Long term dietary deficiency in steers: vital functions and T3 and IGF-1 relationships

Abstract

Pesq. Vet. Bras. 34(9):896-902, setembro 2014 896 RESUMO.-[Carência alimentar prolongada em garrotes: funções vitais e suas relações com os teores de T 3 e IGF-1.] Para avaliar a influência de dietas deficientes de energia sobre o perfil hormonal e as funções vitais em bovinos, 12 garrotes foram aleatoriamente distribuídos em três grupos com quatro animais para receber por 140 dias, as seguintes dietas: (G1) adequada, para ganho de peso de 900g/dia (17,7 Mcal/d de ED e 13% de PB); (G2) 80% dos requerimentos de mantença (5,8 Mcal/d de ED e 7% de PB); e (G3) 60% desses requerimentos (4,7 Mcal/d de ED e 5% de PB). O déficit energético provocou nos grupos G2 e G3 acentuada diminuição da frequência cardíaca e da frequência respiratória além da redução nos teores sanguíneos de IGF-1 e T 3 . A diminuição do número de batimentos cardíacos, movimentos respiratórios e em menor grau a queda na temperatura retal refletiram o baixo status energético imprimido e foram influenciados negativamente pelos baixos teores de T 3 .Houve correlação de alta intensidade entre os hormônios T3 e IGF-1 (r=0,833). As correlações entre os hormônios T3 e IGF-1 e as funções vital exibiram altas e médias intensidades. Houve elevada correlação entre T3 e FC (r=0,701), T3 e FR (r=0,632), IGF-1 e FC (r=0,731), IGF-1 e FC (r=0,679). Houve média correlação entre T 3 e T o C (r=0,484), T 3 e insulina (r=0,506), IGF-1 e insulina (r=0,517) e IGF-1 e T o C (r=0,548). O presente trabalho apontou a influência do longo período do oferecimento de dietas deficientes em energia sobre o desempenho animal correlacionando o perfil hormonal e as funções vitais nos bovinos em crescimento. Os resultados indicaram que os parâmetros avaliados podem ser uma ferramenta importante na detecção precoce da carência nutricional. In G2 and G3, the energy deficit caused a marked decrease in the heart rate and respiratory rate and a reduction in the blood levels of Insulin like growth factor-1 (IGF-1) and triiodothyronine (T 3 ). The decrease in heart rate, respiratory movement and, to a lesser extent, reduction of the rectal temperature, reflected the low status of energy and was negatively impacted by the low levels of T 3 . There was a strong correlation between the hormones T 3 and IGF-1 (r=0.833). There were also strong correlations between T 3 and HR (r=0.701), T 3 and RR (r=0.632), IGF-1 and HR (r=0.731), and IGF-1 and RR (r=0.679). There were intermediate correlations between T 3 and T o C (r=0.484), T 3 and insulin (r=0.506), IGF-1 and insulin (r=0.517), and IGF-1 and T o C (r=0.548). This study showed the influence of a long period of providing an energy-deficient diet on animal performance, correlating hormonal status and vital functions in growing cattle. The results indicated that the evaluated parameters represent an important tool for the early detection of dietary deficiency.INDEX TERMS: Cattle, vital functions. IGF-1, ruminants, T 3 .1

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