scholarly journals Correlated response in early embryonic development in rabbits selected for litter size variability

2017 ◽  
Vol 25 (4) ◽  
pp. 323 ◽  
Author(s):  
E. W. Calle ◽  
M. L. García ◽  
A. Blasco ◽  
M.J. Argente

<p>A divergent selection experiment for litter size variability was carried out in rabbits. The litter size variability was estimated as the phenotypic variance of litter size within female. The aim of this study was to assess the effect of selecting for litter size variability on early embryonic development and survival after 7 generations of divergent selection (high and low variability lines). A total of 30 non-lactating multiparous does per line were used. The ovulation rate and early embryonic development were analysed using Bayesian methodology. Ovulation rate was not affected by the selection process. At 28 h of gestation, embryonic development and survival were similar in both lines. At 48 h of gestation, the majority of embryos in the high line were in the early morulae stage. The high line had a higher proportion of early morulae (79.54 vs. 53.43%; P=0.94) and a lower proportion of compacted morulae (20.46 vs. 46.57%; P=0.93%) than the low line. At 72 h of gestation, the high line had 1.59 fewer embryos than the more homogeneous line (P=0.85), due to reduced embryonic survival (0.60 vs. 0.74; P=0.93). The high line continued to show a higher proportion of early morulae (21.01 vs. 3.69%; P=0.93) and a lower proportion of compacted morulae and blastocysts (78.99 vs. 96.31%; P=0.94) than the low line at 72 h of gestation, indicative of reduced embryonic development. In conclusion, selection for homogeneity in litter size had a positive impact on embryonic traits.</p>

Author(s):  
Ivan Agea ◽  
María-Luz García ◽  
Agustín Blasco ◽  
María-José Argente

A divergent selection experiment on environmental sensitivity was performed in rabbits. The aim of this study was to estimate the correlated response in kits&rsquo; weight and its survival, and weight distance from birth to weaning. Weight distance was calculated as the absolute values of the differences between the individual value and the mean value of its litter. Also, relationship between probability of survival at 4 d of age and weight at birth was studied. Environmental sensitivity was measured as litter size variability. A total of 2484 kits from 127 does of the low line (selected for reducing litter size variability) and 1916 kits of 114 does of the high line (selected for increasing litter size variability) of the 12th generation were weighed. Bayesian methodology was used to estimate the correlated response to selection, and LOGISTIC procedure of SAS was used to estimate the relationship between weight and probability of survival. Both lines showed similar individual weight at birth and at weaning, and similar survival at birth and at 4 d of age. Survival at weaning was higher in the low line than in the high line (0.67 and 0.62; P= 0.93). Weight distance was higher at birth but lower at weaning in the low line (47.8 g and 54.1 g; P=0.98). Kit&rsquo;s weight at birth affected its survival. In conclusion, selection for environmental sensitivity showed correlated response in kits survival and in homogeneity of litter weight at weaning.


Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 604
Author(s):  
Iván Agea ◽  
María de la Luz García ◽  
María-José Argente

A divergent selection for litter size residual variability has been carried out in rabbits during 12 generations. Litter size residual variability was estimated as phenotypic variance of litter size within females after correcting for the year-season and the parity-lactation status effects. Stress causes an increase in core body temperature. Infrared thermography (IRT) has been shown to be a useful technique for identifying changes in body temperature emissivity. The aim of this work is to study the correlated response to selection for litter size residual variability in body temperature emissivity at natural mating. Natural mating can be considered a stressful stimulus for does. Temperature was measured in the eyeball by IRT before mating (basal temperature) and after 5 min, 30 min, and 60 min in does of the lines selected to decrease and to increase litter size residual variability (i.e., the Low and the High lines). Both lines showed similar basal temperature. Eyeball temperature was increased slightly in the Low line from basal state to 5 min after stressful stimulus (from 35.69 °C to 36.32 °C), and this increase remained up to 60 min after stress (36.55 °C). The High line showed a higher temperature than the Low line at 30 min (+0.96 °C, p = 0.99). At 60 min, temperature was similar between lines. The evolution of temperature was different between lines: the High line reached the peak of temperature later than the Low line (at 30 min vs. 5 min), and its peak was higher compared to the Low line (36.95 °C vs. 36.32 °C). In conclusion, the does selected for reducing litter size variability showed a lower increase in temperature after a stressful stimulus, therefore showing lower stress and consequently better welfare.


2003 ◽  
Vol 2003 ◽  
pp. 82-82
Author(s):  
F. Forcada ◽  
J.A. Abecia ◽  
J.A. Valares

The efficacy of melatonin implants inserted around the spring equinox to improve fertility and ovulation rate or litter size in Mediterranean ewes has been previously reported (Chemineau et al., 1996; Forcada et al., 2002a.), indicating the ability of the hormone to regulate the hypothalamic activity (Viguié et al., 1995). Moreover, a direct effect of melatonin on corpora lutea and embryonic development has been also reported (Wallace et al., 1988; Abecia et al., 2002). The use of prolific Rasa Aragonesa (RA) ewes (a Mediterranean breed) before culling as embryo donors has been previously tested in the breeding season (Forcada et al., 2002b.). The aim of this experiment was to improve embryo production during the seasonal anoestrus period in selected superovulated RA ewes at the end of their reproductive lives through the use of melatonin.


Animals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2591
Author(s):  
Rosa Peiró ◽  
Celia Quirino ◽  
Agustín Blasco ◽  
María Antonia Santacreu

The aim of this work was to estimate correlated responses in growth traits and their variabilities in an experiment of selection for ovulation rate during 10 generations in rabbits. Individual weight at 28 days old (IW28, kg) and at 63 days old (IW63, kg) was analyzed, as well as individual growth rate (IGR = IW63 − IW28, kg). The variability of each growth trait was calculated as the absolute value of the difference between the individual value and the mean value of their litter. Data were analyzed using Bayesian methodology. The estimated heritabilities of IW28, IW63 and IGR were low, whereas negligible heritabilities were obtained for growth variability traits. The common litter effect was high for all growth traits, around 30% of the phenotypic variance, whereas low maternal effect for all growth traits was obtained. Low genetic correlations between ovulation rate and growth traits were found, and also between ovulation rate and the variability of growth traits. Therefore, genetic trends methods did not show correlated responses in growth traits. A similar result was also obtained using a cryopreserved control population.


Reproduction ◽  
2004 ◽  
Vol 127 (5) ◽  
pp. 587-592 ◽  
Author(s):  
M Holt ◽  
O Vangen ◽  
W Farstad

The aim of the present study was to evaluate how ovulation rate and survival rate through pregnancy had been affected by more than 110 generations of upwards selection on litter size in mice. The mean number of pups born alive was 22 in the high line (selected line) and 11 in the control line (an increase in 2.6 standard deviations). Selection on litter size increased ovulation rate by 4.6 standard deviations, and it is suggested that selection also increased embryonic mortality in late pregnancy. Embryo survival from ovulation until birth was 66% in the selected line and 69% in the control line, and the observed loss in litter size from day 16 of pregnancy until birth was possibly higher in the high line compared with the control line. Selection for higher litter size has significantly increased body weight in both males and females, as the mean weight at mating for the females was 46 g in the high line and 33 g in the control line respectively.


Animals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 920
Author(s):  
Nora Formoso-Rafferty ◽  
Katherine Natalia Chavez ◽  
Candela Ojeda ◽  
Isabel Cervantes ◽  
Juan Pablo Gutiérrez

Birth weight (BW) in animal production is an economically important trait in prolific species. The laboratory mouse (Mus musculus) 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. The objective of this study was, therefore, to compare and evaluate the differential response of each line. The animals were from the 17th generation of both low and high BW variability lines of the divergent selection experiment, including in addition animals from the control line. The dataset contained 389 records from 48 litters of the high line, 734 records from 73 litters of the low line, and 574 records from 71 litters of the control line. The studied traits were as follows: the BW, the BW variance, the BW standard deviation, the BW coefficient of variation within-litter, the weaning weight (WW), the litter size at birth and at weaning, the weight gain, and the preweaning survival. The model included the line effect jointly with the parturition number and its interaction, the linear and quadratic LS as covariates except for the LS trait itself when analyzing litter traits, as well as the pup sex when analyzing individual traits. The low line had a lower BW and WW, but a higher litter size, and greater robustness owing to a higher survival at weaning. As a model of livestock animals, the findings from this experiment led to a proposal of selection for pig production that would combine an increase in litter size with higher survival and welfare. Compared with the control line, a much higher response was observed in the low variability line than in the high line, making it extremely satisfactory given that homogeneity provides advantages in terms of animal welfare and robustness.


1979 ◽  
Vol 48 (3) ◽  
pp. 509-516 ◽  
Author(s):  
P. J. Cunningham ◽  
M. E. England ◽  
L. D. Young ◽  
Dwane R. Zimmerman

animal ◽  
2019 ◽  
Vol 13 (4) ◽  
pp. 784-789 ◽  
Author(s):  
M.L. García ◽  
A. Blasco ◽  
M.E. García ◽  
M.J. Argente

2015 ◽  
Vol 23 (4) ◽  
pp. 241 ◽  
Author(s):  
R. Peiro ◽  
M. Gallego ◽  
A. Blasco ◽  
M.A. Santacreu

<p>Uterine capacity has been proposed as an indirect way to increase litter size. The aim of this work is to study the effect of a divergent selection for uterine capacity (UC) on reproductive traits at 30 h post mating in unilaterally ovariectomized (ULO) females. A total of 62 ULO females from the high line (selected to increase UC) and 39 ULO females from the low line (selected to decrease UC) were used. Ovulation rate was estimated as the number of corpora haemorrhagica and early embryonic survival was estimated as the ratio between number of embryos and ovulation rate. No differences in ovulation rate and early embryonic survival at 30 h post mating were found between high and low lines. Selection for UC did not change the embryonic stage of development either, the majority of embryos being at 4-cell stage. Additionally, the embryos were evaluated according to morphological criteria and more than 95% of the embryos were evaluated as good or fair quality. No differences in embryonic morphological criteria between high and low lines were found either. Thus, selection for UC did not modify the early embryonic survival and development in ULO females at 30 h post mating.</p>


Animals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1540 ◽  
Author(s):  
Dhekra Beloumi ◽  
Agustín Blasco ◽  
Raquel Muelas ◽  
María Antonia Santacreu ◽  
María de la Luz García ◽  
...  

A divergent selection experiment for environmental variance of litter size variance was carried out in rabbits over thirteen generations. The aim of this study was to evaluate the inflammatory response in the two lines of the experiment, in order to analyse the effect of selection on susceptibility to diseases after challenging to stressful situations, such as 24 h after the first delivery. A total of 78 females were used in this study, 39 from each line. The line selected for litter size heterogeneity (the high line) showed lower white blood leukocyte count (WBC; −0.87 × 103/µL), lower percentage of basophils (−0.11%), higher concentration of TNF-α (+13.8 pg/mL), and greater concentration of CRP (+38.1 µg/mL) than the line selected for litter size homogeneity (the low line). The high line had also higher concentrations of bilirubin, cholesterol, gamma-glutamyl transferase (GGT) and alkaline phosphatase (ALP) compared to the low line (difference between lines were +0.08 µmol/L, +0.14 µmol/L, +0.35 U/L and +2.4 U/L, respectively). The high line showed higher inflammatory response than the low line, in accordance with a larger susceptibility to infectious disorders. In conclusion, the line selected to increase litter size environmental variability seems to have poor capacity coping with environmental stressors. Therefore, selection for litter size environmental variability can be a useful way to improve animal welfare.


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