The impact of bacterial contamination of the ejaculate and extender on the quality of swine semen doses

Abstract

The aim of this study was to verify the influence of the degree of bacterial contamination of boar ejaculate and semen extender on the quality of semen doses. The experiment was conducted in four boar studs, from which raw semen and two semen doses from each ejaculate were collected to evaluate the number of colony-forming units (CFU), pH, sperm morphology and motility. Extender samples were also evaluated for CFU. Ejaculates that had higher levels of contamination (> 220 CFU mL -1 ) resulted in semen doses with a greater degree of bacterial contamination but with no reduction in motility or alteration in pH. When the semen doses were classified according to the degree of contamination of the extender, a decrease in motility was observed after 108 and 168 h of storage (P < 0.05) in the group whose extender had ≥14,000 CFU mL -1 versus the group whose extender had ≤ 330 CFU mL -1 . The pH remained stable during 168 h of storage in semen doses with extender that had lower contamination levels, but decreased from 7.2 to 6.0 between 24 and 168 h of storage (P < 0.05) in the group with extender that had higher levels of contamination. A higher number of abnormal acrosomes (P < 0.05) was observed after 168 h of storage in the semen doses whose extender was highly contaminated. The production of semen doses with low bacterial contamination and high sperm cell viability will only be possible with a strict hygienic control in semen processing, primarily with respect to the extender, combined with minimal contamination during collection. Key words: Boar. Coliforms. Ejaculate contamination. Total mesophiles. ResumoO objetivo desse estudo foi verificar a influência do grau de contaminação bacteriana do ejaculado do macho suíno e do diluente na qualidade das doses inseminantes. O estudo foi conduzido em quatro centrais de inseminação, onde foram colhidas amostras de sêmen fresco e duas doses inseminantes produzidas a partir de cada uma das referidas amostras de sêmen. As amostras foram avaliadas quanto ao número de Unidades Formadoras de Colônia (UFC) de bactérias mesófilas totais e coliformes, pH, morfologia espermática e motilidade. de acordo com a contaminação do diluente, um decréscimo na motilidade foi observado após 108 e 168 horas de armazenamento (P < 0,05) no grupo em que o diluente apresentava ≥14.000 UFC mL -1 se comparado com o observado no grupo cujo diluente apresentava ≤330 UFC mL -1 . O pH permaneceu estável durante as 168 h de armazenamento em doses inseminantes que apresentavam diluentes com menor nível de contaminação, mas diminuiu de 7,2 para 6,0 entre 24 e 168 h de armazenamento (P < 0,05), no grupo com diluente que apresentava o maior nível de contaminação. Um número maior de acrossomas anormais (P < 0,05) foi observado após 168 h de armazenamento em doses inseminantes cujo diluente era altamente contaminado. A produção de doses inseminantes com baixa contaminação bacteriana e alta viabilidade de células espermáticas só é possível com um estrito controle de higiene durante o processamento do sê...

Bacteria and Boar Semen Storage: Progress and Challenges

“…The degree of bacterial contamination in ejaculates directly influences sperm quality parameters during cold preservation ( Figure 1 ) [ 28 ]. Many studies have exemplified the consequences of bacterial growth on spermatozoa, which are summarized in Table 1 .…”

Semen quality and total microbial load: An association study in important Indian Goat breeds during different seasons

“…However, Goldberg et al. (2017) reported more number of bacterial contaminations in fresh boar semen. Similarly, Zampieri et al.…”