Deniz Yeni

The effect of cysteine and glutathione on sperm and oxidative stress parameters of post-thawed bull semen.

The aim of this study was to determine the effects of antioxidants such as reduced glutathione (GSH) and cysteine in Laiciphose® extender on semen parameters, fertilizing ability, lipid peroxidation (LPO) level and glutathione peroxidise (GPx) activity of post-thawed bull semen. Totally 54 ejaculates of three bulls were used in the study. Five groups, namely; GSH (0.5 and 2 mM), cysteine (5 and 10 mM) and control group, were conducted to test the antioxidants in Laiciphose®. Insemination doses were processed that each 0.25-mL straw contained 15 x 10⁶ sperm. The addition of antioxidants did not present any significant effect on the percentages of post-thaw sperm morphology (acrosome and total abnormalities), subjective, CASA and progressive motilities, as well as sperm motility characteristics (VAP, VSL, VCL, LIN and ALH), compared to the control groups (P > 0.05). GSH 0.5mM (55.5±7.38%) and cysteine 10 mM (48±5.65%) led to lower rates of DNA damage, compared to control (P < 0.05). As regards to MDA level, cysteine at 10 mM dose gave the highest level (4.99±0.44 nmol/L) (P < 0.001). GPx activity was demonstrated to be higher level upon the addition of 5 mM cysteine when compared to the other groups (P < 0.05). With respect to fertility results based on 60-day non-returns, the supplementation of antioxidants did not present significant differences (P > 0.05). The results of this study may provide an useful information for the future studies in this area. So, further studies could be suggested to achieve better information in terms of the DNA damage and fertilizing capacity of bull sperm frozen with effective antioxidants.

The effect of raffinose and methionine on frozen/thawed Angora buck (Capra hircus ancryrensis) semen quality, lipid peroxidation and antioxidant enzyme activities.

The aim of the present study was to determine the effects of different doses of raffinose and methionine on post-thawed semen quality, lipid peroxidation and antioxidant enzyme activities of Angora buck (Capra hircus ancryrensis) sperm following cryopreservation. Ejaculates collected from three Angora bucks were evaluated and pooled at 37 degrees C. Semen samples, which were diluted with a Tris-based extender containing the additives raffinose (2.5, 5, 10mM) and methionine (2.5, 5, 10mM) and an extender containing no antioxidants (control), were cooled to 5 degrees C and frozen in 0.25 ml French straws. Frozen straws were thawed individually at 37 degrees C for 20s in a water bath for evaluation. The freezing extender supplemented with 2.5 and 5mM methionine led to higher percentages of CASA motility (63.6+/-7.0; 63.4+/-3.1%, respectively), in comparison to the controls (P<0.01) following the freeze-thawing process. The addition of antioxidants did not provide any significant effect on the percentages of post-thaw subjective and CASA progressive motilities as well as sperm motion characteristics (VSL and VCL), compared to the control groups (P>0.05). The freezing extender with raffinose (5 and 10mM) and methionine at three different doses (2.5, 5 and 10mM) led to lower percentages of acrosome abnormalities, in comparison to the controls (P<0.001). In the comet test, raffinose (5 and 10mM) and methionine (10mM) gave scores lower than those of the controls, and thereby reduced DNA damage (P<0.05). Malondialdehyde formation was found to be lower (1.8+/-0.1 nmol/L) in the group of 5mM raffinose, compared to the controls following the freeze-thawing process (P<0.01). The additives did not show any effectiveness on the maintenance of SOD, GSH-PX and GSH activities, when compared to the controls (P>0.05). In conclusion, methionine and raffinose play a cryoprotective role against sperm CASA motility, acrosome abnormality and DNA damage. Raffinose 5mM exhibited antioxidative properties, decreasing MDA levels. Further studies are required to obtain more concrete results on the characterization of microscopic parameters and antioxidant activities in cryopreserved goat sperm with different additives.

Influence of sperm concentration on the motility, morphology, membrane and DNA integrity along with oxidative stress parameters of ram sperm during liquid storage

The aim of this study was to determine the influences of two different concentrations in terms of motility, morphology, membrane integrity (viability and HOST response: HE-test; modified hypoosmotic swelling test (HOST) associated with supravital eosin staining test), DNA integrity (COMET assay) and oxidative stress parameters (MDA, malondialdehyde; AOA, total antioxidant activity; GSH, reduced glutathione; NOx, nitric oxide) of liquid stored ram sperm for 5 days. Two different concentrations suitable for laparoscopic and cervical inseminations were employed. A total of 5 Pirlak rams (Daglic × Kivircik, local breed) with satisfactory breeding potential were selected. Semen samples were collected by artificial vagina. Ejaculates were extended to 25 and 100 million sperm per ml with Tris-based egg-yolk (T) extender at room temperature and stored at 4°C. The concentration significantly had effects on motility, morphology, membrane and DNA integrity along with oxidative stress parameters (P<0.05). Overall changes in the motility, morphology, membrane and DNA integrity along with oxidative stress parameters of ram sperm diluted with T in the 100 × 10(6)ml(-1) concentration and preserved at 4°C for a short term was found to be better preservation than that of diluted with T in the 25 × 10(6)ml(-1) concentration. Significant concentration × days of storage interactions were found for all parameters except the NOx. Further studies are required to elucidate the oxidative stress changes on sperm quality parameters in different concentrations during the liquid storage of ram semen.

Reproductive Seasonality in Sheep

Unlike most domestic livestock species, sheep are widely known as animals with marked seasonality of breeding activity. The annual cycle of the daily photoperiod has been identified as the determinant factor of this phenomenon, while environmental temperature, nutritional status and social interactions may modulate it. The aim of this paper is to review the current state of knowledge of reproductive seasonality in sheep. Following general consideration of the importance of seasonal breeding as a reproductive strategy for the survival of the species, the paper describes manifestations of seasonality in both the ram and the ewe. Both determinant and modulating factors are discussed, and special emphasis is given to the neuroendocrine base of photoperiodic regulation of seasonal breeding. Other aspects such as the role of melatonin, the progestogens and ram effects with or without anestrus period are also reviewed.

Effect of α-lipoic acid on sperm quality, reproductive tract measures in thinner exposed rats.

The aim of this study was to investigate the effect of alpha lipoic acid (ALA, an universal antioxidant) on thinner‐induced testicular toxicity regarding spermatological features, body and reproductive tract measures in rats. Adult male Sprague‐Dawley rats were divided into five treatment groups, eight rats in each. Control group was treated with placebo. Group O was given only olive oil. The group L received only α‐lipoic acid. Thinner + Lipoic Acid group received thinner + α‐lipoic acid and group T received only thinner. Thinner alone administration caused significant decreases in body and some reproductive organ weights, sperm count, motility and sperm membrane integrity, and significant increases in seminal vesicle weight and abnormal sperm rates compared with the values in the control group. However, concomitant administration of thinner with α‐lipoic acid provided significant improvements in sperm parameters compared with values in alone group T. In conclusion, the results of this study suggest that α‐lipoic acid has a protective effect against thinner‐induced reproductive dysfunction in male rats.

Relationships Age and Pregnancy Rates with Certain Oestrus Characteristics at the Insemination Time in Holstein Cows

Sunulan arastirmada saha sartlarinda ostrus gosteren ineklerde gebelik uzerine tohumlama esnasindaki bazi ostrus belirtilerinin yasa gore etkisini karsilastirmak amaclanmistir. Bu calismada 96 Holstayn inek kullanildi, bazi ostrus bulgulari gozle muayene ve klinik testlerle degerlendirildikten sonra tum ineklere dondurulmus-cozdurulmus sperma ile suni tohumlama yapildi. Butun hayvanlarda dominant follikulun soldan (%38.54) cok sag (%61.46) ovaryumda yerlestigi ancak yerlesimin gebelik orani uzerine etkisinin gozlenmedigi belirlendi (p<0.01). Bununla beraber, butun hayvanlarda gebelik oranlari ile vaginal sicakliklar (r=0.661, P<0.05) ve mukus kristalizasyonu (r=0.732, P<0.01) ayrica mukus kristalizasyonu ile dominant follikul buyuklukleri ve vaginal sicakliklar arasindaki (P<0.05) pozitif yondeki iliskiler onemli bulundu. Bununla birlikte onemli derecede (P<0.01) yuksek gebelik oranlari 4 ile 7 yas arasindaki 14-18 mm arasinda follikul capina sahip kendiliginden ostrus gosteren ineklerin tohumlanmalariyla elde edildi. Sonuc olarak, vaginal sicaklik ile mukus kristalizasyonu yuksek ve orta buyuklukte follikule sahip olan 4-7 yasli ineklerin tohumlanmalariyla gebelik sansi yuksek bulundugundan dominant follikul buyuklugu ve mukus kristalizasyonun yas ile birlikte degerlendirilerek tohumlama zamaninin ayarlanmasiyla gebelik sansinin arttirilabilecegi kanaatine varildi.