Effects of dietary fish oil and alpha-tocopherol supplementation on selected blood parameters and fatty acid profiles in mares and their foals.

Abstract

The effects of fish oil (40ml/day) supplementation, with or without synthetic all-rac-alpha-tocopherol-acetate (2,500IU/day), during the last 65days before expected parturition were investigated in 15 adult mares (553±24kg BW) and their foals. Mares were assigned to one of three diets: control (n=5), control plus fish oil and alpha-tocopherol (n=4; FO+AT) or control with just fish oil (n=6; FO). Blood samples were obtained from the mares before a 15-day dietary adaptation period (T1) and from mares and foals the first (T2) and fifth (T3) days post-partum. Colostrum was collected at T2 and milk at T3. Routine haematological, biochemical and alpha-tocopherol analyses were undertaken on all blood samples. Fatty acid concentrations were determined in the foal serum and alpha-tocopherol concentrations measured in the milk and colostrum. Diet had no effect on haematology or biochemistry in the mares. Alpha-tocopherol concentrations were significantly higher at T2 & T3 in the FO+AT mares. Foal WBCs were higher in FO (11.33±2.59×109 /l), comparing to FO+AT and control groups (9.18±1.24×109 /l and 7.26±1.03×109 /l, respectively), at T3 (p<.05). There was no significant effect of the fish oil supplementation on the foal's serum fatty acid profile. In the FO+AT group, both colostrum and milk alpha-tocopherol concentrations (2.56±0.36 and 1.36±0.22µg/ml, respectively) were higher compared than those of the FO group (1.33±0.39 and 0.72±0.31µg/ml, respectively; p<.05). Additional 2,500IU/day of synthetic alpha-tocopherol in the last 65days of pregnancy increased alpha-tocopherol concentrations in colostrum and milk and the foal's serum. 40ml/day fish oil, however, did not significantly increase serum eicosapentaenoic acid and docosahexaenoic acid concentrations in the foals.