HERITABILITY AND RESPONSE TO SELECTION OF EGG PRODUCTION AND EGG QUALITY TRAITS IN THREE GENERATIONS OF JAPANESE QUAIL (Cortunix cortunix japonica)

HERITABILITY AND RESPONSE TO SELECTION OF EGG PRODUCTION AND EGG QUALITY TRAITS IN THREE GENERATIONS OF JAPANESE QUAIL (Cortunix cortunix japonica)

Abstract:

This experiment was conducted to study the heritability and response to selection of egg production and quality traits in three generations of Japanese quail (Cortunix cortunix japonica). A total of 300, 450 and 420 adult Japanese quails mated at seventh week of age and in the ratio of 1:2 male to female ratio were used. A total of 4906 eggs (2461, 1365 and 1080) in base population, Generation One and Generation Two were collected and incubated. Egg collection for egg quality analyses was done at ninth week of age. At mating, Sire body weight was weighed and grouped into four weight groups. Selection for egg number was carried out and the correlated response estimated. Traits measured included body weight of sire at mating, egg number and egg internal and external quality traits. The egg quality trait was carried out using the breakout analysis. Data was analyzed using SAS Statistical Software. The effect of sire bodyweight at mating and the generation of selection on reproductive performance as well as phenotypic correlation between egg quality traits after two generations of selection were also estimated. Selection was carried out for two generations G1, G2 along with a base population G0. The generations of selection for egg production significantly (P<0.05) increased egg number, yolk length, yolk index and shell thickness; while egg weight, egg length, and shell weight significantly (P<0.05) decreased. Sire body weight at mating does not significantly affect all the measured reproductive traits (p>0.05) but there was a significant effect of generation of selection (p<0.05) on early embryonic mortality (13.46, 12.86 and 5.91) and late embryonic mortality (16.63, 17.44 and 11.40), respectively. There was a significant effect (p<0.05) of interaction between sire body weight at mating and generation of selection on all the traits measures. Phenotypic correlation between egg quality traits varied in magnitude and direction (-0.90-1.00) also, heritability estimates of egg production and quality traits ranged from low to high (0.09-0.77). Correlated responses among the egg production and quality traits also varied in magnitude and direction. It was observed that egg number improved by 2.37 and 1.56 in generation one and two respectively, as a result of selection. It was concluded that short term selection for increased egg number lead to increased yolk length, yolk index and shell thickness but decreased egg weight, egg length, and shell weight. In addition, heritability and response of egg production and its correlated response with egg quality can be maximized in quail egg improvement program. It is therefore recommended that medium to heavy eggs should be used in hatcheries for better hatchability and reduced embryonic mortality. Also, correlation between traits should be considered in selection designs.

HERITABILITY AND RESPONSE TO SELECTION OF EGG PRODUCTION AND EGG QUALITY TRAITS IN THREE GENERATIONS OF JAPANESE QUAIL (Cortunix cortunix japonica)

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