ObjectiveTo determine the effects of dietary HyD on male turkey production, physiology and immune function.
BackgroundProper nutrition, including optimal dietary vitamin D is essential to maintain the health and production performance of modern commercial turkeys. This study investigated the use of a natural vitamin D compound (25-hydroxy vitamin D3; commercially available as ‘HyD’), either alone or in combination with vitamin D3 on the early immune function, skeletal health and body composition of turkeys. Vitamin D3 is central to calcium and phosphorus metabolism, and is necessary for proper bone development. Dietary vitamin D3 is converted in the liver to 25-OH D3, which is then converted in the kidney to the active metabolite, 1,25(OH)2D3. Recent research in Dr. Korver’s lab indicates that the initial conversion step appears to be impaired in young broiler chicks and may also be so in turkey poults. In addition, the absorption of fat, and therefore fat-soluble vitamins like vitamin D, appears to be impaired in young poults as compared to older turkeys. Studies with broilers have shown a beneficial effect of dietary HyD on early immune function, growth and breast meat yield, particularly when fed throughout the bird’s life. No such data are available for turkeys.
OutcomesThis study showed that inclusion of HyD in turkey feed, particularly early in life, has beneficial effects on meat yield and early innate immune function. The inclusion of HyD also limited the reduction in plasma 25-OH D3, that occurred from 1 to 3 wk of age, and also supported a greater plasma 25-OH D3 from 1 to 6 wk of age, over the turkeys fed D3 only. The incidence of skeletal defects during the study was minimal, so it was difficult to ascertain the effect of HyD on skeletal health of turkeys. However, there was no effect of dietary treatment on bone mineral density at 9, 19 and 22 wk of age. Ongoing bone sample analysis using quantitative computed tomography may shed more light on this topic. Data analyses of feed and meat composition are ongoing.
ApplicationHyD is commonly used throughout the turkey industry. A better understanding of the physiological effects of HyD, especially as they relate to dose and timing, will help turkey producers evaluate their feeding programs.
Funding$241,843 ($97,675 AAFC*, $43,468 AFC, $63,200 DSM including $2,500 in-kind)
*This research was part of the 2010-2013 Poultry Science Cluster which was supported by AAFC as part of Growing Forward, a federal-provincial-territorial initiative.