The accumulation of α‐Tocopherol and Retinol in the milk of water buffalo is correlated with the plasma levels of triiodothyronine

Abstract

Milk is the most important source of Retinol and alpha-Tocopherol for calves. These antioxidants save the food quality and prevent lipid oxidation in the mammary gland and the calf growing tissues. In Bubalus bubalis, seasonal changes for the plasma levels of both antioxidants were not found. The levels of Retinol and alpha-Tocopherol in the milk were 2 and 1.7 times higher in winter than in summer, respectively. These levels were correlated with the plasma level of triiodothyronine, and markedly increased in cows injected with triiodothyronine in summer. The cytosol from alveolar epithelial cells of mammary glands was incubated with alpha-Tocopherol and 3H-Retinol and, after gel filtration chromatography, both antioxidants were found associated with proteins migrating as a single peak of 33 kD. The amount of alpha-Tocopherol and Retinol binding proteins was 1.5 and 2.3 times higher in winter than in summer respectively. The Retinol binding proteins migrated as two bands (33 and 16 kD) by electrophoresis in denaturing and reducing conditions. Our data suggest that triiodothyronine enhances the transport of both liposoluble antioxidants through the blood-mammary barrier, and demonstrate that proteins of the mammary epithelial cells are involved in such a transport.

Analysis of plasma indices of redox homeostasis in dairy cows reared in polluted areas of Piedmont (northern Italy)

“…Ret and Toc levels were measured according to a published procedure (Spagnuolo et al, 2003), and analyzed by HPLC, using a reverse phase C1 8 column (Nova-PAK C1 8, 4 μm, 125x2 mm i.d. ;…”

“…Color development was monitored at 492 nm, as previously described (Spagnuolo et al, 2003). Data were reported as nmol of N-Tyr per mg of proteins.…”

“…Color development was monitored at 492 nm, as previously described (Spagnuolo et al, 2003 GPx activity was measured indirectly by a coupled reaction with glutathione reductase (GR), using the glutathione peroxidase assay kit of Cayman Chemical, according to the manufacturer's instructions. GPx activity was expressed as nmol of NADPH oxidized per minute per ml of sample.…”

Influences of different space allowance on reproductive performances in buffalo

“…Ascorbate, retinol and α-tocopherol blood levels were measured according to Spagnuolo et al (2003). Briefly, plasma samples for determination of Asc concentration were prepared and analysed by HPLC using an anion exchange column (Nucleosil 100NH 2 , 5 μm, 250 × 4·6 mm i.d.…”

“…N-Tyr was detected by incubation with rabbit anti-N-Tyr antibody (1:500 dilution in 130mM-NaCl, 20mMTrisHCl, 0,05% Tween 20, pH = 7.3, supplemented with 0,25% BSA; 1 h, 37°C) followed by goat anti rabbit IgG-horseradish peroxidase linked (GAR-HRP) diluted 1:2000 as the primary antibody. Colour development was monitored at 492 nm, as previously described (Spagnuolo et al 2003). Data were reported as nmol of N-Tyr per mg of protein.…”