It was postulated that administration of a probiotic to chickens can stimulate their antioxidant status while at the same time inhibiting oxidation processes. The objective of the study was to determine whether and how different levels and durations of application of a probiotic preparation containing live cultures of Enterococcus faecium and enriched with cholecalciferol and ascorbic acid influences indicators of lipid status and the redox reaction in the blood of broiler chickens. Four hundred day-old Ross 308 chickens were raised until their 42nd day of age. The animals were assigned to five experimental groups of 80 broilers each: a control group that did not receive the probiotic, T1 groups, which received the probiotic at 0.25 (E-0.25) or 0.1 g/l (E-0.1) throughout the rearing period, and T2 groups, which received the probiotic at the same levels, but during days 1–7, 15–21 and 29–35 of life. The probiotic preparation reduced the level of peroxides (LOH), malondialdehyde (MDA), cholesterol (TC), low density (LDL) cholesterol, and non-esterified fatty acids (NEFA), and the activity of catalase (CAT), gamma-glutamyltransferase (GGT), acid phosphatase (AC), alkaline phosphatase (ALP) and 3-hydroxybutyrate dehydrogenase (HBDH), while ferric reducing ability of plasma (FRAP) and glutathione (GSH + GSSG) levels were increased in the blood plasma of the chickens. The results obtained indicate that administration of this probiotic to chickens, especially in the amount of 0.25 g/l for the entire rearing period, stimulates synthesis of low-molecular-weight antioxidants responsible for maintaining redox homeostasis, without exerting a negative effect on liver metabolism in chickens.
