Genomic inbreeding measures applied to a population of mice divergently selected for birth weight environmental variance.

This study aimed to compare different inbreeding measures estimated from pedigree and molecular data from two divergent mouse lines selected for environmental birth weight during 26 generations. Furthermore, the performance of different approaches and both molecular and pedigree data sources for estimating were tested in this population. A total of 1,699 individuals were genotyped using a high-density genotyping array.

Differential patterns in runs of homozygosity in two mice lines under divergent selection for environmental variability for birth weight.

Runs of homozygosity (ROH) are defined as long continuous homozygous stretches in the genome which are assumed to originate from a common ancestor. It has been demonstrated that divergent selection for variability in mice is possible and that low variability in birth weight is associated with robustness. To analyse ROH patterns and ROH-based genomic inbreeding, two mouse lines that were divergently selected for birth weight variability for 26 generations were used, with: 752 individuals for the high variability line (H-Line), 766 individuals for the low variability line (L-Line) and 74 individuals as a reference population.

Differential sensitivity of climate conditions on birth weight genetic values in mice divergently selected for birth weight residual variance.

After 32 generations of a divergent selection experiment for residual variance of birth weight in mice, two divergent lines were thus obtained: the heterogeneous line (H-line) and the homogeneous line (L-line). Throughout the generations, differences were observed between the two lines in traits such as litter size, survival at weaning, and birth weight variability caused by unidentified environmental conditions. The L-line exhibited advantages in terms of higher survival rates, larger litter sizes, and less sensitivity to changes in food intake.

Embryo survival and fertility differ in lines divergently selected for birth weight homogeneity in mice.

The selection of animals for lower environment sensitivity around the optimum trait value can also provide benefits in productivity and welfare. A divergent selection experiment for birth weight environmental variability in mice was successfully conducted over 17 generations. Animals from low variability selected line (L-line) were more robust by having a higher litter size and survival at weaning in a common breeding environment, than those from high variability line (H-line).

Genetic parameters for fleece uniformity in alpacas.

Fiber diameter is the main selection objective and criterion in alpaca breeding programs, but it can vary across anatomic regions of the animal. As fiber diameter is usually registered from a unique sample from the mid side of the body, fiber diameter variability within fleece is never addressed and phenotypic and genetic differences may exist for fleece uniformity in alpaca populations. The objective of this work was to estimate the genetic parameters of fleece uniformity in an alpaca population.

Impact of selection for birth weight variability on reproductive longevity: A mice model.

Uniformity, understood as a similar performance in relevant livestock traits, such as birth weight within the litter, is being included as one of the selection objectives in breeding programmes, especially for polytocous livestock species. A divergent selection experiment for birth weight within-litter variability in mice during 23 generations showed that homogeneous animals were better for litter size, survival and feed efficiency but less heavy than heterogeneous animals. The aim of this study was to compare the reproductive longevity in both divergent lines as time to the end of the reproductive period.

Effects of feed restriction during pregnancy on maternal reproductive outcome, foetal hepatic IGF gene expression and offspring performance in the rabbit.

Primiparous female rabbits have high nutritional requirements and, while it is recommended that they are subjected to an extensive reproductive rhythm, this could lead to overweight, affecting reproductive outcomes. We hypothesised that restricting food intake during the less energetic period of gestation could improve reproductive outcome without impairing offspring viability. This study compares two groups of primiparous rabbit does in an extensive reproductive programme, one in which feed was restricted from Day 0 to Day 21 of gestation (R021), and another in which does were fed ad libitum (control) throughout pregnancy.

Long-Distance Transport of Finisher Pigs in the Iberian Peninsula: Effects of Season on Thermal and Enthalpy Conditions, Welfare Indicators and Meat pH.

Current legislation in the European Union places limits on live pig transport according to outside temperature, but less is known about the effects of sudden changes in the thermal microenvironment in trailers, particularly during long-distance transport. In this study, we measured the temperature and relative humidity inside livestock vehicles carrying 1920 Spanish finisher pigs (live weight 100 kg and 240 animals per journey) during eight long-distance (>15 h) commercial journeys to slaughter from northern Spain to Portugal in the summer and winter. Here, we report the rate of change in the air temperature (°C × min) and air enthalpies in the transport vehicle (kg water kg dry air-1).

Selection Response in a Divergent Selection Experiment for Birth Weight Variability in Mice Compared with a Control Line.

Birth weight (BW) in animal production is an economically important trait in prolific species. The laboratory mouse ( ) is used as an experimental animal because it is considered a suitable model for prolific species such as rabbits and pigs. Two mouse lines were divergently selected for birth weight variability with a third line of non-selected control population of the same origin as the animals starting the experiment.

Supplementation with Fish Oil Improves Meat Fatty Acid Profile although Impairs Growth Performance of Early Weaned Rabbits.

Our objective was to analyze the influence of replacing lard (control) with fish oil (FO) rich in long-chain n-3 polyunsaturated fatty acids in the diet of rabbits weaned at 25 days of age on their growth performance, meat quality, cecal fermentation, and ileal morphology. Twenty-four litters (12 control and 12 FO) of nine kits each were fed the experimental diets from weaning (25 days) until slaughter at 60 days of age. Half of the litters (six per diet) were used to monitor productive performance, carcass characteristics, and ileal morphology, and cecal fermentation was assessed in the rest of litters.

The Statistical Scale Effect as a Source of Positive Genetic Correlation Between Mean and Variability: A Simulation Study.

The selection objective for animal production is the highest income with the lowest production cost, while ensuring the highest animal welfare. A selection experiment for environmental variability of birth weight in mice showed a correlated response in the mean after 20 generations starting from a crossed panmictic population. The relationship between the birth weight and its environmental variability explained the correlated response.

Effect of feed restriction on the environmental variability of birth weight in divergently selected lines of mice.

Background: Selection of mice for decreased environmental variability of birth weight has achieved higher survivability and larger litter size as a correlated response to canalized selection, which suggests higher welfare and robustness, and animals that are more homogeneous. However, in these studies, animals were not exposed to an environmental challenge. To demonstrate the advantages of this mouse line with a low environmental variability of birth weight, animals from two divergent lines (high and low variability of birth weight) were subjected to feed restriction.

Feed and reproductive efficiency differences between divergently selected lines for birthweight environmental variability in mice.

Sustainability has come to play an important role in agricultural production. A way to combine efficiency with sustainability might be by searching for robust animals that can be selected for the homogeneity of certain traits. Furthermore, the optimization of feed efficiency is one of the challenges to improve livestock genetics programmes, but this might compromise reproductive efficiency.

Improvements in the conception rate, milk composition and embryo quality of rabbit does after dietary enrichment with n-3 polyunsaturated fatty acids.

This work attempts to confirm the effect of an enriched diet with n-3 polyunsaturated fatty acids (PUFA) trying to mitigate the reproductive performances issues such as low conception rate of primiparous rabbits. A total of 127 does were fed ad libitum throughout their two first cycles with two diets with different fat sources: mixed fat in the control and salmon oil in the enriched one, with 3.19 g/100 g (n=63 does) and 28.

Effects of dietary fish oil supplementation on performance, meat quality, and cecal fermentation of growing rabbits.

The objective of this study was to investigate the effect of dietary supplementation with fish oil on growth performance (during all fatening period), carcass characteristics and fatty acid (FA) profile of muscle and fat tissues (at slaughter), as well as cecal fermentation and ileal mucosa morphology of growing rabbits (at 30, 45, and 60 d of age). Two isonitrogenous and isoenergetic diets, only differing in their fat source, were formulated and provided each to 24 does (12 per diet) and their offspring during pregnancy and lactation. The control diet contained 4.

A diet supplemented with -3 polyunsaturated fatty acids influences the metabomscic and endocrine response of rabbit does and their offspring.

The aim of the present study was to evaluate the productive, endocrine, and metabomscic responses as well as oxidative stress of rabbit does and their offspring when fed a diet supplemented with -3 PUFA during their first productive cycle. To this aim, a total of 105 rabbit does were fed ad mscibitum from d 60 to 172 of age 2 isoenergetic and isoproteic diets differing in fatty acid composition. The control diet ( = 52 does) contained 45.

Modulating birth weight heritability in mice.

Expected genetic response is proportional to the heritability of the trait, and this parameter is considered inherent of a specific trait in a particular population. However, models assuming heterogeneity in residual variance lead to different estimates of heritability across combinations of systematic (environmental) effects. Modifying the residual variance of the birth weight by artificial selection was shown to be feasible in a divergent selection experiment in mice.

Correlated genetic trends for production and welfare traits in a mouse population divergently selected for birth weight environmental variability.

The objective of this work was to study the changes that, selecting for environmental variability of birth weight (BW), could bring to other interesting traits in livestock such as: survivability at weaning (SW), litter size (LS) and weaning weight (WW), their variability assessed from standard deviations of LS, standard deviation of WW (SDWW) and also the total litter weight at birth (TLBW) and total litter weight at weaning. Data were registered after eight generations of a divergent selection experiment for BW environmental variability in mice. Genetic parameters and phenotypic and genetic evolution were assessed using linear homoscedastic and heteroscedastic models in which the traits were attributed to the female, except BW and WW that were in some models also attributed to the pup.

Characterization of early changes in fetoplacental hemodynamics in a diet-induced rabbit model of IUGR.

Intrauterine growth restriction (IUGR) is associated with adverse perinatal outcomes and late-onset diseases in offspring. Eating disorders, voluntary caloric restriction and maternal undernutrition can all induce IUGR but a relevant model is required to measure all its possible consequences. In this work, pregnant rabbits were used as an IUGR model.

Genetic control of the environmental variance for birth weight in seven generations of a divergent selection experiment in mice.

Data from seven generations of a divergent selection experiment designed for environmental variability of birth weight were analysed to estimate genetic parameters and to explore signs of selection response. A total of 10 783 birth weight records from 638 females and 1127 litters in combination with 10 007 pedigree records were used. Each record of birth weight was assigned to the mother of the pup in a heteroscedastic model, and after seven generations of selection, evidence of success in the selection process was shown.

Reproductive long-term effects, endocrine response and fatty acid profile of rabbit does fed diets supplemented with n-3 fatty acids.

The effect of a diet enriched with polyunsaturated n-3 fatty acids (PUFA) on endocrine, reproductive, and productive responses of rabbit females and the litters has been studied. Nulliparous does (n=125) were fed ad libitum from rearing to second weaning two diets supplemented with different fat sources: 7.5g/kg lard for the control diet (group C; n=63) or 15g/kg of a commercial supplement containing a 50% ether extract and 35% of total fatty acids (FAs) as PUFA n-3 (Group P; n=62).