The Regulatory Effects Of Conjugated Linoleic Acid On Fatty Liver Hemorrhage Syndrome In Laying Hens

Fatty liver hemorrhagic syndrome（FLHS）is a nutritional metabolic disease that occurs mainly in caged hens at the peak of egg production.FLHS is endemic in many countries and regions,and has become one of the most common nutritional metabolic diseases in large-scale egg production.Conjugated linoleic acids（CLA）are a mixture of positional and geometric isomers of octadecadienoic acid,a functional polyunsaturated fatty acid,which has biological properties of modulating lipid metabolism,anti-inflammatory and antioxidant.Therefore,this experiment is intended to establish a pathological model of FLHS,to investigate the regulatory effects of CLA on FLHS from the perspectives of lipid metabolism,oxidative stress and inflammation,and to provide theoretical basis and experimental support for the comprehensive prevention and control of FLHS in production.Research content.A total of 100 healthy 120-day-old Hyland White laying hens were randomly divided into two groups: 30 hens in the control group（Con）and 70 hens in the model group（M）,both fed the same basal diet.A total of 14 days were spent on injections.After 14 days,the hens in the M group were depressed,the colour of the crown beard was lighter,the abdominal circumference was enlarged,the liver was enlarged,the texture was soft and fragile,the surface was bleeding in spots and stripes,the body weight,liver index and liver lipid rate were significantly higher than those in the Con group,and the serum and liver lipid metabolism index were also significantly higher than those in the Con group,indicating that the FLHS model was successfully established.The serum and liver lipid metabolism indexes were also significantly higher than those of the Con group,indicating that the FLHS model was successfully established.After the successful establishment of the FLHS model,the M group was randomly grouped into 2 groups of 32 birds each,as the model control group（MT）and the CLA control group（CLA group）,with the MT group continuing to feed the basal diet and the CLA control group feeding the basal diet with 0.5% CLA.After 56 days of feeding,6birds were randomly selected from each group for blood collection from the wing saphenous vein and liver tissue sample collection;serum,liver lipid metabolism and oxidative stress related indexes were measured;liver paraffin sections were prepared for HE staining to observe histopathological changes;liver frozen sections were prepared for oil red O staining to observe liver fat deposition;total liver RNA was extracted and detected by fluorescent quantitative PCR method The m RNA expression levels of lipid metabolism and inflammation-related factors in the liver of laying hens were detected by fluorescence quantitative PCR;the protein expression levels of liver NF-κB pathway-related proteins were detected by western blot.The test results were as follows.Compared with the MT group,liver index and abdominal lipid rate were significantly lower in the CLA group（P < 0.05）;serum levels of TG,TCH,AST and LDL-C were highly significant decreased and HDL-C was highly significant increased（P < 0.01）;liver lipid rate,liver levels of TG,TCH,ALT,LDL-C,NEFA and MDA were significantly decreased,and levels of HDL-C,CAT,SOD and GSH-Px levels were highly significantly increased（P< 0.05 or P < 0.01）.Compared with the MT group,the relative m RNA expressions of CD36,ACC,FAS,SCD,DGAT2,CPT1 A,SREBP-1c,SREBP-2,PPARγ and HMGR were highly significantly decreased（P < 0.01）and the relative m RNA expressions of LIPE,ATGL and PPARα were highly significantly increased（P < 0.01）in the liver of the CLA group.The relative expression of m RNA of NF-κB,INOS,TNF-α,COX-2,IL-1β and IL-6 in the liver was highly significantly decreased in the CLA group compared with the MT group（P< 0.01）.The relative protein expressions of NF-κB,TNF-α and IL-1β were highly significantly decreased in the liver of CLA group compared with MT group（P < 0.01）.Conclusion.1.The pathological model of FLHS was successfully replicated by intramuscular injection of estradiol benzoate.2 The addition of CLA to the diet alleviated FLHS by reducing hepatic oxidative stress,lipid metabolism disorders and inflammation in laying hens.