Precision biotic modulates the impact of mixed Eimeria infection in broiler chickens fed wheat–corn–soybean meal diets

Coccidiosis leads to gut damage, impairing nutrient digestibility and modifying the substrates available to the microbiome. This study assessed the supplementation of a precision biotic (PB) on growth performance, ileal amino acid digestibility, mRNA expression of nutrient transporter genes, jejunal histomorphology, and litter surface ammonia emission in broilers challenged with a mixed Eimeria inoculum (CH) and fed corn-SBM (C) or wheat-corn-SBM (W) diets. Zero-day-old male chicks (1,012) were used (6 treatments with at least seven replicates) in a randomized incomplete block design. Treatments were: C diet, no challenge (C-NCH); or with challenge (C-CH-0); W diet plus challenge, without PB (W-CH-0); W diet plus challenge, plus 300 (W-CH-300), 600 (W-CH-600), or 900 (W-CH-900) mg/kg of PB. On d 12, all birds, except C-NCH, were challenged with mixed Eimeria oocysts by feed inoculation to induce enteric stress. Jejunal tissues were collected on d 20 and 42 for gene expression and histomorphology. On d 42, ammonia emissions were recorded, and ileal digesta were collected for digestibility. The Eimeria challenge significantly (P < 0.05) reduced weight gain (WG) and feed intake (FI) during the challenge phase, and increased FCR compared to C-NCH. PB supplementation tended to reduce FCR in a quadratic fashion (P =0.053). The expression of GLUT2 and EAAT3 was significantly reduced by the challenge (P < 0.05) compared to C-NCH. Apparent ileal digestibility of DM, N, and amino acids (AA) was significantly (P < 0.001) reduced in challenged birds but improved quadratically (P < 0.01) with PB. Litter ammonia levels were significantly (P = 0.01) lower in W-CH-0 than C-CH-0. It can be concluded that PB supplementation improved the gastrointestinal tract functionality likely via modulation of microbiome metabolism, which produced increased digestible nutrient intake, especially during the compensatory growth phase, which might have contributed to partially reversing the adverse effect of the Eimeria challenge on the growth performance of the broiler chickens.