ABSTRACT
This study investigated the protective effects of chlorogenic acid (CGA) on production performance and liver function of rabbits under heat stress (HS) condition. A total of 120 healthy New Zealand weaned rabbits with similar initial body weight, were randomly divided into 3 treatments with 20 replicates per treatment and 2 weaned rabbits per replicate: control (CON) group (rabbits were housed at 25 ± 1°C and fed a basal diet), HS group (rabbits were housed at 35 ± 1°C and fed a basal diet), and HS + CGA group (rabbits were housed at 35 ± 1°C and fed a basal diet supplemented with 800 mg/kg CGA). The trial lasted for 28 days. The results showed that HS challenge decreased (p < 0.05) growth performance, induced oxidative stress and hepatic apoptosis, and caused liver damage in rabbits. However, dietary CGA supplementation increased (p < 0.05) body weight gain and feed efficiency, and enhanced (p < 0.05) antioxidative capacity in serum and liver in HS-challenged rabbits; attenuated HS-induced increases in urea nitrogen (p = 0.03), alanine aminotransferase (p = 0.03), aspartate aminotransferase (p = 0.01), caspase-8 (p = 0.02), and caspase-3 (p = 0.04) as well as decrease albumin (p = 0.04). Moreover, supplementation with CGA upregulated Nrf2/HO-1 pathway-related genes expressions, including Nrf2 (p = 0.009), HO-1 (p = 0.03) and SOD1 (p = 0.04) in HS-challenged rabbits. Our findings demonstrated that dietary CGA supplementation could alleviate HS-induced decline in growth performance, and protect against HS-induced liver damage partially through enhancing antioxidant capacity via acting Nrf2/HO-1 pathway and inhibiting hepatic apoptosis in rabbits.
ABSTRACT
This study was conducted to investigate the impacts of chlorogenic acid (CGA) on growth performance, intestinal permeability, intestinal digestion and absorption-related enzyme activities, immune responses, antioxidant capacity and cecum microbial composition in weaned rabbits. One hundred and sixty weaned rabbits were allotted to four treatment groups and fed with a basal diet or a basal diet supplemented with 400, 800, or 1,600 mg/kg CGA, respectively. After a 35-d trial, rabbits on the 800 mg/kg CGA-supplemented group had higher (p < 0.05) ADG and lower (p < 0.05) F/G than those in control (CON) group. According to the result of growth performance, eight rabbits per group were randomly selected from the CON group and 800 mg/kg CGA group to collect serum, intestinal tissue samples and cecum chyme samples. Results showed that compared with the CON group, supplementation with 800 mg/kg CGA decreased (p < 0.05) levels of D-lactate, diamine oxidase, IL-1ß, IL-6, and malondialdehyde (MDA), and increased IL-10 concentration in the serum; increased (p < 0.05) jejunal ratio of villus height to crypt depth, enhanced (p < 0.05) activities of maltase and sucrase, increased (p < 0.05) concentrations of IL-10, T-AOC, MHCII and transforming growth factor-α, and decreased (p < 0.05) levels of TNF-α and MDA in the jejunum of weaned rabbits. In addition, results of high-throughput sequencing showed that CGA supplementation elevated (p < 0.05) microbial diversity and richness, and increased (p < 0.05) the abundances of butyrate-producing bacteria (including genera V9D2013_group, Monoglobus, Papillibacter, UCG-005, and Ruminococcus). These results indicated that dietary supplementation with 800 mg/kg CGA could improve the growth performance of weaned rabbits by enhancing intestinal structural integrity, improving the intestinal epithelium functions, and modulating the composition and diversity of gut microbiota.
