Table 1.

Examples of studies on the effects of probiotics and male reproductive health and fertility.

Test group	Probiotic species	Result
Studies on humans
Infertile male patients with semen and/or prostatic secretions positive for gram-negative bacteria	Enterococcus faecium, Saccharomyces boulardi, Lactobacilli	Negative semen culture more likely in combined probiotic and antibiotic group (73)
Men with asthenozoospermia	Lactobacillus rhamnosus CECT8361 and Bifidobacterium longum CECT7347	Improved sperm motility, decreased DNA fragmentation, decreased intracellular hydrogen peroxide, no change in cell viability (74)
Men with idiopathic oligoasthenoteratospermia	Lactobacillus paracasei, arabinogalctan, oligo-fructosaccharides and l-glutamine	Improved sperm count, sperm concentration, progressive motility, and percentage of typical forms in group treated with probiotics (75)
Men with idiopathic oligoasthenoteratozoospermia	Lactobacillus casei, Lactobacillus rhamnosus, Lactobacillus bulgaricus, Lactobacillus acidophilus, Bifidobacterium breve, Bifidobacterium longum, and Streptococcus thermophil	Improved serum testosterone, ejaculate volume, sperm concentration, total antioxidant capacity of plasma in men taking probiotics (76)
Studies on animals
Zebrafish	Lactobacillus rhamnosus and Bifidobacterium longum	Increased sperm concentration, motility, and progressive sperm motility and treatment group (77)
Male broilers	Bacillus amyloliquefaciens TOA5001	Improved sperm concentration, improved activity of antioxidative associated enzymes (78)
Male mice	Lactobacillus rhamnosus PB01	Improved serum testosterone, LH, and FSH, more motile sperm, increased sperm kinetic parameters (79)