Abstract:
Frizzled (Ff) and normally feathered (ff) genotypes were reciprocally mated
to produce the first generation: frizzled (Ff-F and Ff-N) and normally
feathered (ff-F and ff-N) genotypes. Later the second generation produced
by internal mating within each genotype. The produced genotypes were:
Frizzled (Ff-FF and Ff-FN), over frizzled (FF and normally feathered ( ff-FF,
ff-FN, ff-NF and ff-NN) genotypes. 192 and 288 chicks were used for the
1st and the 2nd generation. All chicken were kept on open sided houses
and reared under the same environmental, managerial and hygienic
condition.
Feed and water were supplied ad libitum. No significant differences
between the frizzled and normally feathered genotypes in body weight,
body gain, feed consumption and feed conversion ratio at 0-12 weeks of
age although, the frizzled genotype Ff-FN was heavier than the Ff-F. More
over, the frizzled hens were heavier than the normally feathered one at
sexual maturity age. Likewise, no significant differences were recorded in
egg production and egg quality except for egg weight, egg width egg shell
thickness, Albumin weight, yolk height and yolk color. The fertility and
hatchability of the frizzled is higher than the normally feathered genotypes,
but there is no significant difference
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The homozygous over frizzled (FF) genotype showed significantly lower
percentages in feather, liver and Giblets weight, similarly higher weight in
heart, spleen and abdominal fat, but with no significant differences.
This could be attributed to the fact that, the values of the growth rate and
the feed consumption and egg production measured during the winter and
autumn seasons. However, the effect of the frizzle gene is only well
pronounced at high constant temperature.
There is no superiority of the frizzled genotypes in most of the egg quality
traits. The mortality of the frizzled genotypes proved to be lower than the
other normally feathered genotypes. This was attributed to its tolerance to
heat stress and disease resistance .Therefore, introducing frizzle (F) genes
in selection programs for its characteristics in heat tolerance and disease-
resistance must be taken into consideration.
