Probiotics could be a supportive nutritional tool during peak performance, a high productive period where the hens are also more sensitive for microbial disorders in their digestive tract. A probiotic* was tested in 120 Tetra SL Laying hens in the first period of production between 19 to 42 weeks of age. The addition of 3×10>8 CFU Bacillus subtilis C-3102 per kg feed resulted in a faster increase of egg weight, higher egg mass and better utilisation of the feed (Figure 1 a-c). Reduced hen weight could reflect the mobilisation of body reserves for egg production. However, similar feed intake and improved performance did not negatively influence live hen weight in the probiotic group. Additionally, larger eggs did not result in thinner egg shells and poorer shell quality. An average of 0.52% of egg disorders was already low for the control group, but even numerically lower for the probiotic group with 0.37% over the 24 week period.
Prolong laying period
Optimal feeding of layers enables egg producers to prolong the laying period till 100 weeks of age. Maintaining egg laying performance and egg shell quality are key for a long productive life. In a second study with 120 brown Tetra SL laying hens, the addition of 3×10>8 CFU Bacillus subtilis C-3102 per kg complete feed was tested for a period of one year, from 19 to 70 weeks of age. Inclusion of the probiotic resulted in improved laying rate, egg weight, egg mass and feed conversion over the whole period. Larger eggs (Figure 2) and similar feed intake did not result in reduced hen weight in the probiotic group, in line with the results in the first trial. Improved performance could be explained by a better feed utilisation by the hens, as it was shown that the apparent digestibility of protein, fibre and ash was significantly higher in the Calsporin group measured at 70 weeks of age. The hens receiving B. subtilis in their feed had a persistent higher egg weight over the whole laying period compared to the control group (Figure 2). In practice, increase in egg size is negatively correlated with shell quality. However, the trial results showed that larger eggs did not result in differences in shell thickness and shell density. Meanwhile, breaking strength was even numerically higher and the amount of egg disorders (cracked, dirty, misshapen and unsaleable eggs) was significantly lower in the probiotic group, with 0.64% and 0.46% of the control and probiotic group respectively.
Bacillus subtilis to fight gut pathogens
Laying hen performance can easily be disturbed by the emergence of an intestinal pathogen. Changes in feed intake, colour and composition of the faecal droplets and liveability of the flock are the first signs that something is happening. Disruption of the intestinal microflora causes increased susceptibility of hens to Clostridium perfringens, avian pathogenic Escherichia coli, Salmonella spp. and Campylobacter spp. The latest three bacterial strains are also associated with food safety and zoonotic diseases2,4. Laying hen farmers have limited possibilities for the use of antimicrobial products due to withdrawal times for eggs. The administration of B. subtilis to laying hen feed can be a safe and practical option, as numerous trial results have shown a reduction or even exclusion on the most common pathogens like Clostridium perfringens, Salmonella, E.coli and Campylobacter 5-11.