Influence of incubation, diet, and sex on avian uncoupling protein expression and oxidative stress in market age broilers following exposure to acute heat stress.

Genetic selection for rapid growth in broilers has inadvertently resulted in increased susceptibility to heat stress, particularly in male birds. Increased oxidative stress associated with hyperthermia may be reduced by avian uncoupling protein (avUCP), which has been proposed to modulate free radical production. However, the relationship between avUCP expression and current heat stress management strategies is unclear. Embryonic acclimation or thermal manipulation (TM) and dietary fat source are 2 heat stress interventions that may alter avUCP expression and oxidative stress, but the literature is inconclusive. The objective of this trial was to investigate the effect of TM and dietary fat source on avUCP gene expression and oxidative damage in the breast meat of market age broilers before and after acute heat challenge. The influence of bird sex was also evaluated as broilers exhibit a high degree of sexual dimorphism in growth and stress susceptibility. Concentration of thiobarbituric acid reactive substances (TBARS) was measured as a marker of oxidative damage. Embryonic TM occurred from incubation d 7 to 16 for 12 h daily at 39.5°C. Dietary treatments were applied during the finisher period using either poultry fat, soya oil, or olive oil supplemented at 4.5% in the diet. Acute heat stress (AHS) occurred on d 43 at 32°C for 4 h. Bird performance was decreased by TM, but no significant differences were noted between dietary fat source treatments. Neither avUCP nor TBARS concentrations were significantly influenced by TM or dietary fat source. Downregulation of avUCP was observed following AHS, concurrent with an increase in TBARS concentration. Male birds exhibited higher levels of both avUCP expression and TBARS compared to females and a significant interaction was noted for heat stress by sex, with avUCP expression being greatest in males prior to AHS. The increase in avUCP expression and TBARS concentrations in male birds may be associated with an increased susceptibility to stress arising from the increased growth rate noted for male broilers.

Characterization of In Vivo Function(s) of Members of the Plant Mitochondrial Carrier Family.

Although structurally related, mitochondrial carrier family (MCF) proteins catalyze the specific transport of a range of diverse substrates including nucleotides, amino acids, dicarboxylates, tricarboxylates, cofactors, vitamins, phosphate and H+. Despite their name, they do not, however, always localize to the mitochondria, with plasma membrane, peroxisomal, chloroplast and thylakoid and endoplasmic reticulum localizations also being reported. The existence of plastid-specific MCF proteins is suggestive that the evolution of these proteins occurred after the separation of the green lineage. That said, plant-specific MCF proteins are not all plastid-localized, with members also situated at the endoplasmic reticulum and plasma membrane. While by no means yet comprehensive, the in vivo function of a wide range of these transporters is carried out here, and we discuss the employment of genetic variants of the MCF as a means to provide insight into their in vivo function complementary to that obtained from studies following their reconstitution into liposomes.

Platelet bioenergetics correlate with muscle energetics and are altered in older adults.

BACKGROUND: Physical function decreases with age, and though bioenergetic alterations contribute to this decline, the mechanisms by which mitochondrial function changes with age remains unclear. This is partially because human mitochondrial studies require highly invasive procedures, such as muscle biopsies, to obtain live tissue with functional mitochondria. However, recent studies demonstrate that circulating blood cells are potentially informative in identifying systemic bioenergetic changes. Here, we hypothesize that human platelet bioenergetics reflect bioenergetics measured in muscle biopsies. METHODS & RESULTS: We demonstrate that maximal and ATP-linked respiratory rate measured in isolated platelets from older adults (86-93 years) correlates significantly with maximal respiration (r = 0.595; P = 0.003) measured by muscle biopsy respirometry and maximal ATP production (r = 0.643; P = 0.004) measured by 31P-MRS respectively, in the same individuals. Comparison of platelet bioenergetics in this aged cohort to platelets from younger adults (18-35 years) shows aged adults demonstrate lower basal and ATP-linked respiration. Platelets from older adults also show enhanced proton leak, which is likely due to increased protein levels of uncoupling protein 2, and correlates with increased gate speed in this cohort (r = 0.58; P = 0.0019). While no significant difference in glycolysis was observed in older adults compared to younger adults, platelet glycolytic rate correlated with fatigability (r = 0.44; P = 0.016). CONCLUSIONS: These data advance the mechanistic understanding of age-related changes in mitochondrial function. Further, they suggest that measuring platelet bioenergetics provides a potential supplement or surrogate for muscle biopsy measurement and may be a valuable tool to study mitochondrial involvement in age-related decline of physical function.

Dietary enzymatically treated Artemisia annua L. improves meat quality, antioxidant capacity and energy status of breast muscle in heat-stressed broilers.

BACKGROUND: Heat stress (HS) is detrimental to animal-origin food production. Artemisia annua L., a natural source of phenolic compounds and flavonoids, exhibits antioxidant properties. This study was conducted to evaluate the effects of dietary enzymatically treated Artemisia annua L. (EA) supplementation on meat quality, antioxidant capacity, and energy status of breast muscle in heat-stressed broilers. RESULTS: The inclusion of EA increased the redness, reduced drip loss, decreased reactive oxygen metabolites and thiobarbituric acid-reactive substances, increased antioxidant enzyme activities, and reduced the ferric reducing antioxidant power and free-radical scavenging abilities of breast muscle in heat-treated broilers. Dietary EA supplementation increased adenosine phosphate concentrations and energy charge, and decreased the mRNA expression levels of heat-shock protein 70 and 90, but increased the mRNA expression levels of avian uncoupling protein, peroxisome proliferator-activated receptor-γ coactivator-1α, and sirtuin 1 in the breast muscle of broilers exposed to HS. CONCLUSION: Dietary EA supplementation improved meat quality, antioxidant capacity, and energy status in breast muscle of heat-stressed broilers, which might be associated with altering pertinent mRNA expression; EA could therefore be used as a promising feed additive to mitigate HS in the poultry industry. This study recommended 1.00-1.25 g/kg EA in broiler diet. © 2018 Society of Chemical Industry.

Physiological functions of Vitamin D in adipose tissue.

Adipose tissue has long been identified as the major site of vitamin D storage. Recent studies have demonstrated that VDR and vitamin D metabolizing enzymes are expressed in adipocytes. Furthermore, it has been shown that vitamin D regulates adipogenic gene expression as well as adipocyte apoptosis. Vitamin D is active in adipocytes at all levels. It interacts with membrane receptors, adaptor molecules, and nuclear coregulator proteins. Several functions of unliganded nVDR were discovered by studying human samples from patients having hereditary vitamin D resistant rickets, transgenic mice overexpressing the VDR and VDR knockout mice. Through its genomic action, vitamin D participates in the regulation of energy metabolism by controlling the expression of uncoupling proteins. In vitro, vitamin D stimulates lipogenesis and inhibits lipolysis by interacting with mVDR. mVDR is present in caveolae of the plasma membrane and is the same as the classic nVDR. In addition, vitamin D affects directly the expression of the appetite regulating hormone, leptin. Some researchers reported also that vitamin D regulates the expression of the insulin sensitizing hormone, adiponectin. Vitamin D reduced cytokine release and adipose tissue inflammation through the inhibition of NF-κB signaling. Scientific research investigating the role of adipose tissue resident immune cells in the pathogenesis of obesity-associated inflammation is scarce. Obesity is associated with vitamin D deficiency. However there is no scientific evidence to prove that vitamin D deficiency predispose to obesity. Vitamin D supplementation may prevent obesity but it does not lead to weight loss in obese subjects.