Application of nanoencapsulated silymarin to improve its antioxidant and hepatoprotective activities against carbon tetrachloride-induced oxidative stress in broiler chickens

The objective of this study was to evaluate antioxidant and hepatoprotective activities of nanoencapsulated silymarin (NES) against carbon tetrachloride-induced oxidative stress in broiler chickens. An in vitro study was conducted using a 20 kHz ultrasound with 62.5% amplitude to produce NES, stabilized by alginate for controlled release of its bioactive compounds in simulated gastrointestinal tract of broiler chickens. Results showed that sonication reduced the size of particles from 657.5 to 169.1 nm and polydispersity index from 0.60 to 0.31. Simulated gastrointestinal digestion in vitro indicated that NES was more resistant to gastric fluid compared to intestinal fluid. An animal model study was designed to investigate the antioxidant and hepatoprotective effects of NES on broiler chickens subjected to carbon tetrachloride-mediated oxidative stress. A total of 640 oneday-old mail broiler chickens were randomly assigned to 8 treatments with 4 replicate cages of 20 broiler chickens per cage as 2 x 2 x 2 factorial arrangement of treatments in a completely randomized design, including 2 concentrations of silymarin (0 and 100 mg/kg of body weight), NES (0 and 100 mg/kg of body weight), and carbon tetrachloride (0 and 1 mL/kg of body weight). All broiler chickens were fed a common diet throughout the study. From d 21, broiler chickens of control group received saline (intraperitoneally), while other treatment groups received silymarin (orally), carbon tetrachloride (intraperitoneally), and NES (orally). On d 42, 2 broiler chickens per replicate cage were euthanized for blood and tissue sampling. The interactions of silymarin x carbon tetrachloride (P = 0.003) and NES x carbon tetrachloride (P = 0.001) improved protein metabolism and lipid oxidative stability (P = 0.001). Combination of NES and carbon tetrachloride decreased serum content of alanine aminotransferase (P = 0.001), whereas combination of silymarin and carbon tetrachloride and NES increased (P = 0.02) its serum content as compared to broiler chickens that received none of those treatments. Carbon tetrachloride down-regulated (P = 0.03) the expression of superoxide dismutase 1, while silymarin, NES, and combination of silymarin and NES up-regulated its expression (P = 0.03). In contrast to carbon tetrachloride (P = 0.001), NES down-regulated (P = 0.03) heat shock protein 47 as compared with broiler chickens that received none of those treatments. In conclusion, NES has potential to mitigate the oxidative stress-induced hepatotoxicity in broiler chickens through modulation of oxidative stress biomarkers and expression of superoxide dismutase 1 and heat shock protein 47 genes.