Curcumin attenuates hepatic mitochondrial dysfunction through the maintenance of thiol pool, inhibition of mtDNA damage, and stimulation of the mitochondrial thioredoxin system in heat-stressed broilers.

The aim of this study was to investigate the effects of dietary curcumin supplementation on the performance, mitochondrial redox system, mitochondrial DNA (mtDNA) integrity, and antioxidant-related gene expression in the liver of broiler chickens after heat stress treatment. At day 21, a total of 400 Arbor Acres broiler chickens with similar body weight (BW) were divided into 5 groups with 8 replicates per group and then reared either at a normal temperature (22 ± 1 °C) or at a high ambient temperature (34 ± 1 °C for 8 h and 22 ± 1 °C for the remaining time) for 20 d. Broilers in the 5 groups were fed a basal diet at a normal temperature (NT group) and a basal diet with 0, 50, 100, and 200 mg/kg curcumin at a high ambient temperature (HT, CUR50, CUR100, and CUR200 groups), respectively. The serum and liver samples were analyzed for the parameters related to hepatic damage, mitochondrial function, and redox status. The results showed that the G:F was increased in the CUR50 and CUR100 groups, and the final BW was increased in CUR100 group in comparison with the HT group (P < 0.05). When compared with those in the HT group, both serum aspartate and alanine aminotransferase activities were decreased in the curcumin-supplemented groups (P < 0.05). Curcumin decreased the reactive oxygen species (ROS) production but increased the mitochondrial membrane potential in the hepatocytes of the broilers after heat stress (P < 0.05). The broilers in curcumin-supplemented groups had lower malondialdehyde and protein carbonyl concentrations as well as greater thiol concentrations (P < 0.05). The mitochondrial manganese superoxide dismutase (MnSOD) activity in the liver was increased (P < 0.05) in the CUR100 group compared with the HT group. Compared with the heat-stressed broilers, the broilers that were fed curcumin had greater (P < 0.05) mtDNA copy number and ATP concentrations than those in the HT group. Curcumin supplementation attenuated the depression of the thioredoxin 2 and peroxiredoxin-3 gene expressions (P < 0.05). The MnSOD gene expression was increased in the CUR100 and CUR200 groups, and the thioredoxin reductase 2 gene expression was increased in the CUR50 group in comparison with the HT group (P < 0.05). In conclusion, curcumin mitigated the mitochondrial dysfunction in heat-stressed broilers, as evidenced by the suppression of the ROS burst, the maintenance of the thiol pool and mtDNA content, and the enhanced mitochondrial antioxidant gene expression.

Protective effects of leucine on redox status and mitochondrial-related gene abundance in the jejunum of intrauterine growth-retarded piglets during early weaning period.

The aim of this study was to investigate the effects of dietary supplementation with 0.35% l-leucine on redox status and gene abundance relating to mitochondrial biogenesis and function in the jejunum of intrauterine growth-retarded (IUGR) piglets during early weaning period. According to a 2 × 2 factorial arrangement, 16 IUGR and 16 normal body weight (NBW) piglets were fed a basal diet without l-leucine supplementation or a basal diet plus 0.35% l-leucine supplementation from the age of 14 to 35 d. The results showed that compared with NBW piglets, IUGR piglets had a lower (p < 0.05) jejunal DNA concentration, a reduced (p < 0.05) manganese superoxide dismutase (MnSOD) and total antioxidant capability (T-AOC) activities and mitochondrial DNA content in the jejunum. Leucine supplementation increased (p < 0.05) MnSOD and T-AOC activities and decreased (p < 0.05) the malondialdehyde content in the jejunum of IUGR piglets. The mRNA gene abundance of nuclear respiratory factor-1 (NRF1), mitochondrial transcription factor A (TFAM), ATP synthase (ATPs), cytochrome c oxidase V (CcOX V), cytochrome c and glucokinase in the jejunum of IUGR piglets was reduced (p < 0.05) compared with NBW piglets. However, NRF1, peroxisome proliferation-activated receptor gamma coactivator-1 alpha, TFAM, ATPs and CcOX I mRNA gene abundance in the jejunum of IUGR piglets were increased (p < 0.05) by diets supplemented with leucine. These data indicate that leucine supplementation has therapeutic potential for attenuating intestinal oxidative stress and mitochondrial dysfunction in IUGR piglets during the early period of life via increasing enzyme activities and up-regulating mRNA gene abundance.