ARS | Publication request: Effects of a dietary yeast extract on hematological parameters, heterophil function, and bacterial clearance in turkey poults challenged with Escherichia coli and subjected to transport stress

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: July 17, 2007
Publication Date: August 26, 2007
Citation: Huff, G.R., Farnell, M., Huff, W.E., Rath, N.C., Solis De Los Santos, F., Donoghue, A.M. 2007. Effects of a dietary yeast extract on hematological parameters, heterophil function, and bacterial clearance in turkey poults challenged with Escherichia coli and subjected to transport stress. In: Proceedings of the XVIth European Symposium on Poultry Nutrition, August 26-30, 2007, Strausbourg, France. p. 200.

Interpretive Summary: There is a need to develop nutritional methods for controlling pathogens in poultry production. A feed supplement derived from yeast, Alphamune™ (YE), was added to male turkey diets. Turkeys were challenged by air sac injection with 60 cfu of E. coli at 1 week of age. At 3 weeks of age challenged birds were subjected to transport stress and birds were bled and necropsied the following morning. Blood cell numbers, percentages, and various parameters were determined. A test that measures the ability of blood cells to kill bacteria was conducted. The numbers of a type of blood cell that can kill bacteria was increased and their ability to kill bacteria was stimulated by YE. Transport stress also increased the ability of these cells to kill bacteria and this increase was modulated by YE treatment. Blood levels of calcium, phosphorus, and triglycerides were decreased and uric acid levels, red blood cell numbers, hemoglobin and hematocrit were increased by YE supplementation. Bacteria were isolated from the air sac and liver of a lower percentage of birds provided with YE. These results suggest that dietary YE has potential as a non-antibiotic alternative for decreasing bacterial pathogens in turkey production.

Technical Abstract: There is a need to develop nutritional methods for controlling pathogens in poultry production. A standardized yeast extract supplement, Alphamune™ (YE), was added to turkey poult diets. Male poults were challenged by air sac injection with 60 cfu of E. coli at 1 week of age. At 3 weeks of age challenged birds were subjected to transport stress and birds were bled and necropsied the following morning. Blood cell numbers and percentages and hematological parameters were determined. Oxidative burst activity of isolated heterophils was measured using stimulation with phorbol myristate acetate and a 2',7'-dichlorofluorescein diacetate (DCF-DA) assay. Data was analyzed using GLM and LS Means procedures of the SAS® program. The percentage of heterophils in peripheral blood was increased and their oxidative burst activity was stimulated by YE. Transport stress also increased oxidative burst and this increase was modulated by YE treatment. Serum levels of calcium, phosphorus, and triglycerides were decreased and uric acid levels, erythrocyte numbers, hemoglobin and hematocrit were increased by YE supplementation. Bacteria were isolated from the air sac and liver of a lower percentage of birds provided with YE. These results suggest that dietary YE has potential as a non-antibiotic alternative for decreasing bacterial pathogens in turkey production.