Effect of feeding exercised horses on high-starch or high-fat diets for 390 days.

The research article examines the long-term impacts of feeding exercised horses with either a high-starch or high-fat diet over a period of 390 days. Despite expectations of negative effects due to horses not naturally being fat eaters, the study did not find any major adverse effects from the high-fat diet as compared to the high-starch diet when substantial bodyweight changes were prevented.

Study Design and Hypothesis

• The study was instigated with a hypothesis that horses, not being natural fat eaters, might experience adverse long-term metabolic effect when placed on a high-fat diet. This was compared to a high-starch diet which was expected to have lesser or no adverse effects.
• The aim of the study was to discern any potential long-term effects of these diet types and compare them.
• The study implemented a randomised block design with 20 exercised horses. Over a span of 390 days, the horses were fed either a high starch (HS) or high fat (HF) diet in three different periods; during stabling, pasture and stabling again.

Feeding Method and Measurements

• The horses received either a high-starch or high-fat concentrate along with straw, hay and pasture time of 6 hours per day in the pasture period.
• In the high-fat group, the horses gained weight, amounting to 2% of their initial body weight. Consequently, fat intake was reduced for these horses from 1.43 to 0.88 g/kg body weight per day.

Findings and Results

• Horses on the high-fat diet had higher concentrations of glucose, total protein, albumins, gamma-globulins, free fatty acids, phospholipids and cholesterol in their blood plasma. Conversely, urea concentrations were lower in comparison to horses on high-starch diet.
• Other values such as triglycerides, bilirubin and pre-beta lipoproteins in plasma remained unaffected by the diet type.
• There was a distinct change in all variables aside from triglycerides and pre-beta lipoproteins dependent on the period (stable or pasture).
• Measurements of various enzymes in blood serum revealed them to be within normal range, regardless of the fat content in diet.

Conclusion

• No apparent adverse effects of long-term high fat feeding were identified given the condition that substantial bodyweight changes were prevented.
• The study found no evident disadvantages of feeding on high fat compared with high starch diets for horses over a long-term period.