جستجوی مقالات مرتبط با کلیدواژه « رادیکال های آزاد » در نشریات گروه « علوم دام »

The most worthwhile technique for preservation and management of bird genetic resources is semen cryopreservation, which has been studied in domestic birds like chicken. Despite years of intensive investigations, still more work should be done in order to perform successful cryopreservation of poultry sperm. The lower quality of frozen-thawed poultry sperm and consequently the poor fertilization rates compared to mammalian species are due to the exceptional morphological properties of poultry sperm, which cause freeze damages because of their vulnerable structure to low temperatures. During sperm cryopreservation, it is exposed to cold and osmotic shock, and resulted in increasing oxidation due to raise in oxidative reactions. It reduces sperm motility, viability, and ultimately reduces fertility. Oxidative stress occurs when oxidants are more potent than antioxidants. Hence, increased production of reactive oxygen species (ROS) caused by oxidative stress leads to lipid peroxidation (LPO), apoptosis, and DNA damage. Generally, the most important effect of lipid peroxidation on cells is the disruption of membrane structure and function. Plasma membrane damage is considered as one of the reasons for decreasing motility and fertility of rooster sperm. The aim of this study was to investigate the effects of different levels of curcumin antioxidants (0, 100, 200 and 300 μM) in Beltsville modified diluents for the cryopreservation of rooster semen. The present hypothesis was that curcumin antioxidants would be effective during cryopreserving of rooster sperm. Several parameters such as sperm motility, abnormalities, membrane integrity, viability and abnormality were assessed in this study to find the best level of curcumin antioxidants for cryopreservation of rooster sperm.
Material and Semen samples were collected from eight Ross 308 rooster three times a week by massaging along the backbone and abdomen .The criteria in normal quality of sperm was as follows: the volume between 0.2 and 0.6 ml (semen volume was measured visually using a graduated collection tube); the concentration of sperm ≥ 3˟109 sperm/ml (ejaculate concentration was evaluated by haemocytometer); total motility ≥80% and abnormal morphology (Hancock method [17]) ≤ 10%. Then, the semen samples were pooled to remove individual variations and obtain sufficient sperm for analysis. Different levels of curcumin were added to semen samples and followed by freezing. After thawing following sperm parameters were evaluated: total motility (TM, %), progressive motility (PM, %), average path velocity (VAP, μm/s), curvilinear velocity (VCL, μm/s), straight linear velocity (VSL, μm/s), amplitude of lateral head displacement (ALH, μm), beat cross frequency (BCF, Hz), straightness (STR, %), and linearity (LIN, %) using CASA software, viability by Eosin-Nigrosine Staining, membrane integrity by HOST test, and sperm abnormality by Hancock test. .
The freezing extender supplemented with 200 μM of curcumin resulted in higher percentages of total and progressive motilities in comparison with other groups and control group following the freeze-thawing process (P The results of this study showed that adding 200 μM curcumin can have favorable effects on post-thawed rooster sperm motility parameters, viability, plasma membrane integrity, and abnormality.

In order to improve the quality of ram semen after freezing-thawing process, different levels of ethanol extract of Bilberry plants were investigated. In this study five rams were used for semen collection twice a week by an artificial vagina. In order to eliminate the effects of the individual, the semen samples were pooled. Different levels of Bilberry extract (0, 100, 150, 200 μl/ml) were added to the Tris- Egg yolk based extender. Following cooling and freezing of semen samples, they were stored in liquid nitrogen until evaluation. After freezing-thawing, motility parameters were evaluated using the Computer-assisted sperm analysis system (CASA), the viability of sperms by Eosin-Nigrosin staining, membrane integrity using the hypo-osmotic swelling test, sperm abnormality by Hancock solution and lipid peroxidation by measuring malondialdehyde concentration. The results showed that the addition of 150 μl of Bilberry extract improved sperm parameters following freezing-thawing process compared to the control group (P

One of the reasons for reduction of fertility in sperm is extra production of free radicals during various stages including cryopreservation, storage and freeze-thawing process of sperm. Free radicals lead to changes in biochemical and ultrastructure of the sperm membrane, decreasing survival rate after thawing of sperm. Butylated hydroxytoluene (BHT) is a synthetic analogue of vitamin E that controls the auto-oxidation reaction by converting peroxy radicals to hydroperoxides.
OBGECTIVES: The purpose of this study was to investigate the effects of different levels of Butylated hydroxytoluen (BHT) to improve the quality of ram semen in the process of freezing/thawing.
In this study, five rams were used for semen collection twice a week. Different levels of BHT (1, 1.5, 2, 3 mM) were added to tris-yolk based diluents. After freezingthawing of semen samples, the dynamic parameters, viability, membrane integrity‚ sperm abnormality and lipid peroxidation (MDA) were evaluated.
the addition of 1.5, 2 mM BHT significantly improved total and progressive motility, viability and plasma membrane integrity and decreased the sperm abnormality percentage compared with the control group (P Statistical analysis of data showed that the addition of BHT to semen diluent improves the majority of sperm parameters after thawing.

Four mature stallions were used to study the effect of enzymatic antioxidant catalase on freezability of Turkmen stallion's sperm. Collected semen from stallions were processed and pooled before being divided treatments (200×106 sperm/ml) and diluted with extenders supplemented with different levels of catalase [0 (control), 100 U/ml (CAT100), 150U/ml (CAT150) and 200U/ml (CAT200)]. Extended and supplemented semen's were frozen according to a standard protocol. After thawing, motility, viability, membrane integrity, total abnormality and lipid peroxidation were assessed. Results showed that addition of 200U/ml catalase could improve progressive and total motility, viability, membrane integrity and decreased lipid peroxidation compared to control and other levels of catalase (p0.05). The results showed that different levels of catalase could not decreased total abnormality (p>0.05). We concluded that addition of 200U/ml catalase could improve freezability of Turkmen stallion’s sperm.