Comparative survivability of ovine spermatozoa in egg yolk citrate and graded mixture of pawpaw juice-coconut milk citrate at room temperature

Abstract

Ovine spermatozoa survivability in egg yolk citrate (EYC) and graded mixture of pawpaw juice-coconut milk citrate was studied using three matured West African Dwarf (WAD) rams (18.67 ±1.45 kg). Five mixtures of pawpaw juice and coconut milk citrate at a ratio of 10:90 (P₁C₉), 30:70 (P₃C₇), 50:50 (P₅C₅), 70:30 (P₇C₃), and 90:10 (P₉C₉) into which Sodium Citrate was added at the ratio 20%:80% were constituted. 80% EYC (control) was also constituted. Diluents were evaluated for pH and kept at room temperature. Semen was collected in nine trials using electro-ejaculator method and evaluated immediately for colour, volume, pre-extended sperm motility and morphology. Thereafter a drop of semen was added to 7.5ml of all diluents and evaluated for sperm motility at zero, one, two, three, four, five, six and twenty-four hours post extension. Morphological abnormalities were evaluated at six hours post extension. P₁C₉ had the highest pH value (6.73 ± 0.15) among the text diluents but was significantly different from just P₉C₁ (6.57 ± 0.09) however pH of egg yolk citrate (7.12 ± 0.16) was significantly higher than P₁C₉. Six hours post extension sperm motility score for P₁C₉ (40.56 ± 9.59%) and morphological abnormality (20.33 ± 2.99%) were adequate for achieving good conception rate with ram semen. These values were not significantly different from EYC’s (46.11 ± 9.16%; 20.44 ± 3.47). The work established that pawpaw juice and coconut milk mix at ratio of 10:90, stored for up to six hours post extension, at room temperature, competes well with standard EYC and is adequate for artificial insemination in WAD sheep.