Förekomst av leukocyter i råsperma hos semingaltar

Abstract: Detection of leukocytes in semen from boars is part of the routine control of semen quality. Leukocytes in semen can cause damage to spermatozoa that leads to impaired fertilization. In the artificial insemination (AI) industry there are standard routines for the quality control of the boars and of the neat semen before use. Since 2001, Quality Genetics has not done the leukocyte examination on semen samples from boars which are used for the production of pigs for slaughter. The purpose of this study was to investigate the occurrence of leukocytes in semen from AI-boars. The questions addressed were whether there are boars that have leukocytes in their semen and how frequently it occurs and, moreover, if there are differences between breeds, or even between individuals whose semen was checked before use in AI-dose production compared to those which were not. The study included a total of 135 AI-boars, of which 67 were Hampshire, 35 Yorkshire and 33 Landrace, all belonging to Quality Genetics AI-station in Hållsta. The period of sampling was from 1st January until 31st August, 2008. The semen collections were done by staff at the AI-station according to their regular routines. A smear was prepared using an aliquot of neat semen from each ejaculate. The smears were stained with Papanicolau stain and examined by light microscopy. The results of the study confirmed that there are boars that have leukocytes in their semen. In the first screening there were 23 boars (17%) showing leukocytes in their semen. However, the majority of the boars had only a few leukocytes. When a new examination was done following a positive test, the number of leukocytes was reduced. Subdivided by breed, leukocytes were found most commonly in Hampshire, followed by Landrace, while they were rare in the semen of Yorkshire boars. Hampshire boars that are not normally tested showed a higher incidence of leukocytes in their semen than the boars which are routinely tested. Most of the studies of leukocytes in semen and their effects are done in men, but the test could be useful in the pig AI-industry. The research on leukocytes is complicated and there are different opinions about their effects on sperm quality. Furthermore, it is difficult to define the origin of the leukocytes. Leukocytes produce a large amount of reactive oxygen species (ROS), which have a negative effect on the fertilizing ability of the spermatozoa. When diagnosing leukocytes in semen from men, the recommended method is peroxidase-staining: It is possible that this method could facilitate the analysis of boar semen in the swine AI-industry. According to the result in this study the recommendation is to do further analyses, investigating the presence of leukocytes from additional Hampshire boars during a longer period. The establishment of a broader database would enable an informed decision to be made on how the boars should be examined in the future before use in the production of AI-doses.