title: Daily exposure to summer circadian cycles affects spermatogenesis, but not fertility in an in vivo rabbit model.
abstract: Heat stress (HS) in mammals is a determining factor in the deterioration of spermatogenesis and can cause infertility. The aim of this study was to evaluate the effect of continuous summer circadian cycles on semen production, sperm cell features, fertility, prolificacy, and fecal cortisol metabolites from rabbits kept under an in vivo HS model. We split randomly 60 New Zealand White rabbits into two temperature-controlled rooms: The control group was maintained at comfort temperature (18 °C-22 °C) and an HS group, where the environmental temperature was programmed to increase from 22 °C to 31 °C and be maintained for 3 hours to this temperature at the central part of the day. Fecal cortisol metabolites were assessed to evaluate the stress conditions. Seminal parameters were analyzed. Although animals exposed to HS showed higher values of fecal cortisol metabolites (P = 0.0003), no differences were detected in fertility or prolificacy. Semen samples from HS males showed a significant decrease (P < 0.05) with respect to the controls in the percentage of viable spermatozoa (80.71% vs. 74.21%), and a significant (P ≤ 0.01) increase in the percentage of acrosomic abnormalities (22.57% vs. 36.96%) and tailless spermatozoa (7.91% vs. 12.83). Among motility parameters, no differences were found. This study describes a model of HS simulating a continuous summer daily cycle that allows periods of time to recover as it occurs under natural conditions. Although negative effects have been detected in several sperm parameters, fertility and prolificacy were not affected, suggesting a recovery of the reproductive function when normal conditions are reestablished.
authors.affiliation: Department of Animal Health and Anatomy, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain. Electronic address: maria.sabes@uab.cat.
authors.forename: Maria
authors.initials: M
authors.lastname: Sabés-Alsina
authors.affiliation: Department of Gastroenterology and Bioinformatics Platform, CIBERehd, Barcelona, Spain.
authors.forename: Núria
authors.initials: N
authors.lastname: Planell
authors.affiliation: Department of Animal Health and Anatomy, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
authors.forename: Elen
authors.initials: E
authors.lastname: Torres-Mejia
authors.affiliation: Department of Animal Health and Anatomy, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
authors.forename: Ester
authors.initials: E
authors.lastname: Taberner
authors.affiliation: Department of Animal Health and Anatomy, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
authors.forename: Maria José
authors.initials: MJ
authors.lastname: Maya-Soriano
authors.affiliation: Unitat de Cunicultura, Institut de Recerca i Tecnologia Agroalimentàries, Torre Marimon s/n, 08182 Caldes de Montbui, Barcelona, Spain.
authors.forename: Llibertat
authors.initials: L
authors.lastname: Tusell
authors.affiliation: Unitat de Cunicultura, Institut de Recerca i Tecnologia Agroalimentàries, Torre Marimon s/n, 08182 Caldes de Montbui, Barcelona, Spain.
authors.forename: Josep
authors.initials: J
authors.lastname: Ramon
authors.affiliation: Subprograma de Benestar Animal, Institut de Recerca i Tecnologia Agroalimentàries, Veinat de Sies s/n, 17121 Monells, Girona, Spain.
authors.forename: Antoni
authors.initials: A
authors.lastname: Dalmau
authors.affiliation: Unitat de Cunicultura, Institut de Recerca i Tecnologia Agroalimentàries, Torre Marimon s/n, 08182 Caldes de Montbui, Barcelona, Spain.
authors.forename: Miriam
authors.initials: M
authors.lastname: Piles
authors.affiliation: Department of Animal Health and Anatomy, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain. Electronic address: manel.lopez.bejar@uab.cat.
authors.forename: Manel
authors.initials: M
authors.lastname: Lopez-Bejar
mesh_terms: D000177:Acrosome / Q000648:ultrastructure; D000818:Animals; D002470:Cell Survival; D002940:Circadian Rhythm / Q000502:physiology*; D005243:Feces / Q000737:chemistry; D005298:Fertility / Q000502:physiology*; D006358:Hot Temperature; D006854:Hydrocortisone / Q000032:analysis; D008297:Male; D023421:Models, Animal; D011817:Rabbits; D012621:Seasons; D013081:Sperm Motility; D013091:Spermatogenesis / Q000502:physiology*; D013094:Spermatozoa / Q000002:abnormalities / Q000502:physiology*
chemical_list: D006854:Hydrocortisone
keywords: Fertility; Heat stress; Prolificacy; Rabbit; Sperm viability