The effect of a probiotic preparation containing Bacillus subtilis ATCC PTA-6737 on egg production and physiological parameters of laying hens

A total of 288 Lohmann Brown laying hens were randomly divided into two groups (9 replicates of 16 birds each). The hens were housed in three-tier battery cages for 26 weeks, including a two-week pre-laying period. All birds were fed iso-nitrogenous and iso-caloric diets, and had free access to water. Control group (C) hens were fed a basal diet, and experimental group (BS) hens received a basal diet supplemented with a commercial probiotic preparation of Bacillus subtilis ATCC PTA- 6737 at 1×108 CFU/kg feed. The number and weight of eggs laid, feed intake, feed conversion, egg quality, the fatty acid profile and cholesterol content of yolk lipids, and selected blood biochemical parameters of hens were determined throughout the experiment. No significant differences (P>0.05) were noted between the groups in average egg weight, laying performance (%), daily feed intake or feed conversion. Eggs laid by BS group hens received significantly higher scores for yolk color (Roche yolk color fan) and albumen quality (Haugh units), and they were characterized by a significant improvement in shell thickness and breaking strength (P<0.05) in comparison with eggs laid by control group hens. No significant differences (P>0.05) were observed between the groups in the fatty acid profile of yolk lipids, except for a significant increase (P<0.05) in oleic acid concentrations in group BS. No significant differences (P>0.05) were noted between the groups in selected blood biochemical parameters of laying hens. Group BS eggs had a significantly lower (P<0.05) cholesterol content of yolk lipids. It can be concluded that a probiotic preparation containing Bacillus subtilis ATCC PTA-6737 had a beneficial influence on selected performance parameters of laying hens, egg quality and the cholesterol content of yolk lipids.