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1. Effect Of Taurine Supplementation On Post-Thaw Quality Of Sahiwal Bull Semen

by Muhammad Irfan (2013-VA-599) | Dr. Aijaz Ali Cheema | Dr. Muhammad Younas | Dr. Amjad Riaz | Dr. Muhammad Haroon Akbar.

Material type: book Book; Literary form: not fiction Publisher: 2015Dissertation note: It is well recognized that cryopreservation of bovine semen results in decreased spermatozoal viability due to cryodamages. Oxidative stress is produced due to Reactive Oxygen Species (ROS) during freez-thaw process.Extreme production of ROS during cryopreservation has been associated with decreased post thaw %age motility, viability, and membrane integrity and sperm fertility capability. Basically antioxidants works to reduce or, taking up the formation of ROS. In recent years, taurine has been used as anti-oxidant in semen extenders and has been used in the cryopreservation of sperm from many species to improve post-thaw quality of spermatozoa by inhibiting lipid peroxidation and protecting cells against accumulation of ROS. Therefore, supplementation of taurine in semen extendercontaining 0,15,30,45 and 60mM concentration was used to decrease the harmful effects of cryopreservation on Sahiwal bull spermatozoa. Three Sahiwal bulls (4-8years) were used in the present study. The bulls were maintained at Semen production unit, Qadirabad and were offered good quality seasonal fodder (at the rate of 10% body weight), supplemented with concentrates (2-4kg/day). The semen was collected from each bull twice a week. Initially the semen was assessed for volume, motility, and concentration. Then the semen was pooled from all bulls and divided into 5 aliquots (150 ul each). Each aliquots diluted with 5groups extender which contain 0, 15, 30, 45 and 60mM taurine concentration. The semen was filled in 0.5ml straws cooled to 5c for 4 h, then frozen and stored in liquid nitrogen (-196c). Post-thaw motility, viability, plasma membrane integrity, acrosome and DNA integrity was evaluated and statistically analyzed by one way ANOVA. The group supplemented with 60mM concentration of taurine decreased all parameters of post thaw quality ofSahiwal bull spermatozoa. However the group supplemented with 15mM concentration of taurine show higher significantly (p<0.05) results than control and other groups. The post-thaw motility of the group supplemented with 15mM taurine concentration (54.50±2.1) higher significantly (p<0.05) than control (45.50±0.90) and other groups. The treatment group of 15mM taurine concentration show signifantly (p<0.05) higher viability (58.60±1.58 vs50.80±0.70) , plasma membrane integrity (57.10±1.43 vs 49.00±0.65) acrosome integrity (56.80±0.59 vs48.10±1.66) and DNA integrity (98.80±0.23 vs 97.54±0.39) as compared to the control and other groups. It is concluded that the maximum beneficial effect of addition 15mM taurine in tris-based egg yolk extender gives better post-thaw parameters. Availability: Items available for loan: UVAS Library [Call number: 2269-T] (1).

2. Development Of A Suitable Semen Extender For The Cryopreservation Of Nili Ravi Buffalo Bull (Bubalus Bubalis) Semen

by Fazal Wadood (2007-VA-557) | Prof. Dr. Muhammad Aleem | Dr. Muhammad Younas | Prof. Dr. Nasim Ahmad | Prof. Dr. Ijaz Ahmad.

Material type: book Book; Literary form: not fiction Publisher: 2015Dissertation note: Presently, buffalo farmers are dissatisfied with fertility rates of the frozen semen used in the field and tend to use bulls. This study was designed to develop a suitable semen extender for cryopreservation of Nili Ravi buffalo semen that can improve conception rate in buffaloes. Experiment-I, an attempt was made to develop semen extender with optimal osmotic pressure for buffalo semen using tris citric acid (TCAE), skim milk (SME) and coconut water (CWE) extenders (each extender have 260, 270, 280, 290 and 300 mOsm/kg osmotic pressure levels). In Experiment-II, best extender (TCAE: 300 mOsm/kg) of experiment-I was tried to improve post thaw spermatozoa characteristics by supplementing antioxidants [0.0, 1.75, 2.0 and 2.25 mM butylated hydroxy toluene (BHT) and 0.0, 2.0, 5.0 and 8.0 mM L-cysteine]. Post thaw spermatozoa motility, viability, plasma membrane integrity (PMI), DNA damage rate and lipid peroxidation were assessed in first two experiments. In Experiment-III, pregnancy rate assessment of extended semen was carried out by using Trial extender (best of experiment II) or Control extender of Semen Production Unit (SPU), Qadirabad, Pakistan (50 inseminations of each extender). Higher spermatozoa motility at ≥ 270 mOsm/kg was noted in TCAE than both SME and CWE could be due to less intracellular ice formation in zwitterions extender. Higher spermatozoa viability in TCAE and CWE compared to SME may be attributed to extender effectiveness. Higher acrosomal integrity rate at 300 mOsm/kg in TCAE and SME may be because of less intracellular ice formation in isotonic extenders. At 290 mOsm/kg, higher spermatozoa PMI in SME and lesser DNA damage in three extenders might be due to lesser intracellular ice formation at cryopreservation. Decreased spermatozoa DNA damage in SME might be due to the presence of natural antioxidants i.e., casein. Higher lipid peroxidation in CWE than TCAE and SME may be due to presence of natural antioxidants (in SME) and higher cell dehydration potential of TCAE. Higher spermatozoa motility recorded at 2.0 mM BHT compared to other BHT groups including DMSO might be due to fact that BHT protects spermatozoa mitochondria by reducing oxidative stress. Lower spermatozoa viability, PMI rates and higher DNA damage at 2.25 mM of BHT may be due to BHT toxic effects. Lower lipid peroxidation in BHT treated groups compared to DMSO and BHT control groups might be related to BHT strong antioxidant properties. L-cysteine caused higher spermatozoa DNA damage at highest level (i.e., 8 mM) that could also be due to antioxidant’s toxic effect. Pregnancy rate 18 % higher was noted in Trial than Control semen extender; however no significant difference have been noted that might be due to less no of inseminations. In conclusion, TCA extender (300 mOsm/kg) having BHT (2.0 mM) improved post thaw semen quality and yielded numerically better pregnancy rates. Results of study indicated that osmotic stress damaged the spermatozoa internal structures more severely than injury to plasma membrane. Availability: Items available for loan: UVAS Library [Call number: 2360-T] (1).

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