Changes in proacrosin levels during preservation of ram semen

The percentual change in the content of pro-acrosin taking place in ram semen preserved for a short and long time was examined in the period from April to October. Two diluents for keeping semen at the temperature of 16 degrees C and one diluent for keeping semen at 3 to 4 degrees C were used in short-time preservation. The content of pro-acrosin was measured 2, 8 and 12 hours after dilution. The lactoso-yolk diluent and the diluent after Milovanov (1980) were used for cryopreservation. The content of pro-acrosin was examined before and after semen freezing. In short-time preservation, no statistically significant decrease of pro-acrosin content was demonstrated in the H Milch diluent (Peter, 1975) at the storage temperature of 16 degrees C and in the diluent after Milovanov (1980) at the temperature of 3 to 4 degrees C. In the diluent prepared after Milovanov (1980) a significant decrease of pro-acrosin content during preservation was recorded at the storage temperature of 16 degrees C. When the short-time preservation diluents were compared, significant differences in pro-acrosin content were found between them. In the long-time preservation diluents a significant difference in pro-acrosin content was found before and after semen freezing; the difference between the short- and long-time preservation diluents was also significant. A positive correlation was found between sperm activity and pro-acrosin content.     

抗氧化剂在哺乳动物精液冷冻保存中的应用

从20世纪50年代哺乳动物精液冷冻研究开始,国内外研究者通过几十年对精液冷冻程序以及冷冻稀释液、解冻液等的筛选,牛、羊等家畜的冷冻精液已经商业化生产,广泛用于人工授精进行优良品种的繁殖.     

Effects of seasons on some semen parameters and bacterial contamination of Awassi ram semen

The objectives of the present study were to determine the effects of season on some semen parameters and bacterial contamination of Awassi ram semen. Semen samples from six mature Awassi rams were used in this study. Semen collection was performed with artificial vagina every week, from September 2009 to October 2010. Volume, sperm concentration, mass motility, individual motility, percentage live sperm and sperm abnormalities were evaluated. Moreover, determination of viable bacterial count of the rams was also recorded weekly. Higher (p < 0.05) semen volume in the hot summer and spring months was observed of August (1.55 ± 0.08 ml) and March (1.27 ± 0.15 ml). Sperm concentration was highest (p < 0.05) in the breeding season (late summer to early autumn) of September (4.21 ± 0.86 × 10(9) sperm/ml). Sperm individual motility and percent of live sperm observed in August (summer) and May (end of spring) when the environmental temperature started to increase were recorded highest values and differed significantly (p < 0.05) from December and January (winter). The highest value of the mean sperm acrosomal defects (13.33 ± 0.63%) was recorded in December. The highest value of the mean viable bacterial count (138.3 ± 21.6) was recorded in July (summer). A significant decrease (p < 0.01) in the mean viable bacterial count was observed from the middle of winter towards the end of spring. The lowest bacterial count was noted in January (60.5 ± 2.98). It could be concluded from the results of the present study that there is an effect of season on ram semen quality, and summer high temperature in northern Iraq has no effect on Awassi ram semen. There is a significant effect of season on bacterial count on Awassi ram semen.     

用澳洲美利奴种公羊细管冻精改良当地绵羊试验效果

为了提高五大连池市绵羊的生产性能,解决绵羊种公羊短缺、种质差、近亲繁殖等问题,从1998年引进澳洲美利奴种公羊的细管冻精改良当地绵羊,近几年来,改良效果明显,现将试验效果报告如下。     

Effects of bovine serum albumin and trehalose in semen diluents for improvement of frozen-thawed ram spermatozoa

In this study, two following experiments were performed to improve post-thaw motility and viability of frozen-thawed ram spermatozoa. We examined i) the effects of different concentrations of bovine serum albumin (0, 0.3, 1, 5, 10 and 15% BSA) in semen diluents lacking egg yolk and ii) the effects of four semen diluents, fructose (F: control) and trehalose (T) in semen diluents containing egg yolk, 15% BSA in semen diluents without egg yolk (BSA), and modified phosphate buffered saline (m-PBS). Frozen-thawed spermatozoa were examined for progressive sperm motility, viability, morphological abnormality, sperm tail swelling test, and sperm acrosome integrity. In Experiment 1, the rates of sperm motility immediately after thawing (0 h) were significantly (P<0.05) higher in the 10 and 15% BSA groups (55.0 +/- 2.9 and 58.3 +/- 6.7%, respectively) than in the positive control (F) group (41.7 +/- 4.4%). The rate of sperm viability in the negative control (0% BSA) group (80.2 +/- 3.3%) was significantly (P<0.05) lower than in the positive control (F) group (89.8 +/- 1.5%), but when compared with the F group, no significant differences were found among the 0.3, 1, 5, 10 and 15% BSA groups at 0 h. The rates of sperm morphological abnormality of the 10 and 15% BSA groups (6.5 +/- 1.3 and 6.3 +/- 1.1%, respectively) were significantly (P<0.05) lower at 0 h than that in the 1% BSA group (16.3 +/- 5.2%). In Experiment 2, T addition improved (P<0.05) the post-thaw motility compared with the F and BSA groups. Furthermore, at 3 and 6 h, the post-thaw motility of the T group (36.3 +/- 2.4 and 25.0 +/- 2.0%, respectively) was significantly (P<0.05) higher than in the BSA (26.3 +/- 2.4 and 18.8 +/- 1.3%, respectively) and F (28.8 +/- 3.8 and 18.8 +/- 2.4%, respectively) groups. The post-thaw sperm motility and viability in the m-PBS group were significantly (P<0.05) lower than those of the control (F), T, and BSA groups throughout all observation points. These results indicate that 10 and 15% BSA can be substituted for egg-yolk for ram semen diluent and that the addition of trehalose enhances motility and viability of ram spermatozoa after freezing and thawing.     

Conception rates in ewes after AI with ram semen preserved in milk-egg yolk extenders supplemented with glycerol

This study aimed at comparing the effect of ram semen preserved at 5°C on two milk‐based extenders (UHT skim milk or INRA‐96^®, 5% egg yolk) supplemented with 2% glycerol, and the preservation time (24 and 48 h) on conception rates after cervical AI of ewes. In two field trials, 1198 Merino ewes were cervical AI in spontaneous oestrus. In Experiment 1, pooled semen (6 rams) was extended in UHT‐base (fresh, control) or chilled for 24 h in UHT5Y (UHT‐base 5% egg yolk), INRA5Y (INRA‐96^® 5% egg yolk), UHT5Y2G (UHT5Y 2% glycerol) or INRA5Y2G (INRA5Y 2% glycerol). In Experiment 2, AI was performed with pooled semen (7 rams) used fresh (extended in UHT‐base or UHT5Y2G, control groups) or chilled (extended in UHT5Y2G) for 24 or 48 h. Conception rate was determined by ultrasound 40 days after AI. INRA‐96^®– had similar conception as UHT‐preserved semen (56.7 vs 55.4%, p > 0.05). Addition of 2% glycerol did not modify the results (56.8 vs 55.2%, p > 0.05). Fresh semen extended in UHT‐base, and UHT5Y2G yielded similar conception rates (60 vs 64%, p > 0.05). Preservation for 24 or 48 h in UHT5Y2G gave similar results (49 vs 47%; p > 0.05). In conclusion, ram semen chilled for 24 h in UHT‐ or INRA‐96^®‐based extenders yielded similar results, and glycerol addition did not have a detrimental effect. UHT5Y2G might be used to extend ram semen for fresh AI, or to preserve it for 24 or 48 h with acceptable results.     

Influence of supplementing diet with Oleic and Linoleic acid on the freezing ability and sex-sorting parameters of ram semen

In an effort to improve the cryosurvival of both non-sorted and sex-sorted ram spermatozoa the effect of supplementing the ram diet with Oleic and Linoleic acid, in the form of extra virgin olive oil and sunflower oil, respectively, was assessed. Rams (n = 4/group) were fed either (i) a standard maintenance diet (Control), (ii) maintenance diet + 5% (w/w) sunflower oil (Linoleic), or (iii) maintenance diet + 5% (w/w) extra virgin olive oil (Oleic) for a period of 6 weeks. The effect of these diets on the post-thaw (incubated 37 °C, 6 h) motility characteristics (as measured by CASA) of non-sorted, frozen-thawed ram spermatozoa were assessed every 2 weeks. The sex-sorted, frozen–thawed spermatozoa were assessed at the end of the 6 week trial period in the same manner. Linoleic and Oleic diets had a negative impact (P < 0.05) on the total sperm motility, viability and acrosome integrity after a 6 week period of dietary supplementation. Furthermore, the average path velocity and straight line velocity of spermatozoa from Oleic-fed rams was less when compared to samples originating from rams fed linoleic acid or the control diets after both 2 and 6 weeks post-diet modification. Curvilinear velocity of oleic spermatozoa 2 weeks post diet modification were inferior for Oleic—(P < 0.05) compared with Linoleic—but not control-fed rams. Spermatozoa from rams fed Oleic diets exhibited lower (P < 0.05) linearity than spermatozoa from rams fed Linoleic acid (2, 4 and 6 weeks) or the control diets (6 weeks). Diet did not significantly affect any motility characteristic or the viability/acrosome integrity of sex-sorted spermatozoa. Nutritional supplementation with the mono-unsaturated fatty acid, Oleic acid, or the polyunsaturated fatty acid, Linoleic acid, did not improve the cryosurvival of ram spermatozoa — whether or not it had been processed for sex-sorting by flow cytometry. However, these results provide insight into the relationship between nutrition and male reproductive characteristics and further research to elucidate the mechanisms by which diet manipulation affects sperm membranes and subsequent sperm quality is warranted.     

Pathology of varicocele in the ram

A total of 40 mature or aged rams with spontaneous varicocele detected by scrotal palpation were subjected to detailed necropsy examination. Varicocele was bilateral in 22 rams or was located on the left or right sides only, in 8 and 10 rams, respectively. This distribution contrasted with varicocele in man in which the left side is involved in 70 to 100% of cases. Mean sizes of varicoceles in mm (length x diameter) were 117 x 46 and 104 x 45 for the left and right sides, respectively, and they were located high in the pampiniform plexus, approximately 100 mm from the dorsal pole of the corresponding testis. All varicoceles were thrombosed. Changes associated with large varicoceles included testicular mineralisation and occluding thrombosis of testicular vessels. Total testis weight-bodyweight ratio in rams with varicocele (5.8 to 6.4 x 10(-3] was significantly less (P less than 0.05) than in normal (control) rams from the same flocks (7.9 x 10(-3] suggesting that some degree of testicular atrophy resulted from presence of a varicocele.     

Comparative antiviral and proviral factors in semen and vaccines for preventing viral dissemination from the male reproductive tract and semen

Many animal and human viruses are disseminated via semen, but there is little information on how to measure and stimulate protective antiviral immunity in the male reproductive tract and semen. This information is important since successful vaccination through the stimulation of protective immune responses could be a mechanism to prevent viral contamination of semen and subsequent wide spread viral dissemination. Even control of the infection by shortening the duration of viral shedding and lowering the viral load in semen would lessen the chances of viral dissemination through this route. This review will highlight the current knowledge of immunity in the male reproductive tract and summarize 'antiviral' as well as 'proviral' factors in semen such as cytokines, cells, antibodies, antimicrobial peptides, enzymes, hormones and growth factors. These factors must provide a fine balance between 'immunosuppression' in semen needed to protect sperm viability and 'immunocompetency' to prevent pathogen contamination. The review will also suggest continuing challenges to researchers for preventing viral dissemination via semen and propose a large animal model for continued research in this important area.     

Comparative evaluation of the fluorescent antibody test and microtiter immunoperoxidase assay for detection of bovine viral diarrhea virus from bull semen.

An indirect immunoperoxidase staining technique (IP) is described for the detection of bovine viral diarrhea virus (BVDV) in bovine semen. The performance of the IP was compared to the reference immunofluorescent staining test in its ability to detect BVDV in 23 coded field semen samples. The IP assay which can be applied with ease to a large number of samples and does not require expensive fluorescence microscope equipment, appears to be an alternative method for BVDV detection. The IP assay can be strongly recommended for certification of BVDV-free bovine semen for artificial insemination and trading purposes and for laboratories which are not equipped for performing the immunofluorescent test.     

Influence of methionine and dithioerythritol on sperm motility, lipid peroxidation and antioxidant capacities during liquid storage of ram semen

The aim of this study was to investigate the effects of methionine and dithioerythritol, added to the Tris extender, on ram sperm motility and LPO (lipid peroxidation) and antioxidant capacities during liquid storage up to 72 h at 5 °C. Ejaculates collected from five Merino rams, were evaluated and pooled at 37 °C. This study included two experiments. In experiment 1, each pooled ejaculate was divided into four equal aliquots and diluted (37 °C) with the base extender, containing 0 (control), 1, 2 and 4 mM methionine, at a final concentration of approximately 4 × 10⁸ sperms/ml (single step dilution), in a 15-ml plastic centrifuge tube. In experiment 2, dithioerythritol, at concentrations of 0 (control), 0.5, 1 and 2 mM, was used as an additive in the extender, and the procedure explained above was applied for the division of aliquots and the dilution of semen. Diluted semen samples were kept in glass tubes and cooled from 37 to 5 °C in a cold cabinet, and maintained at 5 °C. Sperm motility and LPO and total glutathione (GSH) and glutathione peroxidase (GPx) capacities were determined at 5 °C for periods of 0, 24, 48 and 72 h of liquid storage.The extender supplemented with 1 mM methionine led to higher motility percentages (77.0 ± 1.2%), in comparison to the control group (66.0 ± 4.9%), during 72 h of liquid storage (P < 0.05). As regards dithioerythritol, it did not statistically improve the motility rates for any of the storage times at 5 °C. In biochemical assays, differences in LPO levels between the groups with antioxidants and the control groups were not statistically significant. Compared to the control group, no significant difference was observed in GSH and GPx activities following the addition of methionine, during 72 h of storage. Total GSH and GPx activities did not increase significantly upon supplementation with 0.5 and 1 mM of dithioerythritol, compared to the control group, at any of the time points (P > 0.05). Dithioerythritol at 2 mM led (P < 0.01) to elevating GSH activity, compared to the control group, during 72 h of liquid storage. GPx activity was approximately 10 times higher for 2 mM of dithioerythritol (P < 0.001), compared to that of the control group at all time points.The question regarding the sustainability of sperm survival, LPO and antioxidant capacities following liquid storage of semen remains unanswered. Further studies are required for a better understanding of the biochemical changes and to obtain more information on the determination of lipid peroxidation and antioxidant capacities during cooled storage of ram semen.     

Progesterone plus PMSG Priming in seasonally anovulatory lactating Sarda ewes exposed to the ram effect

The aim of this trial was to evaluate the effectiveness (fertility and lambing) of priming with a single injection of progesterone plus PMSG in anovulatory lactating Sarda ewes subjected to the ram effect (RE) in spring. Thirty ewes (P4 group) were i.m. injected with 30 mg progesterone and 500 IU PMSG 36 h before ram introduction (d 0). This treatment was compared to a 12-day treatment with fluorogestone acetate intravaginal sponges that was followed by injections of 350 IU PMSG upon sponge withdrawal (FGA group, n=30). All ewes responded to RE, showing plasma progestrone concentrations >1 ng/mL between d 6 and 12 (FGA) or 6 and 9 (P4). Eighty-nine percent of the P4 ewes conceived at first ovulation, and 11% conceived following a short estrus cycle. Lambings occurred on d 150.4 +/- 3.9, and the lambing rate was 100%. The fertility of the FGA ewes was 83% for the induced ovulation and was 7% for the second ovulation after a normal cycle. The FGA ewes lambed on d 149.8 +/- 4.4, and the lambing rate was 83%. Two abortions were recorded for the FGA ewes, which had higher prolificacy than the P4 group (2.2 +/- 0.8 vs. 1.8 +/- 0.4, respectively; P<0.05). Both fertility and the lambing rate were high in both groups, with a high degree of estrus synchronization, and there were no significant differences between the groups. We concluded that priming of lactating Sarda ewes in spring with P4+PMSG before RE is an effective and competitive method (cheaper and more practical than FGA+PMSG) of inducing fertile ovulations in these ewes.     

饲料抗氧化剂作用机理及其活性评价方法研究进展

饲料内的脂类化眢物在储存过程中不断的进行氧化反应,造成饲料的感光性质下降、营养价值降低、储存期缩短和适口性下降。氧化严重的可以导致饲料酸败、蛋白质破坏和色素氧化。而且还具有一定的毒性,对畜禽造成一定程度的危害。常常给饲料行业和畜禽养殖业带来较大的损失。抗氧化剂（Antioxidant）是一类能够有效阻止或者延缓脂类化合物自动氧化的物质,是指在相对可氧化底物（糖类、脂质、DNA或蛋白质等）浓度更低的情况下,能有效地延缓或阻止底物发生氧化反应的物质（Halliwell,1990）,是饲料工业生产中不可缺少的一种添加剂。但目前对抗氧化剂作用机理及其活性评价方法的研究尚不多见．本文就饲料用抗氧化剂的作用机理及其活性的评价方法做一综述。