Nano-Encapsulated Phytogenic Compounds Modulate Gut-Liver Axis Integrity, Oxidative Balance, And Immunological Activity in Broilers Exposed to Cyclic Heat Stress

Heat stress significantly hinders broiler output by compromising gut integrity, oxidative balance, and immune function.This study evaluated nano-encapsulated phytogenic compounds (NEP) as a nutritional strategy to alleviate heat stress.Three hundred sixty males of Cobb500 broilers were allocated to a 2×3 factorial design with two ambient temperatures and three dietary treatments (6 replicate pens × 10 birds).Birds received a basal diet supplemented with a conventional phytogenic extract (CPE, 500mg/kg), NEP (250mg/kg), or no supplementation (CON).The phytogenic blend contained curcumin (40%), resveratrol (30%), and quercetin (30%) and the NEP consisted of this blend encapsulated in PEGylated liposomes (80-120nM particle size, >85% encapsulation efficiency).From 22-42 days, birds were exposed to a cyclic heat stress treatment (HS; 38°C, 8h/day) or maintained under thermoneutral conditions (TN; 24°C).In CON birds, HS reduced body weight gain (BWG) and feed intake by 24 and 11%, respectively, and increased the feed-togain (F:G) ratio by 16% (P<0.05).Compared with HS-CON, NEP increased BWG (+21%) and improved the F:G ratio (-13%).Under HS, NEP reduced serum interleukin-6 (IL-6; -55%), hepatic malondialdehyde (-50%) and jejunal NF-κB mRNA expression (-2.5-fold), and increased serum IL-10 (+89%), IgA (+114%), IgG (+47%), hepatic superoxide dismutase activity (+46%) and glutathione peroxidase (+90%) activities, and jejunal occludin (+2.4-fold), claudin-1 (+2.3-fold) and Nrf2 (+2.2-fold) mRNA expression (P<0.05).NEP also increased the villus height/crypt depth ratio (+2-fold) and cecal Lactobacillus counts (+1.43 log10 copies/g) and reduced cecal Escherichia coli counts (-1.20 log10 copies/g).In direct comparisons under HS, NEP produced greater responses than CPE for most variables.These findings indicate that NEP, supplemented at half the CPE inclusion rate, attenuated several heat-stress-induced impairments in broilers.Because each formulation was tested at a single, non-equivalent inclusion level without a carrieronly control and bioavailability was not measured, dose-response, carrier-controlled and pharmacokinetic studies are needed to confirm a dose-sparing effect and the underlying mechanisms.