The effect of probiotic baker’s yeast on egg quality, tibia characteristics, and hepatic lipid peroxidation in laying hens

This study evaluated the effects of dietary baker's yeast (Saccharomyces cerevisiae) supplementation on egg and eggshell quality, bone strength, and liver oxidative status in laying hens. A total of 120 Lohmann Brown hens were allocated to five groups (12 replicates, 2 birds per replicate), which received a basal diet (T1) or the same diet supplemented with 50 (T2), 100 (T3), 150 (T4), or 200 (T5) g/t of yeast. The body weight of birds and the feed conversion ratio were monitored. At the end of weeks 1, 5, and 11 of the experiment, 12 eggs from each group were randomly selected for quality assessment (weight, eggshell thickness and strength, yolk and albumen quality: Haugh units, color). Liver function was evaluated based on weight, proximate composition, and malondialdehyde content, while bone characteristics were assessed based on tibia ash content, dimensions, and mechanical strength analysis. In conclusion, this study demonstrated that the analyzed yeast product may positively affect selected indicators of eggshell quality, lipid peroxidation, and mechanical resilience. Improvements were observed at lower inclusion levels (50-100 g/t), indicating economic benefits, as higher doses did not yield additional effects. While the results suggest the potential for practical applications in poultry production, the underlying mechanisms remain somewhat speculative, since parameters such as gut microbiota composition, mineral metabolism, and digestive enzyme activity were not assessed. Therefore, further research on live baker's yeast preparation is warranted.