42 research outputs found
Hepatic lipogenesis gene expression in two experimental egg-laying lines divergently selected on residual food consumption
Two Rhode Island Red egg-laying lines have been divergently selected on residual food intake (low intake R- line, high intake R+ line) for 19 generations. In addition to direct response, correlated responses have altered several other traits such as carcass adiposity and lipid contents of several tissues, the R+ animals being leaner than the R- ones. In a search for the biological origin of the differences observed in fat deposit, the hepatic mRNA amounts of genes involved in lipid metabolism were investigated. No difference was found between lines for mRNA levels of ATP citrate-lyase, acetyl-CoA carboxylase, fatty acid synthase, malic enzyme and CCAAT/enhancer binding protein α, a transcription factor acting on several lipogenesis genes. The genes coding for stearoyl-CoA desaturase and apolipoprotein A1 displayed significantly lower mRNA levels in the R+ cockerels compared to the R-. All together these mRNA levels explained 40% of the overall variability of abdominal adipose tissue weight, suggesting an important role of both genes in the fatness variability
Performance comparison of dwarf laying hens segregating for the naked neck gene in temperate and subtropical environments
This study compares laying performances between two environments of dwarf laying hen lines segregating for the naked neck mutation (NA locus), a selected dwarf line of brown-egg layers and its control line. Layers with one of the three genotypes at the NA locus were produced from 11 sires from the control line and 12 sires from the selected line. Two hatches produced 216 adult hens in Taiwan and 297 hens in France. Genetic parameters for laying traits were estimated in each environment and the ranking of sire breeding values was compared between environments. Laying performance was lower, and mortality was higher in Taiwan than in France. The line by environment interaction was highly significant for body weight at 16 weeks, clutch length and egg number, with or without Box-Cox transformation. The selected line was more sensitive to environmental change but in Taiwan it could maintain a higher egg number than the control line. Estimated heritability values in the selected line were higher in France than in Taiwan, but not for all the traits in the control line. The rank correlations between sire breeding values were low within the selected line and slightly higher in the control line. A few sire families showed a good ranking in both environments, suggesting that some families may adapt better to environmental change
Diretrizes curriculares nacionais para a formação inicial e continuada dos profissionais do magistério da educação båsica: concepçÔes e desafios
Les objectifs et les critÚres de sélection. Interactions génotype à environnement et adaptation au milieu chez les volailles
Chantier qualitĂ© spĂ©cifique "Auteurs Externes" dĂ©partement de GĂ©nĂ©tique animale : uniquement liaison auteur au rĂ©fĂ©rentiel HR-AccessNational audienceLes exemples passĂ©s en revue incluent lâadaptation Ă des tempĂ©ratures Ă©levĂ©es, par des gĂšnes influant sur la taille corporelle ou lâemplumement, ainsi que par lâapport de lignĂ©es locales. Vis-Ă -vis de lâintensitĂ© lumineuse, la rĂ©ponse particuliĂšre du gĂšne albinos liĂ© au sexe en ce qui concerne la ponte est dĂ©crite. Des diffĂ©rences gĂ©nĂ©tiques de rĂ©ponse Ă la composition de lâaliment sont briĂšvement discutĂ©es, avec lâexemple dâun gĂšne rĂ©pandu dans les lignĂ©es de type "oeuf brun", responsable dâune odeur "de poisson" des oeufs en prĂ©sence de tourteau de colza. Pour la rĂ©sistance Ă des agents pathogĂšnes spĂ©cifiques, en dehors des nombreuses Ă©tudes concernant le complexe majeur dâhistocompatibilitĂ© ou dâautres gĂšnes, lâapport de facteurs de rĂ©sistance contenus dans des lignĂ©es locales est illustrĂ© dans le cas de la race Ă©gyptienne Fayoumi
Effect of the slow (<it>K</it>) or rapid (<it>k</it><sup>+</sup>) feathering gene on body and feather growth and fatness according to ambient temperature in a Leghorn Ă brown egg type cross
<p>Abstract</p> <p>Chicks of both sexes issued from the cross of heterozygous <it>K</it>/<it>k</it><sup>+ </sup>cocks for the slow-feathering sex linked <it>K </it>allele with <it>k</it><sup>+ </sup>(rapid feathering) hens, were compared from the age of 4 to 10 weeks at two ambient temperatures. In individual cages, 30 male chicks of each genotype (<it>K</it>/<it>k</it><sup>+ </sup>and <it>k</it><sup>+</sup>/<it>k</it><sup>+</sup>) were raised at 21°C, and 60 others, distributed in the same way, were raised at 31°C. 71 <it>K</it>/<it>W </it>females and 69 <it>k</it><sup>+</sup>/<it>W </it>females were raised in a floor pen at 31°C till 10 weeks of age. In the males, the body weight, feed consumption and feed efficiency at different ages were influenced only by temperature (lower growth rate and feed intake at 31°C); no significant effects of the genotype at locus <it>K </it>nor genotype à temperature interaction were observed. In females, all at 31°C, the genotype (<it>K</it>/<it>W </it>or <it>k</it><sup>+</sup>/<it>W</it>) had no significant effect on growth rate. Plumage weight and weight of abdominal fat (absolute or related to body weight) were measured on half of the males of each group in individual cages, at 10 weeks of age. Moreover, on 36 males and 48 females of the two genotypes, in a group battery at 31°C, the absolute and relative weight of plumage were measured on a sample every two weeks between 4 and 10 weeks. In the first case, no significant effect of genotype appeared. In the second case, an interaction between age and genotype was suggested from plumage weight: its growth, especially in male chicks, appears to be temporarily and unexpectedly faster from 4 to 6 weeks of age for the <it>K</it>/<it>k</it><sup>+ </sup>and <it>K</it>/<it>W </it>genotypes.</p
Performance comparison of laying hens segregating for the frizzle gene under thermoneutral and high ambient temperatures
Chantier qualité GAThe effect on thermotolerance of the incompletely dominant frizzle (F) gene, which causes feather curling and feather mass reduction, was investigated in 281 laying hens that were homozygous for the frizzle mutation (FF), heterozygous (FN), or normally feathered (NN). One-half of the birds were kept under standard conditions (22°C) and half were exposed to high ambient temperatures (32°C) between 24 and 46 wk of age. Egg production, egg quality, feed efficiency, and dissection traits were recorded and compared. At standard conditions, egg production and quality traits did not differ among the 3 genotypes, whereas feed efficiency was lower for the homozygous birds. Under heat stress conditions, the superiority of the FF hens was evident for all egg quantity and quality traits. No significant difference was measured between heterozygous carriers and normally feathered hens, indicating that the incomplete dominant frizzle mutation behaved as a recessive mutation regarding heat tolerance. From this study, we deduced that the F mutation in its homozygous state has a beneficial effect in decreasing heat stress in poultry production, and it could be particularly advantageous in tropical countries where average temperatures are never too low to negatively affect feed efficiency
Hepatic lipogenesis gene expression in two experimental egg-laying lines divergently selected on residual food consumption
Two Rhode Island Red egg-laying lines have been divergently selected on
residual food intake (low intake R line, high intake R line) for 19
generations. In addition to direct response, correlated responses have
altered several other traits such as carcass adiposity and lipid contents
of several tissues, the R animals being leaner than the R ones. In a
search for the biological origin of the differences observed in fat
deposit, the hepatic mRNA amounts of genes involved in lipid metabolism
were investigated. No difference was found between lines for mRNA levels
of ATP citrate-lyase, acetyl-CoA carboxylase, fatty acid synthase, malic
enzyme and CCAAT/enhancer binding protein , a transcription factor
acting on several lipogenesis genes. The genes coding for stearoyl-CoA
desaturase and apolipoprotein A1 displayed significantly lower mRNA
levels in the R cockerels compared to the R. All together these mRNA
levels explained 40% of the overall variability of abdominal adipose
tissue weight, suggesting an important role of both genes in the fatness
variability.Expression hépatique de gÚnes de la lipogénÚse chez des lignées
divergentes de poules pondeuses sélectionnées sur la consommation
alimentaire résiduelle. Deux lignées de poules pondeuses Rhode Island Red
ont été sélectionnées de façon divergente sur la consommation alimentaire
résiduelle (R/R) pendant 19 générations. En plus de la réponse directe
à la sélection, des réponses corrélées ont été observées sur d'autres
caractÚres comme l'adiposité de la carcasse et le taux de lipides de
plusieurs tissus, les animaux de la lignée R étant plus maigres que ceux
de la lignée R. Afin d'identifier l'origine biologique des différences
observées dans l'état d'engraissement, les niveaux d'ARNm de gÚnes
impliqués dans le métabolisme des lipides ont été étudiés. Aucune
différence d'accumulation n'a été trouvée entre lignées concernant les
ARNm de l'ATP citrate-lyase, l'acétyl-CoA carboxylase, la synthase des
acides gras, l'enzyme malique et le facteur de transcription
CCAAT/enhancer binding protein qui agit sur plusieurs gĂšnes de la
lipogénÚse. Les niveaux d'ARNm des gÚnes codant la stéaroyl-CoA désaturase et
l'apolipoprotéine A1 sont significativement plus faibles chez les animaux de la
lignée R que chez ceux de la lignée R. Ces deux taux d'ARNm expliquent
ensemble 40 % de la variabilité du poids de tissu adipeux abdominal entre les
deux lignées, suggérant un rÎle important de ces deux gÚnes dans la variabilité de
l'Ă©tat d'engraissement
Divergent selection for residual food intake in Rhode Island Red egg-laying lines : gross carcase composition, carcase adiposity and lipid contents of tissues
Chantier qualité spécifique "Auteurs Externes" département de Génétique animale : uniquement liaison auteur au référentiel HR-AccessInternational audienc
Effects of separate calcium feeding on laying hens selected for low (R) or high (R) residual feed consumption
The experiment was carried out with a sample of females from the 21st generation of
lines R and R selected divergently for residual food intake in the laying period.
After a breeding period of 18 weeks the hens of each line had been distributed among
climatic rooms into two groups, one fed with a complete commercial feed (control group)
and the other one with both a low calcium feed and oyster shells given in two separate
troughs (treated group). Egg production was recorded during 77 days, egg and shell
traits were obtained during the third and fourth weeks of the experiment, and the
voluntary consumption of feed was measured over a period of 28 days. The treatment
had a significant effect for both lines on average egg weight (), shell
weight (), shell thickness (), and albumen thickness ().
However, the line Yen treatment interaction was significant for yolk weight ()
and voluntary calcium consumption (), indicating that the under-consuming
line (R) showed a better response to separate calcium feeding with a 40% decrease of
its residual feed consumption, and better egg and shell qualities. The advantage of
line R might be related to the expression of a specific calcium appetite which is
masked in line R which ingests excess nutrients.Réponse à l'alimentation calcique séparée de poules sélectionnées pour une faible (R)
ou forte (R) consommation alimentaire résiduelle. L'expérience a été réalisée sur un
échantillon de poules pondeuses issues de la 21e génération des lignées R et R
sélectionnées de façon divergente sur la fraction résiduelle de la consommation
alimentaire en période de ponte. AprÚs une phase d'élevage de 18 semaines les poules
de chaque lignée ont été réparties dans des chambres conditionnées en deux lots :
l'un recevant un aliment commercial complet (lot témoin), l'autre, un aliment de
base appauvri en calcium d'une part et des coquilles d'hußtres d'autres part, distribués
dans deux mangeoires distinctes (lot traité). Les mesures individuelles ont porté sur la
ponte pendant 77 jours, celles relatives à la consommation alimentaire sur une période de
28 jours. Entre la 3e et la 4e semaine de l'expérience, étaient effectuées des mesures
sur la qualitĂ© de l'Ćuf et de la coquille. Le traitement, indĂ©pendamment de la lignĂ©e,
a eu un effet significatif sur le poids moyen de l'Ćuf (), le poids de la
coquille (), l'Ă©paisseur de la coquille () et l'Ă©paisseur de l'albumen
(). Pour deux variables, le poids du jaune () et la consommation du
nutriment calcique (), l'interaction lignée traitement s'est révélée
significative indiquant que la lignée sous-consommatrice d'aliment (R) répond davantage
à l'alimentation calcique séparée avec une diminution de 40 % de sa consommation
rĂ©siduelle, et une augmentation de 6 % de sa masse d'Ćufs. Ces rĂ©ponses favorables
de la lignĂ©e sous-consommatrice d'aliment (R) peuvent ĂȘtre expliquĂ©es par l'expression
d'un appétit calcique spécifique qui est mal exprimé par la lignée sur consommatrice
R à cause de l'ingestion excessive du nutriment énergétique
Effects of separate calcium feeding on laying hens selected for low (R) or high (R) residual feed consumption
The experiment was carried out with a sample of females from the 21st generation of
lines R and R selected divergently for residual food intake in the laying period.
After a breeding period of 18 weeks the hens of each line had been distributed among
climatic rooms into two groups, one fed with a complete commercial feed (control group)
and the other one with both a low calcium feed and oyster shells given in two separate
troughs (treated group). Egg production was recorded during 77 days, egg and shell
traits were obtained during the third and fourth weeks of the experiment, and the
voluntary consumption of feed was measured over a period of 28 days. The treatment
had a significant effect for both lines on average egg weight (), shell
weight (), shell thickness (), and albumen thickness ().
However, the line Yen treatment interaction was significant for yolk weight ()
and voluntary calcium consumption (), indicating that the under-consuming
line (R) showed a better response to separate calcium feeding with a 40% decrease of
its residual feed consumption, and better egg and shell qualities. The advantage of
line R might be related to the expression of a specific calcium appetite which is
masked in line R which ingests excess nutrients.Réponse à l'alimentation calcique séparée de poules sélectionnées pour une faible (R)
ou forte (R) consommation alimentaire résiduelle. L'expérience a été réalisée sur un
échantillon de poules pondeuses issues de la 21e génération des lignées R et R
sélectionnées de façon divergente sur la fraction résiduelle de la consommation
alimentaire en période de ponte. AprÚs une phase d'élevage de 18 semaines les poules
de chaque lignée ont été réparties dans des chambres conditionnées en deux lots :
l'un recevant un aliment commercial complet (lot témoin), l'autre, un aliment de
base appauvri en calcium d'une part et des coquilles d'hußtres d'autres part, distribués
dans deux mangeoires distinctes (lot traité). Les mesures individuelles ont porté sur la
ponte pendant 77 jours, celles relatives à la consommation alimentaire sur une période de
28 jours. Entre la 3e et la 4e semaine de l'expérience, étaient effectuées des mesures
sur la qualitĂ© de l'Ćuf et de la coquille. Le traitement, indĂ©pendamment de la lignĂ©e,
a eu un effet significatif sur le poids moyen de l'Ćuf (), le poids de la
coquille (), l'Ă©paisseur de la coquille () et l'Ă©paisseur de l'albumen
(). Pour deux variables, le poids du jaune () et la consommation du
nutriment calcique (), l'interaction lignée traitement s'est révélée
significative indiquant que la lignée sous-consommatrice d'aliment (R) répond davantage
à l'alimentation calcique séparée avec une diminution de 40 % de sa consommation
rĂ©siduelle, et une augmentation de 6 % de sa masse d'Ćufs. Ces rĂ©ponses favorables
de la lignĂ©e sous-consommatrice d'aliment (R) peuvent ĂȘtre expliquĂ©es par l'expression
d'un appétit calcique spécifique qui est mal exprimé par la lignée sur consommatrice
R à cause de l'ingestion excessive du nutriment énergétique