The purpose of this study was to explore whether conjugated linoleic acid (CLA) could alleviate fatty liver hemorrhagic syndrome (FLHS) induced by estradiol benzoate intramuscular injection in laying hens. One hundred male Hy-Line white chickens were randomly divided into two groups, namely, the control (CON) and estradiol benzoate (E) groups, and both groups were fed the same basal diet. After injections of estradiol benzoate at 2 mg/kg every two days for a total of 7 times, chickens in the E group showed FLHS symptoms, including liver enlargement, hemorrhage, and steatosis. Then half of the chickens in the E group received an additional diet containing 5000 mg/kg CLA for 8 weeks. The results of morphological observations, hematoxylin and eosin staining, and Oil Red O staining showed that CLA alleviated liver enlargement, hemorrhage, and lipid accumulation in FLHS chickens. In addition, we measured liver function and lipid metabolism indicators, including ALT, AST, TG, TCH, HDL-C, and LDL-C, which further suggested that CLA mitigated the disturbance of serum and liver metabolism in FLHS chickens. Mechanistically, CLA inhibited hepatic de novo lipogenesis, cholesterol synthesis, and TG accumulation and increased TG hydrolysis in FLHS chickens by regulating the gene expression of CD36, ACC, FAS, SCD 1, DGAT2, LIPE, ATGL, CPT1A, SREBP-1c, SREBP-2, PPARγ, and PPARα. Furthermore, CLA ameliorated hepatic oxidative stress and inhibited NF-κB signaling pathway-mediated inflammation in FLHS chickens. In conclusion, CLA regulated lipid metabolism, thus further alleviating oxidative stress and inflammation to alleviate FLHS induced by estrogen in chickens.
Keywords: conjugated linoleic acid; fatty liver hemorrhage syndrome; inflammation; laying hens; lipid metabolism; oxidative stress.
Fatty liver hemorrhagic syndrome (FLHS) has become one of the most common noninfectious diseases that contribute to laying hen mortality. Conjugated linoleic acid (CLA) is a functional polyunsaturated fatty acid with antioxidant and anti-inflammatory properties The purpose of this study was to investigate the effect of CLA on FLHS induced by estradiol benzoate in laying hens. We successfully replicated the FLHS pathological model by intramuscular injection of estradiol benzoate. The results of morphological and histopathological observations showed that CLA alleviated liver lipid accumulation in FLHS chickens. In addition, we measured liver function and lipid metabolism indicators, which further suggested that CLA mitigated the disturbance of serum and liver metabolism in FLHS chickens. Moreover, CLA inhibited hepatic de novo lipogenesis, cholesterol synthesis, and TG accumulation and increased TG hydrolysis in FLHS chickens by regulating related gene expression. Furthermore, CLA ameliorated hepatic oxidative stress and inhibited inflammation in FLHS chickens. In conclusion, CLA regulated lipid metabolism, thus further alleviating oxidative stress and inflammation to alleviate FLHS induced by estrogen in chickens. Our results provide new evidence and insights for applying CLA as an effective treatment for FLHS.
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