Vitamin E plasma kinetics in swine show low bioavailability and short half-life of -α-tocopheryl acetate

Pre- and post-treatment of α-Tocopherol on cognitive, synaptic plasticity, and mitochondrial disorders of the hippocampus in icv-streptozotocin-induced sporadic Alzheimer's-like disease in male Wistar rat

Objective

Most dementia cases in the elderly are caused by Alzheimer's disease (AD), a complex, progressive neurological disease. Intracerebroventricular (ICV) administration of streptozotocin (STZ) in rat's results in aberrant brain insulin signaling, oxidative stress, and mitochondrial dysfunction that impair cognition change neural plasticity, and eventually lead to neuronal death. The current study aims to define the neuroprotective action of alpha-tocopherol in enhancing mitochondrial function and the function of synapses in memory-impaired rats brought on by icv-STZ.

Methods

Male Wistar rats were pre-treated with (α-Tocopherol 150 mg/kg) orally once daily for 7 days before and 14 days after being bilaterally injected with icv-STZ (3 mg/kg), while sham group rats received the same volume of STZ solvent. After 2 weeks of icv-STZ infusion, rats were tested for cognitive performance using a behaviors test and then were prepared electrophysiology recordings or sacrificed for biochemical and histopathological assays.

Results

The cognitive impairment was significantly minimized in the behavioral paradigms for those who had taken α-Tocopherol. In the hippocampus of icv-STZ rat brains, α-Tocopherol ocopherol effectively prevented the loss of glutathione levels and superoxide dismutase enzyme activity, lowered mitochondrial ROS and mitochondrial membrane potential, and also brought about a decrease in Aβ aggregation and neuronal death.

Conclusion

Our findings demonstrated that by lowering neurobehavioral impairments caused by icv-STZ, oxidative stress, and mitochondrial dysfunction, α-Tocopherol enhanced intracellular calcium homeostasis and corrected neurodegenerative defects in the brain. These findings examine the available approach for delaying AD connected to mitochondrial malfunction and plasticity issues.

Metabolomic Analysis of Wooden Breast Myopathy Shows a Disturbed Lipid Metabolism

Myopathies have risen strongly in recent years, likely linked to selection for appetite. For white striping (WS), causes have been identified; but for wooden breast (WB), the cause remains speculative. We used metabolomics to study the breast muscle of 51 birds that were scored for both at 35 days of age to better understand potential causes. A partial least square discriminant analysis revealed that WS and WB had distinct metabolic profiles, implying different etiologies. Arginine and proline metabolism were affected in both, although differently: WB increased arginine in breast muscle implying that the birds did not use this pathway to increase tissue blood flow. Antioxidant defenses were impeded as shown by low anserine and beta-alanine. In contrast, GSH and selenium concentrations were increased. Serine, linked to anti-inflammatory properties, was increased. Taurine, which can stabilize the cell's sarcolemma as well as modulate potassium channels and cellular calcium homeostasis, was also increased. Mineral data and depressed phosphatidylethanolamine, cAMP, and creatine-phosphate suggested compromised energy metabolism. WB also had drastically lower diet-derived lipids, suggesting compromised lipid digestion. In conclusion, WB may be caused by impaired lipid digestion triggered by a very high appetite: the ensuing deficiencies may well impair blood flow into muscle resulting in irreparable damage.

Tocopherol more bioavailable than tocopheryl-acetate as a source of vitamin E for broilers

Vitamin E is typically supplied in the form of tocopheryl-acetate (T-Ac) since tocopherol (T) has stability issues. Tocopheryl-acetate, however, must be hydrolyzed in the intestines before it can be absorbed, a step that is purportedly rate-limiting for its bioavailability. The objective of this study was to compare the efficiency of absorption of T-Ac and T in broilers. In addition, two test procedures were evaluated in which animals received the test substances for either 2 or 4 days only. Animals were adapted to diets without supplemental vitamin E (feedstuffs contributed 14±1 ppm natural vitamin E (RRR-tocopherol)) till the age of 25 d (individual housing) or 28 d (group housing). Subsequently, they were fed T-Ac at 80, 53, 36, 24, or 16 ppm or T at 80, 40, 20, 10, or 5 ppm for a period of 4 d (4-di) or 2 d (2-dg), after which serum and liver were collected for analysis of vitamin E. Measured feed vitamin E levels were used for the data analysis; the recovery of T-Ac was 85%, and that of T was 39%. Both test procedures (2 or 4 days) yielded good quality data. Based on linear regression analysis, the relative efficiency with which T-Ac raised tissue levels as compared to T was 0.24 (2-dg) to 0.37 (4-di), with liver and serum yielding similar results. Analysis using more complex dose response models imply that the hydrolysis of T-Ac was strongly dose-dependent and that it could be saturated at doses above approximately 50 ppm in animals only briefly fed T-Ac; for T there was no evidence of saturation. These data imply that T, provided that stable forms can be developed, has the potential to be much more efficient at providing vitamin E to the animal, and on top, can yield much higher tissue levels, than T-Ac.

Dietary vitamin E reaches the mitochondria in the flight muscle of zebra finches but only if they exercise

Whether dietary antioxidants are effective for alleviating oxidative costs associated with energy-demanding life events first requires they are successfully absorbed in the digestive tract and transported to sites associated with reactive species production (e.g. the mitochondria). Flying birds are under high energy and oxidative demands, and although birds commonly ingest dietary antioxidants in the wild, the bioavailability of these consumed antioxidants is poorly understood. We show for the first time that an ingested lipophilic antioxidant, α-tocopherol, reached the mitochondria in the flight muscles of a songbird but only if they regularly exercise (60 min of perch-to-perch flights two times in a day or 8.5 km day-1). Deuterated α-tocopherol was found in the blood of exercise-trained zebra finches within 6.5 hrs and in isolated mitochondria from pectoral muscle within 22.5 hrs, but never reached the mitochondria in caged sedentary control birds. This rapid pace (within a day) and extent of metabolic routing of a dietary antioxidant to muscle mitochondria means that daily consumption of such dietary sources can help to pay the inevitable oxidative costs of flight muscle metabolism, but only when combined with regular exercise.

Cocrystals to tune oily vitamin E into crystal vitamin E

d-α-tocopherol (d-αToc), the most biologically active form of natural Vitamin E, is oily in appearance and unstable to oxygen. Esterification and encapsulation are generally needed to stabilize and solidify d-αToc for the purpose of its expanding applications. In this study, we propose a more effective way to stabilize and solidify d-αToc oil in one step. By cocrystallization, the melting point of d-αToc is significantly increased, such that the oily d-αToc is successfully transformed into solid form at room temperature. The single crystal structure of d-αToc was firstly uncovered and the molecular interaction in cocrystals was revealed. Crystalline Vitamin E shows high stability to light and temperature. Its spherical crystallization affords good powder flowability, which is extremely important as food or feed additives. Moreover, cocrystal Vitamin E remains the original form of tocopherol without esterification and thus has a great advantage on higher bioavailability. Cocrystallization of oily d-αToc spares the use of acetic ester and a mass of excipients, which is of great environmental importance and greatly reduces the production cost.

Effects of Vitamin Forms and Levels on Vitamin Bioavailability and Growth Performance in Piglets

The objective of this study was to quantify the relative bioavailability of microencapsulated vitamins A and E in nursery pigs and compare the effects of vitamin forms and vitamin levels on the plasma vitamin content and growth performance of weaned piglets. In experiment (Exp.) 1, 12 nursery pigs (fitted with jugular catheters) were supplied at 0 h with non-microencapsulated or microencapsulated vitamin A and E. Blood samples were collected at 1, 3, 6, 9, 12, 16, 18, 21, 24, 27, 30, 36, 48, and 72 h after feeding to compare the bioavailability of oral vitamins A and E. In Exp. 2, a total of 216 crossbred weaned piglets were assigned to six treatments. This experiment was a 2 × 3 factorial arrangement, with two factors for vitamin forms (non-microencapsulated and microencapsulated) and three factors for vitamin levels (the National Research Council level of vitamins, 75% commercial recommendations of vitamins (CRV) level, and a 100% CVR level). In Exp. 1, the relative bioavailability of microencapsulated vitamin E was significantly greater than that of non-microencapsulated vitamin E. In Exp. 2, the pigs fed diets containing 75% or 100% CRV levels of vitamins increased their growth performance and plasma vitamin concentrations compared to the control group. In conclusion, microencapsulation can improve the bioavailability of vitamins, and supplementation with high levels of vitamins was able to improve the growth performance of the piglets.

Water-soluble all-rac α-tocopheryl-phosphate and fat-soluble all-rac α-tocopheryl-acetate are comparable vitamin E sources for swine

Vitamin E, as all-rac α-tocopheryl-acetate (TAc), has a bioavailability of only 5.4% in swine and, therefore, is a poor vitamin E source. Tocopheryl-phosphate (TP) has been used successfully as a vitamin E source around 1940 but it was subsequently replaced by TAc as it was easier to manufacture. Recently, it has been proposed as an in vivo intermediate in vitamin E metabolism with possibly gene-regulatory functions. TP may be more bioavailable than TAc as intestinal hydrolysis and emulsification are not required. The objective of this work was to compare the bioavailability of TAc and TP in swine. Piglets (18.6 ± 0.6 kg) fitted with jugular catheters received a single test meal (350 g) containing either deuterated (trimethyl-d9) TAc or TP (75 IU/kg body weight, n = 8 per treatment). Twelve serial blood samples were obtained starting premeal until 78 h postmeal for analysis of deuterated T and TP using LC MS/MS. Results were standardized by dividing them by the dose per kg body weight and were subsequently modeled with a multicompartment model. T from TAc had a slow appearance rate (0.040 ± 0.014 h-1) and rapid disappearance rate (0.438 ± 0.160 h-1) with a plateau value of 0.414 ± 0.129 µM/(µmol/kg BW). TP appeared faster in plasma (0.119 ± 0.058 h-1, P = 0.01) while the elimination rate was similar (0.396 ± 0.098 h-1, P = 0.51). The plateau value of TP was only numerically higher (0.758 ± 0.778 µM/(µmol/kg BW), P = 0.34). TP was quickly converted to T; its appearance rate was 0.026 ± 0.009 h-1, slower than the appearance rate of T from TAc (P = 0.01), whereas the elimination rate was 0.220 ± 0.062 h-1, slower than that of T from TAc (P = 0.00). The conversion of TP to T may have been incomplete, as its plateau value was only 0.315 ± 0.109 µM/(µmol/kg BW). The area under the curve, expressed relative to area under the curve for T from TAc, was 34.5% for TP and 107.3% for T from TP. These data confirm that TP is more quickly absorbed than T from TAc. TP is also converted to T and thus a functional precursor of T. Nevertheless, as a source of T, TP failed to offer a clear advantage over TAc in bioavailability.