• Asian-Australasian Journal of Animal Sciences
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• v.27 no.1
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• pp.69-76
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• 2014

This study was carried out to evaluate the relationship between threonine (Thr) efficiency and Thr dehydrogenase (TDG) activity as an indicator of Thr oxidation on chicks fed with levels of diets (CP [17.5% and 21.5%] and Thr [3.8 and 4.7 g/100 g CP]; glycine [Gly][0.64% and 0.98%] and true digestible Thr [dThr] [0.45% and 0.60%]). Calculation of the Thr efficiency was based on N-balance data and an exponential N-utilization model, and TDG activity was determined as accumulation of aminoacetone and Gly during incubation of hepatic mitochondria. This study found that in the liver of chicks who received a diet containing up to 0.79% Thr (4.7 g Thr/100 g of CP) in the 17.5% CP diet, no significant (p>0.05) effect on TDG activity was observed. However, significantly (p = 0.014) increased TDG activity was observed with a diet containing 21.5% CP (4.7 g Thr/100 g of CP) and the efficiency of Thr utilization showed a significant (p = 0.001) decrease, indicating the end of the Thr limiting range. No significant (p>0.05) effect on the total TDG activity and accumulation of Gly was observed with addition of Gly to a diet containing 0.45% dThr. In addition, addition of Gly to a diet containing 0.60% dThr also did not result in a change in accumulation of Gly. Due to an increase in accumulation of aminoacetone, an elevated effect on total TDG activity was also observed. No significant (p>0.05) reduction in the efficiency of Thr utilization was observed after addition of Gly at the level of 0.45% dThr. However, significantly (p<0.001) reduced efficiency of Thr utilization was observed after addition of Gly at the level of 0.60% dThr. Collectively, we found that TDG was stimulated not only by addition of Thr and protein to the diet, but also by addition of Gly, and efficiency of Thr utilization was favorably affected by addition of Gly at the level near to the optimal Thr concentration. In addition, no metabolic requirement of Gly through the TDG pathway was observed with almost the same accumulation of Gly and a slight increase in TDG activity by addition of Gly. Thus, our findings suggest that determination of TDG activity and parameter of efficiency of Thr utilization may be useful for evaluation of dietary Thr level.

• The Korean Journal of Food And Nutrition
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• v.15 no.3
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• pp.235-240
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• 2002

The aim of this investigation was to determine the influence of different protein and threonine (Thr) levels on the liver threonine dehydroaenase (TDG) activity b\ulcorner rats. In rats fed on CP (crude Protein) - diets, TDG activity was increased during an CP rise to 12.0% CP, decreased slightly down to 18.0% CP and showed .a trend to increase from 18.0 to 24.0% CP. In rats the feeding with graded Protein supply gavee no indication for additional stimulation of threonine-oxidation by TDG over a wide range of CP-content in the diets. The increase in threonine content from 0.28 to 0.72% in the presence of 12.0% CP caused a gradual increase in TDG activity in rat liver. This similarly applied to the feed admixed with 18.0% CP, but at a higher level.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.1
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• pp.17-24
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• 1994

The urinary excretion of ${\delta}$-aminolevulinic acid has been widely used as a measure of the biological effect of lead in lead exposed workers. It is usually measured by colorimetric method based on the color reaction of ALA-pyrrole with Ehrlich's reagent. But the results of ${\delta}$-ALA in urine by this method are somewhat artificially higher than expected due to the urinary ALA-like compound such as aminoacetone. On the other hand, the recently developed fluorometric HPLC method is very sensitive and specific for the measuring urinary ALA. In order to compare the data obtained by two methods and to investigate the interrelation between two methods, 117 lead workers with different lead exposure were checked urinary ${\delta}$-ALA, blood lead and other lead exposure related indices. The results obtained are as follows; 1. Urinary excretion of ${\delta}$-ALA by colorimetric method is 2.15 times higher than HPLC method in overall, revealing 2.47 times in workers of blood lead less than $20{\mu}g/dl$, 2.53 times in workers of blood lead $21-40{\mu}g/dl$ and 1.86 times in workers of blood lead over $41{\mu}g/dl$, respectively. 2. While the correlation coefficients of ${\delta}$-ALA measured by colorimetric method with blood lead and blood ZPP was 0.571 and 0.629, those of ${\delta}$-ALA measured by HPLC with blood lead and blood ZPP were 0.6l0 and 0.637. All the correlation coefficients were statistically significant, but there was no statistical difference of correlation coefficients between two methods. 3. The correlation coefficient of urinary excretion of ${\delta}$-ALA between two method was 0.838 without any correction, but it was 0.852 with the correction of specific gravity 1.024. 4. Simple linear regression of ${\delta}$-ALA measured by HPLC method on ${\delta}$-ALA measured by colorimetric method was (ALA-UPH)=-0.245+0.536 (ALA-UCO) without any correction and it was (SP ALA)=-0.525+0.598 (SP ALA-UCO) with the correction of specific gravity 1.024. With above results, it is recommended that the diagnostic criteria of ${\delta}$-ALA for lead poisoning needed to be revised if ${\delta}$-ALA is measured by HPLC rather than colorimetric method.