Effect of dietary supplementation of Spirulina (Arthrospira platensis) and thyme (Thymus vulgaris) on serum biochemistry, immune response and antioxidant status of rabbits

Growing rabbits' (42 rabbits/group, 3 rabbits/cage, 14 cages/treatment) diet was supplemented with 5% Spirulina (Arthrospira platensis) and 3% thyme (Thymus vulgaris L.) powder single (S or T) and in combination (ST) between 35 and 77 days of age. On day 0 (weaning at 35 days of age) 14 rabbits were vaccinated with 100 mu g/animal ovalbumin to provoke immune response. Blood samples were taken on days 0, 14, 28 and 42 of the experimental period. Sampling dates significantly influenced total protein, albumin, glucose, cholesterol, urea, creatinine concentration and enzyme (AST, ALT, GGT) activities, with a significant age x diet interaction in the case of TP and CREA. There was a significant increase in ALT (+45 and 74%) and GGT (+87 and 102%) activity after immunisation. While Spirulina and thyme significantly ameliorated the rise in AST activity, their effect was inefficient in the case of GGT. Spirulina, both single and in combination showed a tendency in higher IgG level as compared to control (P<0.05). No significant effect of sampling date or treatment on phagocytic activity or secretory IgA was demonstrable (P>0.05). Higher MDA concentration was measured in the red blood cells of S, T and ST animals, while no other significant diet effect on the antioxidant parameters was detected, however, significant sampling date x diet interaction was found in the case of GPx activity. Plasma GGT (increase by 19-66%) was inversely associated with GSH (decrease by 66-113%) between days 0 to 42 of the experimental period (r=-0.57, P<0.05). It can be concluded that Spirulina supplementation alone resulted in higher IgG production, but none of the phytobiotics, at the dose used, affected significantly the antioxidant status of blood.