Effects of whole wheat feeding on the development of coccidial infection in slow-growing broiler chickens

Whole wheat feeding has been shown to have an effect on coccidial development in fast-growing standard lines of chickens. As whole wheat is used for rearing slow-growing chickens, the effect of this mode of feeding was studied in this type of chickens during an experimental coccidiosis. After two weeks of consumption of whole wheat and a pelleted protein concentrate (W) or a complete ground and pelleted diet (C), birds of each dietary treatment were either used as uninfected control, or inoculated (22 d of age) with either 250,000 oocysts of Eimeria acervulina, 5,000 oocysts; of E. maxima, or 20,000 oocysts of E tenella, infecting duodenum, jejunum/ileum or caeca, respectively. Whatever the Eimeria species, whole wheat led to a lower weight gain than the C diet: from 4 to 5 day post-inoculation (d PI) with E acervulina, from 5 to 7 d PI with E. maxima and from (-1) to 5 d PI with E tenella. From 6 to 7 d PI, E. acervulina-infected birds fed with W diet showed a higher weight gain than their uninfected counterparts. The specific serum IgG antibody response to E acervulina and E maxima was higher with the W than the C diet, and tended to be higher with E tenella. Total oocyst excretion was similar between the two diets for E acervulina and E maxima, and slightly increased in E tenella-infected. W-fed compared to C-fed chickens. After coccidial infection (14 d PI), no effect on the faecal microflora was observed in C-fed birds, while in E tenella-infected W-fed chickens E coli counts were increased. in conclusion, feeding wheat as whole grain compared to ground wheat to slow-growing chickens led to more detrimental effects during an experimental coccidial infection, but may have no impact on the weight at the end of the rearing period.