Influence of free and microencapsulated recombinant rabbit nerve growth factor with chitosan on rabbit sperm quality parameters.

ß-nerve growth factor (ßNGF) plays a crucial role in reproductive physiology and sperm quality. Enzymatic activity of seminal plasma and vaginal fluids reduces available ßNGF and it has been demonstrated that chitosan microspheres could protect rrßNGF from degradation. This study examined the effects of microencapsulated rrbNGF with chitosan on rabbit sperm viability, motility and capacitation status. Results showed that 0.5 and 1 µg/mL of microencapsulated rrßNGF, as well as free rrßNGF or empty microspheres, did not adversely affect sperm viability or total motility after 2 h of incubation. However, the highest progressivity kinetic parameters were observed with 1 µg/mL free rrßNGF, while the highest curvilinear velocity (VCL) occurred with 0.5 µg/mL microencapsulated rrßNGF. Empty chitosan microspheres did not induce acrosome reaction (AR), but both concentrations of free and rrßNGFch favoured AR during in vitro incubation. The study suggests that using chitosan spheres did not show any adverse effects on sperm traits, unlike free rßNGF and rrßNGFch promoted capacitation and AR. Further research is needed to explore the potential of rrßNGFch in modifying in vitro capacitation and inducing ovulation during artificial insemination.

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). The objective of this study was to analyze the differences between those divergently selected lines for embryo and fetal survival and for fertility and prolificacy rate. To study embryo survival and ovulation rate, a total of 98 females (34 H-line and 50 L-line) were studied in four generations of the divergent experiment. To analyze fetal survival and fertility rate, 378 female mice (138 H-line and 240 L-line) in 10 generations or the divergent experiment were studied. Ultrasound scans were performed at day 14 of gestation to establish the number of total fetal and the embryo absorptions. Mortality was addressed as the difference between litter size at birth and the number of fetuses at 14 days of gestation. The number of pregnant females in the first 3 days after mating was used to measure fertility. A linear model was also fitted to analyze embryo mortality, litter size, and the number of embryos at 14 days of gestation. A categorical model was then used to study fertility, including line, generation, and its interaction as effects. Despite the fact that there were no significant differences in the ovulation rate, litter size at birth was significantly higher in the L-line than in the H-line (9.82 vs. 8.36 pups, p < 0.001). Moreover, embryo mortality was significantly lower in the L-line than in the H-line (1.39 vs. 2.87 fetuses, p < 0.001). L-line females were more fertile (53.49% vs. 23.26% for the H-line). According to these results, the line selected for low environmental variance would be preferable for robustness and animal welfare.

Models of Intrauterine growth restriction and fetal programming in rabbits.

Intrauterine growth restriction (IUGR) affects approximately 10% of human pregnancies globally and has immediate and life-long consequences for offspring health. However, the mechanisms underlying the pathogenesis of IUGR and its association with later health and disease outcomes are poorly understood. To address these knowledge gaps, the use of experimental animals is critically important. Since the 50's different environmental, pharmacological, and surgical manipulations have been performed in the rabbit to improve our knowledge of the control of fetal growth, fetal responses to IUGR, and mechanisms by which offspring may be programmed by an adverse gestational environment. The purpose of this review is therefore to summarize the utility of the rabbit as a model for IUGR research. It first summarizes the knowledge of prenatal and postnatal development in the rabbit and how these events relate to developmental milestones in humans. It then describes the methods used to induce IUGR in rabbits and the knowledge gained about the mechanisms determining prenatal and postnatal outcomes of the offspring. Finally, it discusses the application of state of the art approaches in the rabbit, including high-resolution ultrasound, magnetic resonance imaging, and gene targeting, to gain a deeper integrative understanding of the physiological and molecular events governing the development of IUGR. Overall, we hope to engage and inspire investigators to employ the rabbit as a model organism when studying pregnancy physiology so that we may advance our understanding of mechanisms underlying IUGR and its consequences in humans and other mammalian species.

Gene expression and immunolocalization of low-affinity neurotrophin receptor (p75) in rabbit male reproductive tract during sexual maturation.

This study reports the gene expression and immunolocalization of the low-affinity neurotrophin receptor, p75, in accessory glands (prostate and bulbourethral glands) and epididymis (caput and cauda) of male rabbits during sexual maturation. We showed that p75 was expressed in all tissues studied with similar mRNA levels during this period. However, it was differentially immunolocalized in bulbourethral glands and stereocilia of epididymis. These findings may be related with some remodeling processes in the accessory glands during sexual maturation, which could be associated with sperm maturation. The interaction of p75 with neurotrophins in rabbit male reproductive tract suggests the possible implication of this system in sexual maturation in rabbits.

The effects of sildenafil citrate on feto-placental development and haemodynamics in a rabbit model of intrauterine growth restriction.

The present study evaluated the effectiveness of sildenafil citrate (SC) to improve placental and fetal growth in a diet-induced rabbit model of intrauterine growth restriction (IUGR). Pregnant rabbits were fed either ad libitum (Group C) or restricted to 50% of dietary requirements (Group R) or restricted and treated with SC (Group SC). The treatment with SC improved placental development by increasing vascularity and vessel hypertrophy in the decidua. The assessment of feto-placental haemodynamics showed higher resistance and pulsatility indices at the middle cerebral artery (MCA) in fetuses treated with SC when compared with Group R, which had increased systolic peak and time-averaged mean velocities at the MCA. Furthermore, fetuses in the SC group had significantly higher biparietal and thoracic diameters and longer crown-rump lengths than fetuses in Group R. Hence, the SC group had a reduced IUGR rate and a higher kit size at birth compared with Group R. In conclusion, SC may provide potential benefits in pregnancies with placental insufficiency and IUGR, partially counteracting the negative effects of food restriction on placental development and fetal growth. However, the present study also found evidence of a possible blood overflow in the brain that warrants further investigation.

Fatty acid composition of the follicular fluid of normal weight, overweight and obese women undergoing assisted reproductive treatment: a descriptive cross-sectional study.

BACKGROUND: It has been well documented that the maturing oocyte is very vulnerable to changes in its micro-environment, the follicular fluid (FF). Recent research has focused on different components within this FF, like hormones, growth factors and metabolites, and how their concentrations are altered by diet and the metabolic health of the mother. It has been proposed that fatty acids (FAs) are potential factors that influence oocyte maturation and subsequent embryo development. However, a thorough study of the specific FF FA composition per lipid fraction and how this may be affected by BMI is currently lacking. Therefore, we investigated the BMI-related concentration of FAs in the phospholipid (PL), cholesteryl-ester (CHE), triglyceride (TG) and non-esterified (NE) lipid fraction in the FF of women undergoing assisted reproductive treatment (ART). METHODS: In this descriptive cross-sectional study, the FF of normal weight (18.5 ≤ BMI < 25.0 kg/m(2), n = 10), overweight (25.0 ≤ BMI < 30.0 kg/m(2), n = 10) and obese (BMI ≥ 30.0 kg/m(2), n = 10) women, undergoing ART, was sampled and analyzed for 23 specific FAs in the PL, CHE, TG and NEFA fraction, using a gas chromatographic analysis method. Differences between BMI-groups were studied by means of univariate general linear models and post hoc Sheffé tests. RESULTS: Total FA concentrations in the PL and CHE fraction did not differ between BMI groups. Total TG concentrations tended to differ and total NEFA concentrations differed significantly between BMI groups. Interestingly, 42% and 34% of the total FAs was esterified in the PL and CHE fraction, respectively, while only 10% were present in both the TG and NEFA fraction. Only few individual FA concentrations differed in the PL, CHE and TG fraction between BMI groups, whereas abundant BMI-related differences were found in the NEFA fraction. CONCLUSIONS: Our data show that differences in BMI are associated with alterations in the FA composition of the FF, an effect most pronounced in the NEFA fraction. These BMI-related variations could possibly affect granulosa cell viability, oocyte developmental competence and subsequent embryo quality possibly explaining differences in oocyte quality in obese patients described by others.

Acquisition of fertilization competence in guinea pig spermatozoa under different capacitation protocols.

Guinea pig in vitro fertilization (IVF) are poorly developed due to the limited accessibility to oocytes and the lack of an efficient method of sperm capacitation. Thus, we aimed to evaluate different capacitation protocols that we validated through sperm analysis and using heterologous (He) IVF with zona-intact bovine oocytes. Spermatozoa of guinea pigs were collected and processed separately by 4 different protocols: A) Spermatozoa were obtained by flushing the lumen of one cauda epididymis and incubated in a minimal culture medium (MCM); B) One epididymis was placed in a prewarmed of M2 medium and gently minced with fine scissors. Spermatozoa were incubated in a modified human tubal fluid medium (HTF). In both protocols, the spermatozoa were capacitated at 37 °C under an atmosphere of 5% CO2 for 2 h. In the protocols C and D, the spermatozoa were collected by flushing the lumen of the cauda epididymis and selected by commercial density gradient Bovipure® (Nidacon Laboratories AB, Göthenborg, Sweden), according to the manufacturer's instructions. Then for Protocol C) spermatozoa were incubated in MCM medium supplemented with 10 mg/mL heparin (MCM-Hep); while for Protocol D) spermatozoa were incubated in FERT medium supplemented 10 mg/mL heparin (FERT-Hep). Incubation of C and D protocols were performed at 38.5 °C under an atmosphere of 5% CO2 for 2 h. Capacitation protocols C and D showed a higher percentage of viability, total and hyperactive-like motility, and acrosome reaction compared to protocols A and B. For this reason, protocols C and D were used for further He-IVF analysis. Guinea pig sperm and matured zona-intact bovine oocytes were co-incubated at 5% CO2 and 38.5 °C. Sperm-oocyte interaction was assessed at 2.5 h post-insemination (hpi) and pronuclear formation (PrF) were evaluated at 18, 20, 22, 24 and 26 hpi, while the cleavage rate was evaluated at 48 hpi. In protocol D, PrF was significantly higher than in protocol C (P ≤ 0.05) at every time point evaluated. Also, the cleavage rate at 48 hpi was higher (P ≤ 0.05) in He-IVF protocol D (69.8 ± 1.7%) compared to He-IVF protocol C (49.1 ± 1.1%). In conclusion, we determined the most adequate sperm capacitation conditions for guinea pig that allow zona-intact bovine oocyte penetration and lead to hybrid embryo formation, suggesting that these conditions could be optimal to develop IVF in guinea pigs.

Female reproduction and the microbiota in mammals: Where are we?

While it is generally accepted that the mammalian vagina contains a site-specific microbiota that plays relevant roles in genital and reproductive health, the existence of an extra-vaginal microbiota in the female reproductive tract (i.e. follicular fluid, oviduct, endometrium, and placenta) is, at least, a matter of controversy. Many conclusions in this field have failed to consider the technical limitations, biases, and confounding factors inherent to next-generation sequencing (NGS) approaches. While this creates uncertainty in the field, there is no doubt this subject is set to be the focus of new research efforts because of its scientific and practical connotations in female reproductive health. The current art state, its limitations, and gaps in our knowledge about the female reproductive tract's microbiota and, particularly, about the microbes of the extra-vaginal environment are presented in this review. Also are discussed possible relationships between the gut and oral microbiota and reproductive events.

Gestation Food Restriction and Refeeding Compensate Maternal Energy Status and Alleviate Metabolic Consequences in Juvenile Offspring in a Rabbit Model.

Nutritional status during gestation can influence mother and offspring metabolism. Undernutrition in pregnancy affects women in both western and developing countries, and it is associated with a high prevalence of chronic diseases in later life. The present work was conducted in the rabbit model, as a longitudinal study, to examine the effect of food restriction during early and mid-gestation, and re-feeding ad libitum until the end of pregnancy on metabolic status and body reserves of mother and, its association with development and metabolism of fetuses and female offspring to the juvenile stage. Little changes in live body weight (LBW), compensatory feed intake, similar body reserves, and metabolism were observed in dams. Placenta biometry and efficiency were slightly affected, but fetal BW and phenotype were not modified. However, hyperinsulinemia, insulin resistance, and hypertriglyceridemia were demonstrated in pre-term fetuses. In the juvenile period, these changes were not evidenced, and a similar pattern of growth and serum metabolic parameters in offspring of food-restricted mothers were found, except in serum aminotransferases levels, which increased. These were associated with higher liver fibrosis. Maternal food restriction in the early and mid-pregnancy followed by re-feeding in our rabbit model established a compensatory energy status in dams and alleviated potential long-term consequences in growth and metabolism in the offspring, even if fetal metabolism was altered.

Influence of Different Regimes of Moderate Maternal Feed Restriction during Pregnancy of Primiparous Rabbit Does on Long-Term Metabolic Energy Homeostasis, Productive Performance and Welfare.

In this study, a maternal feed restriction (MFR; 105 g/d) in primiparous rabbit does was applied from day 0 to 7 post artificial insemination (AI) (R07, n = 96), from day 7 to 21 post AI (R721, n = 92), from day 0 to 21 post AI (R021, n = 94) or fed ad libitum during whole pregnancy (Control, n= 92). Feed intake (FI) was measured after MFR was over. On day 28 of gestation, fetoplacental development was evaluated (n = 11/group) and the productive parameters of the remaining dams were analyzed. Plasma free tri-iodothyronine (T3) and thyroxine, glucose, insulin, non-esterified fatty acids (NEFA), and corticosterone were analyzed during gestation and lactation (n = 5/group). After MFR, all groups significantly increased their voluntary FI. The longer MFR was, the lower the weight and length of the fetuses, but no long-term effects over litter performance were observed. R021 groups had the lowest T3 and the highest NEFA concentrations during pregnancy and showed insulin resistance at the end of gestation, but during lactation, energy homeostasis was balanced in all groups. MFR did not affect corticosterone concentrations. In conclusion, the ration setting applied slightly involved the energy homeostasis and metabolism of the animals, but their overall metabolic condition, productive performance and welfare were not compromised.

[Development and validation of a new questionnaire to assess health care satisfaction and the device in stomized patients: espejo questionnaire]. / Cuestionario espejo. Valorar la satisfacción de pacientes ostomizados con la atención sanitaria y el dispositivo.

OBJECTIVES: To develop a questionnaire to measure the satisfaction of stomatised patients with healthcare professionals and with the stomal device. METHODS: An initial review of the literature was performed and in meetings with experts, the most relevant items were selected. In a pilot study with patients that had been recently stomatised (three months from intervention), the comprehensibility and discriminatory ability of each item was tested. Items were eliminated on the grounds of frequent "no response" or low correlation with others on the provisional scale (determined by means of Cronbach's alpha). RESULTS: Following meetings with experts, 12 items were eliminated by reason of irrelevance or low frequency of use. Subsequently by means of administration of the questionnaire to a sample of 72 patients, five more items were selected for elimination. An analysis of the 13 items that remained confirmed an acceptable level of reliability (Cronbach's alpha of 0.917) and also the significant differences in the global scores between the patients who have had stoma for more than three months (higher satisfaction) and patients who had been recently stomatised. The items in the questionnaire referred to aspects of easy and comfort of use of the stoma, as well as satisfaction with information received and interaction with healthcare professionals from the point of view of the patient. CONCLUSIONS: This is the first questionnaire to measure satisfaction with healthcare professionals and the stomal device from the perspective of the stomatised patient. In a subsequent study the other properties of the measurement tool (validity responsiveness and longitudinal validation) will be evaluated.

Physiological effects on rabbit sperm and reproductive response to recombinant rabbit beta nerve growth factor administered by intravaginal route in rabbit does.

Beta nerve growth factor (ß-NGF) is present in the seminal plasma of some species, including rabbits, acting as an ovulation-inducing factor in camelids. Traditionally, GnRH analogues are used to induce ovulation by intramuscular route when artificial insemination (AI) is performed in rabbit does. A specific rabbit recombinant ß-NGF (rrß-NGF) produced in our laboratory was tested as an alternative method to conventional treatment with GnRH analogues to induce ovulation. In the present work, different concentrations (0, 20, 100 ng/mL and 1, 20 and 100 µg/mL) of rrß-NGF were added to diluted semen to assess its effect on sperm traits (viability and motility parameters). rrß-NG was used also, incorporated to the AI dose, to evaluate ovulation response (LH and progesterone plasma concentrations, ovulation rate (OR) and embryo implantation at Day 7) after intravaginal administration. A negative control group stimulated with an empty catheter, and a positive control group inseminated and intramuscularly treated as usual with GnRH were also set up. Results showed that seminal quality was influenced by rrß-NGF depending on the concentration added, being the highest concentrations tested deleterious for semen. Whereas the highest OR was found in the positive control group (100%), concentrations of 20 ng/mL, 1 µg/mL and 20 µg/mL of rrß-NGF triggered intermediate OR (30, 60 and 42.9%, respectively), and 100 ng/mL and 100 µg/mL had the lowest OR (20 and 14.3%, respectively). Although LH peak was not observed in the first 2 h after AI in the ovulated females from rrß-NGF groups, plasma progesterone significantly increased at Day 7, except in those females treated with 20 and 100 µg/mL. Also, 98.4% of ovulated females were pregnant on Day 7. In conclusion, rrß-NGF added to diluted semen affects seminal quality and provokes ovulation, the development of functional CL and conception by intravaginal route in rabbit does, depending on the concentration added.

Characterization of ß-Nerve Growth Factor-TrkA system in male reproductive tract of rabbit and the relationship between ß-NGF and testosterone levels with seminal quality during sexual maturation.

ß-Nerve Growth Factor (ß-NGF) is a neurotrophin which acts through its receptors TrkA and p75, performing important actions in male reproductive physiology and its presence in seminal plasma (SP) has been related to male fertility. The aim of the present study was to evaluate the gene expression profile and the immunolocalization of ß-NGF and its high-affinity receptor TrkA in sex organs in rabbits during sexual maturation period. ß-NGF concentration for both SP and blood plasma (BP) and BP testosterone levels were determined as well as the seminal parameters during such period. Ten New Zealand White x California young rabbits were trained to semen collection since 20 weeks of age and routinely done once a week with two ejaculations per session. At 22 and 37 weeks of age, semen collection was carried out three times a week and seminal parameters were evaluated. Four males were randomly assigned and slaughtered in each age (n = 8); sex organs (prostate, bulbourethral glands and epididymis) were dissected and collected to determine ß-NGF and TrkA gene expression and immunolocalization. SP and BP were also taken at each semen collection session to evaluate ß-NGF concentration, and testosterone levels were also assessed in BP. The highest ß-NGF mRNA expression was observed in prostate compared to bulbourethral glands and epididymis. These two last tissues showed residual ß-NGF mRNA expression and limited localization of the neurotrophin. The prostate epithelial cells and lumen were strongly stained with regard to the other sex organs indicating that immunolocalization of ß-NGF rely mainly in the prostate. TrkA gene expression was lower but constant and differentially immunolocalized in the sex organ tissues. Finally, ß-NGF concentration in SP and BP remained unchanged in accordance to age, while some seminal characteristics such as sperm concentration, percentage of live sperm and mass and progressive motility were enhanced as endowed by BP testosterone variation. ß-NGF and its cognate TrkA receptor are expressed and immunolocalized in the male reproductive tract in the two ages studied, independently of the circulating levels of testosterone and ß-NGF.

Recombinant rabbit beta nerve growth factor production and its biological effects on sperm and ovulation in rabbits.

In some induced-ovulating species, beta nerve growth factor (ß-NGF) has important roles in ovulation, though data for rabbits are still inconclusive. In this study we first synthesized functional recombinant ß-NGF from rabbit tissue (rrß-NGF) to address the following objectives: 1) to compare rabbit ß-NGF amino acid sequence with those of other induced- or spontaneous-ovulating species; 2) to assess the effects of rrß-NGF on rabbit sperm viability and motility, and 3) to examine the in vivo ovulation inducing effect of rrß-NGF added to the seminal dose in rabbit does. The NGF gene in rabbit prostate tissue was sequenced by Rapid Amplification of cDNA Ends and annotated in GenBank (KX528686). Recombinant rß-NGF was produced in CHO cells and purified by affinity chromatography. Once confirmed by Western blotting and mass spectrometry (MALDI-TOF) that the amino acid sequence of the recombinant protein corresponded to ß-NGF, its functionality was validated in PC12 cells in a successful dose-response study over 8 days. The amino acid sequence of prostate rabbit NGF differed to that of other species mainly in its receptor binding sites. In all the spontaneous ovulating species examined, compared with rabbit, alanine and proline residues, which interact with the high-affinity receptor, were replaced by a serine. In rabbits, asparagine and methionine were substituted by lysine at the low-affinity receptor binding site. In time- and dose-response experiments, the in vitro addition of rrß-NGF to the ejaculate did not affect sperm viability whereas sperm motility parameters were enhanced by the addition of 1 µg/mL of the neuropeptide. Addition of this same concentration of rrß-NGF to the seminal dose administered via the intravaginal route in does induced ovulation with a delayed LH peak, leading to a plasma progesterone increase, gestation and delivery. Our findings suggest that rrß-NGF could be a useful option for biotechnological and reproduction assisted techniques in rabbits but further studies are needed.

Correction: Recombinant rabbit beta nerve growth factor production and its biological effects on sperm and ovulation in rabbits.

[This corrects the article DOI: 10.1371/journal.pone.0219780.].

Competition for Materno-Fetal Resource Partitioning in a Rabbit Model of Undernourished Pregnancy.

The major goal of animal production is to obtain abundant and healthy meat for consumers. Maternal food restriction (MFR) is often applied in farms to reduce production costs. However, the suitability of MFR in livestock animals is questionable, as this management may compromise maternal fitness due to a severe negative energetic balance and can induce Intrauterine Growth Restriction (IUGR) and prenatal programming in the offspring. Here, we sought to determine, using pregnant rabbits, the consequences of MFR on maternal endocrine and metabolic status and conceptus development. Pregnant dams were distributed into three groups: CONTROL (ad libitum feeding throughout the entire pregnancy; mean pregnancy length being around 31 days), UNDERFED (50% MFR during the entire pregnancy) and EARLY-UNDERFED (50% MFR only during the preimplantation period, Days 0-7). Maternal leptin concentrations and glycemic and lipid profiles were determined throughout pregnancy, whilst conceptus development was assessed ex-vivo at Day 28. Placental parameters were determined by macroscopic and histological evaluations and apoptotic assessments (TUNEL and Caspase-3). The main results of the study showed that, despite MFR altered maternal plasma lipid concentration (P<0.05), there were no effects on maternal bodyweight, plasma leptin concentration or glycemic profile. Fetal crown-rump lengths were reduced in both undernourished groups (P<0.001), but a significant reduction in fetal weight was only observed in the UNDERFED group (P<0.001). Growth in both undernourished groups was asymmetrical, with reduced liver weight (P<0.001) and significantly increased brain: fetal weight-ratio (P<0.001) and brain: liver weight-ratio (P<0.001) when compared to the CONTROL group. A significant reduction in placental weight was only observed in the UNDERFED group (P<0.001), despite both undernourished groups showing higher apoptotic rates at decidua and labyrinth zone (P<0.05) than the CONTROL group. Thus, these groups evidenced signs of placental degeneration, necrosis and stromal collapse. In summary, MFR may encourage the mother to make strategic decisions to safeguard her metabolic status and fitness at the expense of growth reduction in the litter, resulting in enhanced apoptotic and pathological processes at placental level and IUGR.

Elevated non-esterified fatty acid concentrations during in vitro murine follicle growth alter follicular physiology and reduce oocyte developmental competence.

OBJECTIVE: To study how long-term elevated non-esterified fatty acid (NEFA) concentrations, typical in metabolic disorders such as obesity or type 2 diabetes, affect murine follicular development, follicle quality, and subsequent oocyte developmental competence in vitro. DESIGN: Experimental study. SETTING: In vitro culture setting. ANIMAL(S): Female and male 13-day old, B6CBAF1 mice of proven fertility were sacrificed for harvesting ovaries and epididymal sperm, respectively. INTERVENTION(S): Early secondary murine follicles were cultured in vitro in the presence of NEFAs until the antral stage (12 days). Treatments consisted of one or a mixture of NEFAs (stearic acid [SA], palmitic acid [PA], oleic acid [OA]) in physiological (basal) or pathological (high SA, high OA, high NEFA) concentrations. MAIN OUTCOME MEASURE(S): Follicular development; follicle and oocyte diameters; secretion of progesterone, estradiol, and inhibin B; and luteinized granulosa cell gene expression patterns were investigated. Oocytes from NEFA-exposed follicles were fertilized in vitro, and presumptive zygotes were cultured until the blastocyst stage. RESULT(S): Exposure to high SA reduced follicle diameters and day-12 antrum formation. Elevated NEFA concentrations changed luteinized granulosa cell messenger-ribonucleic acid abundance of genes related to energy/fatty acid/steroid metabolism, apoptosis, and oxidative stress. High NEFA and high SA treatments increased progesterone synthesis, compared with high OA follicles. Oocyte developmental competence was substantially reduced in oocytes retrieved from high OA-, high SA-, and high NEFA-exposed follicles compared with basal-treated follicles. CONCLUSION(S): This study showed, for the first time, that lipolysis-linked, elevated NEFA concentrations can potentially impair fertility, by altering follicular physiology and reducing oocyte developmental competence.

The main factors affecting the reproductive performance of rabbit does: a review.

This paper reviews the main factors affecting the reproductive performance of rabbit does. In the last 15 years the profitability of rabbit farms has increased mainly due to improvements in management and genetic selection but several problems related to animal welfare have also occurred. The replacement and the mortality rates of female per year are very high and the replaced does often show poor body condition and poor health status. The effect of kindling order, litter size, genetic strain, weaning age and reproductive rhythm on the reproductive performance and welfare of females and mechanisms implicated in these effects are discussed. The rabbit doe of modern strains produces a lot of milk with high energetic value, which leads to a mobilization of body fat resulting in a negative energy balance. In the current reproductive rhythms, there is an extensive overlap between lactation and gestation. The resulting energetic and hormonal antagonism reduces the fertility rate and lifespan of the doe. Strategies to optimize these parameters are discussed. An approach that combines various strategies seems to be required to meet these objectives. Since the factors involved in this system are predetermined (genetic strain, environment) the most powerful way to improve doe welfare is to choose a reproductive rhythm more adapted to the physiology of the does.