Dietary Super-Doses of Cholecalciferol Fed to Aged Laying Hens Illustrates Limitation of 24,25-Dihydroxycholecalciferol Conversion

Matthew F Warren; Pete M Pitman; Dellila D Hodgson; Nicholas C Thompson; Kimberly A Livingston

doi:10.1016/j.cdnut.2024.102156

Dietary Super-Doses of Cholecalciferol Fed to Aged Laying Hens Illustrates Limitation of 24,25-Dihydroxycholecalciferol Conversion

Curr Dev Nutr. 2024 Apr 9;8(5):102156. doi: 10.1016/j.cdnut.2024.102156. eCollection 2024 May.

Authors

Matthew F Warren¹, Pete M Pitman², Dellila D Hodgson¹, Nicholas C Thompson³, Kimberly A Livingston¹

Affiliations

¹ Prestage Department of Poultry Science, North Carolina State University, Raleigh, NC, United States.
² Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States.
³ Department of Animal Science, North Carolina State University, Raleigh, NC, United States.

Abstract

Background: Older humans taking high concentrations of vitamin D₃ supplementation for a prolonged time may be at risk of vitamin D toxicity. It is unclear how dietary super-doses (10,000 times greater than the requirement) can affect vitamin D₃ status in aged animals. Aged laying hens could be a model to compare vitamin D₃ supplementation effects with women in peri- or postmenopausal stages of life.

Objectives: We investigated the dietary super-dose impacts of cholecalciferol (vitamin D₃) on vitamin D₃ status in aged laying hens in production.

Methods: Forty-eight 68-wk-old Hy-Line Brown laying hens were individually housed in cages with 8 hens per dietary treatment for 11 wk. Hens were randomly assigned to 1 of 6 treatment groups of dietary vitamin D₃ supplementation and consumed ad libitum. Supplementation concentrations were 400, 800, 7400, 14,000, 20,000, and 36,000 IU D₃/kg of feed. At the end of the study, all hens were sacrificed, and tissue samples and feces were collected. Plasma and egg yolk vitamin D₃ metabolites, calcium and phosphorus composition of eggshells, ileal digesta, and feces were measured. Duodenal, ileal, liver, and kidney gene expression levels were also measured.

Results: We observed that increasing dietary vitamin D₃ increased plasma vitamin D₃ and egg yolk vitamin D₃ (P < 0.0001 for both sites). We also observed an increase in plasma 24,25-dihydroxycholecalciferol as dietary vitamin D₃ concentrations increased (P < 0.0001). The plasma 25-hydroxycholecalciferol:24,25-dihydroxycholecalciferol ratio exhibited an asymptotic relationship starting at the 14,000 IU/kg D₃ treatment.

Conclusions: Dietary super-doses of vitamin D₃ led to greater plasma and egg yolk vitamin D₃ concentrations, which shows that aged laying hens can deposit excess vitamin D₃ in egg yolk. We suggest future research should explore how 24-hydroxylation mechanisms are affected by vitamin D₃ supplementation. Further understanding of 24-hydroxylation can help ascertain ways to reduce the risk of vitamin D toxicity.

Keywords: 24,25-dihydroxycholecalciferol; 25-hydroxycholecalciferol; aged laying hen; chicken; dietary vitamin D3; egg; egg yolk vitamin D3; plasma vitamin D3; super-dose.