Glucagon attenuates lipid accumulation in cow hepatocytes through AMPK signaling pathway activation.

The ketotic cows displayed hepatic lipid metabolic disorder and high blood concentration of glucagon. Importantly, adenosine monophosphate-activated protein kinase (AMPK) signaling pathway plays an important role in the hepatic lipid homeostasis. Therefore, the aim of this study was to investigate the effect of glucagon on AMPK pathway and its underlying mechanism on lipid metabolism in cow hepatocytes. Cow hepatocytes were cultured and treated with glucagon and AMPK inhibitor (BML-275). The results showed that glucagon significantly promoted the expression of glucagon receptor and increased the phosphorylation level and activity of AMPKα. Activated AMPKα increased the expression level and transcriptional activity of peroxisome proliferator-activated receptor α, which further increased the expression of fatty acid oxidation genes and lipid oxidation. Furthermore, activated AMPKα inhibited the expression level and transcriptional activity of sterol regulatory element binding protein-1c and carbohydrate response element binding protein, which decreased the expression of lipogenic genes, thereby decreasing lipid synthesis. In addition, glucagon also increased the expression of very-low-density lipoprotein (VLDL) assembly to export intracellular triglycerides (TG). Consequently, the content of intracellular TG was significantly decreased in cow hepatocytes. These results indicate that glucagon activates the AMPK signaling pathway to increase lipid oxidation and VLDL assembly and decrease lipid synthesis in cow hepatocytes, thereby reducing liver fat accumulation.

Deoxynivalenol Induces Intestinal Damage and Inflammatory Response through the Nuclear Factor-κB Signaling Pathway in Piglets.

Deoxynivalenol (DON) is highly toxic to animals and humans, but pigs are most sensitive to it. The porcine mucosal injury related mechanism of DON is not yet fully clarified. Here, we investigated DON-induced injury in the intestinal tissues of piglet. Thirty weanling piglets [(Duroc × Landrace) × Yorkshire] were randomly divided into three groups according to single factor experimental design (10 piglets each group). Piglets were fed a basal diet in the control group, while low and high dose groups were fed a DON diet (1300 and 2200 µg/kg, respectively) for 60 days. Scanning electron microscopy results indicated that the ultrastructure of intestinal epithelial cells in the DON-treated group was damaged. The distribution and optical density (OD) values of zonula occludens 1 (ZO-1) protein in the intestinal tissues of DON-treated groups were decreased. At higher DON dosage, interleukin (IL)-1ß, IL-6, and tumor necrosis factor-α mRNA levels were elevated in the intestinal tissues. The mRNA and protein levels of NF-κB p65, IκB-α, IKKα/ß, iNOS, and COX-2 in the small intestinal mucosa were abnormally altered with an increase in DON concentration. These results indicate that DON can persuade intestinal damage and inflammatory responses in piglets via the nuclear factor-κB signaling pathway.

In vivo effects of Allium cepa L. on the selected gut microflora and intestinal histomorphology in broiler.

The experiment was conducted to evaluate the effect of onion (Allium cepa L.,) on the performance, gut microflora and intestinal histomorphology of broiler chicks. Three hundred and twenty day old broiler chicks (Ross) were randomly divided into four groups as A, B, C and D. Group A served as control without any supplementation, group B, C and D was supplemented with onion powder at the rate of 1.5, 2 and 2.5g/kg of feed respectively. Supplementation of onion significantly (P<0.05) increased weight gain and feed consumption. Supplementation of onion showed a significant (P<0.05) reduction in the population of E. coli and increased significantly Lactobacillus and Streptococcus species. Onion supplementation significantly (P<0.05) increased the morphometry of length, width, crypt depth and surface area of the villus in duodenum, jejunum and ileum of the small intestine. In conclusion, onion supplementation in broiler produced a positive effect on performance, gut microflora and intestinal histomorphology.