SPERMATOZOAL QUALITY OF CRYOPRESERVED CANINE SEMEN USING DIFFERENT EXTENDERS AND CHLOROQUINE PHOSPHATE

Abstract

Sub-zero degree preservation is critical for effective semen quality extension in artificial insemination of animals. The use of certain drugs and extenders have been reported to enhance the quality of semen in cattle and swine. This is yet to be reported in canines. The effects of different extenders and chloroquine phosphate on the quality of cryopreserved semen of two exotic dog breeds were therefore investigated. Six studs made up of three Rottweilers and three German Shepherd Dogs (GSD) aged 2 to 3 years, weighing 38 to 40kg, were purposively selected through a spermatogram pilot study. They were then assigned to three replicates of two dogs each, in a completely randomised design. Ejaculates from each stud were analysed for volume (V), Concentration (C), Mass Activity (MA), Progressive Motility (PM), Live to Dead Ratio (LDR), Percentage Abnormality (PA), DNA Integrity (DI), Acrosome Integrity (AI) and Survival Time (ST). Individual ejaculates were diluted (100 million spermatozoa/ml) in Sodium Citrate Glycine Extender (SCGE); Coconut Water Extender (CWE); Skim Milk Extender (SME) and Hibiscus sabdarifa (Zobo Extender (ZE)). These samples were preserved at 28oC and 4oC and analysed hourly until zero percent motility was observed. The extended semen samples were cryopreserved using liquid nitrogen. The extended semen samples were then subjected to post preservation evaluation. Chloroquine Phosphate (CP), 0.2ml of 3mM, was added to portions of the cryopreserved samples and also evaluated. Data were analysed using descriptive statistics and ANOVA at p < 0.05. Effects of breeds on all the dependent variables were not significant, hence the results were pooled. The SME had optimum significant values of 71.2% PM, 4.0 hrs ST, 3.7% AI, 9.9% PA and MA of 77.5% and 76.3% at 28oC and 4oC, respectively. The highest initial values of MA were observed in ZE (60.0%) which had the greatest PM of 90.3% and 91.9% at 28oC and 4oC respectively. The SCGE had the least values of 30.9% PM, 26.3% MA and 0.9 hrs ST, and also recorded significantly higher values of 15.3% PA and 8.5% AI. Although SCGE had the highest DI (2.0%), the apparent differences in values were not however significant compared with those obtained for CWE, SME and ZE. The AI had a 77.0% higher chance of being affected than DI (23%). The inclusion of CP had significant effects on the initial MA in SCGE (10.8%), CWE (58.3%) and SME (66.7%) but not in ZE (64.2%). Similarly, CP significantly influenced the initial PM in SCGE (12.5%) and CWE (68.0%). The effects of CP on PA were significant only in SME (10.9%) and ZE (13.0%) but similar in SCGE (18.5%) and CWE (15.9%). The CP however significantly affected the survival time of SCGE (0.3hrs), CWE (1.9hrs), SME (2.7hrs) and ZE (2.2hrs). Skim milk extender was the best extender for cryopreservation in dogs. Addition of Chloroquine phosphate just before insemination enhanced the fertilising potential of cryopreserved canine semen.