Astragalus Polysaccharides Antagonized Liver Injury Induced By Transport Stress In Chicks

Transportation is a necessary process for chicks transfer between hatchery and farm after they hatch.Transportation stress will make a great impact on the growth and production performance of chicks,resulting in the loss of livestock and poultry breeding industry.The liver,as the main metabolic organ in the body,has an obvious response to transport stress.The heat shock protein can react quickly in the stress process and play a protective role.Astragalus polysaccharides(APS),an extract of astragalus membranaceus,has an anti-stress effect,but its antagonistic effects on liver damage caused by transport stress,especially the effect and mechanism of heat shock protein response,are still unclear.In this study,the liver weight,liver structure and function,and expression of heat shock protein-related factors of chicks before and after transportation stress were measured by using the method of simulated transportation and the APS droplet pretreatment.The results showed that:(1)Transport stress can lead to increased liver weight of chicks,swelling of liver cells,disorder of arrangement,hyperemia of tissues,and congestion of central veins.Serum liver function indicators: alanine aminotransferase(ALT),aspartate aminotransferase(AST)increased significantly;γ-glutamyl transpeptidase(GGT),alkaline phosphatase(ALP),total bilirubin(TBIL),Direct bilirubin(DBIL),total protein(TP),albumin(ALB)and globulin(GLB)content increased;indirect bilirubin(IBIL)and white ball ratio(A/G)decreased.While the APS pretreatment can relieve hepatocellular swelling and hyperemia and congestion,regulate related abnormally expressed enzyme activity,and protect liver function,indicating that APS can antagonize the damage of chicken liver caused by transportation stress.(2)Transport stress can lead to increased expression of heat shock transcription factor hsf1 in the liver of chicks,expression of hsf2 and hsf3 decreased at 2h and 4h,and increased at 8h.APS pretreatment can correct HSF expression disorder caused by transportation stress and relieve liver damage.(3)Transportation stress can cause the decrease of the expression of heat shock proteins(HSPs)in the liver of chicks,including hsp10,hsp47,hsp60,hsp90 and hsp110.Meanwhile,hsp25 and hsp70 increase at 2h and 4h,hsp70 increase at 2h,and the expression hsp27 and hsp40 increased at 8h.The protein levels of hsp60 and hsp70 are basically consistent with their gene expression levels,which indicate that the heat shock response(HSR)can be induced by transport stress.APS can regulate the expression of heat shock protein-related factors in the liver,improve its disordered expression level,make its expression tend to normal,and restore its protective function,proving that improving heat shock protein expression disorder is one of the mechanism by which APS antagonizes transport stress-induced liver injury.In summary,transport stress can lead to damage to the liver function and structure of chicks,and disorder of heat shock protein response.APS has the effect of antagonizing liver injury and correcting the disorder of heat shock protein response.This research is based on production practice and provides a new direction and theoretical basis for reducing the stress response of chick transportation and reducing economic losses in the breeding industry.It has certain practical significance and development prospects.