Author
 |
Allen, Patricia |
|
Danforth, Harry |
|
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/6/1998 Publication Date: N/A Citation: N/A Interpretive Summary: The ethyl esters of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids were added to broiler starter ration singly or in combination [as bulk purified ethyl ester concentrate from menhaden oil (n3FAC)] in quantities similar to those found in a diet supplemented with 5% menhaden oil. Diets were fed to chickens from 1 day of age through 3 weeks of age. At two weeks of age, chickens were infected with E. tenella, E. acervulina or E. maxima. At 6 d PI the effects of the diets were assessed on weight gains during infection, plasma carotenoids, lesion scores, and parasite scores in gut cross sections or oocyst output. Significant ameliorating effects of diet on lesion scores and parasite scores were only seen in E. tenella infections and were only produced by the n3FAC and MO supplements. These two supplements, containing higher molar concentrations of double bonds than the other supplements also significantly reduced plasma carotenoids in nuninfected chickens indicating they promoted a state of oxidative stress. These results are consistent with previous reports on the interaction of coccidiosis with dietary n-3 fatty acids and strengthen the hypotheses that dietary induced oxidative stress is an effective deterrent against cecal coccidiosis in chickens. Technical Abstract: Coccidiosis, caused by protozoan parasites of the host's intestinal tissues, cause large economic losses to poultry producers from reduced feed efficiencies, morbidity and mortality. Parasite control is generally through prophylactic addition of anticoccidial drugs in the feed, at an annual cost of about $100 million. However, increased resistance of coccidia to these drugs, as well as an increasing consumer demand for reduced drug exposure from food, has prompted research on alternative strategies for coccidiosis control. As part of this effort, we are investigating natural products for their anticoccidial potential when used as dietary supplements. Previously we found that menhaden oil (MO) and flaxseed oil (FLO), when added to starter rations and fed to chicks from 1 day of age, effectively reduced lesions from the cecal parasite Eimeria tenella. It was hypothesized that the highly unsaturated n-3 fatty acids (n3FA) in these products generate a state of oxidative stress detrimental to E. tenella. In this study, we tested the anticoccidial activity of the purified n3FA from (MO), and found that their effectiveness against E. tenella varied with the total amount of unsaturation added to the diet, upholding the previous hypothesis. These substances could be used in conjunction with, and may allow for reduction in use of conventional anticoccidial drugs, and may be of interest to producers of "organically grown" flocks. |
