Comparative effects of feeding single- and multi-strain probiotics to commercial layers on the productive performance and egg quality indices

This experiment investigated the effects of dietary supplementation of single-strain probiotic (SSP) containing Bacillus subtilis 2 × 109 cfu/g and multi-strain probiotic (MSP) containing Lactobacillus acidophilus 3 × 107–108 cfu/g, Bacillus subtilis 3 × 107-108 cfu/g, and Saccharomyces cerevisiae 106–107 cells/g on ISA Brown layers' productive performance and egg quality traits for 26 to 51 wk. Eighty-four birds were reared in cages of an open-sided house. SSP was fed either at 0.375, 0.50, or 0.625 g/kg feed or MSP either at 0.75, 1.00, or 1.25 g/kg feed, and a control group were maintained. Each dietary treatment was replicated 6 times, having 2 birds each. Egg production increased linearly with dose increment in the MSP-fed birds. Both SSP and MSP caused an improvement in egg weight, egg mass, and FCR. Feed intake and body weight gain were not affected by probiotic feeding. At 37 wk, MSP-fed birds had a higher shell percentage, whereas the value was higher for both SSP and MSP at 49 wk. Shell thickness rose linearly by MSP at 37 wk and followed a similar trend at 49 wk along with SSP. Haugh unit also increased in both weeks with SSP and MSP. Due to MSP feeding, the predicted yolk index dose was 0.67g/kg at 37 wk and increased linearly at 49 wk. The yolk percent varied with doses of SSP and MSP, while albumen percent with MSP doses at 37 wk. In conclusion, MSP increased egg production, and both SSP and MSP positively influenced other laying performances and egg quality, notably shell and albumen quality.