Effect Of Astragalus Polysaccharides On Alleviating Transport Stress-induced Hepatic Glucose And Lipid Metabolism Disorders In Chick

Chicks need to be transported from the hatchery to the farm after breaking their shells.During transportation,chicks are frequently subjected to various physical and psychological stressors,including capture,vibration,collision,temperature extremes,thirst,and hunger,which can lead to alterations inimmune,energy supply and neuroendocrine systems,resulting in significant economic losses.The liver is a central organ for fat metabolism in poultry.Stress caused by transportation is especially harmful to liver,which can cause significant effects on liver function,disturb glucolipid metabolism,thus reducing the production performance of poultry.Firstly,our experiment making conscientious survey about the basic situation of poultry farming in the Harbin Prefecture of Heilongjiang,the current situation of transporting newborn chicks,and the mortality of chicks at various time stages due to different distances of transport.To investigate the effect of transportation stress on hepatic glucose and lipid metabolism in chicks,one-day old chicks(female,Hy Line White)were transported for 0,2,4,8 h,respectively in order to build the simulation transportation models.Observation of chick behavior before and after transport,and liver tissues were weighed to measure the liver index.H&E staining,oil red O staining,transcriptomics detection,q RT-PCR and Western blotting assays used to observe the pathological changes of liver tissue,measure the expression of genes and proteins related to glucose-lipid metabolism and AMPK/SIRT1/PGC1α pathway.Given the beneficial effects of APS in antagonizing metabolic stress in the liver.Before simulation transport,the chicks were treated with APS by oral drop,to assess the contribution of APS on transport stress-induced disorder of hepatic glucolipid metabolism in neonatal chicks.The results showed as follow:(1)There are 305 poultry farms in Harbin region,including 6 breeder farms,146 broiler farms,153 egg farms,1 national standardized demonstration farm and 74 regional level demonstration farms.The transport distance of newly hatched chicks transferred from poultry farms with over 10 thousand poultry in Harbin region ranged from 0 to 300 km.There was an increased trend for the newborn chick’s mortality rate as the transport distance increased at each time stage.(2)Hepatic relative weight in chicks experienced transport was increased.H&E staining and Oil Red O staining showed that the liver of chicks in simulated transport stress groups displayed significant hepatic triglyceride accumulation and structural abnormalities,and disorganized liver plates with varying degrees of hepatic steatosis.Serum thyroid hormone(TSH),Cortisol(Cor),blood glucose(GLU),triglycerides(TG),direct bilirubin(DBIL)concentration increased significantly;indirect bilirubin(IBIL)significantly decreased.indicating that transportation stress caused damage of chicken liver.(3)Transport stress can influence changes in the transcriptomics of chicken liver,differential expression of 3570 m RNA(p<0.05),1791 m RNAs were up-regulated,1779 m RNAs were downregulated(p<0.05).Encyclopedia of Genes and Genomes(KEGG)enrichment analyses between transport 8 h group and control group showed that differentially expressed m RNAs were mainly enriched in signaling pathways related to carbohydrate digestion and absorption,amino sugar and nucleotide sugar metabolism,lipid metabolism and steroid hormone synthesis.RT-q PCR validations for randomly selected 11 m RNAs showed that the transcriptome date acquired by RNA-seq were reliable.(4)Transport stress stimulated the m RNA abundance of glucose metabolism related molecules(Ch REBP,G6 PC,PFKFB2,PCK1,GCK1 and G6PASE).Transport stress resulted in a timedependent increase in the m RNA and protein abundances of AMPK,SIRT1 and PGC1α.Notably,the value of p-AMPK/ AMPK was downregulated in all the transport groups,indicating transport stress may cause hepatic glucose metabolism disorders in chicks.(5)Transport dramatically decreased m RNA levels of the fatty acid transport-related molecules(LPL,ACBP,FABP1,and FABP3),β-oxidation related molecule(ACSL1,CPT1,and CPT2),fatty acid synthesis-related molecules(SERBP1,FASN,and ACACA),cholesterol metabolism-related molecules(CYP8P1,LXR,and CYP)and VLDL assembly-related molecules(APOB and MTTP).Meanwhile,transport significantly increase the m RNA levels of PPARα,PPARγ,RXRγ and ACOX1.The protein levels of PPARα,PPARγ,and SERBP1 are basically consistent with their gene expression levels.As mentioned above,transport stress may cause hepatic lipid metabolism disorders in chicks.(6)APS could relieve transport stress induced increased liver weight,relieved lipid deposition,decreased the levels of the stress hormone and regulated activity of related abnormally expressed enzyme.KEGG enrichment analyses showed that differentially expressed m RNAs between T+A group and transport 8 h group were mainly enriched in signaling pathways related to protein digestion and absorption,carbohydrate digestion and absorption.These results indicate that APS can improve the liver tissue fat accumulation induced by transport stress in chicks.(7)APS reverse transport stress induced increases in m RNA expression of glycogenolysis and gluconeogenesis-related molecules.APS could simultaneously alleviate these alterations via AMPK/SIRT1/PGC1α/pathway.Meanwhile,APS further alleviated the inhibitory effect of transport on fatty acid transport-related molecules,cholesterol metabolism-related molecules and VLDL assembly in liver.m RNA abundance for β-oxidation related molecules was restored under APS treatment.These results indicate that APS can alleviate transport stress-induced glucose-lipid metabolism disorders in chicksIn conclusion,transport stress caused significant vacuole-like degeneration and lipid deposition,hepatic glucolipid metabolism disorders of the chicken liver,continuing to affect the growth performance of chicks.APS potentially antagonize transport stress-induced hepatic steatosis in chicks by regulating glucolipid metabolism homeostasis.This study provides a theoretical basis and a new direction for recovering the economic losses caused by chick transport stress in the farming industry from production practice,and has good application prospects.