Tibial adaptations to dietary 25-hydroxyvitamin D3 supplementation under two distinct vitamin regimens in young ducks

Abstract

Tibia disorders in modern ducks are frequently associated with rapid weight gain and compromised bone quality, which is defined as the structural and material properties of bone tissue that determines its strength and fracture resistance. These factors significantly increase the risk of fractures and chronic pain. Studies suggest that 25-hydroxycholecalciferol (25-OH-D₃), a vitamin D₃ metabolite, effectively addresses bone disorders, potentially depending on dietary vitamin regimens, which are determined by the amount and ratio of vitamins in the diet. This study used a 2 × 2 factorial design to evaluate the effects of two vitamin regimens (regular and high) with or without exogenous 25-OH-D₃ (0.069 mg/kg) on leg health and tibia quality in meat ducks (1-14 d). The high-vitamin regimen contained greater amounts of all vitamins except biotin and significantly enhanced ash content, tibial microstructure, fracture load, and reduced tibial dyschondroplasia (TD) scores (P < 0.05) compared to the regular regimen, despite no impact on growth performance or tibia length, weight, and diameter (P > 0.05). Additionally, dietary 25-OH-D₃ supplementation increased weight gain (P < 0.05), improved bone quality, and strengthened bone formation and resorption processes. Notably, under the regular vitamin regimen, 25-OH-D₃ reduced TD scores and enhanced weight gain, tibia mechanical properties, and the serum content of procollagen type I N-terminal propeptide (PN1P) that a marker of bone formation (all P < 0.05). However, these effects were diminished in ducks fed the high-vitamin diet. There were some interactions that were noticed regarding serum 25-OH-D₃ content, trabecular area, tibia fracture load, and PN1P levels in the present study (P < 0.05). In conclusion, the biochemical effects of 25-OH-D₃ were influenced by the baseline levels of dietary vitamins, a high-vitamin diet or treatment with 25-OH-D₃ in a regular vitamin diet improved bone quality and reduced tibial dyschondroplasia by enhancing bone formation.

Keywords: 25-hydroxycholecalciferol; Meat duck; Tibia quality; Vitamin regimen.

Figure 1

Effect of dietary vitamin regimen and 25-OH-D₃ on (A, B) tibial dyschondroplasia (TD) score, (C) the mortality due to leg abnormalities, and survival proportion of 14-d-old ducks. Data represent means with standard deviation represented by vertical bars (n = 7). ^a-c Different letters on bars means a significant difference at P < 0.05.

Figure 2

Bone microstructure response to dietary vitamin regimen and 25-OH-D₃ in 14-d-old ducks. (A) Toluidine blue stained and the morphometric analysis for (B) the trabecular bone area (Tb.Ar), (C) trabecular thickness (Tb.Th), (D) number (Tb.N), and (E) spacing (Tb.Sp) determined by histomorphometry. Data represent means with standard deviation represented by vertical bars (n = 7). ^a-c Different letters on bars means a significant difference at P < 0.05.

Figure 3

Impact of dietary vitamin regimen and 25-OH-D₃ on bone formation in 14-d-old ducks. Serum bone formation markers include (A) procollagen type I N-terminal propeptide (P1NP) and (B) alkaline phosphatase (ALP) activity. (C) osteoclast number per bone surface (N.Oc/BS) in tibia were determined through (D) ALP staining. (E) mRNA abundance of vitamin D receptor (VDR) and osteoblastic genes such as collagen Ⅰa (Col1a), osteocalcin, ALP, phosphate regulating endopeptidase homolog x-linked (Phex), (f) sclerostin (Sost), and (g) dentin matrix protein 1 (Dmp1) in the tibia proximal end. Data represent means with standard deviation represented by vertical bars (n = 7). ^a-c Different letters on bars means a significant difference at P < 0.05.

Figure 4

Effect of dietary vitamin regimen and 25-OH-D₃ on bone resorption in 14-d-old ducks. (A) Tartrate-resistant acid phosphatase (TRAP) staining of tibia sections. (B) Osteoclast number per bone surface (N.Oc/BS) in tibia determined by histomorphometry. Serum bone resorption markers (C) tartrate-resistant acid phosphatase (TRAP) and (D) C-terminal cross-linked telopeptide of type I collagen (CTx) content. (E-I) Osteoclastogenesis related genes including osteoprotegerin (OPG), receptor activator of nuclear factor kB ligand (RANKL), the ratio of RANKL to OPG, cathepsin K, and vacuolar-type H⁺-ATPase (V-ATPase) in the tibia proximal end were qualified. Data represent means with standard deviation represented by vertical bars (n = 7). ^{a, b} Different letters on bars means a significant difference at P < 0.05.