Effect of short-term feed restriction and calorie source on hormonal and metabolic responses in geldings receiving a small meal.

The research article explores how short-term feed restriction and the type of caloric intake can affect the metabolism in horses that are fed either high-roughage or high-concentrate diets.

Introduction and Methodology

• The research aimed to examine the metabolic effects that result from varying the amount and type of feed given to horses, specifically focusing on high-roughage and high-concentrate diets.
• Four Thoroughbred geldings were exposed to four different feeding treatments in a 4 x 4 Latin square experiment. This experimental design ensured that each horse experienced all four treatments in different sequences to avoid any bias.
• The four treatments diversified between proportion of roughage and concentrate they contained, as well as the total nutritional intake. AHR and AHC diets met the caloric need of horses doing moderate work, whilst RHR and RHC diets only provided 70% intake of the former.

Data Collection and Analysis

• Over the course of seven days in each period, blood samples were collected to analyze serum T4 (Thyroxine) and T3 (Triiodothyronine) concentrations. These hormones are crucial in assessing metabolic responses.
• Additionally, on the 9th day of each feeding period, horses were fed oats, and their jugular blood was sampled at various timescales – before and after meal completion and then after every hour for 7 hours.
• The researchers were testing for alterations in T4 and T3 concentrations, as well as changes in glucose, insulin, and NEFA (Non-Esterified Fatty Acids) concentrations to better understand the hormonal and metabolic responses to different feeding regimens and calorie sources.

Research Findings

• The study found that day-to-day T4 and T3 concentrations were not influenced by the feeding level or diet composition. However, there was a significant increase in these hormone concentrations when horses adapted to AHR and AHC diets, but not when adjusted to RHR or RHC diets.
• The lowest thyroxine concentrations were observed when horses were adapted to the AHC diet.
• RHR diets resulted in higher glucose, insulin, and NEFA concentrations in response to the meal compared to the other diets. These responses indicate changes in energy metabolism in horses due to nutrient restriction and suggest that the dietary roughage:concentrate ratio may also influence these responses.

In conclusion, this study shows that short-term feed restriction and the source of calories in a diet can significantly influence metabolic responses in horses, implying a need for careful dietary planning.