title: Recovery of normal testicular temperature after scrotal heat stress in rams assessed by infrared thermography and its effects on seminal characteristics and testosterone blood serum concentration.
abstract: Reestablishment of testicular normal temperature after testicular heat stress is unknown and its effect varies widely. The aim of this study was to investigate the impact of scrotal insulation (IN) on testicular temperature and its relation to semen quality and testosterone blood serum concentration. For this, 33 rams were used; 17 submitted to IN for 72 hours (using bags involving the testes) and 16 not submitted to IN (control group). The experiment was performed between August and December 2013 in Pirassununga, Brazil (21°56″13″ South/47°28'24″ West). Seminal characteristics, testosterone blood serum concentration, rectal temperature (RT), respiratory frequency, scrotal superficies mean temperature (SSMT), and eye area mean temperature (EAMT) were analyzed 7 days before IN and 21, 35, 49, 63, and 90 days afterward. Scrotal superficies mean temperature and EAMT were measured by thermography camera FLIR T620. Testosterone was evaluated by radioimmunoassay. Analysis of variance was used to determine the main effects of treatment, time, and treatment-by-time interaction using PROC MIXED of SAS software adding command REPEAT. Pearson correlation test was used to verify correlation between SSMT, EAMT, RT, and respiratory frequency. Significant difference was considered when P ≤ 0.05. At the end of IN, SSMT was higher (P < 0.05) in insulated group (32.26 ± 0.19(o)C) than in control group (30.58 ± 0.18(o)C), and the difference between rectal and testicular (deduced from SSMT) temperatures was 1.12 °C; in the other times of the evaluation this difference was between 2.91 and 4.25 °C in IN group. Scrotal superficies mean temperature was reestablished 24 hours after IN. Rectal temperature and EAMT presented correlation (r = 0.59; P < 0.0001). There was time-by-treatment interaction for total sperm (P = 0.0038) and progressive motility (P = 0.01), abnormal spermatozoa (P < 0.0001), membranes integrity (P < 0.0001), induced thiobarbituric acid reactive substances (TBARSs; P = 0.05), and DNA integrity (P = 0.0004). These semen characteristics were negatively affected 21 days after IN, and excluding induced TBARSs and abnormalities, recovered 35 days afterward; induced TBARSs just were affected after 49 days of IN; sperm abnormalities just recovered after 63 days. Testosterone blood serum concentration was lesser in insulated rams (P = 0.03). Thus, the difference of 1.12 °C between RT and testicular temperature impacts semen quality and testosterone blood serum concentration. Moreover, this study shows that rams can recover testes temperature efficiently toward IN and that infrared thermography is an efficient tool to identify differences on SSMT.
authors.affiliation: Laboratory of Teaching and Research in Pathology of Reproduction, Center of Biotechnology in Animal Reproduction, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, SP, Brazil.
authors.forename: Maíra Bianchi Rodrigues
authors.initials: MB
authors.lastname: Alves
authors.affiliation: Laboratory of Andrology and Embryo Technology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, SP, Brazil.
authors.forename: André Furugen Cesar de
authors.initials: AF
authors.lastname: Andrade
authors.affiliation: Laboratory of Semen Biotechnology and Andrology, Center of Biotechnology in Animal Reproduction, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, SP, Brazil.
authors.forename: Rubens Paes de
authors.initials: RP
authors.lastname: Arruda
authors.affiliation: Laboratory of Teaching and Research in Pathology of Reproduction, Center of Biotechnology in Animal Reproduction, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, SP, Brazil.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Batissaco
authors.affiliation: Laboratory of Teaching and Research in Pathology of Reproduction, Center of Biotechnology in Animal Reproduction, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, SP, Brazil.
authors.forename: Shirley Andrea
authors.initials: SA
authors.lastname: Florez-Rodriguez
authors.affiliation: Laboratory of Teaching and Research in Pathology of Reproduction, Center of Biotechnology in Animal Reproduction, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, SP, Brazil.
authors.forename: Bruna Marcele Martins de
authors.initials: BM
authors.lastname: Oliveira
authors.affiliation: Laboratory of Andrology and Embryo Technology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, SP, Brazil.
authors.forename: Mariana Andrade
authors.initials: MA
authors.lastname: Torres
authors.affiliation: Laboratory of Semen Biotechnology and Andrology, Center of Biotechnology in Animal Reproduction, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, SP, Brazil.
authors.forename: Renata
authors.initials: R
authors.lastname: Lançoni
authors.affiliation: Laboratory of Andrology and Embryo Technology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, SP, Brazil.
authors.forename: Gisele Mouro
authors.initials: GM
authors.lastname: Ravagnani
authors.affiliation: Laboratory of Teaching and Research in Pathology of Reproduction, Center of Biotechnology in Animal Reproduction, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, SP, Brazil.
authors.forename: Roberto Romano do
authors.initials: RR
authors.lastname: Prado Filho
authors.affiliation: Laboratory of Teaching and Research in Pathology of Reproduction, Center of Biotechnology in Animal Reproduction, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, SP, Brazil.
authors.forename: Vinícius Silva
authors.initials: VS
authors.lastname: Vellone
authors.affiliation: Laboratory of Andrology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Sao Paulo, SP, Brazil.
authors.forename: João Diego de Agostini
authors.initials: JD
authors.lastname: Losano
authors.affiliation: Laboratory of Neuroendocrinology and Reproduction, Department of Physiology, Faculty of Medicine, University of São Paulo, Ribeirao Preto, SP, Brazil.
authors.forename: Celso Rodrigues
authors.initials: CR
authors.lastname: Franci
authors.affiliation: Laboratory of Andrology, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Sao Paulo, SP, Brazil.
authors.forename: Marcílio
authors.initials: M
authors.lastname: Nichi
authors.affiliation: Laboratory of Teaching and Research in Pathology of Reproduction, Center of Biotechnology in Animal Reproduction, Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Pirassununga, SP, Brazil. Electronic address: celeghin@usp.br.
authors.forename: Eneiva Carla Carvalho
authors.initials: EC
authors.lastname: Celeghini
mesh_terms: D000818:Animals; D053938:DNA Fragmentation; D006358:Hot Temperature; D008297:Male; D012661:Semen / Q000502:physiology*; D012756:Sheep / Q000097:blood / Q000502:physiology*; D013094:Spermatozoa / Q000166:cytology / Q000502:physiology; D013737:Testis / Q000502:physiology*; D013739:Testosterone / Q000097:blood*; D013817:Thermography / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*
chemical_list: D013739:Testosterone
keywords: DNA; Insulation; Motility; Oxidative stress; Sperm; Testicular degeneration