The effects of addition of omega-3, 6, 9 fatty acids on the quality of bovine chilled and frozen-thawed sperm.

This study was aimed to investigate the effects of omega-3, 6, 9 fatty acids on the characteristics of bovine chilled and frozen-thawed semen. For this purpose, oil containing different levels of omega-3, 6, 9 fatty acids were added to semen extender. To emulsify the oil in semen extender, polyethylene glycol (PEG) was added as a suitable solvent and the solution was finally sonicated. Five proven Holstein bulls were randomly selected and their ejaculates were collected using an artificial vagina. Groups were designed as control, treatments 1, 2, 3 and 4. The control group contained only the basic extender (Tris-citrate buffer, egg yolk and glycerol) without any additives. In treatment 1, only 5% PEG was added to the diluent; while in treatments 2, 3 and 4 different concentrations of omega-3, 6, 9 fatty acids (1.0, 2.5 and 5.0%) in combination with PEG were added to the basic extender. After dilution, the semen samples were packaged into 0.5 ml straws, a process that was followed by cooling the semen straws. Motility, viability and morphology of semen samples were evaluated after 24 and 48 h of storage in refrigerator (5 °C) or after one month of storage in the liquid nitrogen. Immotility was increased and all the other parameters including motility, viability and morphology were significantly decreased in all the groups compared with fresh samples during cold storage and freezing-thawing. Our results demonstrated the following: 1) PEG has significant detrimental effects, especially on the sperm motility; 2) addition of omega-3, 6, 9 fatty acids could not improve the sperm motility in chilled storage condition and after freezing-thawing; and 3) omega-3, 6, 9 fatty acidscould not also attenuate the other deleterious effects of PEG. In conclusion, our findings reveal that addition of these fatty acids to the semen extender does not enhance the resistance of the bovine sperm membrane to cooling and freezing-thawing and that further studies are required to find suitable candidate compounds that can boost the quality of semen that is chilled and freeze-thawed.

Leptin mRNA expresses in the bull reproductive organ.

Leptin, a 167-amino acid hormone, is secreted mainly by fat tissue. It has some powerful effects on the regulation of metabolism and reproductive function through endocrine and probably paracrine mechanisms. The contribution rate of leptin function on the male reproductive system is not still clear. Characterization of leptin expression in reproductive organs will suggest that in addition to its endocrine action, leptin has also paracrine/autocrine effects on reproduction. The expression of functional leptin receptor mRNA has been already recognized in testis of rodents, human and cattle. Thus, the aim of the present study was to investigate the presence of leptin mRNA in the bovine testis, because it will be the first step for understanding of its paracrine/autocrine effects on the male reproductive organs in cattle. The present study was the first to showed leptin mRNA expression in the testis of Holstein cattle using reverse transcription and polymerase chain reaction (RT-PCR) analysis. RT-PCR products were amplified with nested PCR using inner leptin primer pairs to emphasis the first results. Besides, bovine beta actin gene was acted as an internal positive control as well as RNA purification marker. Our findings suggest that in addition to its endocrine actions at the hypothalamic-pituitary axis, leptin can has an autocrine and/or paracrine role in bull testicular function.

Experimental Tribulus terrestris poisoning in sheep: clinical, laboratory and pathological findings.

Eleven native sheep, 1-2 years old, of both sexes were randomly divided into two groups, 6 sheep being allocated to the experimental group and 5 serving as controls. The sheep in the experimental group were fed 80% Tribulus terrestris and 20% alfalfa hay and wheat straw, while the control sheep were given a mixture of 40% alfalfa hay and 60% wheat straw. Clinical signs of hepatogenous photosensitivity were observed from day 11, including reddening and crust formation on the muzzle, nose, ears and eyelids, depression, weight loss, icterus, conjunctivitis, and yellow discoloration of the urine. Laboratory findings on weekly samples indicated significant differences (p < 0.05) in white blood cell count, total plasma protein and fibrinogen, total and direct bilirubin, blood urea nitrogen and creatinine concentrations, and aspartate aminotransferase and alkaline phosphatase activities. There were no significant differences in the packed cell volume, in the neutrophil, lymphocyte or eosinophil counts, or in the serum calcium, phosphorus, potassium, sodium or chloride concentrations. At necropsy of the experimental animals, there were various degrees of generalized icterus and the livers were swollen and discolored by bile pigment. Histopathological examination revealed varying amounts of crystalloid material in the bile ducts and renal tubules, hepatocellular degeneration, biliary fibrosis and proliferation, renal tubular necrosis and focal necrosis of cardiac muscle.