Inheritance of fertility in broiler chickens

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Simulation study on the application of Gibbs sampling for major gene detection in a population of laying hens

A method for the detection of segregating major genes based on the analysis of estimated marginal posterior major gene variance density was examined. The properties of the method were investigated using data sets simulated for a real population of laying hens consisting of eleven generations. Marginal posterior densities of model parameters were estimated by the Gibbs sampling approach proposed by Janss et al. (1995). With the data of about 4000 observations it was possible to detect a major gene responsible for one third of the genetic variance and one tenth of the phenotypic variance, irrespectively of the degree of dominance at the major locus. The inference based on the posterior marginal major gene variance can be sensitive to skewness of the data. It was shown that skewness of 0.2 can lead to a false detection of a major gene. The method is robust against a non-genetic mixture of normal distributions

Repeatability of some traits of boar semen

Целью работы являлась оценка коэффициентов повтормости следующих признаков семени хряков: объем эякулята, процент сперматозоидов с поступательным движением, концентрация семени, общее количество сперматозоидов в эякуляте, количество полезных сперматозоидов. Исследования охватывали 74 хряка трех пород (крупной белой польской, польской белой вислоухой и дюрок) используемых в период трех лет. Хряков брали с четырех Велькопольcких животноводческих центров по разведению и осеменению животных. Коэффициент повторимости определяли методом анализа дисперсии в иерархической системе. Были получены высокие величины коэффициентов повторимости, что свиделельствует о возможности проведения селекции по основным признакам уже в первый год использования хряков.The aim of the respective study was evaluation of repeatability coefficients of the following traits of boar semen: volume of ejaculate, per cent of progressing spermatozoa, concentration of semen, total number of spermatozoa in the ejaculate, number of spermatozoa able to fertilize. The investigated material included 74 boars belonging to three breeds (Polish Landrace, Polish Large White and Duroc) used for reproduction for three years.The boars were in 4 Breeding and Insemination Stations of the Wielkopolska region. The repeatability coefficients were estimated by the method of analysis of variance in hierarchic design. High values of the repeatability coefficients proved the possibility of effective selection for the tested traits already in the first year of reproductive life of the animal

Effect of carcass weight on meat colour of Pekin ducks

Określono barwę mięsa kaczek typu pekin, odchowanych przez 11 tygodni, z uwzględnieniem płci i masy tuszek pogrupowanych w czterech przedziałach wartości. Przedziały masy tuszek: PI – 1567 ÷ 2170 g, PII – 2171 ÷ 2330 g, PIII – 2331 ÷ 2510 g i PIV – 2511 ÷ 2949 g utworzono w taki sposób, żeby liczba próbek w poszczególnych grupach była równa. Barwę mięśni piersiowych i nóg zmierzono instrumentalnie za pomocą kolorymetru w systemie CIE L*a*b*. Określono także odcień (h) i nasycenie barwy (C). Nie wykazano wpływu płci na żadną ze składowych barwy zarówno mięśni piersiowych, jak i nóg. Wykazano wpływ masy tuszki wyłącznie na kształtowanie się barwy żółtej (b*) i odcienia (h) mięśni nóg. Zawartość tłuszczu w mięśniach była zależna od masy tuszki i płci ptaków. Wykazano korelację tej cechy z jasnością mięśni piersiowych (r = 0,58) i nóg (r = 0,76). Tylko w przypadku samic kaczek wykazano istotnie (p ≤ 0,05) różną jasność (L*) mięśni piersiowych pochodzących z grup o lżejszych tuszkach (PI i PII) i z grupy najcięższej (PIV). Tych samych grup dotyczyło istotne (p ≤ 0,05) zróżnicowanie zawartości tłuszczu. Dowiedziono, że w celu uzyskania mięsa (jako surowca do przetwórstwa) wyrównanego pod względem barwy, należy prowadzić oddzielny chów samców i samic kaczek typu pekin. Chów samic kaczek powinien trwać nie dłużej niż do uzyskania tuszki o masie 2500 g, tj. do momentu osiągnięcia przez te ptaki 3500 g masy ciała.Under the research study, the meat colour was determined of Pekin ducks raised for 11 weeks; the determination was made with regard to the sex and carcass weights grouped in four value ranges. The ranges of carcass weights: (i) PI from 1567 to 2170 g; (ii) PII from 2171 to 2330 g; (iii) PIII from 2331 to 2510 g; and (iv) PIV from 2511 to 2949 g were set so as to obtain the same number of samples in the individual groups. The colour of breast and leg muscles was measured instrumentally using a colorimeter, according to a CIE L*a*b* system. The hue (h) and the saturation (C) of colour were also determined. It was found that the sex of ducks had no effect on any of the colour components of breast or leg muscles. It was proved that the carcass weight affected only the development of the yellow colour (b*) and the hue (h) of leg muscles. The fat content in the muscles depended on the carcass weight and the sex of the birds. A correlation was proved to exist between that trait and the brightness of breast muscle (r = 0.581) and leg muscles (r = 0.763). Only in the case of female ducks, a significant difference (p ≤ 0.05) was confirmed to exist between the lightness (L *) of breast muscles from the groups with lighter carcasses (PI and PII) and the breast muscles from the group of the heaviest carcasses (PIV). A significant difference (p ≤ 0.05) was found in the fat content in the muscles from the same groups. It was confirmed that in order to get the meat (to be used as a raw material for further meat processing) of even colour, male and female Pekin ducks should be raised separately. Moreover, the female ducks should not be raised longer than until their carcass weight reaches 2500 g, i.e. until those birds reach a body weight of 3500 g

Detection of the important chromosomal regions determining production traits in meat-type chicken using entropy analysis

<p>1. The objective of this study was to indicate the most informative chromosomal regions and candidate genes connected to body weight at 36 d, body weight at 39 d, body weight changes between 39 and 46 d, feed intake between 39 and 46 d and feed conversion ratio of meat-type chicken based on genomic data using entropy analysis.</p> <p>2. Data contained information about 862 genotyped individuals from a Cobb commercial line using 60K Illumina iSelect chicken array and information from 42 770 Single Nucleotide Polymorphisms (SNPs). Entropy analysis was employed to detect important chromosomal regions determining the target traits. Locations of genes within the designated regions on each chromosome and for each trait were verified using the Ensembl genome database.</p> <p>3. The most informative SNPs were located on chromosomes 1, 2, 4, 8, 12 and Z, whereas clusters of the most informative pairs of SNPs connected to all recorded traits were located on chromosomes 1, 2, 3, 4, 6, 12, 20 and Z. The identified chromosomal localisations overlap with genes functionally connected to the nervous system and gastrointestinal tract.</p

Successful Identification of Duck Genome Region Determining Desirable Uniformity of Meat Performance Traits

ABSTRACT The objective of this study was to identify genome regions determining duck meat performance traits with possible small variation. In total, 368 crossbred ducks of F2 generation obtained from two parental lines: Pekin-type ducks of Polish origin (A55) and Pekin-type ducks of French origin (GL-30) were recorded. The following seven traits were analyzed: body weight, breast muscle weight, leg muscle weight, water holding capacity in the breast and leg muscles, and color lightness L* of the breast and leg muscles. All birds (including parental and F1 generations) were genotyped (29 microsatellite markers). Means and coefficients of variation (CV) were calculated for 28 full-sibs (four sires by six dams and one sire by four dams). Number of progeny per full-sib group ranged from 7 to 17. The multivariate cluster analysis using grouping by k-means algorithm was used on transformed data. The multivariate cluster analysis gave two clusters: first group with 10 full-sibs and second one with 18 families. Differences among half-sibs in the CV of the recorded traits were determined. It should be noted that one out of five sire groups showed statistically significant differences from the other ones. Moreover, the CVs in this group were smaller. The analysis of microsatellite markers indicated three alleles from three loci were present only in the “superior” sire group. The obtained results indicate a promising opportunity of effective selection for improving carcass technological quality using molecular markers