Detection and Localization of Quantitative Trait Loci Affecting Fatness in Broilers

Abstract

A cross between 2 genetically different outcross broiler dam lines, originating from the White Plymouth Rock breed, was used to produce a large 3-generation broiler population. This population was used to detect and localize QTL affecting fatness in chicken. Twenty full-sib birds in generation 1 and 456 full-sib birds in generation 2 were typed for microsatellite markers, and phenotypic observations were collected for 3 groups of generation 3 birds (approximately 1,800 birds per group). Body weight, abdominal fat weight, and percentage abdominal fat was recorded at the age of 7, 9, and 10 wk. To study the presence of QTL, an across-family weighted regression interval mapping approach was used in a full-sib QTL analysis. Genotypes from 410 markers mapped on 25 chromosomes were available. For the 3 traits, 26 QTL were found for 18 regions on 12 chromosomes. Two genomewise significant QTL (P < 0.05) were detected, one for percentage abdominal fat at the age of 10 wk on chicken chromosome 1 at 241 cM (MCW0058 to MCW0101) with a test statistic of 2.75 and the other for BW at the age of 10 wk on chicken chromosome 13 at 9 cM (MCW0322 to MCW0110) with a test statistic of 2.77. Significance levels were obtained using the permutation test. Multiple suggestive QTL were found on chromosomes 1, 2, 4, 13, 15, and 18, whereas chromosomes 3, 7, 10, 11, 14, and 27 had a single suggestive QTL.

Mapping quantitative trait loci affecting fatness and breast muscle weight in meat-type chicken lines divergently selected on abdominal fatness

“…This depicts the actual antagonism between fatness and meat yield. Thus, the adjusted data appears to be highly relevant when studying the potential for accumulating abdominal fat or breast muscle (white meat) in various QTL studies [8,10,21,25,28]. The high correlation between the weight of body parts and whole body weight (Tab.…”

“…II; [2,12]) could confound the identity of genes controlling variability in body weight with those involved in carcass composition variability. However, in experiments where both fat weight and fat ratio (or adjusted weight) have been explored [8,10], Table II. QTL for abdominal fatness and breast muscle weight in an F 2 population derived from a cross of FL and LL broiler chickens.…”

“…Tatsuda and Fujinaka [27] have used crosses between slow-growing (meat-type) native Japanese breeds and fast-growing White Plymouth Rock (broiler) lines. Ikeobi et al [8] have analysed a cross between a commercial broiler sire-line and a White Leghorn layer line, while Jennen et al [10] have investigated crosses between two genetically different broiler lines. Each study has identified from 1-8 QTL for various fatness-related traits that range between 0.2-1.2 phenotypic standard deviations.…”

“…Black boxes: the present results; striped boxes: fat-related trait adjusted for body weight; empty boxes: raw data. a Ikeobi et al [8]; b Jennen et al [10]; c McElroy et al [21]; d Tatsuda et al [29].…”

Identification of quantitative trait loci associated with bone traits and body weight in an F2 resource population of chickens

“…A number of QTL mapping studies have been performed on crosses between genetically and phenotypically divergent lines of chickens. These studies have focused on identifying QTL responsible for body weight [39,46,47,51,52,55], feed-efficiency [57], growth [7,20,27,55,57,62], carcass characteristics [12,23,24,56], and egg traits [27,39,44,54,59]. Other researchers have investigated specific candidate genes potentially associated with variation in traits relating to bone integrity [31,61].…”