Genetic parameters and polymorphisms of prolactin gene for body weight and egg production traits in betong chicken (KU Line)

Name: Kanok Chaovapasee

LCSH: Kasetsart University -- Dissertations. Ph.D. (Animal Science) 2019

Classification :.LCCS: SF498.7

LCSH: Kasetsart University. -- Department of Animal Science -- Dissertations

LCSH: Broilers (Chickens) -- Genetics

LCSH: Broilers (Chickens) -- Growth

LCSH: Prolactin genes

LCSH: Genetic polymorphisms

Abstract: The objectives of this study were to estimate genetic parameters of body weight and egg production traits, to identify the genetic polymorphisms of the prolactin (PRL) gene, to estimate the effect of the gene on those traits, and to compare models with and without molecular information of the gene in Betong chicken (KU line). Body weight at 16 weeks of age (BWT), hen weight at first day of laying (WFE), age at first egg (AFE), first egg weight (FEW) and egg number at 300 days of age (ENO) of Betong chicken (KU line) born during year 2007 to 2016 were used in the analyses. Animals in pedigree file were computed back 11 generations. Variance and covariance components were estimated using restricted maximum likelihood with average information algorithm. Fixed effects were hatching batch (for all traits) and sex (only for BWT). Random effects were additive genetic and residual. The polymorphisms of the PRL gene were identified by polymerase chain reaction and restriction fragment length polymorphism using the CViQI and AluI restriction enzymes. The effects of the PRL genotype were determined by genotypic and allelic substitution for that gene. Eight animal models were used to compare genetic parameters and estimated breeding value. Model 1 was the animal model without molecular information of the gene. Model 2 to 8 were the animal models with different molecular information of the gene. The estimates of heritability for BWT, WFE, AFE, FEW and ENO were 0.44, 0.34, 0.20, 0.40 and 0.38, respectively. The genetic correlations between BWT and FEW, BWT and ENO, and WFE and ENO were low and close to zero. The genetic correlations between BWT and WFE, AFE and FEW, and AFE and ENO were 0.65, 0.60 and -0.68, respectively. The polymorphisms of the gene at site -358, -2161 and -2402 were found in this population, however, the genotypic and allelic substitution of the gene did not affect on BWT, WFE, AFE, FEW and ENO. The animal model with haplotype of the PRL gene (Model 5) was the most appropriate model because of the lowest -2logL. The selected animals differed when various intensities were applied for selection with Model 1 VS others. The molecular information of the PRL gene had an effect when high selection insensity (small proportion of selection) was considered in animal with molecular information. Selection for reducing AFE could increase ENO and may not have any adverse effect on BWT. Molecular information of the PRL gene could not be used as a marker gene independently but it could have benefit when it was combined with animal model and the high selection intensity was considered for selecting animals in replacement flock of Betong chicken (KU line) population.

Kasetsart University. Office of the University Library

Address: Bangkok

Email: tdckulib@ku.ac.th

Name: Panwadee Sopanarath

Role: Thesis Advisor

Name: Sornthep Tumwasorn

Role: Thesis CO-Advisor

Name: Wiriya Loongyai

Role: Thesis CO-Advisor

Created: 2019

Modified: 2025-06-29

Issued: 2025-06-29

วิทยานิพนธ์/Thesis

application/pdf

URL: https://www.lib.ku.ac.th/KUthesis/2562/kanok-cha-all.pdf

CallNumber: SF498.7 .K36

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Animal Science

Grantor: Kasetsart University

©copyrights Kasetsart University

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