Seasonal variation in the concentration of vitamins A and E in the blood plasma of fat-tailed sheep
Asadian, A.; Mirhadi, S.A.; Mézes, M.
Acta Veterinaria Hungarica 43(4): 453-461
1995
ISSN/ISBN: 0236-6290 PMID: 8882743 Document Number: 441284
Non-pregnant ewes and rams, 3-4 years old, of an Iranian fat-tailed sheep breed (Shal) were given restricted amounts of a standard diet supplemented with alpha -tocopherol 25-32 IU/day for 12 months. Blood was sampled monthly for estimating plasma retinol and alpha -tocopherol. Retinol in plasma of ewes was lower in the spring and summer than in the autumn, and in rams was lowest in spring and highest in summer. Seasonal comparisons did not show differences between consecutive seasons for the ewes. The differences were significant between winter and spring, and spring and summer for the rams. Plasma alpha -tocopherol was 1.21+or-0.05, 1.04+or-0.05, 1.24+or-0.05 and 1.24+or-0.08 mg/litre in spring, summer, autumn and winter, respectively, for the ewes and 1.24+or-0.05, 1.11+or-0.06, 1.09+or-0.04 and 1.38+or-0.07 mg, respectively, for the rams. Values differed significantly between spring and summer, and summer and autumn for the ewes. In rams, the values obtained in autumn also differed (P<0.001) from those found in winter. Differences between values found in other seasons were not significant. Retinol and alpha -tocopherol concentrations in blood plasma were similar in the sexes, except for retinol in the summer and alpha -tocopherol in the autumn. It was concluded that the concentrations of vitamins A and E are relatively constant in the plasma of fat-tailed sheep kept on a standardized feed. However, some differences due to the influence of season and sex were observed.