Can Microfiltered Seminal Plasma Preserve the Morphofunctional Characteristics of Porcine Spermatozoa in the Absence of Antibiotics? A Preliminary Study

Artificial insemination is extensively performed in pig farms in Europe, the United States and Canada. Antibiotics are typically added to the inseminating dose to limit bacterial growth during liquid phase storage at 16°C, as bacterial contamination is unavoidable. The World Organization for Animal Health (OIE) and the Food and Agriculture Organization (FAO) take action to control and reduce antibiotic use in animals as more bacteria are becoming resistant to antimicrobials. To avoid the use of antibiotics, we prepared inseminating doses using microfiltered seminal plasma (SP). Microfiltration is a common technology used to reduce bacterial contamination but may retain seminal substances, influencing sperm quality during storage. Therefore, the aim of this study was to evaluate the morphofunctional parameters of spermatozoa during storage at 16°C in doses prepared with or without microfiltered SP, with or without the addition of antibiotics, in a Latin square design. Artificial insemination doses with microfiltered SP and without antibiotic addition preserved spermatozoa viability, mitochondrial membrane potential, acrosome integrity and objective motility, with absolute values equal or even better than those observed in conventional doses. In conclusion, although the results could be considered preliminary due to the small sample size, this study suggests that microfiltration of SP can be a simple method, feasible on farms, to replace antibiotic use in extended doses stored in the liquid phase at 16°C for up to 7 days.     

New techniques for breeding maize (Zea mays) varieties with fall armyworm resistance and market-preferred traits for sub-Saharan Africa

Deploying maize varieties with fall armyworm (Spodoptera frugiperda [J.E. Smith]; FAW) resistance, desirable product profiles (PPs) and climate resilience is fundamental for food and economic security in sub-Saharan Africa (SSA). This study reviewed and identified challenges and opportunities for effective and accelerated breeding of demand-led maize hybrids with FAW resistance and adaptation to the diverse agro-ecologies of SSA. Lessons were drawn on improving breeding efficiency through adequate genetic variation delivered via prebreeding programmes, speed breeding and a reduced breeding stage plan. Appropriate PPs aligned with demand-led breeding approaches were highlighted as foundations for variety design and commercialization. Challenges to accelerated FAW resistance breeding in maize included inadequate funds and modern tools; poor adaptation of some exotic donor parental lines; lack of information on FAW resistance among local varieties; lack of integration of molecular markers associated with FAW resistance and agronomic traits into selection plans; and limited infrastructure for FAW rearing and germplasm screening. Integration of modern breeding tools and scientific innovations were recommended for accelerated development and release of FAW resistant and market-preferred maize varieties.     

Gene flow among different teosinte taxa and into the domesticated maize gene pool

Maize (Zea mays L. ssp. mays) was domesticated from one wild species ancestor, the Balsas teosinte (Zea mays ssp. parviglumis) about 9000 years ago. Higher levels of gene diversity are found in teosinte taxa compared to maize, following domestication and selection bottlenecks. Diversity in maize can be increased via gene flow from teosinte, which has certainly occurred from various taxa, but the rate of flow from different teosinte taxa and the final impact on maize evolution has been difficult to measure. One hundred populations from six Zea taxa, both domesticated (maize) and wild (teosinte), including domesticated landraces from Asia, Africa, and the Americas, were genotyped with 17 SSR markers using 15 individuals per population. Overall levels of diversity were high, and populations could be distinguished based on markers. Relationships between populations followed most published reports, or can now help resolve previously conflicting reports. Gene flow into maize from different teosinte groups, and gene flow between different teosintes, was estimated. Evidence for contributions from the Balsas teosintes and from Chalco teosintes (Z. mays ssp. mexicana) to the maize gene pool was found, as well as from Chalco into ssp. mexicana race ??Durango?? and Z. mays ssp. huehuetenengensis. These contributions are almost certainly the result of post-domestication (and ongoing) exchanges. This information must give more impetus to in situ conservation of teosinte species, and use of these teosintes to continue to direct the evolution of maize, especially in response to new diseases, insect pests, and other biotic and abiotic stresses.     

利用RFLP和SSR标记划分玉米自交系杂种优势群的研究

利用RFLP和SSR标记对29个玉米自交系进行杂种优势群划分,筛选出56个多态性RFLP探针酶组合,66对多态性SSR引物,分别在供试材料中检测到187个和232个等位基因变异。两种方法比较表明,SSR标记的平均多态性信息量(PIC,0.54)高于RFLP(0.42);但对供试材料的遗传多样性评价基本一致,平均遗传相似系数(GS)分别为0.64和0.62。综     

Ion,Protein, Phospholipid and Energy Substrate Content of Oviduct Fluid During the Oestrous Cycle of Buffalo (Bubalus bubalis)

The aim of this research was to analyse the composition of oviduct fluid (ODF) in buffalo cows at different oestrous cycle phases to fulfil the requirements of buffalo embryos in vitro. ODF was collected by chronic cannulation from three cows that were synchronized by administering a synthetic prostaglandin. Based on hormonal profiles, the pre‐ovulatory, ovulatory, post‐ovulatory and luteal phases of the oestrous cycle were defined. The volume of ODF produced (ml/24 h) was influenced by the oestrous cycle, with values (mean ± SE) around ovulation (1.0 ± 0.2) greater (p < 0.05) than in both the luteal (0.4 ± 0.1) and the post‐ovulatory phases (0.5 ± 0.1), but not different from the intermediate values in the pre‐ovulatory phase (0.8 ± 0.2). Among cycle phases, no differences were found in sodium, potassium, calcium and magnesium concentrations (130.0 ± 1.1, 5.1 ± 0.3, 2.8 ± 0.1 and 0.59 ± 0.04 mmol/l respectively). Interestingly, the chloride secretion (μm /24 h) was higher (p < 0.05) at ovulation (150.2 ± 16.5) than during both the luteal (73.7 ± 22.0) and the post‐ovulatory phases (63.7 ± 11.2), with intermediate values in the pre‐ovulatory phase (113.4 ± 23.5). Glucose concentration (mmol/l) was higher (p = 0.056) in the pre‐ovulatory phase (0.06 ± 0.02) than in the luteal (0.02 ± 0.01) and post‐ovulatory (0.02 ± 0.01) phases but not different from values in the ovulatory phase (0.04 ± 0.02). Concentrations of pyruvate and lactate among oestrous cycle phases were similar (0.08 ± 0.01 and 1.0 ± 0.1 mmol/l respectively). The total quantity of phospholipids (μmol/24 h) was greater (p < 0.05) at ovulation (0.21 ± 0.02) compared with the luteal, pre‐ovulatory and post‐ovulatory phases of the cycle (0.09 ± 0.02, 0.13 ± 0.02 and 0.09 ± 0.01 respectively). No differences were found in either the protein concentration (1.8 ± 0.3 mg/ml) or the quantity of proteins secreted in 24 h (1.8 ± 0.4 mg) among oestrous cycle phases. In conclusion, this study provides the first characterization of buffalo ODF during the oestrous cycle, showing species‐specific differences that may be useful for developing suitable media for buffalo in vitro embryo production.     

Corpus Luteum Development and Function after Supplementation of Long‐Acting Progesterone During the Early Luteal Phase in Beef Cattle

Strategic supplementation of P4 may be used to increase conception rates in cattle, but timing of supplementation in relation to ovulation, mass of supplementary P4 and formulation of the P4‐containing supplement has not been determined for beef cattle. Effects of supplementation of long‐acting progesterone (P4) on Days 2 or 3 post‐ovulation on development, function and regression of corpus luteum (CL) were studied in beef cattle. Cows were synchronized with an oestradiol/P4‐based protocol and treated with 150 or 300 mg of long‐acting P4 on Day 2 or 3 post‐ovulation (6–7 cows/group). Colour‐doppler ultrasound scanning and blood sample collection were performed from Day 2–21.5. Plasma P4 concentrations were greater (p < 0.05) from Day 2.5–5.5 in the Day 2‐treated groups and from Day 3.5–5.5 in the Day 3‐treated cows than in the control group. CL area and blood flow during Day 2–8.5 did not differ (p > 0.05) among groups, suggesting no effect of P4 treatment on luteal development. The frequency of cows that began luteolysis before Day 15 was greater (p < 0.04) in cows treated with 300 mg than in the controls, but there were no differences between non‐treated and 150 mg‐treated cows. The interval from pre‐treatment ovulation to functional and structural luteolysis was shorter (p < 0.01) in the combined P4‐treated groups than in the control cows. In conclusion, was showed for the first time that long‐acting P4 supplementation on Day 2 or 3 post‐ovulation increases P4 concentrations for ≥3 day, has no effect on luteal development, but anticipates the beginning of luteolysis in beef cattle.     

Use of Porcine Luteinizing Hormone at Oestrous Onset in a Protocol for Fixed‐Time Artificial Insemination in Gilts

The aim of this study was to evaluate the effect of porcine luteinizing hormone (pLH) given at oestrous onset in gilts, by different routes and doses, on the interval between onset of oestrus and ovulation (IOEO) and reproductive performance using a single fixed‐time artificial insemination (FTAI). A total of 153 gilts were submitted to oestrous detection at 8‐h intervals and assigned to three groups: control – without hormone application and inseminated at 0, 24 and 48 h after oestrous onset; VS2.5FTAI – 2.5 mg pLH by the vulvar submucosal route at oestrous onset and a single FTAI 16 h later; IM5FTAI – 5 mg pLH by the intramuscular route at oestrous onset and a single FTAI 16 h later. More VS2.5FTAI gilts (47.1%; p < 0.05) ovulated within 24 h after oestrous onset than control gilts (25.5%) whereas IM5FTAI gilts had an intermediate percentage (31.4%; p > 0.05). The IOEO tended to be shorter (p = 0.06) in VS2.5FTAI (30.2 ± 1.4 h) than in control (34.7 ± 1.4 h) gilts, but there was no difference (p > 0.05) between control and IM5FTAI (32.8 ± 1.4 h) gilts. Farrowing rate was not different (p > 0.05) among treatments. Total born piglets (TB) was lower (p < 0.05) in VS2.5FTAI (12.3 ± 0.4) than in control gilts (14.1 ± 0.4), whereas intermediate TB was observed in IM5FTAI gilts (13.3 ± 0.4). Due to the advancement of ovulation, reduction of the hormonal dose and the ease of application, the vulvar submucosal route would be the best option for FTAI protocols, but their negative impact on litter size remains to be elucidated. Taking into account the good fertility results obtained in IM5FTAI gilts whose ovulation was not advanced, the possibility of a single FTAI without any hormonal treatment should be further investigated, to establish reliable FTAI protocols for gilts.     

On the Quantum Nature of the Shared Proton in Hydrogen Bonds

The relative influence of thermal and quantum fluctuations on the proton transfer properties of the charged water complexes H5O2+ and H3O2- was investigated with the use of ab initio techniques. These small systems can be considered as prototypical representatives of strong and intermediate-strength hydrogen bonds. The shared proton in the strongly hydrogen bonded H5O2+ behaved in an essentially classical manner, whereas in the H3O2- low-barrier hydrogen bond, quantum zero-point motion played a crucial role even at room temperature. This behavior can be traced back to a small difference in the oxygen-oxygen separation and hence to the strength of the hydrogen bond.