Interaction of dietary flaxseed with coccidia infections in chickens.

Two experiments were conducted to determine effects of diets containing n-3 fatty acids (n-3FA) from whole as well as ground flaxseed on the performance of broilers during coccidia infections. Diets were fed from 1 d of age through 3 wk of age. Chickens were infected with coccidia at 2 wk of age and the effects of infection assessed at 6 d postinfection. The first experiment contrasted effects of several high n-3FA-containing diets, including one supplemented with whole flaxseed, on infections with Eimeria tenella or Eimeria maxima. Infected chickens that consumed the flaxseed-supplemented diet had the lowest weight gains, but they were not significantly different from gains of infected chickens on the control diet. Diets supplemented with 5% menhaden oil or 15% flaxseed significantly reduced lesions caused by E. tenella, but had no effect on lesions caused by E. maxima. In a second experiment, diets supplemented with 5 or 10% ground flaxseed were assessed for effects on the performance of broilers infected with three dose levels (500, 5,000, or 50,000 oocysts) of E. maxima. Neither flaxseed diet protected weight gain during infection with 50,000 oocysts. However, a 5% flax diet protected weight gains in chickens infected with 500 or 5,000 oocysts. Diets supplemented with 5 or 10% ground flaxseed exacerbated lesions in chickens infected with 5,000 or 50,000 E. maxima oocysts compared to the control diet. Thus, diets containing high amounts of n-3 fatty acids do not affect the development of all Eimeria sp. in the same manner. The oxidative stress produced by these diets may more adversely affect development of E. tenella, which infects the relatively oxygen-poor ceca, whereas it does not affect development of E. maxima which parasitizes the middle portion of the small intestine.