Semen evaluation of two selected lines of rabbit bucks

[EN] Twenty rabbit bucks of 9 months of age were used to evaluate semen quality of two lines of New Zealand rabbit bucks selected for litter size at weaning (A line) and growth rate from weaning to slaughter (R line). The morphological semen characteristics indicated that the A line spermatozoa had greater acrosome integrity (+3.6 percentage units; P<0.01) and smaller sperm head size (for example, ¿1.46 ¿m2 for sperm head area) than in the R line. Seminal functional traits were also significantly higher for the A line (+13.4 percentage units for viability, +10.6 percentage units for hypo-osmotic swelling test (HOST) and +3.3 g/L for seminal plasma protein. However, no differences were detected between lines for motility parameters and seminal plasma protein electrophoretic profiles. Both lines had the same twelve bands with the following molecular weights to the nearest 1 kD: 124, 117, 99, 86, 75, 62, 40, 32, 21, 19, 10 and 6 kD. A relationship (r=0.308 for A line and 0.359 for R line; P<0.01) was found between the integrity of the plasmatic membrane (viability rate) and tail membrane (HOST) of the spermatozoa in the A line, but not in the R line, which had greater sperm head size. There was also a significant positive correlation coefficient between sperm concentration and either viability or some kinetic traits (r=0.567 and 0.575 for VCL, r=0.584 and 0.561 for VSL and r=0.588 and 0.588 for VAP, for A and R lines, respectively; P<0.001). We concluded that the A line seems to have better semen characteristics than the R line. We also found an interesting correlation among the seminal morphological, functional and kinetic traits, which could possibly be used to facilitate semen evaluation.Hosam M. Safaa was supported by a grant from ICSC-World Laboratory, Switzerland. This work has been supported by the Spanish Research Project (CICYT AGL2004-02710/GAN). The authors are indebted to F. Marco-Jiménez, Universidad Politécnica de Valencia, Valencia, Spain, and G.M.K. Mehaisen, Department of Animal Production, Faculty of Agricultural, Cairo University, Giza, Egypt, for their excellent cooperation throughout this study and to D.A.A. El-Sayed, Faculty of Agricultural, Cairo University, Giza, Egypt, for her help in preparing the manuscript.Safaa, H.; Vicente, J.; Lavara, R.; Viudes De Castro, M. (2008). Semen evaluation of two selected lines of rabbit bucks. World Rabbit Science. 16(3). doi:10.4995/wrs.2008.62216

Effect of restricted feeding under rearing on reproduction, body condition and blood metabolites of rabbit does selected for growth rate

[EN] Young rabbit females selected for growth rate can have nutritional needs which may not be met by the common practice of feed restriction during rearing in commercial rabbit production. The aim of this study was to analyse the effect of two different feeding programmes: restricted and ad libitum feeding, applied in young rabbit females for one month at the end of rearing, on reproductive performance, body condition and circulating metabolic hormones and metabolites in a rabbit line selected by growth rate in 3 consecutive reproductive cycles. Thus, twenty-four 16-week-old does were randomly assigned to a group in which the daily recommended nutrient intakes were satisfied (fed restricted: 130 g/day, n=13) or a group fed to satiety (ad libitum: 235.5 g/day, n=11) during one month. Then, all does were inseminated in 3 consecutive cycles using a 42-day reproductive cycle. Measurements of does’ body weight, perirenal fat thickness and plasma leptin, non-esterified-fatty-acids (NEFA), beta-hydroxybutyrate (BOHB) and fructosamine were performed at artificial insemination (AI), parturition and weaning time in 3 consecutive cycles. Reproductive performance of does was evaluated based on fertility, litter size at parturition, prolificacy and productivity. Differences in body weight were found only in the 1st cycle, ad libitum fed females being heavier than restricted ones. Nevertheless, body weight variances disappeared in later cycles. No differences were found in perirenal fat thickness. Finally, in ad libitum fed females slight differences were found in plasma levels of NEFAs (452 vs. 258 μekv/L and 527 vs. 306 μekv/L for 1st and 2nd cycles) and BOHB (0.26 vs. 0.03 mM for 2nd cycle), but disappeared in the 3rd reproductive cycle. Fertility, prolificacy and productivity was not significantly affected by the feeding programme. Nevertheless, total litter size showed to be higher in ad libitum fed females at second parturition (8.7 vs. 5.9 kits). Therefore, the evaluated feeding programmes until first AI in females selected by growth rate had no effect on their reproductive outcomes, as the global reproductive performance was not affected.This work was supported by the Spanish Research Project AGL2014- 53405-C2-1-P (CICYT). Carmen Naturil was supported by a research grant from the Education Ministry of the Valencian Regional Government (programme VALi+d. ACIF ⁄ 2013 ⁄ 296). English text version revised by N. Macowan English Language Service.Naturil-Alfonso, C.; Marco-Jiménez, F.; Pascual, J.; Vicente, J. (2017). Effect of restricted feeding under rearing on reproduction, body condition and blood metabolites of rabbit does selected for growth rate. World Rabbit Science. 25(4):303-312. https://doi.org/10.4995/wrs.2017.6848SWORD30331225

An innovative framework for probabilistic-based structural assessment with an application to existing reinforced concrete structures

A novel framework for probabilistic-based structural assessment of existing structures, which combines model identification and reliability assessment procedures, considering in an objective way different sources of uncertainty, is presented in this paper. A short description of structural assessment applications, provided in literature, is initially given. Then, the developed model identification procedure, supported in a robust optimization algorithm, is presented. Special attention is given to both experimental and numerical errors, to be considered in this algorithm convergence criterion. An updated numerical model is obtained from this process. The reliability assessment procedure, which considers a probabilistic model for the structure in analysis, is then introduced, incorporating the results of the model identification procedure. The developed model is then updated, as new data is acquired, through a Bayesian inference algorithm, explicitly addressing statistical uncertainty. Finally, the developed framework is validated with a set of reinforced concrete beams, which were loaded up to failure in laboratory

Development of structural layers PVC incorporating phase change materials for thermal energy storage

The use of poly(vinyl chloride) (PVC) structural layers incorporating phase change materials (PCM) for latent heat thermal energy storage (LHTES) has become more attractive in the recent years compared to other supporting materials. In this study, PVC layers with different types of PCM were prepared using blending and compression moulding methods. Two types of synthesized PCM, one based on paraffin and calcium carbonate (PCM@CaCO3) and the other on paraffin, silica and graphene oxide (PCM@SiGO) have been developed to enhance the thermal conductivity of the PVC matrix and thus achieve a more effective charging and discharging process. PVC layers prepared using a commercial PCM (PCM@BASF) were also prepared for comparison. SEM images and DSC results reveal homogeneous distribution of the PCM in PVC layers and that most PCM particles are undamaged. The shell material (in the case of PCM@BASF) and the shape stability (in the case of synthesized PCM@CaCO3 and PCM@SiGO) prevent leakage of molten paraffin during the PVC layer production. The thermal conductivity profile of the PVC layer without PCM have a decreasing tendency with the temperature increase when determined using different measurement approaches, the transient plane heat source method (HotDisk Analyser, TPS 2500 S) and thermal flux meter method (steady-state method). However, for PVC layers with PCM the thermal conductivity profile shows a different behaviour when the mean surface temperature of the specimen is below the phase change transition temperature range (increasing tendency). During phase change transition (18–26 °C), the thermal conductivity presents two distinct tendencies. Firstly, the thermal conductivity reveals a decreasing tendency as the mean temperature of the specimen rises and afterwards an increasing tendency. Secondly, when the mean surface temperature is above the phase change transition temperature range, the thermal conductivity profile shows a decreasing tendency, independent of the PCM. The mechanical properties of PVC layers were also assessed and the results obtained revealed that the incorporation of PCM into the PVC matrix reduces the mechanical performance of the composites, however for LHETS applications not subjected to high tensile stress levels (over 1 kPa), this is not a significant drawback.publishe

Freezability genetics in rabbit semen

[EN] The aim of this study was to estimate the heritability of semen freezability and to estimate the genetic correlation between frozen-thawed sperm traits and the growth rate in a paternal rabbit line. Estimated heritabilities showed that frozen-thawed semen traits are heritable (ranged between 0.08 and 0.15). In the case of Live-FT (percentage of viable sperm after freezing), the estimated heritability is the highest one, and suggests the possibility of effective selection. After the study of genetic correlations it seems that daily weight gain (DG) was negatively correlated with sperm freezability, but no further conclusions could be drawn due to the high HPD95%. More data should be included in order to obtain better accuracy for the estimates of these genetic correlations. If the results obtained at present study were confirmed, it would imply that selection for DG could alter sperm cell membranes or seminal plasma composition, both components related to sperm cryoresistance. (C) 2017 Elsevier Inc. All rights reserved.This work was supported by the Generalitat Valenciana research program (Prometeo II 2014/036). Lavara R. acknowledges the partial support received from Generalitat Valenciana under VALid program (APOST/2014/034) and from Ministry of Economy and Competitiveness under subprogramme "Formation posdoctoral" (FPDI-2013-16707).Lavara García, R.; Moce Cervera, ET.; Baselga Izquierdo, M.; Vicente Antón, JS. (2017). Freezability genetics in rabbit semen. Theriogenology. 102:54-58. https://doi.org/10.1016/j.theriogenology.2017.07.013S545810

Long-term and transgenerational effects of cryopreservation on rabbit embryos

The short-term effects of cryopreservation and embryo transfer are well documented (reduced embryo viability, changes in pattern expression), but little is known about their long-term effects. We examined the possibility that embryo vitrification and transfer in rabbit could have an impact on the long-term reproductive physiology of the offspring and whether these phenotypes could be transferred to the progeny. Vitrified rabbit embryos were warmed and transferred to recipient females (F0). The offspring of the F0 generation were the F1 generation (cryopreserved animals). Females from F1 generation offspring were bred to F1 males to generate an F2 generation. In addition, two counterpart groups of noncryopreserved animals were bred and housed simultaneously to F1 and F2 generations (CF1 and CF2, respectively). The reproductive traits studied in all studied groups were litter size (LS), number born alive at birth (BA), and postnatal survival at Day 28 (number of weaned/number born alive expressed as percentage). The reproductive traits were analyzed using Bayesian methodology. Features of the estimated marginal posterior distributions of the differences between F1 and their counterparts (F1 - CF1) and between F2 and their counterparts (F2 - CF2) in reproductive characters found that vitrification and transfer procedures cause a consistent increase in LS and BA between F1 and CF1 females (more than 1.4 kits in LS and more than 1.3 BA) and also between F2 and CF2 females (0.96 kits in LS and 0.94 BA). We concluded that embryo cryopreservation and transfer procedures have long-term effects on derived female reproduction (F1 females) and transgenerational effects on female F1 offspring (F2 females).Lavara García, R.; Baselga Izquierdo, M.; Marco Jiménez, F.; Vicente Antón, JS. (2014). Long-term and transgenerational effects of cryopreservation on rabbit embryos. Theriogenology. 81(7):988-992. doi:10.1016/j.theriogenology.2014.01.030S98899281

Spreading lengths of Hermite polynomials

The Renyi, Shannon and Fisher spreading lengths of the classical or hypergeometric orthogonal polynomials, which are quantifiers of their distribution all over the orthogonality interval, are defined and investigated. These information-theoretic measures of the associated Rakhmanov probability density, which are direct measures of the polynomial spreading in the sense of having the same units as the variable, share interesting properties: invariance under translations and reflections, linear scaling and vanishing in the limit that the variable tends towards a given definite value. The expressions of the Renyi and Fisher lengths for the Hermite polynomials are computed in terms of the polynomial degree. The combinatorial multivariable Bell polynomials, which are shown to characterize the finite power of an arbitrary polynomial, play a relevant role for the computation of these information-theoretic lengths. Indeed these polynomials allow us to design an error-free computing approach for the entropic moments (weighted L^q-norms) of Hermite polynomials and subsequently for the Renyi and Tsallis entropies, as well as for the Renyi spreading lengths. Sharp bounds for the Shannon length of these polynomials are also given by means of an information-theoretic-based optimization procedure. Moreover, it is computationally proved the existence of a linear correlation between the Shannon length (as well as the second-order Renyi length) and the standard deviation. Finally, the application to the most popular quantum-mechanical prototype system, the harmonic oscillator, is discussed and some relevant asymptotical open issues related to the entropic moments mentioned previously are posed.Comment: 16 pages, 4 figures. Journal of Computational and Applied Mathematics (2009), doi:10.1016/j.cam.2009.09.04

Embryo vitrification in rabbits: Consequences for progeny growth

[EN] The objective of this research is to examine if there are any effects of the rederivation procedures on rabbit growth pattern and on weight of different organ in adults. For this purpose, three experiments were conducted on two different groups of animals (control group and vitrified transferred group) to evaluate the possible effect of embryo manipulation (vitrification and transfer procedures) on future growth traits. The first experiment studies body weight from 1 to 9 weeks of age from the two groups. The second experiment describes the growth curve of progeny from experimental groups and analyzes their Gompertz curve parameters, including the estimation of adult body weight. The third experiment has been developed to study if there are any differences in different organ weight in adult males from the two experimental groups. In general, the results indicate that rederivation procedures had effect on the phenotypic expression of growth traits. The results showed that rabbit produced by vitrification and embryo transfer had higher body weight in the first four weeks of age than control progeny. Results from body weight (a parameter) and b parameter estimated by fitting the Gompertz growth curve did not show any difference between experimental groups. However, differences related with growth velocity (k parameter of the Gompertz curve) were observed among them, showing that the control group had higher growth velocity than the vitrified transferred group. In addition, we found that liver weight at 40th week of age exhibits significant differences between the experimental groups. The liver weight was higher in the control males than in the VF males. Although the present results indicate that vitrification and transfer procedures might affect some traits related with growth in rabbits, further research is needed to assess the mechanisms involved in the appearance of these phenotypes and if these phenotypes could be transferred to the future progeny.This study was supported by the Generalitat Valenciana research program (Prometeo II 2014/036) and Spanish Research Projects (CICYT AGL2011-29831-C03-01; AGL2014-53405-C2-1-P). Lavara R. acknowledges the partial support received from Generalitat Valenciana under VALid+ program (APOST/2014/034) and from Ministry of Economy and Competitiveness under subprogramme "Formacion posdoctoral" (FPDI-2013-16707).Lavara García, R.; Baselga Izquierdo, M.; Marco Jiménez, F.; Vicente Antón, JS. (2015). Embryo vitrification in rabbits: Consequences for progeny growth. Theriogenology. 84(5):674-680. https://doi.org/10.1016/j.theriogenology.2015.04.025S67468084

Does the inclusion of protease inhibitors in the insemination extender affect rabbit reproductive performance?

[EN] The bioavailability of buserelin acetate when added to the seminal dose appears to be determined by the activity of the existing aminopeptidases. Thus, the addition of amino peptidase inhibitors to rabbit semen extenders could be a solution to decrease the hormone degradation. This study was conducted to evaluate the effect of the protease activity inhibition on rabbit semen quality parameters and reproductive performance after artificial insemination. Seminal quality was not affected by the incubation with protease inhibitors, being the values of motility, viability, and acrosome integrity not significantly different between the protease inhibitors and the control group. In addition, seminal plasma aminopeptidase activity was inhibited in a 55.1% by the protease inhibitors. On the other hand, regarding the effect of protease inhibitors on reproductive performance, our results showed that the presence of protease inhibitors affected the prolificacy rate (9.2 +/- 0.26 and 9.3 +/- 0.23 vs. 8.2 +/- 0.22 total born per litter for negative control, positive control, and aminopeptidase inhibitors group, respectively; P < 0.05), having this group one kit less per delivery. We conclude that the addition of a wide variety of protease inhibitors in the rabbit semen extender negatively affects prolificacy rate. Therefore, the development of new extenders with specific aminopeptidase inhibitors would be one of the strategies to increase the bioavailability of GnRH analogues without affecting the litter size. (C) 2016 Elsevier Inc. All rights reserved.This research was supported in part by the RTA2013-00058-00-00 from INIA, the European Social Fund and the European FEDER Funds. L Casares-Crespo is supported by a scholarship from Institute Valenciano de Investigaciones Agrarias (IVIA) and the European Social Fund.Casares-Crespo, L.; Vicente Antón, JS.; Talavan, A.; Viudes De Castro, MP. (2016). Does the inclusion of protease inhibitors in the insemination extender affect rabbit reproductive performance?. Theriogenology. 85(5):928-932. doi:10.1016/j.theriogenology.2015.10.044S92893285

Orientational pinning and transverse voltage: Simulations and experiments in square Josephson junction arrays

We study the dependence of the transport properties of square Josephson Junctions arrays with the direction of the applied dc current, both experimentally and numerically. We present computational simulations of current-voltage curves at finite temperatures for a single vortex in the array ($Ha^2/\Phi_0=f=1/L^2$), and experimental measurements in $100\times1000$ arrays under a low magnetic field corresponding to $f\approx0.02$. We find that the transverse voltage vanishes only in the directions of maximum symmetry of the square lattice: the [10] and [01] direction (parallel bias) and the [11] direction (diagonal bias). For orientations different than the symmetry directions, we find a finite transverse voltage which depends strongly on the angle $\phi$ of the current. We find that vortex motion is pinned in the [10] direction ($\phi=0$), meaning that the voltage response is insensitive to small changes in the orientation of the current near $\phi=0$. We call this phenomenon orientational pinning. This leads to a finite transverse critical current for a bias at $\phi=0$ and to a transverse voltage for a bias at $\phi\not=0$. On the other hand, for diagonal bias in the [11] direction the behavior is highly unstable against small variations of $\phi$, leading to a rapid change from zero transverse voltage to a large transverse voltage within a few degrees. This last behavior is in good agreement with our measurements in arrays with a quasi-diagonal current drive.Comment: 9 pages, 9 figure