Effects of Embryonic Thermal Manipulation on Body Performance and Cecum Microbiome in Broiler Chickens Following a Post-Hatch Lipopolysaccharide Challenge

Abstract

Thermal manipulation (TM) during embryogenesis has emerged as a promising strategy to enhance post-hatch performance and improve resilience to environmental and bacterial stress, which offers a potential alternative to reduce the reliance on antibiotic growth promoters (AGPs) in broiler production. This study investigated TM&rsquo;s ability to modulate broilers&rsquo; cecal microbiota and enhance resilience to lipopolysaccharide (LPS)-induced stress. Eggs in the control group (CON) were incubated at 37.8 &deg;C and 56% relative humidity (RH), while TM eggs were exposed to 39 &deg;C and 65% RH for 18 h daily from embryonic days 10&ndash;18. Post-hatch, the LPS subgroups (LPS-CON, LPS-TM) received intraperitoneal LPS injections, and body weight (BW) and temperature (BT) were monitored. Cecal samples were collected for microbiome sequencing. Alpha diversity showed no differences (<i>p</i> &gt; 0.05), but beta diversity revealed differences between groups (PERMANOVA, <i>p</i> &lt; 0.05). <i>Firmicutes</i> and <i>Bacteroidota</i> dominated the microbiota at the phylum level. <i>Oscillospirales</i> were enriched in the TM groups (<i>p</i> &lt; 0.001) and <i>Lactobacillales</i> were increased in the LPS-CON group (<i>p</i> &lt; 0.019). LPS reduced BT in the CON group (<i>p</i> &lt; 0.01), but LPS-TM birds bypassed hypothermia. LPS significantly reduced BW (<i>p</i> &lt; 0.001), while TM had no significant effect. These findings demonstrate TM&rsquo;s enduring influence on gut microbiota and stress resilience, highlighting its potential to reduce antibiotic reliance and mitigate antimicrobial resistance (AMR) in poultry production.