Suboptimal Fertility Research Articles

Heterologous beta-nerve growth factor (β-NGF) given at the LH surge enhances luteal function in dairy heifers

Genetic selection for high yield milk production has led to a decline in dairy cattle's reproductive performance over the last 40 years. Low progesterone (P4) plasma content following ovulation is associated with suboptimal fertility in dairy cattle. Several pieces of evidence indicate that the protein beta-nerve growth factor (β-NGF) that is present in the male seminal plasma exerts potent ovulatory and luteotrophic effects following systemic administration in camelids but also in other species. In this study, we determine whether systemic administration of purified llama β-NGF given at the induced preovulatory luteinizing hormone (LH) peak improves corpus luteum (CL) function in dairy heifers subjected to an estradiol (E2) / P4 estrus-synchronization protocol. To achieve this, we first determined plasma E2 and LH hormone profiles to establish the timing of the estradiol benzoate (EB)-induced LH peak in estrus-synchronized heifers. Then, we tested whether the administration of β-NGF given at the end of this peak affects the CL and its function by analyzing diameter, vascular area, and P4 output. Our results show that, with the estrus-synchronization protocol applied, plasma LH concentrations peaked (P < 0.01) 40-h and 16-h after removal of the bovine intravaginal device (DIB; containing 1.0 g of P4) plus cloprostenol injection and subsequent EB administration, respectively; after peaking, plasma LH concentrations remained stable for the next 8-h to then return to basal levels. Heifers synchronized with this protocol and receiving a dose of 1 mg of β-NGF at the end of the LH peak (ie, 48-h after DIB removal) did not show significant differences in CL diameter, but these exhibited a greater CL vascular area (P = 0.01) than the observed in vehicle-injected heifers. Furthermore, plasma P4 concentration in β-NGF-treated heifers was higher (P = 0.001) than those quantified in vehicle-injected heifers. These results support the use of β-NGF in estrus-synchronization protocols to improve the early luteal function in dairy heifers.

Biostimulant Activity of Azotobacter chroococcum and Trichoderma harzianum in Durum Wheat under Water and Nitrogen Deficiency

Biostimulants hold great potential for developing integrated sustainable agriculture systems. The rhizobacteria Azotobacter chroococcum strain 76A and the fungus Trichoderma harzianum strain T22, with demonstrated biostimulant activity in previous systems, were evaluated in Triticum durum cv Creso for their ability to enhance growth and tolerance to drought stress. Growth and drought tolerance were evaluated in conditions of low and high soil nitrogen, with two levels of water stress. T. harzianum increased plant growth (+16%) under control conditions and tolerance to moderate drought stress (+52%) under optimal fertilization, while A. chroococcum conferred a growth penalty (−28%) in well-watered conditions under suboptimal fertilization and increased tolerance only under extreme drought stress (+15%). This growth penalty was ameliorated by nitrogen fertilization. T. harzianum abundance was found to be positively correlated to extreme soil drying, whereas A. chroococcum-induced tolerance was dependent on soil nitrogen availability. These results indicate that while biostimulants may enhance growth and stress tolerance, nutrient availability soil and environmental conditions heavily influence these responses. These interactions should be considered when designing biostimulant products targeted to specific cultural conditions.

Effects of endometritis on reproductive performance of zero-grazed dairy cows on smallholder farms in Rwanda

Endometritis is a prevalent post-partum uterine infection in dairy cows resulting in suboptimal reproductive performance. The hypothesis was that endometritis status is associated with suboptimal reproductive performance of postpartum dairy cows managed under zero-grazing feeding practice on smallholder farms. In this study, there was evaluation of effects of endometritis diagnosed at 38.5 ± 14.7 days postpartum (dpp) on subsequent reproductive performance. Reproductive performance of 436 cows from 345 farms was recorded for 210 dpp. Values for reproductive performance indicators were less (P < 0.05) in cows determined to be positive compared to negative for endometritis. Cows that tested positive, as compared to negative, for endometritis had longer periods after parturition until initiation of oestrous cycles (median, interquartile range; 85.0, 57.5−127.0 and 62.6, 49.0−90.0 days, respectively), longer durations before being detected pregnant (95.5, 61.8−145.5 and 63.0, 50.0−83.0 days, respectively), lesser pregnancy rates as a result of the first breeding postpartum (16.5% and 32.7%, respectively), more natural-mating or artificial inseminations per pregnancy (1.3 ± 0.1 and 1.1 ± 0.0, respectively) and more occurrences of anoestrus postpartum (48.4% and 11.7%, respectively). These results provide evidence of a strong association between endometritis and suboptimal fertility performance in zero-grazed cows on smallholder farms in Rwanda. Considering there were 70.2% of cows in the present study were diagnosed with endometritis, this is indicative of a widespread herd health issue, warranting that field veterinary practitioners prioritise endometritis in their herd health service delivery to smallholder dairy farmers for effective disease management and herd sustainability.

Estimating prevalence of endometritis in smallholder zero-grazed dairy cows in Rwanda.

Endometritis is a postpartum uterine disease of cows that interrupts reproductive cycles resulting in suboptimal fertility, reduced performance and profitability of the dairy herd. The objective of the study was to estimate the perceived and observed prevalence of endometritis among zero-grazed dairy cows in smallholder farms in Rwanda. A snowball sampling method was applied in cross-sectional survey to obtain data from 370 farms on 466 cows within their 21-60days postpartum (dpp). The survey, conducted from September 2018 to March 2019, simultaneously examined cows using the Metricheck Device (MED) to determine the presence and type of vaginal mucus (VMC) based on a score scale of 0 to 3. Cows scoring VMC ≥ 1 were recorded as clinical endometritis (CLE)-positive. Cytotape (CYT) was used to determine the percentages of polymorphonuclear cells (PMN)in endometrial cytology sample. Cows with ≥ 5% PMN were recorded subclinical endometritis (SCLE)-positive, whereas cows with VMC-0 and < 5% PMN were considered healthy cows. At cow-level, endometritis prevalence was 70.2% with 67.2% CLE and 31.8% SCLE while at the herd-level, prevalence was 71.1% with 68.1% CLE and 34.4% SCLE. The differences between the diagnostic performance of the MED and CYT were significant (p < 0.001). Perceived prevalence by farmers was much lower (3.2%) and without agreement with the observed prevalence (kappa = - 0.02, p > 0.05). The highly observed prevalence and farmer underestimation of endometritis prevalence indicate knowledge gaps about endometritis. The extension service therefore needs to increase awareness and education among smallholder farmers about detection and management of endometritis.

Can Trichoderma-Based Biostimulants Optimize N Use Efficiency and Stimulate Growth of Leafy Vegetables in Greenhouse Intensive Cropping Systems?

The present study addresses the effects of Trichoderma-based biostimulants and nitrogen (N) fertilization levels on agronomic performance and functional quality of two important greenhouse leafy vegetables: lettuce and rocket. A factorial analysis of the relative effects of Trichoderma-based biostimulants (Trichoderma harzianum strain T22 and Trichoderma virens strain GV41) and N fertilization levels (sub-optimal, optimal, and supra-optimal) was carried out to evaluate crop productive behavior (marketable and unmarketable yields, leaf dry matter content, and biomass production), nitrogen nutrition (N uptake, apparent N recovery, and nitrogen use efficiency (NUE)) as well as phytochemical qualitative components (antioxidant activity and total polyphenols). The soil plant analysis development (SPAD) index in both leafy vegetables and leaf colorimetry only in rocket were mainly affected by N fertilization levels but not by Trichoderma-based biostimulants. The contribution of native mineral N was 60 and 100 kg N ha−1 of the total uptake in lettuce and rocket, respectively, and N surpluses were observed in both crops, even under optimal fertilization conditions. Trichoderma virens GV41-based biostimulant increased lettuce marketable yield and biomass production, both under optimal and sub-optimal fertilization. In addition, the same treatment increased NUE up to 116% under recommended N fertilization, that was also associated to an increase in phenol content and antioxidant activity. Rocket showed a clear effect of the Trichoderma virens GV41 treatment, only in absence of fertilization, demonstrating an increase in marketable yield and N uptake. Thus, the inoculation of rocket with this Trichoderma biostimulant can be considered as a useful management tool in leafy vegetable cropping systems for the efficient use of residual fertilizers from previous crops, enhancing NUE within the crop rotations. Nevertheless, the application of microbial biostimulant treatments requires good monitoring of soil N fertility in order to avoid an overexploitation of soil N supplying potential.

Machine learning to further improve the decision which boar ejaculates to process into artificial insemination doses

Current artificial insemination (AI) laboratory practices assess semen quality of each boar ejaculate to decide which ones to process into AI doses. This decision is aided with two, world-wide used, motility parameters that come available through computer assisted semen analysis (CASA). This decision process, however, still results in AI doses with variable and sometimes suboptimal fertility outcomes (e.g., small litter size). The hypothesis was that the decision which ejaculates to process into AI doses can be improved by adding more data from CASA systems, and data from other sources, in combination with a data-driven model. Available data consisted of ejaculates that passed the initial decision, and thus, were processed into AI doses and used to inseminate sows. Data were divided into a training set (6793 records) and a validation set (1191 records) for model development, and an independent test set (1434 records) for performance assessment. Gradient Boosting Machine (GBM) models were developed to predict four fertility phenotypes of interest (gestation length, total number born, number born alive, and number of stillborn piglets). Each fertility phenotype was considered as a numeric and as a binary outcome parameter, totaling to eight different fertility phenotypes. Data used to further improve the decision process originated from four sources: 1) CASA information, 2) boar ejaculate information, 3) breeding value estimations, and 4) weather information. These data were used to create seven prediction sets, where each new set added parameters to the ones included in the previous set. The GBM models predicted fertility phenotypes with low correlations (for numeric phenotypes) and area under the curve values (for binary phenotypes) on the test data. Hence, results demonstrated that a combination of more data and GBM did not enable further improvement of the AI dose quality checks, resulting in the rejection of our hypothesis. However, our study revealed parameters affecting boar ejaculate fertility which were not used in today’s decision process. These parameters (listed in the top 10 in at least four GBM models) included one parameter associated with boar ejaculate information, two with breeding value estimations, five with CASA information, and one with weather information. These parameters, therefore, should be further investigated for their potential value when assessing the quality of boar ejaculates in daily routine AI doses processing.

Scanner-Based Minirhizotrons Help to Highlight Relations between Deep Roots and Yield in Various Wheat Cultivars under Combined Water and Nitrogen Deficit Conditions

Breeding for crops in the context of climate change necessitates phenotyping tools for roots in field conditions. Such in-field phenotyping requires the development of rapid and non-destructive measurement techniques for the screening of relevant root traits under sub-optimal conditions. In this study, we used scanner-based minirhizotrons to measure in situ the root length and surface/volume densities of roots for four wheat varieties, under four different growth conditions: irrigated and rainfed coupled with optimal and sub-optimal N fertilization under a Mediterranean climate. For all the treatments, grain yield correlates with minirhizotron-based root surface density measured at anthesis (r2 = 0.48). Irrigated and rainfed conditions led to contrasted relations between roots and grain yield: no correlation was found in irrigated plots, while under rainfed conditions and sub-optimal fertilization, the higher yields are related to a higher root colonization of the deeper soil layers (r2 = 0.40). Shoot biomass was correlated to grain yield in irrigated conditions, but not in rainfed conditions. However, for the latter, the total root weight, the proportion of which being mainly located in the top soil, is not related to the grain yield. In this way, we show the relationship between these higher grain yields and a stress avoidance mechanism of the root system characterized by a higher root density in the deep soil layers. Thus, unlike shoot biomass measurements, scanner-based minirhizotron allows the direct detection of such a stress-related root development, and therefore opens the door to a better prediction of grain yield.

Causes and consequences of the variation in the number of ovarian follicles in cattle

Summary. In cattle we have noted that the antral follicle count (AFC, follicles ≥3 mm in diameter) varies greatly among animals (from 5 to 50), is repeatable within animals, and is highly correlated with the total number of healthy follicles in ovaries. Also, animals with low AFC have higher serum concentrations of FSH and LH, but lower concentrations of Anti-Mullerian Hormone, progesterone and androgens than animals with high AFC. We have investigated the effect of maternal environment during gestation on their offspring AFC by restricting maternal nutrition to 60% of maintenance requirements (compared with 100% in controls) during the first third of gestation. Calves born to nutritionally restricted mothers had 60% lower AFC compared with calves born to mothers fed control diets. In other studies we have evidence to indicate that fertility may be compromised in animals with low AFC due to effects on oocytes, progesterone and the endometrium compared with animals with high AFC. To examine this directly we assessed AFC in post-partum dairy cows and found that cows with a high AFC had higher pregnancy rates, shorter calving to conception intervals and received fewer services during the breeding season compared with cows with a low AFC. In addition, the high variation in follicle numbers in adults may not only be reflective of reproductive disorders and suboptimal fertility, but there is evidence to indicate that it may be associated with alterations in the function of other non-reproductive systems (e.g. cardiovascular) that may have profound effects on the animal's health and welfare.

A single ultrasound determination of ≥25 follicles ≥3 mm in diameter in dairy heifers is predictive of a reduced productive herd life

Fertility and productive herd life (time in herd after birth of first calf) are inferior in dairy cows with relatively low compared with intermediate but not high numbers of follicles growing during ovarian follicular waves. The present study, therefore, tested the hypothesis that fertility and productive herd life are lower in dairy heifers with high follicle numbers compared with age-matched herdmates with fewer follicles. To test this hypothesis, 11 to 15 mo old Holstein heifers were subjected to a single ultrasound measurement of the number of follicles ≥3 mm in diameter. Heifers were classified into a high- (≥25 follicles), mid- (16-24), or low-range (≤15) follicle number group (FNG). All heifers not removed from the herd before first calving (n = 408) had the opportunity to start their fifth or sixth lactation after birth of their first calf. During this time, performance and health parameters for each individual were recorded daily by herd managers. Results showed that heifers in the high-range FNG had a 180-d shorter productive herd life, reduced survival rate, and greater probability of being culled after birth of the first calf, as well as fewer lactations compared with heifers in the low-range FNG. Cows in the high-compared with the mid- or low-range FNG also had greater involuntary culling rates, days open, and services per conception, and lower pregnancy rates during the first, second, or third lactations. We concluded that dairy heifers with ≥25 follicles ≥3 mm in diameter have suboptimal fertility and a shorter productive herd life compared with herdmates with fewer follicles.

Effect of male age on oxidative stress markers in human semen

This study conducted a comprehensive analysis of oxidative stress markers in human semen within the context of assisted reproductive technology (ART) and investigated if these markers varied according to male age. 148 semen samples were collected from 139 men presenting at Concept Fertility Centre, Western Australia, from 2009 to 2012. Semen analyses were performed and demographic information including smoking status and abstinence period was collected. Reactive oxygen species production, lipid peroxidation, oxidative DNA damage (8-hydroxy-2′-deoxyguanosine (8-OHdG)), total antioxidant capacity and DNA fragmentation ( terminal deoxynucleotidyl transferase-mediated deoxyuridine diphosphate nick-end labelling) were measured as markers of oxidative stress. Semen parameters and oxidative stress markers were compared against age as a continuous variable, and between males &lt;40 and males ≥40 years of age. Older males aged ≥40 years exhibited higher levels of sperm oxidative DNA damage (8-OHdG) compared to younger males ( p = 0.029), but no other oxidative stress marker significantly varied with age. An age-related decrease in sperm concentration ( p = 0.011) and motility ( p = 0.015) was observed after processing. Lower sperm concentration and reduced motility pre- and post-semen processing were significantly correlated with elevated oxidative DNA damage (all p &lt; 0.001). Our results suggest that oxidative stress may be an important mediator between male age and fertility. This is concerning within the context of an ageing ART cohort, as sperm oxidative DNA damage is associated with a range of suboptimal fertility outcomes.

The effect of energy balance on the transcriptome of bovine granulosa cells at 60 days postpartum

Dairy cows expend great amounts of energy during the lactation peak to cope with milk production. A state of negative energy balance (NEB) was suggested as a cause for the suboptimal fertility observed during this period, via an interaction with ovarian function. The objective of this study was to identify the impact of NEB on gene expression in granulosa cells of dairy cows at 60 days postpartum and to suggest a potential treatment to improve ovarian function. Dairy cows at 60 days postpartum from 10 typical medium-sized farms were synchronized using a single injection of prostaglandin. Dominant follicles were collected 42 hours later by transvaginal aspiration. Blood concentrations of beta-hydroxybutyrate (BHB) on the day of aspiration were used to classify animals into two groups: severe NEB (high BHB, n = 12) and mild NEB (low BHB, n = 12). The transcriptomes of granulosa cells from both groups were contrasted using microarrays, and the differentially expressed genes were analyzed using Ingenuity Pathway Analysis to identify affected functions and potential upstream regulators. Genes linked with cellular organization (KRT4 and PPL), proliferation (TACSTD2), and fatty acids metabolism (VNN2) were downregulated in granulosa cells from animals with severe NEB. Several genes linked to decitabine, a hypomethylating agent, and with beta-estradiol, were downregulated in the severe NEB group. Numerous genes linked to vitamins A and D were also downregulated in this group of cows, suggesting a potential deficiency of these vitamins in dairy cows during the postpartum period. This study supports the idea that energy balance has an impact on follicular dynamics which could be detrimental to resumption of fertility after calving.

Concentration of anti-Müllerian hormone in dairy heifers is positively associated with productive herd life

Reliable biomarkers predictive of productive herd life (time in herd after birth of first calf) have heretofore not been discovered in dairy cattle. However, circulating concentrations of anti-Müllerian hormone (AMH) are positively associated with number of follicles or antral follicle count (AFC), ovarian function, and fertility, and approximately 25% of cows have a relatively low AFC and low AMH concentrations. The present study tested the hypothesis that heifers with the lowest AMH concentrations have suboptimal fertility and are removed from a herd for poor reproductive performance at a greater rate, and therefore have a shorter productive herd life compared with age-matched herdmates with higher AMH. To test this hypothesis, 11- to 15-mo-old Holstein heifers (n=281) were subjected to a single measurement of AMH. All heifers not removed from the herd had the opportunity to complete 2 lactations and start their third lactation after calving. During this time, performance and health parameters for each individual were recorded daily by herd managers. Results showed that the quartile of heifers with the lowest AMH concentration also had, on average, a shorter productive herd life (by 196 d), a reduced survival rate after birth of the first calf, the lowest level of milk production (first lactation), the lowest total percentage of cows pregnant (across all lactations), the highest culling rates (first and second lactations and overall), and the highest culling rate for poor reproduction (first lactation) compared with age-matched herdmates with higher AMH. We concluded that a single determination of AMH concentration in young adult dairy heifers may be a simple diagnostic method to predict herd longevity, and AMH may be a useful phenotypic marker to improve longevity of dairy cows.

Correlation between Cytoplamic Oocyte Maturation and Chromosomal Aneuploidies - Impact on fertilization, embryo quality and pregnancy.

To establish the relationship between oocyte cytoplasmic maturation and its chromosomal status and determine the effect of this feature over the reproductive outcome in patients with sub-optimal fertilization in ART. Fifty couples who underwent ART were selected. From nineteen patients, 22 metaphase II-MII and 18 failed-fertilized oocytes after ICSI were studied. The first polar body was collected for chromosomal analysis by aCGH. Oocytes were processed by immunocytochemistry (ICC) to determine oocyte maturation: assessment of inactive MPF status and the conformation-alignment of the metaphase plate.Other 31 couples presented sub-optimal fertilization (<50%) after ICSI, and failed-fertilized oocytes were studied by ICC. Two groups were conformed according to the main feature observed: A) cytoplasmic immaturity and sperm premature chromosome condensation and B) sperm nuclear decondensation failure with mature cytoplasm. Regarding MII mature oocytes, 87% had a normal metaphase plate and 84% were chromosomally normal. Contrary, immature oocytes presented abnormal metaphase plate (86%) and just 33% were euploid. In failed-fertilized oocytes: 100% of mature oocytes had a normal metaphase plate and 71% were euploid. When oocytes were cytoplasmic immature, 37% of them were normal (metaphase plate) and 50% were chromosomally normal.The global rate of aneuploidies and metaphase plate disarrangements in immature oocytes (MII+failed-fertilized) were significantly higher than mature oocytes (P<0.05).In patients with sub-optimal fertilization, the percentage of top quality embryos and pregnancy rate was significantly higher in group B (P<0.05). Oocyte cytoplasmic immaturity is related to metaphase plate anomalies and aneuploidies. Fertilized oocytes, from a cohort with sub optimal fertilization with cytoplasmic immaturity, had poorer reproductive outcomes.

Long-term rice rotation, tillage, and fertility effects on near-surface chemical properties in a silt-loam soil

A majority of the rice (Oryza sativa L.) produced in the United States occurs on alluvial soils in the lower Mississippi River Valley, lower coastal plains of Louisiana and Texas, and in the Sacramento River Valley of California. Rice is a staple grain of global importance, so ensuring the sustainability of rice production systems is vital to feeding the world’s population and protecting economic livelihoods. Therefore, a study was conducted at the Rice Research and Extension Center near Stuttgart, Arkansas to evaluate the long-term effects of rice-based crop rotations [with corn (Zea mays L.), soybean (Glycine max L.), and winter wheat (Triticum aestivum L.)], tillage (conventional and no-tillage), and soil fertility treatments (optimal and sub-optimal) after 11 years (1999–2010) on soil organic matter (SOM) content, soil pH, and Mehlich-3 extractable nutrient contents in the top 10 cm of a Dewitt silt loam (fine, smectitic, thermic, Typic Albaqualf). Results revealed increases in SOM (9–14 %) and extractable Mn (68–220 %), Fe (82 %), and Na (37–76 %) contents in most tillage–fertility–rotation treatments over time. Soil P (fourfold to eightfold) and K (twofold to threefold) contents increased in rotations with wheat and soil pH (9 %) increased under sub-optimal fertility. In contrast, extractable Ca (22 %), S (30 %), and Cu (27 %) contents decreased over time in all treatment combinations and Zn (twofold) contents decreased under continuous rice. Understanding the decadal effects field management practices have on soil chemical properties will provide insight into the longer-term economic and environmental sustainability of rice-based cropping systems.

Oocyte and sperm factors implicated in fertilization failure after ICSI

ObjectiveTo identify and report some factors involved in fertilization failures after ICSI.DesignDescriptive.Materials and MethodsAt the present study, 2300 human oocytes with fertilization failure after ICSI were considered. Nine hundred corresponded to sub-optimal fertilization (<50%). For oocyte assessment, fixation and subsequent processing was performed. Acetylated alpha tubulin, beta tubulin and MPF (CyclinB-Cdc2) immuno-staining was performed using monoclonal antibodies. DNA detection was carried out with Hoechst-33342 and TUNEL (DNA damage). When oocyte activation failure and sperm nuclear decondensation failure were observed, Western-Blot and immunocytochemistry detection were performed over semen samples for PLCzeta (oocyte activation protein) and nuclear sperm in-vitro decondensation test was also assessed.ResultsTable 1Fertilization failures eventsICSIFert<50%TOTAL# oocytes14009002300Sperm absence8%3%6%Premature chromosome condensation (oocyte cytoplasmic immaturity)28%50%36.6%Sperm nuclear decondensation failure19%30%23.3%Pronuclear formation defects18%6%13.3%1st mitotic division arrest15%6%11.5Others12%5%9.3% Open table in a new tab Specifically, when oocyte activation failures occurred concomitantly with sperm nuclear decondensation failure (155 oocytes), 13.2% depicted a significant decrease in PLCzeta levels, 21.2% presented sperm DNA fragmentation, 39.4% showed several levels of sperm nuclear decondensation and 10.5% of the oocytes had an inability to perform an adequate chromatin remodeling, probably due to lower levels of glutation.ConclusionIn general, fertilization failure occurs in 28% of cases for an incomplete oocyte cytoplasmic maturation. This value is increased to 50% when fertilization failures take place in ≥ 50% of the oocyte cohort. The second most recurrent event was sperm DNA decondensation failure, 39.4% depicted variable decondensation levels. Oocyte features has more implications over fertilization failures after ICSI. ObjectiveTo identify and report some factors involved in fertilization failures after ICSI. To identify and report some factors involved in fertilization failures after ICSI. DesignDescriptive. Descriptive. Materials and MethodsAt the present study, 2300 human oocytes with fertilization failure after ICSI were considered. Nine hundred corresponded to sub-optimal fertilization (<50%). For oocyte assessment, fixation and subsequent processing was performed. Acetylated alpha tubulin, beta tubulin and MPF (CyclinB-Cdc2) immuno-staining was performed using monoclonal antibodies. DNA detection was carried out with Hoechst-33342 and TUNEL (DNA damage). When oocyte activation failure and sperm nuclear decondensation failure were observed, Western-Blot and immunocytochemistry detection were performed over semen samples for PLCzeta (oocyte activation protein) and nuclear sperm in-vitro decondensation test was also assessed. At the present study, 2300 human oocytes with fertilization failure after ICSI were considered. Nine hundred corresponded to sub-optimal fertilization (<50%). For oocyte assessment, fixation and subsequent processing was performed. Acetylated alpha tubulin, beta tubulin and MPF (CyclinB-Cdc2) immuno-staining was performed using monoclonal antibodies. DNA detection was carried out with Hoechst-33342 and TUNEL (DNA damage). When oocyte activation failure and sperm nuclear decondensation failure were observed, Western-Blot and immunocytochemistry detection were performed over semen samples for PLCzeta (oocyte activation protein) and nuclear sperm in-vitro decondensation test was also assessed. ResultsTable 1Fertilization failures eventsICSIFert<50%TOTAL# oocytes14009002300Sperm absence8%3%6%Premature chromosome condensation (oocyte cytoplasmic immaturity)28%50%36.6%Sperm nuclear decondensation failure19%30%23.3%Pronuclear formation defects18%6%13.3%1st mitotic division arrest15%6%11.5Others12%5%9.3% Open table in a new tab Specifically, when oocyte activation failures occurred concomitantly with sperm nuclear decondensation failure (155 oocytes), 13.2% depicted a significant decrease in PLCzeta levels, 21.2% presented sperm DNA fragmentation, 39.4% showed several levels of sperm nuclear decondensation and 10.5% of the oocytes had an inability to perform an adequate chromatin remodeling, probably due to lower levels of glutation. Specifically, when oocyte activation failures occurred concomitantly with sperm nuclear decondensation failure (155 oocytes), 13.2% depicted a significant decrease in PLCzeta levels, 21.2% presented sperm DNA fragmentation, 39.4% showed several levels of sperm nuclear decondensation and 10.5% of the oocytes had an inability to perform an adequate chromatin remodeling, probably due to lower levels of glutation. ConclusionIn general, fertilization failure occurs in 28% of cases for an incomplete oocyte cytoplasmic maturation. This value is increased to 50% when fertilization failures take place in ≥ 50% of the oocyte cohort. The second most recurrent event was sperm DNA decondensation failure, 39.4% depicted variable decondensation levels. Oocyte features has more implications over fertilization failures after ICSI. In general, fertilization failure occurs in 28% of cases for an incomplete oocyte cytoplasmic maturation. This value is increased to 50% when fertilization failures take place in ≥ 50% of the oocyte cohort. The second most recurrent event was sperm DNA decondensation failure, 39.4% depicted variable decondensation levels. Oocyte features has more implications over fertilization failures after ICSI.

Assessment of nitrate leaching loss on a yield-scaled basis from maize and wheat cropping systems

It is so far a gap in knowledge to assess nitrate (NO3 −) leaching loss linking with crop yield for a given cereal cropping system. We conducted a meta-analysis on 32 published studies reporting both NO3 − leaching losses and crop yields in the maize (N = 20) and wheat (N = 12) systems. On average, 22 % and 15 % of applied fertilizer N to wheat and maize systems worldwide are leached in the form of NO3 −, respectively. The average area-scaled NO3 - leaching loss for maize (57.4 kg N ha−1) was approx. two times higher than for wheat (29.0 kg N ha−1). While, if scaled to crop yields, the average yield-scaled NO3 − losses were comparable between maize (5.40 kg N Mg−1) and wheat (5.41 kg N Mg−1) systems. Across all sites, the lowest yield-scaled NO3 − leaching losses were observed at slightly suboptimal fertilization rates, corresponding to 90 % and 96 % of maximum maize or wheat yields, respectively. Our findings suggest that small adjustments of agricultural N management practices can effectively reduce yield-scaled NO3 − leaching losses. However, further targeted field experiments are still needed to identify at regional scale best agricultural management practices for reducing yield-scaled NO3 − leaching losses in maize and wheat systems.

Maternal Undernutrition in Cows Impairs Ovarian and Cardiovascular Systems in Their Offspring1

Severe prenatal undernutrition is usually associated with low birth weights in offspring and disorders including hypertension, obesity, and diabetes. Whether alterations in maternal nutrition insufficient to impair birth weight or prenatal growth impact the cardiovascular, stress, or metabolic systems is unknown. In addition, little is known about the effects of maternal dietary restriction on development of the reproductive system in mammals. Here, we use the bovine model, which has a gestational length and birth rate similar to humans, to show that offspring from nutritionally restricted dams (during the first trimester) were born with identical birth weights and had similar postnatal growth rates (to 95 wk of age), puberty, glucose metabolism, and responses to stress compared to offspring from control mothers. However, an increase in maternal testosterone concentrations was detected during dietary restriction, and these dams had offspring with a diminished ovarian reserve (as assessed by a reduction in antral follicle count, reduced concentrations of anti-Müllerian hormone, and increased follicle-stimulating hormone concentrations), enlarged aorta, and increased arterial blood pressure compared with controls. Our study links transient maternal undernutrition and enhanced maternal androgen production with a diminished ovarian reserve as well as potential suboptimal fertility, enlarged aortic trunk size, and enhanced blood pressure independent of alterations in birth weight, postnatal growth, or stress response and glucose tolerance. The implications are that relatively mild transient reductions in maternal nutrition during the first trimester of pregnancy (even those that do not affect gross development) should be avoided to ensure healthy development of reproductive and cardiovascular systems in offspring.

Scavenger receptor class B type 1 gene polymorphisms and female fertility

Multiple studies have demonstrated a role for scavenger receptor class B type 1 (SR-B1) in female fertility. Recent studies have implicated specific SR-B1 gene polymorphisms in decreased progesterone production and suboptimal fertility outcomes. The lipoprotein receptor SR-B1 has been known to mediate selective uptake of lipids into steroidogenic tissues such as the ovaries. SR-B1 plays a major role in the ability of the corpus luteum to produce progesterone, which is known to play a key role in sustaining early pregnancy. Animal studies have demonstrated that deficiency in SR-B1 results in subfertility that can be restored with addition of SR-B1 function. Single-nucleotide polymorphisms in SCARB1, the gene encoding SR-B1, have been associated with human lipid levels. Women undergoing infertility treatment with low SR-B1 expression in granulosa cells were noted to have plasma estradiol levels half the normal levels and a significantly lower number of retrieved oocytes. In vitro, deficiency of SR-B1 is associated with lower progesterone secretion in human granulosa cells. Certain SR-B1 polymorphisms have been associated with lower follicular progesterone levels and a significantly lower clinical pregnancy rate. Deficiency of SR-B1, particularly due to single-nucleotide polymorphisms, could explain some features of female human infertility.

Biological Markers of Boar Fertility

The semen evaluation techniques used in most commercial artificial insemination centers, which includes sperm motility and morphology measurements, provides a very conservative estimate of the relative fertility of individual boars. As well, differences in relative boar fertility are masked by the widespread use of pooled semen for commercial artificial insemination (AI) in many countries. Furthermore, the relatively high sperm numbers used in commercial AI practice usually compensate for reduced fertility, as can be seen in some boars when lower numbers of sperm are used for AI. The increased efficiency of pork production should involve enhanced use of boars with strong reproductive efficiency and the highest genetic merit for important production traits. Given that the current measures of semen quality are not always indicative of fertility and reproductive performance in boars, accurate and predictive genetic and protein markers are still needed. Recently, significant efforts have been made to identify reliable markers that allow for the identification and exclusion of sires with reduced reproductive efficiency. This paper reviews the current status of proteomic and genomic markers of fertility in boars in relation to other livestock species.

Does size matter in females? An overview of the impact of the high variation in the ovarian reserve on ovarian function and fertility, utility of anti-Müllerian hormone as a diagnostic marker for fertility and causes of variation in the ovarian reserve in cattle

The mechanism whereby the inherently high variation in ovary size and the total number of high-quality oocytes in ovaries (ovarian reserve) impact on ovarian function and fertility, diagnostics to measure the size of the ovarian reserve and the factors that cause variation in the ovarian reserve are unknown. Our results show that cattle can be phenotyped reliably based on the number of antral follicles growing during follicular waves (antral follicle count, AFC). Young adult cattle with a consistently low v. a high AFC have smaller gonads, a markedly diminished ovarian reserve and many other phenotypic characteristics usually associated with ovarian aging and infertility. A powerful new approach based on a single measurement of serum concentration of anti-Müllerian hormone (AMH) is described to test the longstanding hypothesis that the size of the ovarian reserve is positively associated with fertility. Also, new evidence shows that maternal environment has a critical role in regulation of the high variation in the ovarian reserve and perhaps fertility in offspring. These results support the conclusion that the inherently high variation in the ovarian reserve, potentially caused by alterations in the maternal environment, has a negative impact on ovarian function that may result in suboptimal fertility in young adult cattle, and a single AMH measurement can be used reliably in future studies to determine if fertility is suboptimal in young adult cattle with low circulating AMH concentrations and a correspondingly diminished ovarian reserve.