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.