scholarly journals Effects of Heat Stress on the Ruminal Epithelial Barrier of Dairy Cows Revealed by Micromorphological Observation and Transcriptomic Analysis

2022 ◽  
Vol 12 ◽  
Author(s):  
Zitai Guo ◽  
Shengtao Gao ◽  
Jun Ding ◽  
Junhao He ◽  
Lu Ma ◽  
...  

Heat stress (HS) alters the rumen fermentation of dairy cows thereby affecting the metabolism of rumen papillae and thus the epithelial barrier function. The aim of the present study was to investigate if HS damages the barrier function of ruminal epithelia. Eight multiparous Holstein dairy cows with rumen cannula were randomly equally allocated to two replicates (n = 4), with each replicate being subjected to heat stress or thermal neutrality and pair-feeding in four environmental chambers. Micromorphological observation showed HS aggravated the shedding of the corneum and destroyed the physical barrier of the ruminal epithelium to a certain extent. Transcriptomics analysis of the rumen papillae revealed pathways associated with DNA replication and repair and amino acid metabolism were perturbated, the biological processes including sister chromatid segregation, etc. were up-regulated by HS, while the MAPK and NF-kB cell signaling pathways were downregulated. However, no heat stress-specific change in the expression of tight junction protein or TLR4 signaling was found, suggesting that HS negatively affected the physical barrier of the ruminal epithelium to some extent but did not break the ruminal epithelium. Heat stress invoked mechanisms to maintain the integrity of the rumen epithelial barrier by upregulating the expression of heat shock protein and repairments in rumen papillae. The increase in amino acid metabolism in rumen papillae might affect the nutrient utilization of the whole body. The findings of this study may inform future research to better understand how heat stress affects the physiology and productivity of lactating cows and the development of mitigation strategies.

2015 ◽  
Vol 98 (11) ◽  
pp. 7944-7961 ◽  
Author(s):  
M. Larsen ◽  
C. Galindo ◽  
D.R. Ouellet ◽  
G. Maxin ◽  
N.B. Kristensen ◽  
...  

GeroScience ◽  
2021 ◽  
Author(s):  
Haihui Zhuang ◽  
Sira Karvinen ◽  
Timo Törmäkangas ◽  
Xiaobo Zhang ◽  
Xiaowei Ojanen ◽  
...  

AbstractAerobic capacity is a strong predictor of longevity. With aging, aerobic capacity decreases concomitantly with changes in whole body metabolism leading to increased disease risk. To address the role of aerobic capacity, aging, and their interaction on metabolism, we utilized rat models selectively bred for low and high intrinsic aerobic capacity (LCRs/HCRs) and compared the metabolomics of serum, muscle, and white adipose tissue (WAT) at two time points: Young rats were sacrificed at 9 months of age, and old rats were sacrificed at 21 months of age. Targeted and semi-quantitative metabolomics analysis was performed on the ultra-pressure liquid chromatography tandem mass spectrometry (UPLC-MS) platform. The effects of aerobic capacity, aging, and their interaction were studied via regression analysis. Our results showed that high aerobic capacity is associated with an accumulation of isovalerylcarnitine in muscle and serum at rest, which is likely due to more efficient leucine catabolism in muscle. With aging, several amino acids were downregulated in muscle, indicating more efficient amino acid metabolism, whereas in WAT less efficient amino acid metabolism and decreased mitochondrial β-oxidation were observed. Our results further revealed that high aerobic capacity and aging interactively affect lipid metabolism in muscle and WAT, possibly combating unfavorable aging-related changes in whole body metabolism. Our results highlight the significant role of WAT metabolism for healthy aging.


2020 ◽  
Vol 112 (6) ◽  
pp. 1468-1484 ◽  
Author(s):  
Grith Højfeldt ◽  
Jacob Bülow ◽  
Jakob Agergaard ◽  
Ali Asmar ◽  
Peter Schjerling ◽  
...  

ABSTRACT Background Efficacy of protein absorption and subsequent amino acid utilization may be reduced in the elderly. Higher protein intakes have been suggested to counteract this. Objectives We aimed to elucidate how habituated amounts of protein intake affect the fasted state of, and the stimulatory effect of a protein-rich meal on, protein absorption, whole-body protein turnover, and splanchnic amino acid metabolism. Methods Twelve men (65–70 y) were included in a double-blinded crossover intervention study, consisting of a 20-d habituation period to a protein intake at the RDA or a high amount [1.1 g · kg lean body mass (LBM)−1 · d−1 or >2.1 g · kg LBM−1 · d−1, respectively], each followed by an experimental trial with a primed, constant infusion of D8-phenylalanine and D2-tyrosine. Arterial and hepatic venous blood samples were obtained after an overnight fast and repeatedly 4 h after a standardized meal including intrinsically labeled whey protein concentrate and calcium-caseinate proteins. Blood was analyzed for amino acid concentrations and phenylalanine and tyrosine tracer enrichments from which whole-body and splanchnic amino acid and protein kinetics were calculated. Results High (compared with the recommended amount of) protein intake resulted in a higher fasting whole-body protein turnover with a resultant mean ± SEM 0.03 ± 0.01 μmol · kg LBM−1 · min−1 lower net balance (P < 0.05), which was not rescued by the intake of a protein-dense meal. The mean ± SEM plasma protein fractional synthesis rate was 0.13 ± 0.06%/h lower (P < 0.05) after habituation to high protein. Furthermore, higher fasting and postprandial amino acid removal were observed after habituation to high protein, yielding higher urea excretion and increased phenylalanine oxidation rates (P < 0.01). Conclusions Three weeks of habituation to high protein intake (>2.1 g protein · kg LBM−1 · d−1) led to a significantly higher net protein loss in the fasted state. This was not compensated for in the 4-h postprandial period after intake of a meal high in protein. This trial was registered at clinicaltrials.gov as NCT02587156.


2002 ◽  
Vol 282 (4) ◽  
pp. E931-E936 ◽  
Author(s):  
Bruce W. Patterson ◽  
Jeffrey F. Horowitz ◽  
Guoyao Wu ◽  
Malcolm Watford ◽  
Simon W. Coppack ◽  
...  

The effect of obesity on regional skeletal muscle and adipose tissue amino acid metabolism is not known. We evaluated systemic and regional (forearm and abdominal subcutaneous adipose tissue) amino acid metabolism, by use of a combination of stable isotope tracer and arteriovenous balance methods, in five lean women [body mass index (BMI) <25 kg/m2] and five women with abdominal obesity (BMI 35.0–39.9 kg/m2; waist circumference >100 cm) who were matched on fat-free mass (FFM). All subjects were studied at 22 h of fasting to ensure that the subjects were in net protein breakdown during this early phase of starvation. Leucine rate of appearance in plasma (an index of whole body proteolysis), expressed per unit of FFM, was not significantly different between lean and obese groups (2.05 ± 0.18 and 2.34 ± 0.04 μmol · kg FFM−1 · min−1, respectively). However, the rate of leucine release from forearm and adipose tissues in obese women (24.0 ± 4.8 and 16.6 ± 6.5 nmol · 100 g−1 · min−1, respectively) was lower than in lean women (66.8 ± 10.6 and 38.6 ± 7.0 nmol · 100 g−1 · min−1, respectively; P < 0.05). Approximately 5–10% of total whole body leucine release into plasma was derived from adipose tissue in lean and obese women. The results of this study demonstrate that the rate of release of amino acids per unit of forearm and adipose tissue at 22 h of fasting is lower in women with abdominal obesity than in lean women, which may help obese women decrease body protein losses during fasting. In addition, adipose tissue is a quantitatively important site for proteolysis in both lean and obese subjects.


1989 ◽  
Vol 77 (1) ◽  
pp. 113-120 ◽  
Author(s):  
James D. Albert ◽  
Dwight E. Matthews ◽  
Adrian Legaspi ◽  
Kevin J. Tracey ◽  
Malayappa Jeevanandam ◽  
...  

1. The effect of a daily submaximal exercise regimen on whole-body and peripheral tissue amino acid metabolism during weight-stable intravenous feeding (IVF) was evaluated in 11 normal volunteers. Five of the subjects performed 1 h of daily bicycle exercise at 75 W during IVF, while the remaining six subjects received IVF without daily exercise. Body nitrogen balance, leg and forearm plasma amino acid flux and whole-body kinetics were measured before and on day 10 of IVF using a [1-13C]leucine and [15N]glycine tracer. 2. At the end of the IVF period, exercised subjects demonstrated leg uptake of total amino acids (237 ± 103 nmol min−1 100 ml−1 of tissue, mean ± sem) which was significantly (P < 0.05) different than in non-exercised subjects (− 1101 ± 253 nmol min−1 100 ml−1 of tissue). 3. In the non-exercised forearm, a significant (P < 0.05) decrease in total amino acid flux was observed in exercised subjects (− 162 ± 88 nmol min−1 100 ml−1 of tissue) compared with non-exercised subjects (−460 ± 105 nmol min−1 100 ml−1 of tissue) on day 10 of IVF. 4. Efflux of 3-methylhistidine significantly (P < 0.05) decreased from the leg in those subjects who performed daily exercise (−0.29 ± 0.12 nmol min−1 100 ml−1 of tissue) compared with those subjects receiving IVF without daily exercise (− 1.46 ± 0.35 nmol min−1 100 ml−1 of tissue). 5. Although IVF increased whole-body leucine turnover in both exercised and non-exercised subjects, only exercised subjects demonstrated a significant (P < 0.05) increase in leucine oxidation which was proportionate to an increased muscle uptake of leucine. Whole-body protein breakdown, as assessed by [15N]glycine, was significantly (P < 0.05) decreased in exercised subjects compared with non-exercised subjects during IVF. 6. These data demonstrate that daily submaximal exercise produced a systemic as well as limb-specific enhancement of amino acid balance in muscle, providing an anti-catabolic response under conditions of partial immobility induced by hospitalization.


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