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Integrators rearing replacement broiler breeders should take into account the finding that early flock performance can be influenced by dietary composition, depending on the genetic line and gender, Leslee A. Oden, of Texas A&M University, said at the American Association of Avian Pathologists annual meeting held last July.

Oden and associates conducted a study to determine the effect of diet on oocyst output, gross lesion development and performance in replacement broiler breeders from two genetic lines that received Coccivac-D, a live-oocyst coccidiosis vaccine, at 1 day of age.

There were two lines of breeders in the study — Line A and Line B — and in each group there were 240 males and 576 females. After delivery from the hatchery, birds received either the integrator diet or a diet recommended by the primary breeder of each line, Oden said. The protein concentration was higher in the breeder-recommended diets than in the integrator diets.

Oocyst shedding was evaluated and gross lesion scores were determined, as well as average bodyweight and flock uniformity, she said.

In Line A, oocyst peaks varied with gender and the dietary program. Breeders fed the integrator diet had significantly higher lesion scores in the upper region of the small intestine when compared to breeders fed the breeder-recommended diet. There were no differences in bodyweight during the course of the trial, but on days 28 and 42, males fed the integrator diet had improved uniformity, she said.

In Line B, breeders fed both diets had oocyst peaks between days 14 and 18; the peaks varied with gender and the dietary program.

Males on the integrator diet had an increased lesion score in the mid-intestine compared to birds on the breederrecommended diet. Females fed the breeder-recommended diet had increased bodyweight from days 21 to 42 and improved uniformity on days 28 and 42 compared to birds on the integrator diet, Oden said.

Lesion development and oocyst output are related and tend to be at their highest levels around day 17 when rearing replacement broiler breeders on fresh pine shavings, Oden concluded. The magnitude of oocyst output and number of identifiable peaks are influenced by genetic line, gender and dietary composition.

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