Effects of grain species, genotype and starch quantity on the postprandial plasma amino acid response in horses.

The research article examines the impact of various grain species, their genotypes, and starch quantity on the level of plasma amino acids in horses after meals. The study contends that the availability of amino acids varies depending on the type of grain and its amount consumed.

Research Approach

• The researchers utilized six mares in three consecutive trials. Each trial involved feeding the horses different genotypes of oats, barley, and maize respectively.
• The grain genotypes were offered in three meal sizes that corresponded to 1.0, 1.5 or 2.0 g starch/kg body weight.
• The horses were also offered meadow hay (1.5 kg/100 kg body weight) daily. On test days, 1 kg of hay was fed to the horses 60 minutes prior to grain feeding.
• Blood samples from the horses were then taken before grain feeding (0 min) and then at 30, 60, 90, 120, 180, 240, and 300 minutes after the grain feeding. The remaining hay was then offered to the horses.

Key Findings

• The research found that there was a significant interaction between the grain genotype and starch quantity (what is referred to as “meal size”) in regards to post-meal plasma amino acid concentrations.
• Additionally, the study revealed distinctions in the availability of amino acids at both the digestive and post-digestive level, depending on the respective grain genotypes that were ingested.
• The levels of most plasma amino acids increased quickly after the meal, reaching a maximum around the 30 minute mark.
• The study also suggests that hay feeding might provide a higher amino acid provision than previously thought, considering the immediate increase in plasma amino acids if the intake is already at the 1 kg hay.
• However, it remains unclear as to what portion of the plasma amino acid kinetics response originates from the hay feeding and what portion comes from the cereal grain meals.