ARS | Publication request: Bacterial clearance, heterophil function, and hematological parameters of transport stressed turkey poults supplemented with dietary yeast extract

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 24, 2009
Publication Date: March 1, 2010
Citation: Huff, G.R., Huff, W.E., Farnell, M.B., Rath, N.C., De Los Santos, F.S., Donoghue, A.M. 2010. Bacterial clearance, heterophil function, and hematological parameters of transport stressed turkey poults supplemented with dietary yeast extract. Poultry Science. 89(3):447-456.

Interpretive Summary: Yeast extracts contain substances that may be useful as alternatives to antibiotics for controlling disease causing bacteria in poultry and decreasing the problems caused by production stressors. A yeast extract feed supplement, Alphamune™ (YE), was added to turkey poult diets. Male poults were challenged by injecting a low level of bacteria into the respiratory system at 1 week of age. At 3 weeks of age these challenged birds were subjected to transport stress and birds were bled and necropsied the following morning. Blood cell numbers and percentages and various blood parameters were determined. A type of blood cell was tested for its potential ability to kill bacteria. The numbers and percentages of these blood cells were increased and their potential ability to kill bacteria was stimulated by YE. The stress challenge dramatically increased this function and this increase was significantly lowered by YE treatment. A number of chemicals in blood were affected by YE supplementation. Bacteria were isolated from the respiratory system 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 disease causing bacteria in turkey production.

Technical Abstract: Yeast extracts contain biological response modifiers that may be useful as alternatives to antibiotics for controlling pathogens in poultry production and mitigating the deleterious effects of production stressors. A standardized yeast extract feed 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 wk of age. At 3 wk of age these challenged birds were subjected to transport stress and birds were bled and necropsied the following morning. Blood cell numbers and percentages, hematological parameters, and clinical chemistry values were determined. Oxidative burst activity of isolated heterophils was measured using stimulation with phorbol myristate acetate (PMA) and a 2',7'-dichlorofluorescein diacetate (DCF-DA) assay. Data was analyzed using GLM and LS Means procedures of the SAS® program. The numbers and percentages of heterophils in peripheral blood were increased and their oxidative burst activity was stimulated by YE. The stress challenge dramatically increased oxidative burst and this increase was significantly 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 withYE. These results suggest that dietary YE has potential as a non-antibiotic alternative for decreasing bacterial pathogens in turkey production.