Figure 2.

Effect of chronic heat stress on the mRNA expression levels of jejunum (A) claudin-1, (B) occludin, (C) ZO-1 and (D) ZO-2 in broilers and the intervention effect of guanidinoacetic acid (GAA) supplementation in diets. Data were represented as the means with SE. ^a,b Means 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.