Asian Science Citation Index is committed to provide an authoritative, trusted and significant information by the coverage of the most important and influential journals to meet the needs of the global scientific community.  
ASCI Database
308-Lasani Town,
Sargodha Road,
Faisalabad, Pakistan
Fax: +92-41-8815544
Contact Via Web
Suggest a Journal
 
Articles by I. Yildirum
Total Records ( 3 ) for I. Yildirum
  V.L. Christensen , M.J. Wineland , I. Yildirum , D.T. Ort and K.M. Mann
  The plateau stage in oxygen consumption of turkey embryos occurs at 25 and 26 days of incubation when many embryos die. The plateau stage creates hypoxia, hypercapnia and presents a paradox for growth and embryo metabolism. Prior to the plateau, vital tissues accumulate glycogen to ensure embryonic survival through anaerobic metabolism during the plateau. Intestinal maturation at the plateau demands great amounts of energy. Therefore, the objective of the study was to define the temperature and oxygen concentrations at the plateau that affect intestinal maturation. Three experiments were conducted to test incubator conditions during the plateau stage and their affect on intestinal maturation. In Experiment 1, turkey embryos at the plateau stage were exposed to 36, 37, 38 or 39°C. In Experiment 2, embryos at the plateau stage were exposed to 17, 19, 21 or 23% oxygen concentrations, and in Experiment 3, the extreme levels of temperature and oxygen treatments were combined to test interaction effects on intestinal maturation. Elevating temperature depressed intestinal weight but not length. The elevated temperature also depressed intestinal maltase and alkaline phosphatase activities indicating inhibited function. Increasing oxygen had little effect on intestinal weight or length, but hypoxia increased maltase and decreased alkaline phosphatase activities in hatchlings. When examined in a factorial arrangement, temperature and oxygen displayed independent effects on growth and function and did not interact. Thus, incubator temperature greater than 37°C and oxygen concentrations less than 19% during the plateau stage delay intestinal maturation.
  V.L. Christensen , M.J. Wineland , I. Yildirum , B.D. Fairchild , D.T. Ort and K.M. Mann
  Avian embryo thyroid responses to incubator temperature and oxygen concentrations during the plateau stage in oxygen consumption were measured. It was hypothesized that turkey embryo thyroid responds in a limited way at this critical time to environmental conditions to modulate basal metabolism. Turkey embryos were exposed to one of four incubator temperatures (36, 37, 38 or 39oC) beginning on the 25th day of incubation at the onset of the plateau, a time when plasma thyroxine (T4) and triiodothyronine (T3) concentrations normally increase. Blood was collected and thyroid hormone concentrations were measured at pipping (27th day) and hatching (28th day). Elevated temperatures depressed T3 and T4 concentrations and increased the T3 to T4 ratios. In a second experiment four oxygen concentrations (17, 19, 21 or 23% oxygen) were provided to the embryos using identical procedures. The 21% treatment significantly reduced T3 and T4 at pipping compared to all other treatments, but 23% oxygen increased plasma T3 and the T3 to T4 ratio compared to all other treatments. The 17% oxygen treatment elevated T3 compared to all other treatments. At hatching, 23% oxygen elevated T3 and T3 to T4 ratios compared to all other treatments. When temperature and oxygen treatments were applied together in a factorial arrangement, temperature and oxygen affected T3 and T4 hormone concentrations independently but did not interact. Therefore, we conclude that temperature and oxygen are independent stimuli of the avian embryonic thyroid gland during the plateau stage, and that incubator temperature and oxygen concentrations can modulate development of turkey embryos by changing plasma T3 and T4 concentrations.
  V. L. Christensen , M. J. Wineland , I. Yildirum , D. T. Ort and K. M. Mann
  The plateau stage in oxygen consumption of turkey embryos occurs at 25 and 26 days of incubation and most embryonic deaths occur at that time (Rahn, 1981 and Christensen et al., 2003). At the plateau stage, vital gas diffusion through the shell is insufficient for oxygen to drive metabolism or for expelling the metabolic by products of water vapor and carbon dioxide. The objective of the experiments reported here was to determine the effect of environmental temperature and oxygen concentration during hypoxia and hypercapnia of the plateau stage on turkey embryo cardiac health. Three experiments were conducted. In Experiment 1, turkey embryos at the plateau stage were exposed to 36, 37, 38 or 39 C. In Experiment 2, embryos at the plateau stage were exposed to 17, 19, 21 or 23% oxygen concentrations, and in Experiment 3, the highest and lowest levels of temperature and oxygen treatments were combined to determine interaction effects on cardiac physiology. Temperatures greater than 37 C depressed heart weight but not BW and decreased cardiac tissue energy metabolism. Oxygen concentrations greater than 21% increased BW and improved the cardiac glycogen to lactate ratio with no effect on heart weight. When examined together, the two factors interacted to affect cardiac energy metabolism. It was concluded that the physiologic action of oxygen during the plateau stage favored BW whereas temperature affected cardiac tissue but not BW. Temperature and oxygen interact during the plateau to affect cardiac muscle energy metabolism.
 
 
 
Copyright   |   Desclaimer   |    Privacy Policy   |   Browsers   |   Accessibility