RESUMO
Conservation management of endangered African wild dogs (AWD; Lycaon pictus) can benefit greatly from development of sperm freezing and artificial insemination. Previous freezing attempts yielded nearly 0% motile sperm within 2â¯h of thawing. In this study, two canine freezing protocols were tested: Protocol 1: a one-step dilution in TRIS-20% egg yolk containing 8% glycerol; and Protocol 2: a two-step dilution in TRIS-20% egg yolk containing a final extender concentration of 5% glycerol and 0.5% Equex STM, coupled with a TRIS-citrate-fructose thawing solution. Semen was collected by electroejaculation from nâ¯=â¯24 AWDs, of which eight ejaculates of sufficient quality (four good quality with initial sperm motility of 75.0⯱â¯4.4% and four poor quality; showing rapid decrease in sperm motility to 3.3⯱â¯3.3% prior to freezing) were frozen. For good quality samples, motility and sperm motility index persisted for up to 8â¯h for Protocol 2, and was higher between 2 and 6â¯h after thawing with a decrease from 4â¯h of incubation. Motility dropped to nearly 0% after 2â¯h incubation for Protocol 1. Viability was higher for Protocol 2 throughout the 8â¯h of incubation, with a decrease after 6â¯h, compared to 4â¯h for Protocol 1. Acrosome integrity was higher for Protocol 2 throughout post-thaw incubation, with a decrease after 2â¯h for both protocols. Protocols did not differ in normal sperm morphology or DNA integrity. Poor quality samples yielded similar results, except for acrosome integrity, which declined for Protocol 2. In conclusion, a two-step dilution in TRIS-egg yolk-glycerol extender containing Equex STM yields significantly improved post-thaw quality and longevity of AWD spermatozoa, making it suitable for sperm banking and artificial insemination initiatives.
Assuntos
Canidae , Criopreservação/métodos , Crioprotetores/farmacologia , Gema de Ovo , Glicerol/farmacologia , Preservação do Sêmen/métodos , Trometamina , Acrossomo/efeitos dos fármacos , Animais , Criopreservação/veterinária , Masculino , Preservação do Sêmen/veterinária , Motilidade dos Espermatozoides/efeitos dos fármacosRESUMO
: We captured 14 individual African wolves ( Canis lupaster) a total of 16 times in the Ethiopian Highlands in April 2015 and March 2016 by using rubber-lined foothold traps and immobilized them with dexmedetomidine-ketamine. Traps were baited with sheep meat and surveyed every 2 h. Capture efficiency (number of captures per number of visits) was 0.94, and capture rate (number of captures per number of trap nights) was 0.24. Trapped wolves were immobilized with 0.025 mg/kg dexmedetomidine and 8-10 mg/kg ketamine on the basis of respective estimated body mass. Mean (SD) induction times were 3.4 (0.5) min for subadults ( n=4), 3.5 (0.3) min for adult males ( n=4), and 4.7 (1.0) min for adult females ( n=6). Inductions were calm, muscle relaxation was good, and all animals were completely immobilized. Apart from increased rectal temperatures, no major negative side effects were observed. Atipamezole at 10 mg intramuscularly per milligram of dexmedetomidine administered was used for reversal at a mean of 43.5 (7.7) min after administration of dexmedetomidine-ketamine. Recoveries were relatively smooth, and animals were on feet, leaving the site within a mean of 13.6 (3.9) min, after atipamezole administration. Our results indicate that African wolves can be safely captured and immobilized by using rubber-lined foothold traps and dexmedetomidine and ketamine.