GENETIC ANALYSIS OF EXOTIC AND NATIVE CHICKEN
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Date
2010-12
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SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA
Abstract
ABSTRACT:
The present investigation was carried out for estimation of genetic parameters on
certain production, immunocompetence and egg quality traits in IWH, IWI and IWK
strains and control population of White Leghorns and microsatellite marker based
analysis on IWH and IWK strains and native breeds of Aseel and Kadaknath maintained
at the Project Directorate on Poultry, Hyderabad.
Significant genetic group differences were observed for all the production traits
studied. The age at first egg (AFE) and body weights at 40, 52 and 64 weeks of age
ranged from 143.49 * 0.56 to 155.63 * 0.57 days, 1290.74 * 7.21 to 1428.36 8.36,
1377.72 8.43 to 148 1.82 * 9.77 and 1455.73 * 9.49 to 1547.15 * 1 1.18 g, respectively.
Egg production up to 40, 64 and 72 weeks of age ranged from 94.08 * 0.50 to 106.15 *
0.49, 178.24 * 1.20 to 202.32 k 1.18 and 190.90 + 1.22 to 215.17 1.20 eggs.
respectively while egg weight at 28, 40, 52 and 64 weeks of age ranged from 43.81 *
0.15 to 46.77 * 0.15, 49.89 * 0.18 to 53.13 * 0.17, 53.1.3 k 0.16 to 54.65 * 0.15 and
55.47 * 0.15 to 57.59 * 0.14 g, respectively.
The AFE was low to moderately heritable while the body weights were moderate
to highly heritable. In general, egg production traits were lowly heritable while the egg
weights were low to highly heritable. The genetic and phenotypic correlations of AFE
were positive with body weights and egg weights but negative with egg production. The
genetic and phenotypic correlations of body weight at 52 and 64 weeks of age were
negative with egg production and positive with egg weight. The correlations among egg
production traits and among egg weights were positive and high while the association
between egg production and egg weight traits was moderate to high but negative.
Significant differences among genetic groups were observed for antibody titre
against SRBC and NDV only. Mean anti SRBC titre, anti NDV titre and response to
PHA-P (mrn) ranged from 4.729 * 0.142 to 5.803 * 0.11 8, 10.033 .t 0.056 to 1 1.045 *
0.049 and 0.133 * 0.075 to 0.527 * 0.164, respectively.
Heritability estimates of antibody titre against SRBC, NDV and response to PHA-P
were low to medium. The anti SRBC titre had positive genetic correlation and negative
phenotypic and environmental correlations with AFE. Genetic and phenotypic correlations
with body weights and egg production traits were mostly positive. The genetic and
phenotypic correlations of antibody titre against NDV with AFE and annual egg production
were mostly positive. The correlations of response to PHA-P with other traits varied both in
magnitude and direction.
Significant genetic group differences were observed for various egg quality traits
studied. The egg weight, haugh unit, yolk index, albumen index, yolk weight, albumen
weight, shell weight and shell thickness ranged from 53.89 0.43 to 50.01 0.48 g, 65.38 * 0.92 to 80.98 * 1.01, 0.341 * 0.003 to 0.353 * 0.003, 0.056 * 0.002 to 0.087 * 0.002,
14.16 i 0.13 to 15.58k 0.12 g, 30.92 * 0.39 to 33.18k 0.39 g, 4.32 * 0.05 to 5.12 * 0.05 g
and 0.336 k 0.003 to 0.376 * 0.003 mrn, respectively.
The heritability estimates based on sire, dam and sire + dam components of variance
for egg weight, yolk index, albumen index and albumen weight ranged from low to medium
while those of haugh unit, yolk weight, shell weight and shell thickness ranged from low to
high.
The genetic and phenotypic correlations of egg weight with other egg quality traits
except shell quality traits were mostly positive and moderate to high. High positive genetic
and phenotypic correlations between haugh unit and other traits were observed. Genetic
correlation of yolk weight with albumen weight was positive while that with shell quality
traits was mostly negative. Shell weight was positively correlated with shell thickness.
All the 15 microsatellite loci were polymorphic. The mean number of alleles (Na)
varied from 2.0 to 5.0 among the loci and 3.13 * 0.13 to 3.80 k 0.13 among the populations.
The effective number of alleles varied from 1.041 to 4.755 across the loci and between 2.33
0.09 and 3.21 k 0.1 1 among the populations. The allele frequency ranged from 0.012 to
0.980 across the loci. The overall mean PIC values ranged from 0.038 to 0.756 across the
loci and 0.434 to 0.579 among the populations.
The expected and observed heterozygosity estimates (0.634 * 0.020 and 0.723 *
0.031) were highest in Aseel, while lowest in IWH strain (0.500 i 0.022 and 0.471 *
0.034). Overall mean inbreeding coefficients for IWH, IWK, Kadaknath and Aseel were
0.205, 0.1 16, -0.052 and -0.130, respectively. The mean values of Fls, FST and FIT values
over all the loci were -0.050 & 0.065,0.05 1 & 0.308 and 0.003 k 0.064, respectively.
The genetic distance was least between Kadaknath and Aseel (0.023) and highest
between IWH and Aseel (0.160). Kadaknath and Aseel were closer with maximum genetic
identity index (0.977) while IWH and Aseel were more wide apart with least identity index
(0.852). Phylogenetic analysis grouped IWH and IWK strains in to one cluster and
Kadaknath and Aseel breeds in to another cluster. All the loci except MCW 048 deviated
significantly from equilibrium frequency in at least one of the populations, while all the loci
except MCW 007 and MCW 048 departed from the equilibrium frequency on overall basis.
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