Does the Microbial Flora in the Ejaculate Affect the Freezeability of Stallion Sperm?

• In an attempt to evaluate the possible relationship between the microbial flora in the stallion ejaculate and its ability to freeze, three ejaculates from five stallions were frozen using a standard protocol. Before freezing, an aliquot was removed for bacteriological analysis. Bacterial growth was observed in all the ejaculates studied. The isolated microorganisms were: Staphylococcus spp. and Micrococcus spp. (in all the stallions), beta-haemolytic Streptococcus (in stallions 3 and 4), Corynebacterium spp. (in stallions 1, 3-5), Rhodococcus spp. (in stallion number 2), Pseudomonas spp. (in stallion number 1) and Klebsiella spp. (in stallions 1, 3 and 5). The presence and richness of Klebsiella and beta-haemolytic Streptococcus in the ejaculate were related to two sperm variables post-thaw, namely the proportion of dead spermatozoa (ethidium+ cells; r = 0.55, p less than 0.05) and the amplitude of lateral displacement of the sperm head (ALH, mu m; r = -0.56, p less than 0.05), respectively. The degree of growth of Corynebacterium spp. in the ejaculate was positively correlated with the percentage of spermatozoa showing high caspase activity post-thaw (r = 0.62, p less than 0.05). The presence and number of colonies of beta-haemolytic Streptococcus were negatively correlated (r = -0.55, p less than 0.05) with low sperm caspase activity. It is concluded that the microbial flora of the equine ejaculate may be responsible for some of the sublethal damage experimented by the spermatozoa during cryopreservation.

Subject headings

LANTBRUKSVETENSKAPER  -- Veterinärmedicin (hsv//swe)

AGRICULTURAL SCIENCES  -- Veterinary Science (hsv//eng)

LANTBRUKSVETENSKAPER  -- Husdjursvetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Animal and Dairy Sience (hsv//eng)

Keyword

TECHNOLOGY

TEKNIKVETENSKAP

Publication and Content Type

ref (subject category)

art (subject category)