Figure 4.

Effect of chronic heat stress on the mRNA expression levels of (A) IL-1β, (B) IL-6, (C) TNF-α and (D) IgA⁺cells density in broiler jejunum and the intervention effect of guanidinoacetic acid (GAA) supplementation in diets. Data were represented as the means with SE. ^a,b,cMeans within a row without a common superscript differ significantly among the NC, HS, and PF groups (P < 0.05). ^*Indicates a significant difference between HS vs. HG (P < 0.05). NC, normal control group, 22 ^°C, ad libitum feed basal diet; HS, heat stress group, 32 ^°C, ad libitum feed basal diet; PF, pair-fed group, 22 ^°C, received food equivalent to that consumed by the HS group on the previous day; HG, guanidinoacetic acid group, 32 ^°C, ad libitum feed basal diet with 0.6 g/kg guanidinoacetic acid.