phosphorus ingestion, instead of simply controlling dietary phosphate concentrations, in modifying the bone remodeling process. Body phosphorus rhythms will need to be maintained during the daily eggshell calcification cycle.

Keywords: Body phosphorus rhythm; Bone remodeling; Eggshell formation; Laying hen; Phosphorus feeding regimen.

Abstract

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