Tackling the future challenges of Organic Animal Husbandry - vTI

RAHMANN G & GODINHO D (Ed.) (2012): Tackling the Future Challenges of Organic Animal Husbandry.
Proceedings of the 2 nd OAHC, Hamburg/Trenthorst, Germany, Sep 12-14, 2012
Material and methodology
The experiment was conducted at the Research Centre Foulum, Aarhus University, Denmark. The
study used a 2 x 2 factorial design – with two genotypes and two dietary treatments (supplemented
with A. annua dried leaves or not) as main factors – and with three replicates for each treatment
combination. In total, the experiment thus included 12 flocks of 35 broilers of mixed sex. During
the study, animals were fed a typical organic concentrate, whole wheat and supplemented with water.
30 broilers were randomly allocated to 12 plots outdoor at 29 days of age. Six groups, three of
each genotype, were fed Artemisia mixed in diet while the non-treated groups received diet without
A. annua. 60 broiler called “seeders” were naturally infected with contaminated manure according
with Velkers et al. (2010) and after 10 days, at 39 days of age, 5 “seeders” were introduced to each
of the 12 plots. Ten broilers called “tracers” where randomly selected per plot and monitored twice
weekly for coccidia oocyst (oocysts/g faeces; OPG) and A. galli egg (eggs/g faeces; EPG) excretion.
In the end of the study, at 74 days of age, 5 broilers per plot (n=60) (not “seeders” and not
“tracers”) were harvested for lesion score in accordance with Johnson and Reid (1970) and for
counting nematodes in the intestinal tracts. Consumption of diet was recorded twice a week and a
mean individual feed consumption was calculated for both genotypes. All broilers in this study were
weighed individually in four specific moments at different ages. Analysis of variance was performed
using the MIXED procedure in SAS for infection and performance attributes. Total weight
gain and the daily weight gain were calculated individually while feed conversion rate was calculated
per plot. More information on methods can be found at Almeida et al. (2012).
Results
The overall body weight gain and the weight gain when coccidia infection was subdued showed a
three-way interaction among genotype, sex and treatment (Table 1). Weight gain was higher when
K8R females were supplemented with A. annua whereas supplemented K8R males had a lower
weight gain than non-supplemented males (Table 2). No differences for the overall performance of
flocks treated and untreated were reported at the end of the trial.
Table 1. Levels of significance of factors influencing performance and infection
Weight Gain
(Kg)
Daily gain (g/d) periods a Mean OPG b A. galli larvae
c
29-42 42-56 56-74
Treatment NS * NS * * NS
Genotype ** ** ** ** NS NS
Genotype x Treat. NS NS NS NS NS NS
Sex ** ** ** ** * -
Treatment x Sex * NS NS * NS -
Genotype x Sex * NS NS * NS -
Treat. x Gen. x Sex * NS NS * NS -
NS = Non Significant; * significant at P