الفهرس 
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Abstract
This study was carried out at the poultry farm, Department of Animal and poultry Production,
Faculty of Environmental Agriculture Sciences, Suez Canal University, Al-Arish, North Sinai, Egypt,
during the period from October 2011 to November 2012. This study has been carried out to investigate
the direct and indirect response of Japanese quail to bidirectional individual selection for keel length at
4 wk of age on growth traits, egg production traits and carcass traits as well as the study of the
asymmetry of some bilateral traits (right and left lengths of shank, face and axial feather).
A total number of 1500 (abase population) eggs were purchased as fertilized eggs of three different
strains identified by feather color from the college of Agricultural, Cairo University. Eggs were brought
and used to establish the nucleus of later generations from the experimental flocks. The base
populations consisted of three color types: a. the Wild type (Blacks); b. the Brown type and c. the
White type. The base population of Japanese quail (Parents) was derived from four hatches of a random
mated flock. This flock was used for subsequent divergent selection to produce the next two
generations (G1 and G2).
Traits studied were Biweekly Individual body weights (to the nearest 2 decimal number at hatch
and to the nearest gram at 2, 4, 6, 8 wk of age); weight gain (WG); relative growth rate (RGR). Both
right and left measures of the following traits were estimated (using a digital caliper): 1. Shank
dimensions (length at 6 and 8 wk of age); 2. Face length (at 4, 6 and 8 wk of age); 3. Axial feather
Length (at 2 wk of age). Furthermore, Keel length at 4, 6 and 8 wk of age was measured (using a digital
caliper). Keel length at 4 wk. of age was divergently used as a selection criterion for parents of the later
generations.
Egg production traits were measured Individually (i.e. for each matured hen) as: age (in days) at
the first egg; number of produced eggs till 8 and 12 wk after puberty of each female; egg weight; and
the period needed to produce the first ten eggs (PFE10).
Carcass traits included live weight before slaughter, slaughter weight, shed blood weight; feather
weight; head weighed and carcass weight (after the removal of head, neck, shank, and viscera) as well
as weights of some internal organs ( heart, glandular and muscular stomach, gut, liver, spleen, heart,
and sex organs).
Asymmetry of an individual is measured as the difference between the right and the left value of
the bilaterally paired trait. The recorded morphological bilateral traits right (R) and left (L), shank
length, face length were evaluated at 4, 6, 8 wk of age as well as Axial feather at 2 wk of age. All 3
lengths were measured in millimeters using a digital caliper.