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Effect of antioxidants on motility and morphology of chilled-stored canine semen
No full textINTRODUCTION
Generation of reactive oxygen species and lipid peroxidation of the sperm cell membranes during liquid storage or semen cryopreservation are associated with loss of motility and reduced viability (1). It has been shown that the addition of antioxidants to semen extenders can improve the survival of spermatozoa (2). Antioxidants are present in seminal plasma and inhibit damage induced by free radicals and hydrogen peroxide. In this study, the antioxidants ascorbic acid and catalase were added to dog semen diluted in different extenders. Motility and morphology of spermatozoa during 96h storage at 5°C were investigated.
MATERIALS AND METHODS
Three sexually mature cross-bred male dogs, aged 1 to 6 yrs, were used as the semen donor. Semen was collected by manual stimulation into prewarmed glass tubes. Only the first two fractions of the ejaculate were collected. The percentage of motile spermatozoa was estimated by the CASA (Computer Assisted Semen Analysis) system. Semen smears were stained with fast-green FCF and rose bengal for examination of sperm morphology. Only ejaculates containing a minimum of 70% progressively motile and 50% morphologically normal spermatozoa were included in the study. The three extenders used were egg-yolk-tris (EYT, 3), skim milk (SM, 4), caprogen (CAP, 3) supplemented with antibiotics, with or without antioxidants. The antioxidants were added in the following concentrations: ascorbic acid (0.9 g/L) or catalase (cat, 200,000 U/L). Semen was stored at 5°C for 96h, motility and morphology were evaluated after dilution (0h) and at 6, 24, 48, 72, 96 h of storage. Data were analyzed using general linear model procedure (SAS). A P value <0.05 was considered significant. Values given are least squares means (LSMEAN) + standard error of mean (SEM).
RESULTS AND DISCUSSION
The motility of sperm cells after dilution (0h) was strongly depressed and this was independent of the extender used. This dilution effect was transitory and it was not observed at the following time points. At 96h of storage, the results showed that the extender CAP maintains higher motility (57.6%+6.7) compared to EYT (40.1%+6.7) and SM (30.5%+6.7). The addition of ascorbic acid did not result in any improvement when added to EYT, while it significantly (P<0.05) decreased the motility in SM and CAP. The addition of catalase in CAP significantly increased (62%+6.7; P<0.005) the motility at the end of storage compared to the other extenders (EYT-cat 27.5%+6.7; SM-cat 31.3%+6.7). The beneficial effect of catalase on survival at 96h was only observed when added to the extender CAP (Fig. 1). The positive interaction between CAP and catalase was also clearly evident in the evaluation of the sperm morphology. In fact, this treatment maintains the highest percentage (96.2%+4.9) of morphologically normal cells at 96h.
The present study demonstrated that the addition of catalase to CAP extender reduces the loss of motility of canine spermatozoa after 96h storage at 5°C. Although further research is needed, the presence of antioxidants, such as catalase, in the extender is advisable for the liquid storage of canine semen.
REFERENCES
(1) Alvarez J.G., Touchstone J.C., Blasco L. & Storey B.T. (1987) J. Androl. 8: 338-348. (2) Maxwell W.M.C. & Stojanov T. (1996) Reprod. Fertil. Dev. 8: 1013-1020. (3) Province C.A., Amann R.P., Pickett B.W. & Squires E.L. (1984) Theriogenology 22: 409-415. (4) Kenney R.M., Bergam R.V., Cooper W.L. & Morse G.W. (1975) Proc. 21st Ann. Conv. A.A.E.P.: 327-336
Effects of Galega officinalis L. and Foeniculum vulgare P. Miller on performance of lactating sows
No full textF.I.S.H. mapping in Cattle (Bos taurus) is not yet out of fashion
No full textPhysical mapping of genes by fluorescence in situ hybridization (FISH) seems to be out of fashion in
species whose assembled genome sequences are available. However, in this work we evidence the existence of
errors in gene location in the Btau_4.0 assembly. We show that DFNA5 and CHCHD6 genes are located on
BTA4 and BTA22, respectively, instead of BTA10 and BTA3, as displayed by Btau_4.0. This report emphasizes
the need to verify the data on physical localization of genes in the cattle genome (at least by taking into account
comparative data reported in available papers) and the need to improve the cattle genome assembly. Our results
indicate that FISH mapping in cattle is still useful
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
A new case of Rob (14;17) in cattle
No full textRobertsonian translocations, also called centric fusions, represent the most frequent chromosome anomalies in cattle, and rob (1;29) is the most widespread. However centric fusions involving other chromosomes have been discovered in different cattle breeds. Here we report the appearance of a new case of rob (14;17) in an Italian cattle breed more than ten years from the first and only case observed, and we demonstrate the different origin of this anomaly from the previous case
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