Bacterial contamination of boar semen affects the litter size
Introduction
Microorganisms are important contaminants of many body fluids, including semen of animals and humans. Consequently, the extent of microbial contamination is an important parameter to consider in the quality control of semen that is used for artificial insemination or direct mating. Semen is an ideal medium for the establishment and growth of many microorganisms including bacteria and fungi. In boar semen for example, bacteria belonging to at least 25 different genera have been detected as contaminants, the most frequently occurring ones being Escherichia coli, Pseudomonas, Staphylococcus and Proteus spp. (Tamuli et al., 1984, Dagnall, 1986, Danowski, 1989, Sone et al., 1989, Arredondo et al., 2001, Althouse and Lu, 2005).
Microorganisms have a deleterious effect on sperm function, both directly by altering the structure of the sperm, by affecting its motility (Diemer et al., 1996, Depuydt et al., 1998), or by provoking a premature acrosome reaction (Kohn et al., 1998) and indirectly by stimulating the production of antibodies that can be directed against the sperm glycocalyx complex (Auroux et al., 1991, Kurpisz and Alexander, 1995).
There are two main sources of contamination, i.e. those of animal and those of non-animal origin. The first source includes, among others, contaminations originating from feces, preputial fluids, respiratory secretions, skin and hair. The second source might be contaminated water, non-sterilized glassware, equipment, poor hygienic conditions, and human contamination (Althouse et al., 1998, Althouse and Lu, 2005).
In male mammals, the urethra is a common part of the urinary and the genital system. Consequently, microbial contamination of semen can originate from both systems. Many urinary tract infections are caused by typical uropathogenic bacteria, but often, because of the proximity of the intestinal tract, they are infections provoked by strains that belong to the normal intestinal flora (see Bergsten et al., 2005, for a review). Bacteria infecting the urinary tract express virulence factors that allow colonization, invasion and tissue damage, and provoke diseases such as asymptomatic bacteriuria, cystitis or pyelonephritis (Johnson, 1991, Blanco et al., 1995, Blanco et al., 1997).
Bacteria can also be recovered from the reproductive tract of males as well as of females. Some microorganisms directly affect this system, e.g. Chlamydia trachomatis, which is a major organism that causes sexually transmitted diseases (Eggert-Kruse et al., 1989).
In this paper, we describe the results of investigations on the contamination of boar semen by bacteria and the correlation between the presence of Escherichia coli, sperm-agglutination and litter size.
Section snippets
Origin of semen samples
Semen samples from two different pig farms were collected in Cuba from 115 boars, i.e. 80 samples originated from a farm practicing integral pig production, and 35 samples were from a farm specialized in semen production (the first farm has an average of 55 boars and the second one has 18 boars). In an integral pig production farm all categories of pigs are present from birth till slaughter, i.e. pigs for reproduction (boars, gilts and sows), weaning and post weaning piglets, and pigs that are
General health status of the boars
From all boars used as donor of semen, only one was later reported to show typical signs of a urinary tract infection (recurrent fever, anorexia, frequent urination). All the other boars were considered healthy.
Volume of the ejaculate and concentration of sperm cells
All ejaculates were found to be normal, with an average volume of 127 ml for the sperm-rich phase (2 + 3) fractions and 375 ml for the total ejaculates. The concentrations of sperm cells ranged between 1.35 and 7.60 × 108 cells/ml with an average of 4.50 × 108 cells/ml. The average output in the
Discussion
There are many factors that adversely affect the quality of semen used for artificial insemination, of which bacterial contamination is a very important one (García et al., 1998). Contamination can be the result of urinary tract infection (Serrano et al., 1994) but it may also occur during semen collection (Arauz et al., 2000).
Only few studies are described in literature on the effect of bacteria on sperm cells of animals in general, and of boars in particular. One of the reasons might be that
Conclusion
Our study shows that: (1) the presence of E. coli either alone or together with other Gram negative bacteria may have an important influence on the agglutination of boar spermatozoa and hence negatively affects the litter size obtained from sows inseminated with such semen samples, and (2) that examination of bacterial contamination of semen should be considered as a routine procedure for the evaluation of the quality of semen to be used for artificial insemination. Semen contaminated with more
Acknowledgements
The authors thank VLIR-UDC (Flemish Interuniversity Council – University Development Cooperation) for financial support through an “Own Initiative” project and through an “Institutional University Cooperation” programme. L.O. Maroto Martin also thanks VUBAROS for a scholarship that allowed him to perform research at the Vrije Universiteit Brussel. The Regional Centre of Veterinary Diagnostics, as well as the Laboratory of Microbiology at the Faculty of Agriculture and Animal Science (Santa
References (52)
- et al.
Bacteriospermia in extended porcine semen
Theriogenology
(2005) - et al.
Field investigations of bacterial contaminants and their effects on extended porcine semen
Theriogenology
(2000) - et al.
Escherichia coli, fimbriae, bacterial persistence and host response induction in the human urinary tract
Int. J. Med. Microbiol.
(2005) - et al.
Effects of season and breed on sperm acrosin activity and semen quality of boars
Anim. Reprod. Sci.
(2000) - et al.
Carbohydrate moieties on sperm surface: physiological relevance
Fertil. Steril.
(1995) - et al.
Adherence of Escherichia coli to sperm: a mannose mediated phenomenon leading to agglutination of sperm and E. coli
Fertil. Steril.
(1993) - et al.
Contaminant growth of spermicidal bacteria in extended porcine semen
- et al.
Estudio bacteriológico del semen porcino. Congreso Mercosur de Producción Porcina
(2000) - et al.
Estudio bacteriológico del semen porcino. Valoración preliminar del efecto de las lectinas de Escherichia coli en la aglutinación espermática (Bacteriological studies of swine semen. Preliminar evaluation of the effect of Escherichia coli lectins on spermagglutination)
Rev. Cub. Sal. Animal
(2001) - et al.
Is the sperm bacterial ratio a determining factor in impairment of sperm motility: an in-vitro study in man with Escherichia coli
Int. J. Androl.
(1991)
Virulence characteristics of male genital tract Escherichia coli isolated from semen of suspected infertile men
Andrologia
Factores de virulencia y serogrupos O de Escherichia coli causantes de infecciones urinarias comunitarias
Enferm. Infecc. Microbiol. Clinic
Genes coding for enterotoxins and verotoxins in porcine enteropathogenic Escherichia coli strains belonging to different O:K:H serotypes. Relation with toxic phenotypes
J. Clin. Microbiol.
The incidence of agglutination and its influence on sperm quality and fertility of boar semen
Berl. Munch. Tierarztl. Wochenschr.
Francis Galton: Pioneer of Heredity and Biometry
Evaluación bacteriológica de semen de verracos usados como reproductores en granjas porcinas de la zona de Lurín
Lima. Rev. Inv Vet Perú
Mechanisms of sperm deficiency in male accessory gland infection
Andrologia
Escherichia coli-induced alterations of human spermatozoa. An electron microscopy analysis
Int. J. Androl.
Influence of Escherichia coli on motility parameters of human spermatozoa in vitro
Int. J. Androl.
Effects of four methods of sperm preparation on motion characteristics and nitric oxide concentration in laboratory-prepared oligospermia
Zhonghua Yi Xue Za Zhi (Taipei)
Circulating antisperm antibodies and fertility prognosis: a prospective study
Hum. Reprod.
Sperm-preparation techniques for men with normal and abnormal semen analysis. A comparison
J. Reprod. Med.
Memorias del V Simposium Internacional de Reproducción e Inseminación Artificial en Porcinos
Cited by (103)
Low-density colloid centrifugation removes bacteria from boar semen doses after spiking with selected species
2023, Research in Veterinary ScienceBiological and chemical contaminants in extended porcine semen: Outcomes and diagnosis
2022, Animal Reproduction ScienceCooled storage of semen from livestock animals (part I): boar, bull, and stallion
2022, Animal Reproduction ScienceIcariin improves pig sperm quality through antioxidant and antibacterial effects during liquid storage at 17 °C
2022, Livestock ScienceCitation Excerpt :BC may lead to sperm agglutination, reduced viability, poor survival, acrosome damage and acidic pH, in addition to reducing sperm longevity and fertility potential during storage (Bussalleu and Torner, 2013; Lopez Rodriguez et al., 2017; Pinart et al., 2017). In addition, BC may also lead to reduced conception rates, early embryonic or fetal death, and contamination of the female reproductive tract (Maroto Martín et al., 2010; Kuster and Althouse, 2016; Pinart et al., 2017). Therefore, in practice, it is often necessary to add antioxidants and antibiotics to semen extenders to control the processes of OS and BC development.