Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.psj.2026.106408

Publishing type：Research paper (scientific journal)   Publisher：Wiley  

ABSTRACT

We aimed to identify metabolites and metabolic pathways involved in differences in muscle protein degradation in broiler chicks during the neonatal period. To this end, we performed gas chromatography–mass spectrometry‐based metabolomic analyses of plasma, pectoralis major muscle, and liver samples. Based on body weight gain from 1 to 5 days of age, 5‐day‐old broiler chicks (Ross308) were divided into three groups (slow‐, intermediate‐, and fast‐growing groups). First, we confirmed that muscle protein degradation levels were closely associated with body weight gain. Untargeted metabolomic analysis revealed that 4, 14, and 22 metabolites in plasma, muscle, and liver, respectively, were correlated with the body weight gain of chicks from 1 to 5 days of age (Pearson's correlation, | r | ≥ 0.4). Most metabolic pathways identified in plasma and muscle were involved in either protein or amino acid metabolism, while those in liver were related to tricarboxylic acid cycle and carbohydrate metabolism. Interestingly, the expression of genes encoding enzymes related to branched‐chain amino acid (BCAA) catabolism were higher in the slow‐growing chicks than in the fast‐growing ones. These results suggest that BCAA catabolism is important for muscle protein degradation levels and body growth of broiler chicks during the neonatal period.

DOI： 10.1111/asj.70169

Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/asj.70169

Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: Nτ-methylhistidine released endogenously from muscle into urine is an index of muscle protein breakdown, and part of Nτ-methylhistidine is excreted as the acetylated derivative, N-acetyl-Nτ-methylhistidine. OBJECTIVES: The aim of this study was to measure the urinary concentrations of Nτ-methylhistidine and N-acetyl-Nτ-methylhistidine. A quantitative method was established using liquid chromatography-tandem mass spectrometry (LC-MS/MS) operated in Q1 single-ion monitoring (SIM) mode and multiple reaction monitoring (MRM) mode with stable-isotope dilution analysis. METHODS: We synthesized N-acetyl-Nτ-methylhistidine and its isotopic analog for stable-isotope dilution analysis. Then, we validated a method for quantifying urinary concentrations of intact Nτ-methylhistidine, N-acetyl-Nτ-methylhistidine, and creatinine to precisely determine their concentrations in rats, humans, cattle, and dogs. Creatinine correction was applied to normalize for urine volume. RESULTS: For both SIM and MRM analysis, the acceptable linear ranges of detection were 5 pmol/mL to 10 nmol/mL with r2 = 1.000 in SIM mode and MRM mode. The LC-MS/MS methods operated in both SIM and MRM transitions detected changes in the urinary excretion levels of Nτ-methylhistidine and N-acetyl-Nτ-methylhistidine in response to starvation and refeeding of rats. The methods also detected urinary concentrations of Nτ-methylhistidine and N-acetyl-Nτ-methylhistidine in cattle, humans, and dogs. CONCLUSIONS: These results suggest that the LC-MS/MS method operated in SIM mode and MRM mode can be used to measure urinary concentrations of Nτ-methylhistidine and N-acetyl-Nτ-methylhistidine.

DOI： 10.1016/j.tjnut.2025.09.024

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

The release of Nτ-methylhistidine from muscle cells into the culture medium is considered an index of muscle protein breakdown. The aim of this study was to establish a quantitative method for measuring the intercellular concentrations of Nτ-methylhistidine and its isomer Nπ-methylhistidine in C2C12 myotubes via liquid chromatography-tandem mass spectrometry with stable-isotope dilution analysis. The acceptable linear ranges of detection were both 0.5 to 250 pmol/mL; r2 = 1.000 (Nτ-methylhistidine), r2 = 0.999 (Nπ-methylhistidine). Culture media and cell extracts from C2C12 myotubes grown in a 6-well plate were considered acceptable samples for detecting the concentration of Nτ-methylhistidine. However, Nπ-methylhistidine was detected in neither the culture medium nor cell extracts. The proposed method can be used to confirm the effects of amino-acid-depletion on Nτ-methylhistidine levels in C2C12 myotubes. In C2C12 myotubes, culture in an amino-acid-depleted medium for 48 h increased intracellular Nτ-methylhistidine levels while decreasing its extracellular level.

DOI： 10.1093/bbb/zbaf031

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

This study aimed to evaluate the effect of supplementation with Panaferd®-AX, an astaxanthin-rich dried cell powder obtained from the carotenoid-producing bacterium Paracoccus carotinifaciens, on the muscle concentration of carotenoids, fatty acids, free amino acids, and imidazole dipeptides in broiler chickens. Thirty male broiler chickens (Ross 308) were allocated to three groups at 14 days of age. Until 28 days of age, the control group was fed a basal diet; whereas the two test groups were fed a basal diet supplemented with Panaferd®-AX at 0.025% or 0.15%, corresponding to 5 ppm or 30 ppm astaxanthin, respectively. At the end of the experiment, body weight, body weight gain, feed intake, feed conversion rate, and tissue weight did not differ between the groups. Feeding Panaferd®-AX increased muscle astaxanthin, as well as plasma zeaxanthin, and lutein concentrations, but did not affect fatty acid composition. In the pectoralis major muscle, it decreased lipid peroxidation and drip loss; while increasing carnosine content. In summary, Panaferd®-AX increased muscle antioxidant content (i.e., carotenoids and carnosine), which consequently reduced lipid peroxidation and drip loss in the skeletal muscle of broiler chickens.

DOI： 10.2141/jpsa.2025027

PubMed

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