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Contributed Papers: Posters
Pathology

Phenotypic characterization of chicken selection
lines infected with Eimeria tenella


G.R. Bertani1, C.A.F. Costa1, W. Barioni Jr2,
Gil, L.H.V.G., L3. Brentano1, and E.A.P. Figueiredo1.
1Embrapa Swine and Poultry, Concórdia, SC, 897000-000,
2Southeast Embrapa Cattle, São Carlos, SP and 3CPQAM/FIOCRUZ, Recife, PE. gbertani@cnpsa.embrapa.br

The objective of this study was to characterize the susceptibility to coccidiosis of one broiler line (TT; 12 generations of selection) and two layer lines (CC, selected for egg production, and CCc, is CC control line randomly selected, both with 10 generations of selection). On hatching day, groups of chicks were allocated in cages (10 to 11/cage/line). On day seven, chicks were inoculated with 30,000 E. tenella oocysts and non-inoculated groups were kept as controls. Mortality was evaluated before and after inoculation, and fecal oocysts were counted for each cage (days 5 to 9 post-infection). From 7 to 25 days of age, post-infection mortality rate differed (different letters, P<0.05) as follows: TT = 35.0%a (35/100), CCc = 25.0%ab (24/100) and CC = 18.7%b (18/101). Different traits were evaluated 7 days after infection including feed consumption (FC), body weight at 14 days of age (BW14), weighted weight gain (WWG), average weighted weight gain (AWWG), average feed intake (AFI), weighted feed conversion (WFC). In infected chickens, the results for AWWG includes least square means and standard error are: TT = 131.97g ±6.41a, CCc = 24.08g ±3.42b and CC = 22.68g ±3.44b (P<0.01). In non-infected chickens, the results for AWWG are: TT = 274.7g ±8.45a, CCc = 63.19g ±3.42b and CC = 61.83g ±3.85b (P<0.01). In relation to the WFC, in infected chickens, the results are: TT = 1.90 ±0.26b, CCc = 3.49 ±0.33a, CC = 3.93 ±0.33a (P<0.1). In non-infected chickens, the results are: TT = 1.27 ±0.33b, CCc = 1.81 ±0.39.42a and CC = 1.96 ±0.37a (P<0.1). The level of infection used in the present study significantly decreased production performance by reducing FC, BW14, WWG, AWWG, and WFC (results not shown). The line with the highest mortality rate (TT) presented best performance in terms of AWWG and WFC, when compared to CC, the line least susceptible to mortality. The mortality rate shows a trend, indicating that selection for egg production may be correlated with lower susceptibility to E. tenella infection; however, additional experimentation is required for verification. Summing up, significant differences in mortality and weight gain post-E. tenella infection were demonstrated for two lines.

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