Comparison And Evaluation Of Blood Metabolic Profiles In Peripartum Healthy And Fatty Liver Dairy Cows

Fatty liver is a common metabolic disease in dairy cows during the perinatal period.Cows experience a severe negative energy balance?NEB?during perinatal period,therefore,adipose tissue is mobilized to meet its energy needs.This mobilization leads to an increase in the concentration of non-esterified fatty acids?NEFA?in the blood,which is absorbed by the liver and re-esterified into triglycerides?TAG?and accumulates in the liver,leading to the occurrence of fatty liver.Fatty liver occurs mostly in high-yielding cows at the early stage of lactation,which can cause a decrease in milk production and induce other diseases,leading to premature elimination or even death of cows,which seriously restrict the development of dairy industry in China.At present,the only reliable method for diagnosing fatty liver in dairy cows is liver biopsy,but this method has high technical requirements for operators and will damage the liver of dairy cows,and there is a high probability of infection risk.The method of monitoring certain components in urine,milk,and blood to evaluate the nutritional status of herds and individuals,and then to warn of nutritional metabolic diseases has been widely recognized,namely"Kampton metabolism profiles".Therefore,this study compares and analyzes the metabolism-related indexes,liver and kidney function-related indexes,immunological-related indexes,and mineral elements and bone collagen metabolism-related indexes in the blood of healthy and fatty liver cows,in order to find the key indicators that are convenient for diagnosing fatty liver,and evaluates their sensitivity and specificity,determine the Cut-point value,with a view to effective early warning of the occurrence of fatty liver in dairy cows.In this study,30 healthy cows and 30 fatty liver cows were selected as experimental subjects to evaluate the changes of their blood metabolism.Detection of11 energy metabolism-related indicators such as apolipoprotein B100?ApoB100?,glucagon?GC?,and glucose?Glucose,Glu?;13 liver and kidney function-related indicators such as Alanine aminotransferase?ALT?,Aspartate aminotransferase?AST?,and?-glutamyl transpeptidase?GGT?;11 immunological indicators such as interleukin 1?IL-1?,interleukin 6?IL-6?and interleukin 8?IL-8?;5 mineral element indicators such as Ca,Mg and Zn;and 5 bone collagen metabolism related indicators such as Osteoproterin?OPG?,Hydroxyproline?HYP?and Calcitonin?CT?.The receiver operating characteristic curve?ROC curve?is used to compare the area under the curve?AUC?,sensitivity?Se?,specificity?Sp?and the Cut-point value of corresponding detection indicators.In this way,the effectiveness of related indicators in diagnosing fatty liver was compared,and indicators that can be effectively used for early warning of fatty liver were screened out.The results showed that the negative balance of energy and Ca²⁺of fatty liver dairy cows was prevalent.Meanwhile,cows with fatty liver showed reduced insulin?INS?sensitivity,impaired bilirubin metabolism,severe inflammatory response and liver damage.The ROC curve analysis showed that ApoB100?AUC:0.993,Se:0.97,Sp:0.97,Cut-point:353??g/mL??,GC?AUC:0.979,Se:0.97,Sp:0.90,Cut-point:47.92?ng/mL??,ALT?AUC:0.978,Se:0.97,Sp:0.90,Cut-point:22.1?U/L??,GGT?AUC:0.976,Se:0.90,Sp:0.97,Cut-point:38.2?U/L??,IL-1?AUC:0.976,Se:0.93,Sp:0.93,Cut-point:99?ng/L??,IL-6?AUC:0.975,Se:0.90,Sp:0.97,Cut-point:12.9?ng/L??and IL-8?AUC:0.986,Se:0.93,Sp:0.93,Cut-point:414?ng/L??can be used as the preferred indicators for diagnosis and early warning of fatty liver in dairy cows.TAG,TC,VLDL,Apo E,AST,etc.can be used as auxiliary indicators for the diagnosis and early warning of fatty liver in cows.The determination of sensitivity,specificity and cut-point of the preferred and auxiliary indicators for early warning of fatty liver laid a theoretical foundation for the development of an early warning system of fatty liver in dairy cows based on"Internet+".