Assessment and comparison of four lab made tris-base extenders for preservation of Labrador retriever dog semen at 4ºC

131-139The present study was aimed to develop a most effective extender for long term storage of Labrador dog semen at 4oC. Tris-citric acid-fructose was supplemented with egg yolk (TEY), egg yolk plasma (TEYP), low density lipoproteins (TLDL) and coconut water (TCW) @10, 15 and 20; 10, 15 and 20; 11-15; and 25, 50 and 75 percent, respectively. Extended semen was stored at 4oC and analyzed for sperm attributes and lipid peroxidation. Values for motility, viability and plasma membrane integrity remained significantly (p < 0.05) higher in 15% TEY, 15% TEYP, 13% TLDL and 25%/50% TCW from 0 hr to 72 hrs of storage. It indicated superiority of 15% TEY, 15% TEYP, 13% TLDL and 25% /50% TCW over other concentrations for storage of Labrador dog semen at 4oC. A significant (p < 0.05) decline in motility, viability and membrane integrity was observed from 0-72 hrs of preservation in all extenders, but sperm attributes were still >50% at 72 hrs of preservation. Decline was comparatively less in 15% TEY, 15% TEYP, 25%/50% TCW and 13% TLDL compared to other concentrations. Values for acrosome integrity also differ significantly (p > 0.05) among different concentrations of extenders except TEY. Lipid peroxidation did not vary among different extenders except TEY. In conclusion, both 15% TEY and 15% TEYP were better than 13% TLDL and 25% TCW. TEY extender may be substituted with TEYP for preservation of dog semen at 4°C and further interventions may improve TLDL and TCW extenders

Comparison of follicular dynamics, superovulatory response, and embryo recovery between estradiol based and conventional superstimulation protocol in buffaloes (Bubalus bubalis)

Aim: To evaluate the follicular dynamics, superovulatory response, and embryo recovery following superstimulatory treatment initiated at estradiol-17β induced follicular wave emergence and its comparison with conventional superstimulatory protocol in buffaloes. Materials and Methods: Six normal cycling pluriparous buffaloes, lactating, 90-180 days post-partum, and weighing between 500 and 660 kg were superstimulated twice with a withdrawal period of 35 days in between two treatments. In superstimulation protocol-1 (estradiol group) buffaloes were administered estradiol-17β (2 mg, i.m.) and eazibreed controlled internal drug release (CIDR) was inserted intravaginally (day=0) at the random stage of the estrous cycle. On the day 4, buffaloes were superstimulated using follicle stimulating hormone (FSH) 400 mg, divided into 10 tapering doses given at 12 hourly intervals. Prostaglandin F2α analogs (PGF2α) was administered at day 7.5 and day 8, and CIDR was removed with the second PGF2α injection. In superstimulation protocol - 2 (conventional group) buffaloes were superstimulated on the 10th day of the estrous cycle with same FSH dose regimen and similar timings for PGF2α injections. In both groups, half of the buffaloes were treated with luteinizing hormone (LH) 25 mg and other half with 100 ug buserelin; gonadotrophin releasing hormone (GnRH) analog at 12 h after the end of FSH treatment. All buffaloes in both protocols were inseminated twice at 12 and 24 h of LH/GnRH treatment. Daily ultrasonography was performed to record the size and number of follicles and superovulatory response. Results: Significantly higher number of small follicles (<8 mm) was present at the time of initiation of superstimulatory treatment in the estradiol group compared to the conventional group (12.5±0.80 vs. 7.3±1.21, respectively, p=0.019), however, the number of ovulatory size follicles (≥8 mm) did not differ significantly between the respective groups (15.5±1.24 vs. 12.2±1.30; p=0.054). Total embryos and transferable embryos recovered were non-significantly higher in the estradiol group compared to the conventional group (5.83±0.86 vs. 4.67±1.16, p=0.328, and 3.67±0.93 vs. 2.67±0.68, p=0.437, respectively). The significant higher proportion of transferable embryos were recovered in buffaloes treated with LH compared to GnRH (73.3% vs. 48.5%; p=0.044). Conclusion: The average number of ovulatory size follicles (>8 mm), corpora lutea, and transferable embryos was higher in buffaloes superstimulated at estradiol-induced follicular wave compared to the conventional protocol: Further the percentage of transferable embryos was significantly higher in buffaloes administered with LH compared to GnRH