Protective effects of genistein on the production performance and lipid metabolism disorders in laying hens with fatty liver hemorrhagic syndrome by activation of the GPER-AMPK signaling pathways.

The aim of this study was to evaluate the beneficial effects and potential mechanisms of genistein (GEN) on production performance impairments and lipid metabolism disorders in laying hens fed a high-energy and low-protein (HELP) diet. A total of 120 Hy-line Brown laying hens were fed with the standard diet and HELP diet supplemented with 0, 50, 100, and 200 mg/kg GEN for 80 d. The results showed that the declines in laying rate (P < 0.01), average egg weight (P < 0.01), and egg yield (P < 0.01), and the increase of the ratio of feed to egg (P < 0.01) induced by HELP diet were markedly improved by 100 and 200 mg/kg of GEN treatment in laying hens (P < 0.05). Moreover, the hepatic steatosis and increases of lipid contents (P < 0.01) in serum and liver caused by HELP diet were significantly alleviated by treatment with 100 and 200 mg/kg of GEN in laying hens (P < 0.05). The liver index and abdominal fat index of laying hens in the HELP group were higher than subjects in the control group (P < 0.01), which were evidently attenuated by dietary 50 to 200 mg/kg of GEN supplementation (P < 0.05). Dietary 100 and 200 mg/kg of GEN supplementation significantly reduced the upregulations of genes related to fatty acid transport and synthesis (P < 0.01) but enhanced the downregulations of genes associated with fatty acid oxidation (P < 0.01) caused by HELP in the liver of laying hens (P < 0.05). Importantly, 100 and 200 mg/kg of GEN supplementation markedly increased G protein-coupled estrogen receptor (GPER) mRNA and protein expression levels and activated the AMP-activated protein kinase (AMPK) signaling pathway in the liver of laying hens fed a HELP diet (P < 0.05). These data indicated that the protective effects of GEN against the decline of production performance and lipid metabolism disorders caused by HELP diet in laying hens may be related to the activation of the GPER-AMPK signaling pathways. These data not only provide compelling evidence for the protective effect of GEN against fatty liver hemorrhagic syndrome in laying hens but also provide the theoretical basis for GEN as an additive to alleviate metabolic disorders in poultry.

Fatty liver hemorrhagic syndrome (FLHS) is a nutritional and metabolic disease that seriously threatens the health and performance of laying hens, which is characterized by hepatic steatosis and lipid metabolism disorders. As an isoflavone phytoestrogen, genistein (GEN) exerts many beneficial functions, including alleviating lipid metabolism disorders and anti-inflammatory properties. However, further research is needed on the protective effect and potential mechanism of GEN on the FLHS in laying hens. Here, we found that GEN treatment improved liver injury and decline of production performance in laying hens with FLHS. Moreover, GEN treatment alleviated hepatic steatosis and lipid metabolism disorders through reducing the expression levels of mRNA related to fatty acid transport and synthesis and enhancing the mRNA expression levels of factors associated with fatty acid oxidation in FLHS layers, which may be achieved by activation of the G protein-coupled estrogen receptor­adenosine 5'-monophosphate (AMP)-activated protein kinase signaling pathways. These data not only provide compelling evidence for the protective effects and mechanisms of GEN against FLHS in laying hens but also provide the theoretical basis for GEN to alleviate other metabolic disorders in poultry.

Dietary supplementation of dimethyl itaconate protects against chronic heat stress-induced growth performance impairment and lipid metabolism disorder in broiler chickens.

This study aimed to investigate the protective effects of dietary supplementation of dimethyl itaconate (DI) on chronic heat stress (HS)-induced impairment of the growth performance and lipid metabolism in broiler chickens. 21 days old male Ross 308 broiler chickens (a total of 120, about 700 g body weight) were randomly divided into five treatment groups, including control group, HS group, HS + 50 mg/kg DI group, HS + 150 mg/kg DI group, and HS + 200 mg/kg DI group, and each group contains eight cages of twenty-four broilers. The broiler chickens in the control group were raised in the room (21 ± 1 °C) and fed with a finisher diet for 21 days. The broiler chickens of the HS group and the HS + DI groups were raised in the room (32 ± 1 °C for 8 h/day) and fed with a finisher diet containing DI at 0, 50, 150, and 200 mg/kg diet for 21 days. The results showed that HS-induced decreases in the final body weight (P < 0.01), average daily gain (P < 0.01), and average daily feed intake (P < 0.01) were alleviated by dietary supplementation of DI (P < 0.05). In addition, dietary supplementation of DI attenuated the increases in the liver index (P < 0.01) and abdominal fat rate (P < 0.01) caused by HS in broilers (P < 0.05). Treatment with DI ameliorated HS-induced lipid accumulation in the liver and serum of broiler chickens (P < 0.05). The upregulation of mRNA levels of fat synthesis factors (P < 0.01) and downregulation of mRNA levels of lipolysis-related factors (P < 0.01) caused by HS were markedly blunted after treatment with DI in the liver of broilers (P < 0.05). Broilers exposed to HS exhibited lower phosphorylated protein levels of AMP-activated protein kinase α and acetyl-CoA carboxylase α compared to the control group (P < 0.01), which were improved by treatment with DI (P < 0.01). Collectively, these results demonstrated that dietary supplementation of DI protects against chronic HS-induced growth performance impairment and lipid metabolism disorder in broiler chickens. These results not only provide a theoretical basis for DI to alleviate metabolic disorders but also provide a reference value for DI as a feed additive to improve heat stress in poultry caused by high temperature.

Heat stress (HS) caused by high temperatures can lead to metabolic disorders and decreased growth performance in broilers, which has become a global concern in broiler production. Dimethyl itaconate (DI), as a cell-permeable itaconate derivative, has many benefits in alleviating inflammatory response and antioxidant. However, the beneficial effect of DI on broilers exposed to HS are still unclear. Here, we found that DI treatment improved the decline of growth performance and hormone secretion disorder caused by HS in broiler chickens. Moreover, the treatment with DI alleviated the excessive accumulation of lipids caused by HS through reducing mRNA levels related to liposynthesis and enhancing mRNA levels associated with lipolysis in broiler chickens, which may be achieved by activation of the AMP-activated protein kinase (AMPK) signaling pathway. These data not only provide the potential mechanism for DI to alleviate metabolic disorders but also provide a sufficient theoretical basis for DI as an additive to alleviate HS in broiler chickens.

Dehydroepiandrosterone alleviates oleic acid-induced lipid metabolism disorders through activation of AMPK-mTOR signal pathway in primary chicken hepatocytes.

The incident of lipid metabolism disorders has obviously increased under the undue pursuit of efficiency, which had seriously threatened to the health development of poultry industry. As an important cholesterol-derived intermediate, though dehydroepiandrosterone (DHEA) has the fat-reduction effect in animals and humans, but the underlying mechanism still poorly understood. Herein, the present study aimed to investigate the regulatory effects and its molecular mechanism of DHEA on disturbance of lipid metabolism induced by oleic acid (OA) in primary chicken hepatocytes. The hepatocytes were treated with 0, 0.1, 1, 10 µM DHEA for 4 h, and then supplemented with 0 or 0.5 mM OA stimulation for another 24 h. Our findings demonstrated that DHEA treatment effectively reduced TG content and alleviated lipid droplet deposition in OA-induced hepatocytes. DHEA inhibited the lipogenesis related factors (ACC, FAS, SREBP-1c, and ACLY) mRNA level and increased the lipolysis key factors (CPT-1 and PPARα) mRNA levels. In addition, DHEA obviously elevated the protein levels of CPT-1A, p-ACC, and ECHS1; whereas decreased the protein levels of FAS and SREBP-1 in hepatocytes stimulated by OA. Furthermore, DHEA promoted the phosphorylation of AMP-activated protein kinase (AMPK) and inhibited the phosphorylation of mammalian target of rapamycin (mTOR). Mechanistically, the hepatocytes were pre-treated with AMPK inhibitor compound C or AMPK activator AICAR before addition of DHEA treatment, and the results certified that DHEA activated cAMP/AMPK pathway and which subsequently led the inhibition of mTOR signal, which finally reduced the fat excessive accumulation in OA-stimulated hepatocytes. Collectively, our study unveiled that DHEA protects against the lipid metabolism disorders triggered by OA stimulation through activation of AMPK-mTOR signaling pathway, which prompts the value of DHEA as a potential nutritional supplement in regulating the lipid metabolism and its related disease in poultry.

Dietary supplementation of salidroside alleviates liver lipid metabolism disorder and inflammatory response to promote hepatocyte regeneration via PI3K/AKT/Gsk3-ß pathway.

Fatty liver hemorrhagic syndrome (FLHS) is a chronic hepatic disease which occurs when there is a disorder in lipid metabolism. FLHS is often observed in caged laying hens and characterized by a decrease in egg production and dramatic increase of mortality. Salidroside (SDS) is an herbal drug which has shown numerous pharmacological activities, such as protecting mitochondrial function, attenuating cell apoptosis and inflammation, and promoting antioxidant defense system. We aimed to determine the therapeutic effects of SDS on FLHS in laying hens and investigate the underlying mechanisms through which SDS operates these functions. We constructed oleic acid (OA)-induced fatty liver model in vitro and high-fat diet-induced FLHS of laying hens in vivo. The results indicated that SDS inhibited OA-induced lipid accumulation in chicken primary hepatocytes, increased hepatocyte activity, elevated the mRNA expression of proliferation related genes PCNA, CDK2, and cyclinD1 and increased the protein levels of PCNA and CDK2 (P < 0.05), as well as decreased the cleavage levels of Caspase-9, Caspase-8, and Caspase-3 and apoptosis in hepatocytes (P < 0.05). Moreover, SDS promoted the phosphorylation levels of PDK1, AKT, and Gsk3-ß, while inhibited the PI3K inhibitor (P < 0.05). Additionally, we found that high-fat diet-induced FLHS hens had heavier body weight, liver weight, and abdominal fat weight, and severe steatosis in histology, compared with the control group (Con). However, hens fed with SDS maintained lighter body weight, liver weight, and abdominal fat weight, as well as normal liver without hepatic steatosis. In addition, high-fat diet-induced FLHS hens had high levels of serum total cholesterol (TC), triglyceride (TG), alanine transaminase (ALT), and aspartate aminotransferase (AST) compared to the Con group, however, in the Model+SDS group, the levels of TC, TG, ALT, and AST decreased significantly, whereas the level of superoxide dismutase (SOD) increased significantly (P < 0.05). We also found that SDS significantly decreased the mRNA expression abundance of PPARγ, SCD, and FAS in the liver, as well as increased levels of PPARα and MTTP, and decreased the mRNA expression of TNF-α, IL-1ß, IL-6, and IL-8 in the Model+SDS group (P < 0.05). In summary, this study showed that 0.3 mg/mL SDS attenuated ROS generation, inhibited lipid accumulation and hepatocyte apoptosis, and promoted hepatocyte proliferation by targeting the PI3K/AKT/Gsk3-ß pathway in OA-induced fatty liver model in vitro, and 20 mg/kg SDS alleviated high-fat-diet-induced hepatic steatosis, oxidative stress, and inflammatory response in laying hens in vivo.