Influence of Immunobeta® Dietary Supplementation on Egg Production and Some Parameters of Oxidative Stress in Laying Hens

The aim of this study was to evaluate the effects of the immunostimulant Immunobeta® on egg production and oxidative stress parameters, influenced by the environmental conditions in free range laying hens. A total of 81 laying hens and 9 cocks (Tetra Super Harco) were divided into three groups: group 1 (control) without supplementation; group 2 with 0.2%, and group 3 with 0.4% Immunobeta® as a dietary supplement. The laying period (19-55 weeks of age) was divided into three sub-periods depending on the ambient temperature – cold (from November to March 2015, from 19 to 37 weeks of age), thermoneutral (April and May 2016, from 38 to 46 weeks of age) and hot period (June and July 2016, from 47 to 55 weeks of age). Immunobeta® supplementation dose dependently improved the average egg production and mean egg weight, and in 0.4% dose treatment significantly reduced the feed conversion ratio for the entire laying period. Immunobeta® supplementation influenced the blood oxidative stress parameters, decreasing significantly the lipid peroxidation level during the cold period, increasing the glutathione level in hens supplemented with 0.4% dose in all periods, regulating the catalase activity during the hot period, and increasing glutathione peroxidase activity during the thermoneutral and hot periods. In conclusion, addition of Immunobeta® to the diet reduced the oxidative stress induced by thermal stress and enhanced the performance of free range laying hens.