Plasma Amino Acid Concentrations of Horses Grazing Alfalfa, Cool-Season Perennial Grasses, and Teff.

This research examines the effect of different forage species on the plasma amino acid concentrations and protein synthesis in horses. The result shows that while different forages vary in amino acid content, only plasma threonine concentration had significant differences with no noticeable impact on protein synthesis.

Methodology

• The experiment utilized horses randomly assigned to graze on three types of forages: Alfalfa, mixed perennial cool-season grasses (CSGs), and Teff pastures. This process was arranged in a replicated Latin-square design to provide a balanced distribution of horses among forage types.
• Jugular venous blood samples were collected from each horse before grazing (0 hours) and then two hours and four hours after. This procedure was done to monitor changes in the horse’s plasma amino acid concentrations corresponding to their grazing activity.
• In conjunction with the blood collection, forage samples were also hand harvested and analyzed to determine their amino acid concentrations. This ensured a direct comparison between the ingested forage and the changes observed in the horse’s plasma.
• Equine muscle satellite cell cultures were treated with the collected sera from the grazing horses. The purpose of this process was to investigate the impact of the forage on de novo protein synthesis in horses.
• The gathered data were analyzed using PROC MIXED procedure in SAS software.

Results

• The analysis revealed that among the forages, amino acid concentrations were generally lowest in Teff and highest in Cool-season grasses.
• Threonine concentration in the plasma was observed to have significant differences, however, these differences didn’t result in effect on the de novo protein synthesis of cultured equine muscle satellite cells. The plasma collected from the grazing horses, regardless of the forage type ingested, did not influence protein synthesis.

Conclusion

• Results suggest that the forage species ingested by horses do impact their plasma amino acid concentrations to some extent. However, this does not directly translate into significant effects on their overall protein synthesis.
• Despite forages varying significantly in their amino acid content, only the concentration of threonine in the plasma showed any sizable change after four hours of horse grazing.
• The study concludes that even though significant differences are observed in forage amino acid content and plasma threonine concentration, no evident effect was observed on equine protein synthesis.