Bacillus subtilis C-3102 spores (Bs) in direct-fed microbial CALSPORIN®, are added to poultry diets to maintain normal intestinal microflora and support live performance. The proposed mode of action is that Bs spores vegetate and use oxygen, creating a more anaerobic condition which promotes proliferation of lactic acid producing bacteria (e.g., Lactobacilli). Besides inhibiting certain pathogens (E. coli, Salmonella), this condition appears to increase utilization of calcium. U.S. Patent 6,660,294 (Dec. 9, 2003) was awarded to this "Poultry Eggshell Strengthening Composition", and trials cited in the patent application showed +5.2% average shell thickness improvement. Caged Hy-Line W-36 hen field trials were conducted in the U.S. midwest with 0 or 0.003% Bs spores (CALSPORIN®, 0.05% level) in feed, and microbes in fresh feces and egg breaking strength (EBS) or shell thickness (60 eggs/sampling) were determined. In Exp. 1 (~140,000 hens/flock) at Site 1 (57 wk old), EBS was 3.26 kg (5 wk, 8 samplings) "before" and 3.33kg (7 wk, 9 samplings) "during" Bs addition, with 3.20 kg expected (linear regression); est. +0.13 kg with Bs. At site 2 (94 wk old, molted), EBS was 3.08 kg (8 wk) "before" and 3.23 kg (7 wk) "during" (P < 0.01),with 3.09 kg expected; est. + 0.14 kg increase. In Exp. 2 (~84,230 hens; 57 wk old), shell thickness in microns were: "before" 321 (5 wk), "during" 331 (7 wk), "Bs removed" 313 (2 wk), and "added again" 324(9 wk). In some fecal samples prior to Bs supplementation, Lactobacilli/Total Anaerobes (cfu Log10/g) ratio was considerably below 50%, the desirable threshold level. The Bs improved shell quality.
Key Words:Bacillus subtilis, CALSPORIN®, Direct-fed Microbial, Layer, Shell Quality