Effect of Dietary Salicin Standardized Extract from <i>Salix alba</i> Bark on Oxidative Stress Biomarkers and Intestinal Microflora of Broiler Chickens Exposed to Heat Stress

The implication of heat stress (HS) in the oxidative stress phenomenon and its related diseases in chickens has been widely reported. Salicin is a precursor for the synthesis of salicylic acid and aspirin obtained from the bark of <i>Salix alba,</i> with an undeniable anti-inflammatory effect. However, little attention has been paid to salicin’s antioxidant/oxidative stress-reducing effect compared to its well-known anti-inflammatory effect. The purpose of the study was to investigate the effect of dietary salicin standardized extract from <i>Salix alba</i> bark (SAB) on oxidative stress biomarkers and intestinal microflora of broiler chickens exposed to heat stress. In our study, chickens (14 days) were randomly allocated to three treatment groups (SAB0; SAB25; SAB50), each of which included five replicates with eight birds per replicate. Broilers were exposed to heat stress (32 ± 2 °C) between 14 and 42 days. The liver tissues were collected to analyze oxidative stress biomarkers (total antioxidant capacity, glutathione, catalase, superoxide dismutase). The intestinal content was collected and measurements of the intestinal microbial population were performed (<i>E. coli,</i> staphylococci, lactobacilli). Results indicated that liver malondialdehyde and protein carbonyls activity decreased (<i>p</i>  < 0.05) in SAB50 treatment concomitantly with linearly increased total antioxidant capacity, and glutathione concentration. Dietary supplementation with SAB reduced (<i>p</i> < 0.05) the abundance of staphylococci and increased the number of lactobacilli. Taken together, SAB possesses an advantageous effect on liver oxidative status and the balance of intestinal microflora in broilers exposed to heat stress. These findings provide new insight into the potential use of salicin standardized extract from <i>Salix alba</i> bark for liver damage prevention and dysbiosis related to heat stress.