Dietary Bacillus subtilis C-3102 spores for laying hens: Egg shell quality and brown egg colour score
Bacillus subtilis C-3102 spores are receiving more attention as dietary direct-fed microbial (probiotic) performance enhancers for laying hens and breeders because as a feed supplement, they are typically effective for improving egg shell thickness and brown egg shell colour (in brown-egg strains), have high survivability through steam pelleting, and are economical (B.s. C-3102; CALSPORIN, Calpis Co. Ltd, Tokyo, Japan).
This specific strain of beneficial microorganism was selected for efficacy by screening over 300 strains of beneficial bacteria, including several types of Bacillus spores. University, industry, and manufacturer trials have been conducted to evaluate performance of hens fed the supplement. This article will summarise some of these trial results, modes of action, and expected benefits when using B.s. C-3102 spores in poultry diets.
Although some strains of Bacillus are capable of producing antibiotics or X-factors, and/or enzymes, the main mode of action of B.s. C-3102 appears to be rapid oxygen consumption making the digesta more anaerobic, which favours lactic acid producing bacteria.
Lactobacillus reuteri coating the intestinal tract, especially the crop and ceca, and other Lactobacilli are facultative anaerobes which proliferate under anaerobic conditions as shown by fresh fecal microbial assays.
Lactobacilli produce lactic acid which inhibits pathogens such as Clostridium perfringens, enterotoxic E. coli, and Salmonella. These declines in pathogen counts are also confirmed by fresh fecal microbial assays.
The mode of action by which dietary B.s. C-3102 enhances egg shell calcification is not completely known, but it is understood that laying hen femur osteoclasts, cells which resorb bone to provide about 7/8 of the calcium for egg shell formation, are more active than in unsupplemented control hens. This may be due to more throughput of calcium as it seems unlikely that B.s. C-3102 would affect the carbonate portion of the calcium carbonate in egg shells.
During immune challenges, blood calcium level rises, possibly as a fever dampening mechanism, and some of this circulating calcium may be lost from the body. Therefore, it has been speculated that reducing pathogenic challenges to the intestinal tract due to presence of dietary B.s. C-3102 spores and greater Lactobacillus numbers may allow a more steady blood calcium supply to the oviduct for shell formation.
In recent years, scientists discovered that B.s. C-3102 spores supplemented to laying hen diets could improve brown egg colour of brown-egg strains usually within a matter of days.
There may be a connection between egg shell quality and brown egg shell colour. Joseph et al. (1999) reported that the darker brown the egg shell in four strains of broiler breeders, the higher the egg specific gravity, an indicator of shell quality. There was a small but highly significant positive correlation between brown colour and egg specific gravity.
Concluding, B.s. subtilis C-3102 spores have proven useful in the diets of laying hens to improve egg shell thickness or breaking strength, and to increase brown egg colour score of brown-egg strains compared with results for unsupplemented hens.
When added to the diets of broiler breeder hens, B.s. subtilis C-3102 spores increased cumulative fertile egg production compared with results for hens fed diets containing an antibiotic.
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Article made possible through the contribution of Hooge Consulting Service, Inc.