Bacillus Amyloliquefaciens CECT 5940 Allowed Maintaining of Performance and Accelerated Microbiota Maturation of Broilers Fed Alternative Ingredients

Increasing prices and low availability of common feed raw materials resulted in the use of alternative ingredients in animal production. These ingredients are often characterised by a high amount of soluble fibre resulting in lower performance and intestinal health issues that limits their inclusion rate in the diet. Bacillus amyloliquefaciens CECT 5940 (Ba) is a probiotic that can produce various metabolites and enzymes relieving the negative effects of soluble fiber and therefore it allows a higher inclusion rate of these ingredients resulting in superior economic success. An experiment was conducted to evaluate the effects of 2 alternative ingredients (rye and rice bran) in interaction with the Ba in diets for broilers until day 35 of age. The effect on growth performance and intestinal microbiota was investigated. A total of 672 one-day-old male Cobb 500 slow feathering broilers were used.

Dietary treatments were distributed in a 2 x 2 factorial arrangement, 6 pens of 28 broilers. A corn-soy basal diet was formulated with an inclusion rate of 10, 15, and 20% in starter, grower, and finisher diets of rye or defatted rice bran with and without supplementation of the Ba (1,000 g/ton). Growth performance was evaluated per week and from days 1 to 14, 1 to 21, 21 to 35, and 1 to 35. No interaction was observed between the ingredient and the probiotic. Birds fed the diet with rice bran had a higher BW (+4%) and FCR (-5.5%) compared to rye and probiotic supplementation improved BWG (+ 3.4%) and FCR (-5.2%) compared to non-supplemented groups (P < 0.05). Caecal microbiota composition was determined at days 7, 14, 21 and 35 using 16S amplicon sequencing. The 16S data were processed using QIIME and analyzed using R3.6.3 with base and vegan libraries. Species richness was positively correlated with age and with probiotic supplementation. The differential abundance analysis showed that the relative abundance of the Clostridiales order mainly the Lachnospiraceae family decreased, and the Bacteroidales order mainly the Rikenellaceae family increased with age. Faecalibacterium increased significantly until day 21, then it decreased again on day 35. The Alistepes genus had a positive correlation with time having an abundance between 0.65 and 1.4% when broilers were fed diets not supplemented or supplemented with the probiotic, respectively, and reaching 20.05 and 27.75% on day 35, respectively. On day 7, it was observed that groups supplemented with probiotic had a comparable microbiota composition to the group without probiotic in day 14, indicating that the probiotic may have accelerated the maturation of the microbiota during the early stages. The birds fed rye showed a significantly lower abundance of the Lachnospiraceae compared to the birds fed the rice bran diet on days 7 and 14.

In conclusion, these results confirmed that the probiotic Bacillus amyloliquefaciens CECT 5940 resulted in improved growth performance of broilers fed alternative ingredients such as rye and rice bran. Furthermore, maturation of the cecal microbiota in broilers is mainly driven by time and then affected by the feed ingredients and the probiotic.