Author(s):
Rizzoto, G. ; Ferreira, J. C.P. [UNESP] ; Mogollón Garcia, H. D. [UNESP] ; Teixeira-Neto, F. J. [UNESP] ; Bardella, L. C. ; Martins, C. L. [UNESP] ; Silva, J. R.B. [UNESP] ; Thundathil, J. C. ; Kastelic, J. P.
Date: 2020
Persistent ID: http://hdl.handle.net/11449/200014
Origin: Oasisbr
Subject(s): Heat stress; Testicular thermoregulation; Tissue oxygenation; Tissue perfusion; Heat stress; Heat stress; Testicular thermoregulation; Testicular thermoregulation; Tissue oxygenation; Tissue oxygenation; Tissue perfusion; Tissue perfusion
Description
Made available in DSpace on 2020-12-12T01:55:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-15
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Natural Sciences and Engineering Research Council of Canada
Bull testes must be 4–5 °C below body temperature, with testicular warming more likely to cause poor-quality sperm in Bos taurus (European/British) versus Bos indicus (Indian/zebu) bulls. Despite a long-standing dogma that testicular hyperthermia causes hypoxia, we reported that increasing testicular temperature in bulls and rams enhanced testicular blood flow and O2 delivery/uptake, without hypoxia. Our objective was to determine effects of short-term testicular hyperthermia on testicular blood flow, O2 delivery and uptake and evidence of testicular hypoxia in pubertal Angus (B. taurus) and Nelore (B. indicus) bulls (nine per breed) under isoflurane anesthesia. As testes were warmed from 34 to 40 °C, there were increases (P < 0.0001, but no breed effects) in testicular blood flow (mean ± SEM, 9.59 ± 0.10 vs 17.67 ± 0.29 mL/min/100 g, respectively), O2 delivery (1.79 ± 0.06 vs 3.44 ± 0.11 mL O2/min/100 g) and O2 consumption (0.69 ± 0.07 vs 1.25 ± 0.54 mL O2/min/100 g), but no indications of testicular hypoxia. Hypotheses that: 1) both breeds increase testicular blood flow in response to testicular warming; and 2) neither breed has testicular hypoxia, were supported; however, the hypothesis that the relative increase in blood flow is greater in Angus versus Nelore was not supported. Although these were short-term increases in testicular temperature in anesthetized bulls, results did not support the long-standing dogma that increased testicular temperature does not increase testicular blood flow and an ensuing hypoxia is responsible for decreases in motile, morphologically normal and fertile sperm.
Department of Production Animal Health Faculty of Veterinary Medicine University of Calgary
Department of Animal Reproduction and Veterinary Radiology School of Veterinary Medicine and Animal Science São Paulo State University (UNESP)
Department of Veterinary Surgery and Anesthesiology School of Veterinary Medicine and Animal Science São Paulo State University (UNESP)
School of Medicine Experimental Research Unit
Department of Animal Breeding and Nutrition School of Veterinary Medicine and Animal Science São Paulo State University (UNESP)
Department of Animal Reproduction and Veterinary Radiology School of Veterinary Medicine and Animal Science São Paulo State University (UNESP)
Department of Veterinary Surgery and Anesthesiology School of Veterinary Medicine and Animal Science São Paulo State University (UNESP)
Department of Animal Breeding and Nutrition School of Veterinary Medicine and Animal Science São Paulo State University (UNESP)
FAPESP: #2018/02007-6
Natural Sciences and Engineering Research Council of Canada: RGPIN-2019-04823
