Skeletal muscle composition in various breeds of domestic dogs: (A comparative study)

dc.contributor.advisorKohn, Tertius
dc.contributor.advisorSchoeman, Johan
dc.contributor.authorvan Boom, Kathryn
dc.date.accessioned2020-02-17T07:59:27Z
dc.date.available2020-02-17T07:59:27Z
dc.date.issued2019
dc.date.updated2020-02-14T11:07:00Z
dc.description.abstractThe rising rate of insulin resistance and type 2 diabetes in humans over the past two decades have been linked to increasing rates of obesity, aging and urbanisation. A similar pattern is occurring in domestic animals, specifically cats and dogs. Skeletal muscle is a vital organ in the regulation of blood glucose. Its composition in terms of muscle fibre type, metabolism and contractility can differ substantially between species, but is poorly studied in the domestic dog, in particular the various breeds. It was hypothesised that insulin resistance and type 2 diabetes may be associated with muscle fibre type, in particular, muscle with a low type I fibre content being a predisposing factor. Therefore, the aims of this study were to investigate the skeletal muscle fibre composition and metabolic profile in the Triceps brachii (TB) and Vastus lateralis (VL) of 16 breeds of domestic dogs (Canis lupus familiaris). A secondary aim was to correlate the skeletal muscle composition with breeds reported as having a high incidence of diabetes. Skeletal muscle samples were collected post mortem from the TB and VL of 38 dogs from different breeds, age and sex, and analysed for fibre type composition, fibre size, oxidative and glycolytic metabolic capacity (citrate synthase (CS), 3-hydroxyacetyl co A dehydrogenase (3-HAD), creatine kinase (CK) and lactate dehydrogenase (LDH) enzyme activities). There was no significant difference between the TB and VL in any of the measurements. Type IIA was the predominant fibre type for both muscle groups (TB: 43%; VL: 44%) followed by type I (TB: 33%; VL: 38%) and type IIX (TB: 24%; VL: 18%). The cross sectional area (CSA) of the fibres were all smaller compared to humans and other wild animals. Surprisingly, there was no difference in the CSA between the fibres types and muscle groups: Type I: TB: 1740 µm2 ; VL: 1712 µm2 , Type IIA: TB: 1690 µm2 ; VL: 1720 µm2 , Type IIX TB: 1726 µm2 ; VL: 1791 µm2 ). Metabolically, the muscle of the dog displayed a high oxidative capacity with high activities (all activities in µmol/min/g protein) for CS (TB: 61; VL: 49) and 3-HAD (TB: 53; VL: 46). Lower CK (TB: 6115; VL: 6279) and higher LDH (TB: 1550; VL: 1478) activities than humans indicated a lower and higher flux through the high energy phosphate and glycolytic pathway, respectively. These results indicate that the dog has a predominance of type IIA fibres along with a higher oxidative capacity. There appears to be no pattern in fibre type profile that could be associated with a predisposition of a specific breed to insulin resistance and diabetes, although many of the breeds with a known risk did not form part of the study sample. This is the first study to characterise the skeletal muscle composition of a large population of dogs (16 breeds), but the association of breed to diabetes was not found. Future studies should include younger and more animals, as well as a diabetic population of dogs.
dc.identifier.apacitationvan Boom, K. (2019). <i>Skeletal muscle composition in various breeds of domestic dogs: (A comparative study)</i>. (). ,Faculty of Health Sciences ,Department of Human Biology. Retrieved from http://hdl.handle.net/11427/31125en_ZA
dc.identifier.chicagocitationvan Boom, Kathryn. <i>"Skeletal muscle composition in various breeds of domestic dogs: (A comparative study)."</i> ., ,Faculty of Health Sciences ,Department of Human Biology, 2019. http://hdl.handle.net/11427/31125en_ZA
dc.identifier.citationvan Boom, K. 2019. Skeletal muscle composition in various breeds of domestic dogs: (A comparative study).en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - van Boom, Kathryn AB - The rising rate of insulin resistance and type 2 diabetes in humans over the past two decades have been linked to increasing rates of obesity, aging and urbanisation. A similar pattern is occurring in domestic animals, specifically cats and dogs. Skeletal muscle is a vital organ in the regulation of blood glucose. Its composition in terms of muscle fibre type, metabolism and contractility can differ substantially between species, but is poorly studied in the domestic dog, in particular the various breeds. It was hypothesised that insulin resistance and type 2 diabetes may be associated with muscle fibre type, in particular, muscle with a low type I fibre content being a predisposing factor. Therefore, the aims of this study were to investigate the skeletal muscle fibre composition and metabolic profile in the Triceps brachii (TB) and Vastus lateralis (VL) of 16 breeds of domestic dogs (Canis lupus familiaris). A secondary aim was to correlate the skeletal muscle composition with breeds reported as having a high incidence of diabetes. Skeletal muscle samples were collected post mortem from the TB and VL of 38 dogs from different breeds, age and sex, and analysed for fibre type composition, fibre size, oxidative and glycolytic metabolic capacity (citrate synthase (CS), 3-hydroxyacetyl co A dehydrogenase (3-HAD), creatine kinase (CK) and lactate dehydrogenase (LDH) enzyme activities). There was no significant difference between the TB and VL in any of the measurements. Type IIA was the predominant fibre type for both muscle groups (TB: 43%; VL: 44%) followed by type I (TB: 33%; VL: 38%) and type IIX (TB: 24%; VL: 18%). The cross sectional area (CSA) of the fibres were all smaller compared to humans and other wild animals. Surprisingly, there was no difference in the CSA between the fibres types and muscle groups: Type I: TB: 1740 µm2 ; VL: 1712 µm2 , Type IIA: TB: 1690 µm2 ; VL: 1720 µm2 , Type IIX TB: 1726 µm2 ; VL: 1791 µm2 ). Metabolically, the muscle of the dog displayed a high oxidative capacity with high activities (all activities in µmol/min/g protein) for CS (TB: 61; VL: 49) and 3-HAD (TB: 53; VL: 46). Lower CK (TB: 6115; VL: 6279) and higher LDH (TB: 1550; VL: 1478) activities than humans indicated a lower and higher flux through the high energy phosphate and glycolytic pathway, respectively. These results indicate that the dog has a predominance of type IIA fibres along with a higher oxidative capacity. There appears to be no pattern in fibre type profile that could be associated with a predisposition of a specific breed to insulin resistance and diabetes, although many of the breeds with a known risk did not form part of the study sample. This is the first study to characterise the skeletal muscle composition of a large population of dogs (16 breeds), but the association of breed to diabetes was not found. Future studies should include younger and more animals, as well as a diabetic population of dogs. DA - 2019 DB - OpenUCT DP - University of Cape Town KW - sports medicine LK - https://open.uct.ac.za PY - 2019 T1 - Skeletal muscle composition in various breeds of domestic dogs: (A comparative study) TI - Skeletal muscle composition in various breeds of domestic dogs: (A comparative study) UR - http://hdl.handle.net/11427/31125 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/31125
dc.identifier.vancouvercitationvan Boom K. Skeletal muscle composition in various breeds of domestic dogs: (A comparative study). []. ,Faculty of Health Sciences ,Department of Human Biology, 2019 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/31125en_ZA
dc.language.rfc3066eng
dc.publisher.departmentDepartment of Human Biology
dc.publisher.facultyFaculty of Health Sciences
dc.subjectsports medicine
dc.titleSkeletal muscle composition in various breeds of domestic dogs: (A comparative study)
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMSc
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