Effect of meal schedules and fasting on selected plasma free amino acids in horses.

This study analyses the effects of meal schedules and fasting on plasma free amino acids in horses. The significant finding indicates that the frequency of meals and the size of the meals influence plasma methionine levels, with one meal per day resulting in higher levels than multiple smaller meals.

Research Design and Methodology

• The research involved six 22-month-old Quarter Horses.
• The horses were assigned to one of three feeding schedules: one meal per day (1M), two meals per day (2M), or six meals per day (6M), for a duration of two weeks.
• The meal provided was a complete pelleted ration, given at a rate of 1.75% of the horse’s body weight each day.
• To measure the impact of the feeding schedules on plasma free amino acids (PFAA), blood samples were collected and examined for levels of methionine after the consumption of a meal.

Results and Findings

• Consumption of a meal under the 1M and 2M schedules resulted in an increase in plasma methionine, the peak being observed at 5 hours and 3 hours respectively.
• Horses eating one larger meal per day (1M) had higher methionine levels compared to those eating multiple smaller meals.
• No significant fluctuations in plasma methionine levels were recorded in the 6M group.
• Additionally, certain other amino acids (alanine, glutamine, glutamate, lysine, and leucine) also exhibited an increase, reaching peak levels at 5 hours and then declining.
• Upon 48 hours of withholding feed from the 1M group, the last 24 hours showed an increase in PFAA levels. While glutamine and lysine appeared to level off at 49 hours after the meal, alanine, glutamate, and leucine continued to increase.

Implications and Conclusions

• This study suggests that the frequency and size of meals may have a direct influence on the Methionine levels in horses’ plasma.
• One larger meal per day scenario tends to have higher levels of Methionine post-meal compared to multiple smaller meals in a day.
• The study also showcases an impact on other plasma free amino acids in the event of withholding food, with an elevation noticed after 24 hours.
• This research could be vital in providing insights into the nutritional needs and dietary scheduling for horses to maintain a healthy amino acid balance.