Diferentes fluidos corporais, intervalos de amostragem e efeito do sexo na aplicação do método da água duplamente marcada em gatos
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Data
2018-02-16
Autores
Goloni, Camila
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Universidade Estadual Paulista (Unesp)
Resumo
O gasto energético diário (GED) de gatos tem sido estudado há algum tempo em gatos de laboratório, com ambiente, alimentação e massa corporal controlados. O metabolismo energético destes animais pode ser dividido em quatro compartimentos: taxa metabólica basal que soma o maior GED destes animais em torno de 60%, a atividade muscular voluntária contribuindo em torno de 30%, seguido do incremento calórico e termogênese adaptativa (10%). Nota-se que a atividade muscular voluntária contribui com porção considerável do GED destes animais, não devendo ser limitada, pois interfere diretamente no gasto energético. Estudos com animais em domicílio, com número representativo de grandes populações, que apresentam rotina de vida normal com protocolo prático e eficaz, de fácil aceitação pelos proprietários para mensurar GE, composição corporal (CC) e fluxo de água (FA) no estilo de vida habitual de gatos é importante para estudos nutricionais mais precisos. Método prático e eficaz para mensuração destes parâmetros, de fácil aplicação em domicílio e que não interfira no estilo de vida e atividade física dos animais é o método da água duplamente marcada que os mensura por meio do enriquecimento e decaimento de deutério (2H) e oxigênio 18 (18O) na água corporal. O objetivo do presente trabalho foi avaliar protocolo prático de tempos de coleta de enriquecimento (2, 4, 6, 7 e 8 horas) e decaimento (2, 4, 6, 8, 10, 12, 14, 16, 18 e 20 dias), bem como os fluidos corporais alternativos saliva e urina, em comparação com o fluido padrão sangue para avaliação da concentração dos isótopos em gatos machos e fêmeas. No estudo do protocolo de tempos de coleta, verificou-se que o ponto máximo de enriquecimento foi às 5h (P<0,0001; R2=0,82) e que o decaimento foi linear (R2=0.99; P<0•0001), com resultados semelhantes para estimativa do GED em qualquer dia de coleta(P=0•999). Catorze gatos adultos, sete machos e sete fêmeas, castrados e saudáveis, tiveram sangue, saliva e urina coletados nos tempos basal, 5h, 7, 10 e 14 dias após aplicação de solução isotópica. O enriquecimento de 2H e 18O foi menor na urina (P<0.05), mas semelhante entre sangue e saliva. Já o decaimento não diferiu entre fluidos. Não houve efeito de fluído para as variáveis CC, GED e FA. O GED foi maior nos machos (78kcal/kg0,67/dia) do que nas fêmeas (63kcal/kg0,67/dia), sem diferenças entre sexos na composição corporal percentual. Na estatística Bland e Altman e Correlação de Pearson houve correlação entre o GED estimado com sangue e saliva (viés= 0,4; r=0,86; p<0,001), mas não entre sangue e urina (viés=-4,5; r=0,27; p=0,441). Concluiu-se que o fluido saliva pode ser empregado em substituição ao fluido padrão sangue e, apesar de gatos machos e fêmeas terem apresentado composição corporal semelhantes, machos demonstraram maior gasto energético.
The energy expenditure (EE) of cats has been studied for some time in laboratory cats, with controlled environment, feeding and body mass. The energy metabolism of these animals can be divided into four compartments: basal metabolic rate that sums the highest EE of these animals around 60%, voluntary muscle activity contributing around 30%, followed by caloric increment and adaptive thermogenesis (10%). It is noted that voluntary muscle activity contributes a considerable portion of the EE of these animals, and should not be limited, as it directly interferes with energy expenditure. Studies with animals at home, with a representative number of large populations, that present normal life routine with a practical and efficient protocol, easily accepted by the owners to measure EE, body composition (BC) and water turnover (WT) in lifestyle of cats is important for more accurate nutritional studies. A practical and effective method for measuring these parameters, which is easy to apply at home and does not interfere with the animals' lifestyle and physical activity, is the double labeled water method that measures them through the enrichment and decay of deuterium (2H) and oxygen 18 ( 18O) in body water. The aim of the present study was to evaluate the practical protocol of enrichment collection times (2, 4, 6, 7 and 8 hours) and decay (2, 4, 6, 8, 10, 12, 14, 16, 18 and 20 days ) as well as alternative body fluids saliva and urine compared to blood for assessing the concentration of isotopes in male and female cats. In the study of the collection time protocol, it was verified that the maximum point of enrichment was at 5h (P<0.0001; R2 = 0.82) and that the decay was linear (R2 =0.99; P<0.0001), with similar results for EE estimation on any day of collection (P=0.999). Fourteen adult cats, seven males and seven females, castrated and healthy, had blood, saliva and urine collected at baseline, 5h, 7, 10 and 14 days after application of isotope solution. The enrichment of 2H and 18O was lower in urine (P<0.05), but similar between blood and saliva. The decay did not differ between fluids. There was no fluid effect for the BC, EE and WT variables. EE was higher in males (78 kcal/kg0.67 /day) than in females (63 kcal/kg0.67 /day), with no differences between sexes in the percentage body composition. In Bland and Altman and Pearson correlation, there was a correlation between estimated EE with blood and saliva (bias=0.4, r=0.86, P<0.001), but not difference between blood and urine (bias=-4.5, r=0.27, P=0.441). It was concluded that saliva fluid can be used instead of standard blood fluid, and although male and female cats showed similar body composition, males showed different energy expenditure.
The energy expenditure (EE) of cats has been studied for some time in laboratory cats, with controlled environment, feeding and body mass. The energy metabolism of these animals can be divided into four compartments: basal metabolic rate that sums the highest EE of these animals around 60%, voluntary muscle activity contributing around 30%, followed by caloric increment and adaptive thermogenesis (10%). It is noted that voluntary muscle activity contributes a considerable portion of the EE of these animals, and should not be limited, as it directly interferes with energy expenditure. Studies with animals at home, with a representative number of large populations, that present normal life routine with a practical and efficient protocol, easily accepted by the owners to measure EE, body composition (BC) and water turnover (WT) in lifestyle of cats is important for more accurate nutritional studies. A practical and effective method for measuring these parameters, which is easy to apply at home and does not interfere with the animals' lifestyle and physical activity, is the double labeled water method that measures them through the enrichment and decay of deuterium (2H) and oxygen 18 ( 18O) in body water. The aim of the present study was to evaluate the practical protocol of enrichment collection times (2, 4, 6, 7 and 8 hours) and decay (2, 4, 6, 8, 10, 12, 14, 16, 18 and 20 days ) as well as alternative body fluids saliva and urine compared to blood for assessing the concentration of isotopes in male and female cats. In the study of the collection time protocol, it was verified that the maximum point of enrichment was at 5h (P<0.0001; R2 = 0.82) and that the decay was linear (R2 =0.99; P<0.0001), with similar results for EE estimation on any day of collection (P=0.999). Fourteen adult cats, seven males and seven females, castrated and healthy, had blood, saliva and urine collected at baseline, 5h, 7, 10 and 14 days after application of isotope solution. The enrichment of 2H and 18O was lower in urine (P<0.05), but similar between blood and saliva. The decay did not differ between fluids. There was no fluid effect for the BC, EE and WT variables. EE was higher in males (78 kcal/kg0.67 /day) than in females (63 kcal/kg0.67 /day), with no differences between sexes in the percentage body composition. In Bland and Altman and Pearson correlation, there was a correlation between estimated EE with blood and saliva (bias=0.4, r=0.86, P<0.001), but not difference between blood and urine (bias=-4.5, r=0.27, P=0.441). It was concluded that saliva fluid can be used instead of standard blood fluid, and although male and female cats showed similar body composition, males showed different energy expenditure.
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Palavras-chave
oxigênio 18, deutério, gasto energético, composição corporal, gatos, oxygen 18, deuterium, energy expenditure, body composition, cats