Effect of different concentrations of pentoxifylline on Cryopreservation of German Shepherd dog

Abstract

To investigate the Effect of adding different concentrations of extract pentoxifylline as an antioxidant on specific physical semen characteristics of German Shepherd dogs during various steps of frozen semen processing, this study was carried out. A total (of 20) good Ejaculate semen samples were collected in a plastic bag from German Shepherd dogs aged 3-4 years In different locations (dog breeding).To achieve the current study's main objectives, two experiments were designed through periods extended from the beginning of December 2021 until the end of May 2022. The investigations included studying the physical properties of rawSemen (ejaculate volume, semen color, consistency, motility percentage, progressive motility percentage, dead sperm percentage, sperm abnormalities percentage, and hypo-osmotic swelling test (HOST). After that, semen samples were diluted with Tris supplemented with antioxidants. The physical properties ofSemen were followed after cooling and after freezing (post-thawing). In the first experiment, ten ejaculates were collected.   Dilution ofSemen was performed with Tris supplemented with two different concentrations of pentoxifylline, T1(Tris + (1) mmol/ml. of pentoxifylline / 5 ml diluent). T2( Tris + 5 mmol/ml. of pentoxyfylline / 5 ml diluent).Diluted semen samples (C, T1, T2, and T3) were cooled slowly up to 5C and equilibrated, packed into 0.5 ml straws, and put in vapor nitrogen (-196C) for 5-10  minutes after that, stored for 48 and 72hr in liquid Nitrogen (-196C). Progressive motility percentage, dead sperm percentage, sperm abnormalities percentage, and hypo-osmotic swelling test (HOST) were evaluated after cooling and post-thawing (Submerging the straws in the water bath at 37C for 30 seconds). Semen samples were cooled and frozen, and physical evaluation was performed after cooling and freezing. The results of the first experiment proved for cooling and freezing, the individual motility percentage of sperm was significantly (P˂0.05) higher in T3, which was quite different (P˂0.05)from T2 and all the values were very (P˂0.05) different from control T1. Meanwhile, matters of dead sperms Percentage show the lowest in T1, which is significantly (P˂0.05) different from T2 after cooling, while after freezing, the lowest value in T1 and T3, and the highest in T2 with significantly (P˂0.05) other. Abnormal sperm percentage was most deficient in T1 after cooling with significant (P˂0.05) differences from T2 and T3. After freezing lowest value in T1 and T3 with a significant (P˂0.05) difference from T2. Hypo osmotic swelling test (HOST) Percentage shows a considerable difference (P˂0.05) Among the groups after cooling at different hours (48, 72, 96, 120). Still, after freezing, the highest value was in T3, with a significant difference from T2 and control T1. Regarding the Effect of cooling and freezing on semen quality of German Shepherd dogsSemen, the results show the addition of green tea extract act as a protective factor for sperm to withstand the detrimental Effect of cooling and freezing in liquid Nitrogen by preventing the significant (P˂0.05) decrease of sperm progressive percentage and also prevent the substantial increase in dead, abnormal and defect Hypo osmotic swelling test (HOST) percentage in after freezing compared with after cooling.