Effect of a microencapsulated complex of biofactors and antioxidants on the growth performance, plasma biochemistry, intestinal health, and immune and antioxidant status of broiler chickens challenged with cold stress

The study examined the effects of a microencapsulated complex of biofactors and antioxidants (P(BF + AOx)) on growth and health status of broiler chickens challenged with cold stress. Day-old broilers were allotted to four treatments in a 2 × 2 factorial design with two dietary treatments: (1) Control (CON; corn–wheat–soybean-based) and (2) CON + 0.015% P(BF + AOx), and two thermal treatments: (1) Thermoneutral (TN; 29 °C ± 1 on days 8–10, 54 h) and (2) Cold stress (CS; 20 °C on days 8–10, 54 h). Treatments were allocated to six replicates, with eight chicks/replicate. Growth performance was measured weekly from days 0–21. On day 14, two birds/cage were euthanized. Cold stress reduced ( P < 0.05) total antioxidant capacity (TAC), serum IgM, jejunal villus height (VH), villus width (VW), and VH:crypt depth (VH:CD). Irrespective of CS, P(BF + AOx) improved ( P < 0.05) feed intake (631 vs. 592 g/bird), body weight (BW) (383 vs. 349 g/bird), BW gain (337 vs. 301 g/bird) up to day 14, and plasma TAC. Regardless of the challenge model, P(BF + AOx) increased ( P < 0.05) duodenal VW, VH:CD, jejunal, and ileal VH:CD, and the relative abundance of cecal Intestinimonas and Colidextribacteria, compared to the CON. In conclusion, CS altered broiler blood parameters and gut morphology, but 0.015% P(BF + AOx) improved early life growth performance, TAC, and gut health, irrespective of CS, suggesting that it could be an effective strategy to support overall health and performance.