# Serum biochemical profiles are distinct between White Leghorn chicken lines selected for divergent antibody response to sheep red blood cells

## TL;DR

Chickens bred for high or low antibody responses to a blood cell injection show distinct differences in blood chemistry, which could help improve poultry health and performance.

## Contribution

This study reveals novel serum biochemical differences between chicken lines selected for divergent antibody responses, linking immune selection to metabolic and liver enzyme profiles.

## Key findings

- High antibody response chickens (HAS) had higher globulin and potassium levels and lower A:G ratios than low response chickens (LAS) at multiple ages.
- HAS chickens showed higher creatine kinase (CK) and gamma-glutamyl transferase (GGT) levels at specific ages, indicating potential liver and muscle activity differences.
- Female chickens at 66 weeks showed biochemistry profiles linked to egg production, including higher cholesterol and calcium levels compared to males.

## Abstract

For forty-nine 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. The objective of this study was to determine if selection for systemic antibody concentrations would result in divergence in blood serum biochemistry profiles.

Blood serum samples were collected from the same birds at 4, 8, 12, 16, and 66 weeks to analyze several biochemical serum parameters, including total protein (TP), albumin, globulin, albumin: globulin (A: G) ratio, aspartate transferase (AST), creatine kinase (CK), uric acid, glucose, calcium, phosphorus, potassium, sodium, total bile acid (TBA), gamma-glutamyl transferase (GGT), alanine transferase (ALT), and total cholesterol (TC).

Our results showed that HAS chickens had higher globulin and potassium levels and lower albumin: globulin (A: G) ratio serum concentrations than LAS chickens at 8, 12, and 16 weeks. At 12 weeks, HAS had total protein (TP) higher than LAS. Additionally, at 16 and 66 weeks, HAS had a higher concentration of creatine kinase (CK) than LAS. At 8 weeks, alanine transferase (ALT) levels were lower in HAS than LAS, and at 12 weeks, LAS females’ ALT levels were higher than HAS females. Furthermore, HAS had higher gamma-glutamyl transferase (GGT) levels than LAS at 12 and 16 weeks. The TP, globulin, and A: G ratios are consistent with the selection of HAS for higher antibody concentration. Additionally, our data also showed a divergence in potassium and liver enzyme levels between HAS and LAS. Females at 66 weeks had a biochemistry profile consistent with egg production, including increased total cholesterol (TC), total bile acid (TBA), aspartate transferase (AST), calcium, and phosphorus levels, as well as decreased uric acid and GGT concentrations compared with their male counterparts.

Our findings demonstrate that direct selection on the humoral immune system resulted in distinct serum biochemical profiles. These results are likely to serve as potential informative and diagnostic markers in poultry health, food safety, and performance.