Dietary supplementation with canthaxanthin and 25-hydroxycholecalciferol has beneficial effects on bone and oxidative metabolism in European quail breeders

This study aimed to investigate the effect of supplementation with canthaxanthin (Cx) and 25-hydroxycholecalciferol (25-OH-D3) on the production performance, egg quality, bone mineral content, blood biochemical parameters, and antioxidant status of European quail breeders. Two hundred and forty quail breeders were distributed in a completely randomized design with 5 diets and 8 replicates of 4 females and 2 males were used. All quail breeders received one of 5 diets: basal diet (containing 2,000 IU vitamin D3) or the same diet supplemented with 3 ppm Cx and 34.5 μg 25-OH-D3, 6 ppm Cx and 69 μg 25-OH-D3, 9 ppm Cx and 103.5 μg 25-OH-D3, or 12 ppm Cx and 138 μg 25-OH-D3. Production performance and internal and external egg quality parameters were not influenced by diet. Eggshell dry weight decreased linearly with increasing supplementation levels, and eggshell ash and calcium content increased quadratically. Plasma phosphorus, calcium, and ionic calcium levels in females and plasma ionic calcium levels in males showed a positive quadratic response to dietary supplementation. Femoral and tibiotarsal dry weight and calcium content were influenced by diet. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity in the liver of males and females and in the serum of females showed a positive quadratic relationship with Cx and 25-OH-D3 levels, whereas the malonaldehyde concentration showed a negative quadratic relationship. DPPH scavenging activity in the serum of male quail increased linearly with supplementation. There was a positive quadratic effect on superoxide dismutase gene expression and a positive linear effect on glutathione peroxidase 7 gene expression, suggesting that dietary enrichment with Cx and 25-OH-D3 might help protect spermatozoa against oxidative damage. The dietary supplement was pro-oxidative at high concentrations (above 9 ppm Cx). The results indicate that diets with adequate levels of Cx and 25-OH-D3 have a beneficial effect on calcium and phosphorus metabolism as well as on the antioxidant defense system. We recommend supplementing European quail breeders in the laying period with 6 ppm Cx and 69 μg 25-OH-D3.