Precision biotics enhance growth performance in broiler chickens by selectively modifying their intestinal microbiome to better respond to enteric challenges

Abstract

Precision biotics (PB) are innovative feed additives designed to influence key metabolic pathways in the microbiome, particularly those involved in short-chain fatty acid (SCFA) production. These SCFAs are crucial for the healthy development and functionality of the gastrointestinal tract (GIT) in chickens. Our hypothesis was that adding a glycan-based PB to the diet would steer microbial metabolism towards increased SCFA production in the ceca, thereby reducing the adverse effects of necrotic enteritis (NE) in chickens. These studies evaluated the supplementation of PB on the cecal microbiome and growth performance in broiler chickens exposed to a necrotic enteritis (NE) challenge. Experiment 1: Day-old chicks were assigned to three treatment groups: a control, a challenged control, and a challenged group supplemented with PB. The birds were vaccinated for coccidiosis at day 0 and challenged with Clostridium perfringens. Cecal content was collected from one bird per pen on days 22 and 42 for microbiome analysis. Experiment 2: Day-old chicks were again assigned to three treatments: control, challenged control, and challenged with PB. All birds were vaccinated for coccidiosis and challenged with Eimeria maxima on day 14 and later with C. perfringens. On day 21, birds were euthanized for NE lesion scoring. In Exp. 1, the supplementation of PB significantly improved (P < 0.05) the growth performance of the challenged birds. An increased relative abundance of species related to SCFA production was observed on day 42, including several Faecalibacterium species (P < 0.05). This was paired with an increased relative abundance of both propionate (P<0.05) and butyrate pathways in birds with PB supplementation. In Exp. 2, on day 21, the challenge impaired growth performance, but the supplementation of PB counteracted this effect (P < 0.05). On day 42, the supplementation of PB improved BW by 10 % (P < 0.0001), and the FCR by 8.4 % (P < 0.0001) when compared to the challenged group. The supplementation of PB reduced NE associated mortality (5.5 vs 0.5 %; P = 0.002) and reduced the lesions characteristic of NE (P < 0.0001). Taken together, the microbiome metabolic shift observed with the supplementation of PB explains the improvement in growth performance, resilience to enteric stress and faster recovery of the intestine, which consequently improves welfare and the sustainability of poultry production.