Research articleExtended semen for artificial insemination in swine as a potential transmission mechanism for infectious Chlamydia suis
Introduction
Chlamydia suis, Chlamydophila abortus, Chlamydophila pecorum, and Chlamydophila psittaci are obligate intracellular bacteria that infect swine [1], [2] and may reduce performance of pigs in all stages of the production cycle including reproductive performance [2], [3]. Recently C suis infection of slaughterhouse workers was confirmed [4] suggesting that it has crossed the species barrier and may represent a one-health concern. As with human chlamydia infections, no vaccines for pigs are available but reduced sow-to-piglet transmission rates have been achieved experimentally when sows were treated with probiotics before farrowing [1]. Although antibiotics effectively treat chlamydia infections, their use in animal agriculture continues to draw scrutiny and does not represent an effective long-term solution to prevent infections in a herd. Maintenance of a chlamydia-free herd may best be achieved through stringent biosecurity that restricts movement of animals and production materials. The high number of chlamydia-positive farms in regions where surveillance is performed suggests that transmission is still being achieved despite high biosecurity already in place [5]. One potential avenue for transmission may be through semen which is generally exempt from biosecurity [6]. Instead, semen for artificial insemination (AI) is typically obtained from high health, specific pathogen–free herds, and they are frequently tested for porcine reproductive and respiratory virus (PRRSV) and on occasion other porcine viruses (which do not regularly include C suis or any other bacteria) via polymerase chain reaction to avoid transmission. A number of important swine pathogens have been identified in the semen of infected boars including chlamydia [7], PRRSV [8], circovirus [9], [10], and foot and mouth disease [11]. The following study was conducted to determine if chlamydia negatively impacted sperm viability and if commercial semen stored using industry-standard conditions was a potential mode of transmission for chlamydia [12].
Section snippets
Cell culture and chlamydia propagation
Both swine testicular fibroblast (ST; CRL-1746) and McCoy (CRL-1696) cells were obtained from American Type Culture Collection (Cedarlane, Burlington, Ontario, Canada). ST cells were cultured with minimum essential media (MEM; Sigma–Aldrich, St. Louis, MO, USA) containing 5% fetal bovine serum (FBS; Gibco, Life Technologies, Carlsbad, CA, USA), and 1X Antibiotic-Antimycotic (Gibco) and McCoy cells were cultured with MEM containing 10% FBS, 1 μg/mL cycloheximide (Sigma–Aldrich) and 10 μg/mL
Results
Dead sperm and acrosome reacted sperm were successfully identified by positive staining for PI and PNA, respectively (Fig. 2A, B). No significant increase in acrosome reaction of sperm was observed after chlamydia was stored for up to 7 days (Fig. 2C). With regard to dead sperm (Fig. 2D), no significant difference in sperm survival relative to control samples was observed at chlamydial concentrations ranging from 5 × 104 to 5 × 105 C suis/mL. However, at a chlamydial concentration of 6.25 × 105
Discussion
In today's swine industry, commercial barns use AI as the preferred method of gilt/sow fertilization. With the ability of boars to produce a large number of insemination doses per week and the widespread distribution of the processed semen, there is tremendous risk that semen contaminated with pathogenic bacteria or viruses can be widely spread [6]. To maintain optimal boar health and minimize adverse effects including infertility and reduced sperm production of the boars, commercial boar studs
Acknowledgments
The authors gratefully acknowledge financial support from the Saskatchewan Health Research Foundation (SHRF) Establishment Grant to F.M. and the Alberta Livestock and Meat Agency Grant (2014R041R) to H.L.W. and J.A.P. G.H. is a recipient of the University of Saskatchewan College of Graduate Studies and Research Graduate Research Fellowship. J.A.P. is the recipient of a fellowship from the Saskatchewan Health Research Foundation and a Natural Sciences and Engineering Research Council of Canada
References (30)
- et al.
Diseases in swine transmitted by artificial insemination: an overview
Theriogenology
(2008) - et al.
Detection of chlamydiae in boar semen and genital tracts
Vet Microbiol
(2006) - et al.
Prevalence of PCV2 in Austrian and German boars and semen used for artificial insemination
Theriogenology
(2008) - et al.
Evaluation of the transmission of porcine circovirus type 2 (PCV-2) genogroups a and b with semen from infected specific-pathogen-free boars
Vet Microbiol
(2013) - et al.
Porcine retinal cell line VIDO R1 and Chlamydia suis to modelize ocular chlamydiosis
Vet Immunol Immunopathol
(2015) - et al.
Prevalence of chlamydiae in boars and semen used for artificial insemination
Theriogenology
(2006) - et al.
The effect of porcine parvovirus and porcine reproductive and respiratory syndrome virus on porcine reproductive performance
Anim Reprod Sci
(2000) - et al.
Effects of different concentrations of enterotoxigenic and verotoxigenic E. coli on boar sperm quality
Anim Reprod Sci
(2011) - et al.
Bacterial contamination of boar semen affects the litter size
Anim Reprod Sci
(2010) - et al.
Storage of boar semen
Anim Reprod Sci
(2000)
Semen changes in boars after experimental infection with porcine reproductive and respiratory syndrome (PRRS) virus
Theriogenology
Bacteriospermia in extended porcine semen
Theriogenology
Effects of a probiotic strain of Enterococcus faecium on the rate of natural Chlamydia infection in swine
Infect Immun
Chlamydiaceae infections in pig
Vet Res
PCR-based detection of chlamydial infection in swine and subsequent PCR-coupled genotyping of chlamydial omp1-gene amplicons by DNA-hybridization, RFLP-analysis, and nucleotide sequence analysis
Epidemiol Infect
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These authors contributed equally to this work.