Blood serum biochemistry analysis of White Leghorn chickens selected for divergent blood antibody titer response to sheep red blood cells

Authors: ASSUMPCAO, ANNA - University Of Arkansas; Caputi, Valentina; ASHWELL, CHRISTOPHER - West Virginia University; HONAKER, CHRISTINA - Virginia Tech; SIEGEL, PAUL - Virginia Tech; TAYLOR, ROBERT - West Virginia University; Lyte, Joshua

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/2/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: For fifty generations, White Leghorn chickens have been selected for divergent responses to injection of sheep red blood cells (SRBCs) generating the high (HAS) or low (LAS) antibody response lines. Serum biochemistry provides a wealth of information regarding poultry health, performance, and foodborne pathogen colonization status. Considering humoral immunity is important in bird health and pathogen clearance, we sought to determine how multi-generational selection for high or low antibody titers may impact constitutive levels of biochemical markers known to be modulated by poultry infection, including Salmonella. Males and females HAS and LAS lines were raised under standard conditions. Blood was collected at 4, 8, 12, 16, and 66 weeks of age (n=8-12 chickens/group/sex/age) and were processed to collect serum. Serum samples were loaded in the Avian rotors and analyzed using MicroChem II (MicroVet Diagnostics) equipment [total protein (TP), albumin, globulin, albumin:globulin (A:G) ratio, aspartate transferase (AST), total bile acid (TBA), creatinine kinase (CK), uric acid (UA), glucose, calcium, phosphorus, potassium, and sodium]. Data were analyzed by two-way ANOVA followed by Sídák posthoc test, P<0.05 was considered significant. HAS had higher globulin, TP (12 weeks), potassium, and lower A:G ratio serum concentrations than LAS (P<0.05). Globulin is a group of blood pro-inflammatory proteins, which includes alpha-globulins, beta-globulins, and gamma-globulins or immunoglobulins (antibodies). TP is the sum of albumin and globulin concentrations, and A:G ratio is a marker for inflammatory diseases (lower values are related to increased globulin levels). The TP, globulin, and A:G ratios are consistent with the selection of HAS for higher antibody concentration. High levels of serum potassium are usually caused by kidney diseases or high-potassium diets, which were not reported in our study, suggesting that the high potassium levels were a result of the divergent selection for SRBC. Additionally, at 66 weeks of age higher concentration of CK was observed in HAS than in LAS (P<0.05). CK is known to be increased in birds following Salmonella infection, is also a muscle injury marker, and animals with higher blood concentrations of antibodies are known to develop deposits of these proteins in diverse tissues that cause tissue damage. At 66 weeks females from both groups had higher TBA, calcium, phosphorus, and lower uric acid than their male counterparts (P<0.05). TBA is a liver function marker, when higher than reference levels indicate liver damage, however, the levels in the present study were within the reference indicating increased liver function, consistent with the production of proteins and lipids necessary for egg production and leading to decreased UA production. Our findings demonstrated selection pressure on the humoral immune system can alter serum biochemical values that serve as potential informative and diagnostic markers in poultry performance and foodborne pathogen carriage.