The impact of ovulation mode on sperm quantity and quality in mammals

Ovulation generally takes two forms: spontaneous and induced. These two ovulatory modes are predicted to cause different levels of male–male competition due to differences in males’ ability to predict the timing of ovulation of females that use each mode. Ovulation mode has been shown to be correlated with differences in testis size, but it is not known whether ovulation type influences ejaculate traits, specifically sperm quantity (sperm concentration, ejaculate volume, total motile sperm per ejaculate) and/or sperm quality (% sperm motility, % normal sperm). Using a cross-species comparative analysis of 130 mammals, we found that sperm concentration and total motile sperm per ejaculate were significantly greater in spontaneous ovulators. In contrast, ejaculate volume, % sperm motility and % normal sperm were unrelated to ovulation type. These data show that ovulation alters sperm quantity by increasing sperm concentration but not ejaculate volume, and that sperm quality does not vary with ovulation mode.     

Sperm competition selects for sperm quantity and quality in the Australian Maluridae

When ejaculates from rival males compete for fertilization, there is strong selection for sperm traits that enhance fertilization success. Sperm quantity is one such trait, and numerous studies have demonstrated a positive association between sperm competition and both testes size and the number of sperm available for copulations. Sperm competition is also thought to favor increases in sperm quality and changes in testicular morphology that lead to increased sperm production. However, in contrast to sperm quantity, these hypotheses have received considerably less empirical support and remain somewhat controversial. In a comparative study using the Australian Maluridae (fairy-wrens, emu-wrens, grasswrens), we tested whether increasing levels of sperm competition were associated with increases in both sperm quantity and quality, as well as an increase in the relative amount of seminiferous tubule tissue contained within the testes. After controlling for phylogeny, we found positive associations between sperm competition and sperm numbers, both in sperm reserves and in ejaculate samples. Additionally, as sperm competition level increased, the proportion of testicular spermatogenic tissue also increased, suggesting that sperm competition selects for greater sperm production per unit of testicular tissue. Finally, we also found that sperm competition level was positively associated with multiple sperm quality traits, including the proportion of motile sperm in ejaculates and the proportion of both viable and morphologically normal sperm in sperm reserves. These results suggest multiple ejaculate traits, as well as aspects of testicular morphology, have evolved in response to sperm competition in the Australian Maluridae. Furthermore, our findings emphasize the importance of post-copulatory sexual selection as an evolutionary force shaping macroevolutionary differences in sperm phenotype.     

不同禁欲时间对少精、弱精精液质量的影响

目的:了解不同禁欲时间对少精、弱精精液质量的影响,为临床治疗不育提供参考。方法:对正常精液、少精症、弱精症患者分别根据禁欲天数随机分成两组,禁欲2-4天为A组,禁欲5-7天为B组,对上述各组进行精液分析。结果:在正常组、少精组及弱精组中,A组的精液量、精子密度及精子总量低于B组,A组a b级精子百分率高于B组,差异有统计学意义。在少精组及弱精组中A组精子正常形态率高于B组,差异有统计学意义。结论:正常精液及弱精症患者禁欲2-4天的精液质量最好,少精症患者禁欲5-7天的精液质量最好。     

The role of antioxidants in sperm freezing: a review

Cryopreservation of spermatozoa is becoming more important because of new clinical requirements and current clinical practice. Despite the success of sperm cryopreservation this routinely used procedure induces serious detrimental changes in sperm function. Some researchers believe that cryopreservation is associated with DNA fragmentation and DNA single strand breaks in sperm. Mechanisms of cryodamage to human spermatozoa are thought to be multifactorial including: cold shock, osmotic stress, intracellular ice crystal formation, oxidative stress, and combinations of these conditions. Additives showing antioxidative properties reported to reduce the impact of ROS-induced and cold shock damages. Many studies exist as regards the effects of antioxidants on the cryopreservation aimed at improving the quality of post-thaw semen. Hence, this review will clarify results of recent applications of various antioxidants used in numerous research efforts to improve cryopreservation of spermatozoa. This review is to increase the understanding of the roles of these antioxidants concerning mechanisms which enhance resistance to cryodamage of spermatozoa.     

Approaches to influence starch quantity and starch quality in transgenic plants

Starch plays a major role as a transitory and long-term storage compound in higher plants, and therefore is of prime importance for plant growth and development. Additionally, starch serves as a widely used material for a variety of industrial uses. The formation of starch can arbitrarily be divided into three types of event: (I) those leading to the supply of glucose-1-phosphate in the plastids; (II) the conversion of glucose-1-phosphate to ADP-glucose catalysed by the enzyme ADP-glucose pyrophosphorylase; and (III) the enzymatic reactions converting ADP-glucose to long-chain glucans (amylopectin, amylose). In recent years, numerous cDNA and genomic sequences encoding enzymes involved in starch metabolism have been identified. Some of these have been used to down-regulate enzyme activities via the antisense RNA technique. Additionally, bacterial genes have been ectopically expressed in transgenic plants in order to increase corresponding enzyme activities. By modulating the activity of ADP-glucose pyrophosphorylase in plastids, it was possible to decrease and increase, respectively, the starch content in source and sink organs of transgenic plants. In addition, down-regulation of granule-bound starch synthase (isoform I) resulted in the production of starch that was almost completely free of amylose. Further experiments aimed to modulate starch structure are currently underway and will briefly be discussed.     

Effect of maca supplementation on bovine sperm quantity and quality followed over two spermatogenic cycles

Maca (Lepidium meyenii Walpers), is an Andean crop that grows between 3,800 and 4,500 m a.s.l. The persistent interest in this plant is based on its assumed effects on fertility of male mammals due to the prevalence of certain, partially specific, secondary compounds. The present study aimed at evaluating the effect of maca supplementation on quality and quantity of semen, mating behavior, and clinical status of peripubertal breeding bulls. The experiment followed a cross-over design lasting for 23 wk with 3 wk of adaptation and baseline measurements, and 2 × 10 wk of treatment feeding thus covering two times the complete 8-wk spermatogenic cycle. Seventy-eight 55 wk to 84 wk old breeding bulls received either no maca (control) or maca (233 mg dried hypocotyls/kg body weight/day) for 10 wk followed by 10 wk without maca (maca early) or maca only in the last 10 wk (maca late). Measurements were always made in the last 2 wk of each period. Apart from standard analyses, ejaculates were analyzed by flow cytometry. Data was evaluated by analysis of variance considering the repeated measurement structure of the data. Significant treatment by measurement period indicated direct or carry-over effects of maca. Maca supplementation had no direct effect on body weight, testes circumference, rectal temperature, mating behavior, and ejaculate volume. However, supplementing maca in the first 10 wk period increased the number of sperms in the second 10 wk period, i.e., when the animals no longer received maca. The DNA fragmentation index and the visually assessed motility of the sperms of bulls, that initially showed a borderline sperm quality, were significantly improved with early maca supplementation, while no such effect was observed in the two other groups. No effects occurred in the proportion of intact sperm plasma membranes or acrosomes or both. In conclusion, maca supplementation seems to improve sperm quantity and quality of bulls to a certain degree, while mating behavior appears unaffected.     

Evolution of sperm quality but not quantity in the internally fertilized fish Xiphophorus nigrensis

Abstract Species with alternative reproductive strategies are characterized by discrete differences among males in suites of traits related to competition for fertilizations. Models predict sneaker males should allocate more resources to their ejaculates because they experience sperm competition more frequently and often occupy a disfavoured ‘role’ owing to subordinance in intramale competition and female preferences for larger males. We examined whether sperm number and quality differed between male strategies in the internally fertilized fish Xiphophorus nigrensis and explored the relationship between sperm morphology and performance. We found sneaker males had similar testes sizes compared to courting males but ejaculates with both more viable and longer lived sperm. Sneaker sperm also had longer midpieces, which was positively correlated with both velocity and longevity. Our study suggests that the evolution of sperm quantity and quality can be decoupled and that the sperm morphology is likely to play an important role in mediating sperm competition through its effects on sperm performance.     

Green roof performance towards management of runoff water quantity and quality: A review

This review paper addresses the role of green roofs in urban drainage considering both management of water quantity and quality. Results from investigation of full scale installations as well as from laboratory models are reviewed. The following factors affecting runoff dynamics from green roofs are discussed: type of green roof and its geometrical properties (slope); soil moisture characteristics; season, weather and rainfall characteristics; age of green roof; vegetation. Design parameters as suggested by different authors are also reviewed. Factors which affect influence of a green roof on runoff water quality are discussed in general terms followed by the review of data regarding concentrations of phosphorus, nitrogen, and heavy metals in green roof runoff, its’ pH, and first flush effect. Linking among fertilization, runoff pollution and vegetation development is given a particular focus. The review indicates clearly that there is a need for more research into a green roof performance in an urban environment. The differences measured by few existing studies between the early years performance of green roofs and the later years indicate a need for long term monitoring of green roofs.     

Supply determines demand: influence of partner quality and quantity on the interactions between bats and pitcher plants

Interspecific relationships such as mutualism and parasitism are major drivers of biodiversity. Because such interactions often comprise more than two species, ecological studies increasingly focus on complex multispecies systems. However, the spatial heterogeneity of multi-species interactions is often poorly understood. Here, we investigate the unusual interaction of a bat (Kerivoula hardwickii hardwickii) and two pitcher plant species (Nepenthes hemsleyana and N. bicalcarata) whose pitchers serve as roost for bats. Nepenthes hemsleyana offers roosts of higher quality, indicated by a more stable microclimate compared to N. bicalcarata but occurs at lower abundance and is less common than the latter. Whereas N. hemsleyana benefits from the roosting bats by gaining nitrogen from their feces, the bats’ interaction with N. bicalcarata seems to be commensal or even parasitic. Bats stayed longer in roosts of higher quality provided by N. hemsleyana and preferred them to pitchers of N. bicalcarata in a disturbance experiment. Moreover, bats roosting only in pitchers of N. hemsleyana had a higher body condition and were less infested with parasites compared to bats roosting in pitchers of N. bicalcarata. Our study shows how the local supply of roosts with different qualities affects the behavior and status of their inhabitants and—as a consequence—how the demand of the inhabitants can influence evolutionary adaptations of the roost providing species.     

Supplementation of prebiotics in fish feed: a review

Aquaculture is one of the fastest growing industries in the world. There is a need for enhanced disease resistance, feed efficiency and growth performance of cultured fish species. The cost of production are likely to be reduced if growth performance and feed efficiency are increased in commercial aquaculture. Also if the survivility of the fishes increase, then their overall production cost would be remarkably reduced. Dietary supplementation of different feed additives e.g. immunostimulants, probiotics and prebiotics usually in small quantities for the purpose of fortifying it with certain nutrients have been found to be beneficial for improving immune status, feed efficiency and growth performance of crustaceans and finfishes. The present article was constructed to highlight the effect of dietary prebiotics on different body growth parameters of fish. However, the application of prebiotics and supplementary enzymes in fish feed is now gradually gaining importance in commercial aquaculture practices, the article stresses on the effect of prebiotics on live body weight gain, dressing percentage, weight of vital organs and muscles and mean villus lengths in digestive tract of fish along with their application as growth promoters in commercial aquafeed (Gatesoupe in Aqua Feeds Formul Beyond 2(3):3–5, 2005; Ganguly et al. in Israeli J Aquac Bamidgeh 62(3):130–138, 2010a, Fish Chimes 30(7):64, 2010b).     

Information from pharmaceutical companies and the quality, quantity, and cost of physicians' prescribing: a systematic review

Background

Pharmaceutical companies spent $57.5 billion on pharmaceutical promotion in the United States in 2004. The industry claims that promotion provides scientific and educational information to physicians. While some evidence indicates that promotion may adversely influence prescribing, physicians hold a wide range of views about pharmaceutical promotion. The objective of this review is to examine the relationship between exposure to information from pharmaceutical companies and the quality, quantity, and cost of physicians'' prescribing.

Methods and Findings

We searched for studies of physicians with prescribing rights who were exposed to information from pharmaceutical companies (promotional or otherwise). Exposures included pharmaceutical sales representative visits, journal advertisements, attendance at pharmaceutical sponsored meetings, mailed information, prescribing software, and participation in sponsored clinical trials. The outcomes measured were quality, quantity, and cost of physicians'' prescribing. We searched Medline (1966 to February 2008), International Pharmaceutical Abstracts (1970 to February 2008), Embase (1997 to February 2008), Current Contents (2001 to 2008), and Central (The Cochrane Library Issue 3, 2007) using the search terms developed with an expert librarian. Additionally, we reviewed reference lists and contacted experts and pharmaceutical companies for information. Randomized and observational studies evaluating information from pharmaceutical companies and measures of physicians'' prescribing were independently appraised for methodological quality by two authors. Studies were excluded where insufficient study information precluded appraisal. The full text of 255 articles was retrieved from electronic databases (7,185 studies) and other sources (138 studies). Articles were then excluded because they did not fulfil inclusion criteria (179) or quality appraisal criteria (18), leaving 58 included studies with 87 distinct analyses. Data were extracted independently by two authors and a narrative synthesis performed following the MOOSE guidelines. Of the set of studies examining prescribing quality outcomes, five found associations between exposure to pharmaceutical company information and lower quality prescribing, four did not detect an association, and one found associations with lower and higher quality prescribing. 38 included studies found associations between exposure and higher frequency of prescribing and 13 did not detect an association. Five included studies found evidence for association with higher costs, four found no association, and one found an association with lower costs. The narrative synthesis finding of variable results was supported by a meta-analysis of studies of prescribing frequency that found significant heterogeneity. The observational nature of most included studies is the main limitation of this review.

Conclusions

With rare exceptions, studies of exposure to information provided directly by pharmaceutical companies have found associations with higher prescribing frequency, higher costs, or lower prescribing quality or have not found significant associations. We did not find evidence of net improvements in prescribing, but the available literature does not exclude the possibility that prescribing may sometimes be improved. Still, we recommend that practitioners follow the precautionary principle and thus avoid exposure to information from pharmaceutical companies. Please see later in the article for the Editors'' Summary     

The sperm chromatin structure assay: a review of clinical applications

The sperm chromatin structure assay (SCSA) was introduced by as a method to determine the susceptibility of sperm DNA to denaturation and how those results related to fertility. This initial study used human sperm and was followed by studies in bulls and boars . This assay was one of the first to introduce the technique of flow cytometry, which has the ability to evaluate specific sperm compartments of large numbers of sperm in a short time, as a methodology to evaluate sperm quality and further define the relationship of sperm quality to fertility. For any assay to be of use clinically, it must not only be validated and adapted for the species of interest, but guidelines that associate specific levels of fertility with assay results must be defined. This review will describe how our laboratory uses the SCSA for clinical diagnosis of reduced fertility in the stallion.     

The effect of climate change on the occurrence and prevalence of livestock diseases in Great Britain: a review

There is strong evidence to suggest that climate change has, and will continue to affect the occurrence, distribution and prevalence of livestock diseases in Great Britain (GB). This paper reviews how climate change could affect livestock diseases in GB. Factors influenced by climate change and that could affect livestock diseases include the molecular biology of the pathogen itself; vectors (if any); farming practice and land use; zoological and environmental factors; and the establishment of new microenvironments and microclimates. The interaction of these factors is an important consideration in forecasting how livestock diseases may be affected. Risk assessments should focus on looking for combinations of factors that may be directly affected by climate change, or that may be indirectly affected through changes in human activity, such as land use (e.g. deforestation), transport and movement of animals, intensity of livestock farming and habitat change. A risk assessment framework is proposed, based on modules that accommodate these factors. This framework could be used to screen for the emergence of unexpected disease events.     

Two decades of plant-based candidate vaccines: a review of the chimeric protein approaches

Genetic engineering revolutionized the concept of traditional vaccines since subunit vaccines became reality. Additionally, over the past two decades plant-derived antigens have been studied as potential vaccines with several advantages, including low cost and convenient administration. More specifically, genetic fusions allowed the expression of fusion proteins carrying two or more components with the aim to elicit immune responses against different targets, including antigens from distinct pathogens or strains. This review aims to provide an update in the field of the production of plant-based vaccine, focusing on those approaches based on the production of chimeric proteins comprising antigens from human pathogens, emphasizing the case of cholera toxin/E. coli enterotoxin fusions, chimeric viruses like particles approaches as well as the possible use of adjuvant-producing plants as expression hosts. Challenges for the near future in this field are also discussed.     

The influence of fluorides on mouse sperm capacitation

Increasing infertility, due to pathological changes on sperm, has become a serious issue. Eco-toxicological effect of rising concentration of fluorides can be enhanced in the presence of aluminium ions by forming fluorometallic complexes, analogues of phosphate groups that interfere with the activity of G-proteins and P-type ATPases, which are part of several signalling pathways during sperm maturation. In order for sperm to gain fertilizing ability, they must undergo in the female reproductive tract, capacitation that includes tyrosine phosphorylation and consequent actin polymerization. The present paper reports the findings of 3-month oral toxicity in mice of fluorides at the concentrations 0, 1, 10, and 100ppm and their synergic action with aluminium at dose of 10ppm. There were no mortalities, clinical signs of discomfort or body weight loss during the experiment. The analysis revealed, for the concentrations of 10 and 100ppm, abnormalities of spermatogenesis and ability of epididymal spermatozoa to capacitate in vitro, as the result of decreased sperm head tyrosine phosphorylation and actin polymerization. The enhancing overload caused by fluorides represents a potential factor, having an impact on function of sperm, hence contributing to a growing infertility in the human population.     

大型猫科动物饲料结构与日饲量的探索

大型猫科动物(如狮虎)是野生动物园和城市动物园必须配备的骨干动物,它们具有很高的观赏、科普宣传和科研价值。野生动物园在充分发挥其环境保护和动物保护教育功能的同时,也为圈养的野生动物创造了良好的移地生存环境而使它们得到了很好的保护。最直接的证据就是它们的繁殖性能得到了充分的发挥,如成都野生世界从2001年开园至今,大型猫科动物从引进时的20只(东北虎10只非洲狮10只)增至目前的72只。随着动物种群和数量的不断扩大,同时也给企业带来了沉重的饲料成本负担。     

Historical review and insights on the livestock tick-borne disease research of a developing country: The Philippine scenario

Tick-borne diseases (TBDs) remain to be a global animal health threat. Developing countries like the Philippines is not exempt to this. Despite the potential impact TBDs can give to these countries, local government initiatives and researches remain to be limited. In the Philippines, most epidemiological studies were confined only to specific areas, and predominantly in the Northern Area. Due to its unique geography and limited studies, the current nationwide status of most TBDs could not be clearly established. This review mainly covered published studies and presented challenges in the conduct of TBD research in the Philippines, which may be similar to other Southeast Asian or developing countries. To date, reported livestock TBD pathogens in the Philippines include Anaplasma, Babesia, Theileria, and Mycoplasma spp. With the ubiquitous presence of the Rhipicephalus microplus ticks in the country, it is highly probable that other pathogens transmitted by these vectors could be present. Despite studies on different TBDs in the livestock sector, the Philippine government has not yet heightened its efforts to implement tick control measures as part of the routine animal health program for local farmers. Further studies might be needed to determine the nationwide prevalence of TBDs and the presence of other possible tick species and TBD pathogens. The Philippine scenario may present situations that are similar to other developing countries.