Comparative hematological and serum biochemical profiling of grassland Xichun and Xilingol horses.

Overview

• This study compares blood and serum biochemical parameters of two horse breeds: Grassland Xichun horses (a crossbreed) and their maternal breed, Xilingol horses.
• The research identifies significant physiological and metabolic differences between the breeds under similar grazing conditions, providing insights for breeding and health monitoring.

Background and Purpose

• <strongGrassland Xichun horse: A newly developed crossbreed in Inner Mongolia, China, created by breeding Thoroughbred stallions with Xilingol mares.
• Xilingol horse: The maternal breed, native to the region, with established blood physiological data.
• Research gap: The physiological characterization of Grassland Xichun horses had not been systematically performed before.
• Study goal: To assess and compare hematological (blood) and serum biochemical parameters of the two breeds maintained in the same natural grazing environment.

Methods

• Subjects: 177 Grassland Xichun and 35 Xilingol horses, all kept under extensive grazing conditions.
• Parameters analyzed: 32 hematological and serum biochemical markers including blood cell counts, enzyme levels, metabolic indicators, etc.
• Statistical analysis: Used Benjamini-Hochberg False Discovery Rate correction to control for multiple comparisons and identify significant differences.
• Data interpretation: Effect sizes computed to evaluate the magnitude of differences between breeds.
• Multivariate analysis: Conducted principal component analysis (PCA) and Fisher’s linear discriminant analysis to assess breed separation based on blood profiles.

Key Findings

• Hematological differences:
  • Grassland Xichun horses have significantly higher red blood cell (RBC) counts, hemoglobin concentration, hematocrit, and mean corpuscular hemoglobin concentration (MCHC), indicating greater oxygen-carrying capacity.
  • The differences in these parameters had large effect sizes (absolute > 0.8), underscoring biological significance.
• Muscle enzyme profiles:
  • The enzyme lactate dehydrogenase (LDH) was markedly lower in Grassland Xichun horses (largest effect size = -2.117).
  • Other muscle-related enzymes, aspartate aminotransferase (AST) and creatine kinase (CK), were also lower, suggesting differences in basal muscle metabolism and aerobic capacity between breeds.
• Metabolic indicators:
  • Higher blood glucose levels were observed in Grassland Xichun horses, suggesting altered energy metabolism.
  • Total cholesterol was lower in Grassland Xichun, pointing to distinct lipid metabolism profiles.
• Immune-metabolic differences in Xilingol horses:
  • Xilingol horses showed higher counts of monocytes, mean platelet volume (MPV), blood urea nitrogen (UREA), and gamma-glutamyl transferase (GGT).
  • These differences may reflect adaptive physiological states tied to long-term environmental exposure and management rather than strictly breed genetics.
• Population and breed discrimination:
  • PCA indicated partial separation between breeds, consistent with shared maternal lineage but distinguishing physiological profiles.
  • Fisher’s linear discriminant analysis achieved 97.6% accuracy in classifying horses by breed based on the blood data.

Implications and Conclusions

• The study provides the first comprehensive hematological and biochemical profile of Grassland Xichun horses relative to their maternal breed.
• The differences highlight effects of crossbreeding with Thoroughbreds on oxygen transport and metabolism.
• Lower muscle enzyme activity in Grassland Xichun horses suggests potential breed-specific metabolic and physiological adaptations.
• The identified blood parameter ranges can aid clinical assessments and health monitoring in these horses.
• These physiological markers can be integrated into breeding programs to evaluate and improve performance traits and adaptability.
• Further research could explore how these differences impact exercise performance, endurance, and disease susceptibility between breeds.