Effects of dietary energy intake and cold exposure on kinetics of plasma phenylalanine, tyrosine and protein synthesis in sheep

Abstract

An isotope dilution method of [2H5]phenylalanine (Phe) and [2H2]tyrosine (Tyr) was used to determine the effects of metabolisable energy (ME) intake and cold exposure on plasma Phe and Tyr turnover rates in sheep. Whole body protein synthesis (WBPS) was calculated with the [2H5]Phe model. Eight adult sheep were assigned to two dietary treatments receiving the same amount of crude protein and either 515 or 828 kJ x kg BW(-0.75) x d(-1) of ME (Me-ME diet and Hi-ME diet, respectively) with a crossover design for two 28 d periods. The sheep were exposed from a thermoneutral environment (23 +/- 1 degrees C) to a cold environment (2 +/- 1 to 4 +/- 1 degrees C) for 6 d for each dietary treatment. The primed-continuous infusion method of isotope dilution was conducted in both environmental temperatures. Plasma Phe turnover rate (PheTR) tended to be greater and plasma Tyr turnover rate (TyrTR) was greater (p = 0.03) for the Hi-ME diet compared with the Me-ME diet. Plasma PheTR increased (p = 0.04) and plasma TyrTR tended to increase during cold exposure. Whole body protein synthesis tended to be greater for the Hi-ME diet compared with the Me-ME diet and increased (p = 0.03) during cold exposure compared to the thermoneutral environment, but no interaction was detected. It was concluded that in sheep, plasma PheTR and WBPS (as determined by the [2H5]Phe model) tended to be influenced by and plasma TyrTR was influenced by ME intake. Further, plasma PheTR and WBPS increased and plasma TyrTR tended to increase during cold exposure.

Effects of Chinese herbal medicine and cold exposure on plasma glucose, leucine and energy metabolism in sheep

“…Miaron and Christopherson (1997) stated that acute cold exposure may exert relatively small effects on whole blood arterial amino acid concentrations in sheep. A previous report of Sano, Murakami, Sasaki, and Al-Mamun (2010) showed that plasma amino acid concentrations were little influenced (only leucine, valine and glutamine changed) by cold exposure in sheep, which agrees with our present observation.…”

Effect of feeding garlic leaf on microbial nitrogen supply, kinetics of plasma phenylalanine, tyrosine and protein synthesis in sheep

“…The current study demonstrated that GL feeding might have positive effects on plasma PheTR and WBPS in sheep. The values of PheTR, TyrTR and WBPS found by our present study were comparable with previous results (Fujita et al 2006;Sano et al 2010). Until recently, to the best of our knowledge, effects of feeding garlic constituents on amino acid kinetics and WBPS have not been investigated clearly either in humans or in animals, except our previous report (Kamruzzaman et al 2011).…”

“…; Sano et al . ). Until recently, to the best of our knowledge, effects of feeding garlic constituents on amino acid kinetics and WBPS have not been investigated clearly either in humans or in animals, except our previous report (Kamruzzaman et al .…”