Effect of vitamin D3 and strontium on performance, nutrient retention, and bone mineral composition in broiler chickens

The therapeutic use of vitamin D-3 and strontium has been successful for the treatment of osteoporosis in humans; however, the value of similar strategies in poultry is not clear. Male Ross broiler chicks (n = 216) were used in a 28-day broiler trial to assess effects of vitamin D-3 and strontium supplementation on performance, nutrient retention, bone composition, and bone mass. Treatments included an industry-standard control diet and five additional diets where vitamin D-3 was added at 5000, 20 000, or 35 000 IU/kg and strontium was added at 0 or 1200 mg/kg in a 3 x 2 factorial design. Broiler chickens supplemented with strontium and additional vitamin D-3 did not increase bodyweight; however, there was a significant improvement in feed efficiency at medium levels of vitamin D3, and although not statistically significant, there was also an improvement in feed conversion ratio with strontium supplementation at normal vitamin D-3 concentrations. Strontium supplementation at normal levels of vitamin D-3 significantly (P < 0.01) increased calcium, phosphorus, sodium, potassium, and magnesium retention. Ahigh concentration of vitamin D-3 produced a significant improvement in apparent metabolisable energy, protein, and dry matter utilisation in the broiler chicken. Paradoxically, however, there was a detrimental effect of high vitamin D-3 on bodyweight and feed efficiency, which was partially ameliorated by strontium supplementation. Strontium addition did not change bone mass but did change bone composition. High levels of vitamin D-3 significantly (P < 0.01) reduced bone ash content and increased strontium content of bone. In conclusion, both vitamin D-3 and strontium have the potential to positively influence the performance, mineral retention, and bone characteristics of broiler chicks. However, as with calcium and phosphorus, vitamin D-3 and strontium interact and so more research is required with strontium on the optimum dose rate and its relationship with vitamin D-3, calcium, phosphorus, and IGF-1 in broiler nutrition.