Microbiome modulation by a precision biotic leads to increased production of short-chain fatty acids in the intestine of broiler chickens

    

The objective of the present studies was to evaluate: (1) the impact of the supplementation with a Precision Biotic (PB) on the modulation of the cecal microbiome collected from broiler chickens submitted to a necrotic enteritis challenge model (Experiment 1); (2) to measure the cecal production of shorth-chain fatty acids (SCFA; Exp. 2). In Exp. 1, day-old chicks were placed on a completely randomized block design with 3 treatments, 10 replicates, and 25 birds/rep. The treatments consisted of a control group, a challenged control, and a challenged group supplemented PB at 0.9 kg/MT. The challenge consisted of a coccidia vaccine (Coccivac B52) at d 0 applied to all treatments, and Clostridium perfringens via drinking water to the challenged groups on d 15, 21, and 28. On d 22 and 46, 1 bird/pen was selected, and the cecal content was collected for microbiome analysis. In Exp. 1, it was observed that the supplementation of PB significantly (P < 0.05) improved the growth performance of the challenged birds. In the microbiome, an increased relative abundance of several species related to SCFA production was observed at both d 21 and d 42, including increased relative abundance of several Faecalibacterium species (a known butyrate producer) on day 42 (P < 0.05). This was paired with an increased relative abundance of both the propionate (P< 0.05) and butyrate pathways in birds with PB supplementation at both d 21 and d 42. In Exp. 2, day-old chicks were placed on a completely randomized block design with 2 treatments, 8 replicates, and 25 birds/replicate. The treatments consisted of a control group, and a group supplemented with PB at 0.9 kg/MT. At d 14, all the birds were challenged with 30X of a coccidiosis vaccine (Zhengdian, Fushan, China) via oral gavage. On d 21 and 43, 2 birds/pen were selected, and the cecal content was collected for SCFA analysis. PB led to an increase in the production of propionate (P=0.02; 47%) and valerate (P=0.08; 29%) on d 21, and numerically increased ac[1]etate, propionate, and butyrate on d 42. Taken together, the microbiome metabolic shift observed with the supplementation of PB, plus the observations with increased SFCA production, may explain the improvement in growth performance obtained with the supplementation of PB.

Key Words: Broilers, microbiome, metabolism, precision biotic, metagenome.