Effect of feeding thoroughbred horses a high unsaturated or saturated vegetable oil supplemented diet for 6 months following a 10 month fat acclimation.
Study Goal
The researchers aimed to compare the effects of diets supplemented with predominantly saturated or unsaturated vegetable oils on exercising horses, focusing on metabolic and physiological responses.
Results Summary
The study found no significant adverse effects from either saturated or unsaturated vegetable oil supplementation. While some metabolic differences (e.g., cholesterol, triglycerides) were noted between the groups, overall, both diets were well-tolerated with no clear disadvantages of one over the other.
Population
Eight Thoroughbred horses engaged in standardized treadmill exercise.
Effective Dosage
Approximately 12% of digestible energy (DE) from the oil source for 10 months, then increased to 20% DE for an additional 6 months.
Duration
16 months total (10 months at lower dosage, 6 months at higher dosage).
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
diet supplemented with a predominantly unsaturated vegetable oil | no change | insulin or lactate responses to the STEP tests | exercising Thoroughbred horses | no significant effect | no significant effect | #1 |
diet supplemented with a predominantly saturated vegetable oil | no change | insulin or lactate responses to the STEP tests | exercising Thoroughbred horses | no significant effect | no significant effect | #2 |
diet supplemented with a predominantly unsaturated vegetable oil | increase | glucose response | exercising Thoroughbred horses | P < 0.05 | significant effect | #3 |
diet supplemented with a predominantly saturated vegetable oil | increase | glucose response | exercising Thoroughbred horses | P < 0.05 | significant effect | #4 |
diet supplemented with a predominantly unsaturated vegetable oil | no change | TOL glucose response (% change from Time '0') | exercising Thoroughbred horses | no significant effect | no significant effect | #5 |
diet supplemented with a predominantly saturated vegetable oil | no change | TOL glucose response (% change from Time '0') | exercising Thoroughbred horses | no significant effect | no significant effect | #6 |
diet supplemented with a predominantly saturated vegetable oil | decrease | glucose concentrations | exercising Thoroughbred horses | nonsignificant | trend for glucose concentrations to be lower | #7 |
diet supplemented with a predominantly saturated vegetable oil | increase | insulin responses | exercising Thoroughbred horses | nonsignificant | trend for insulin responses to be higher | #8 |
diet supplemented with a predominantly unsaturated vegetable oil | no change | haematological parameters | exercising Thoroughbred horses | no significant effect | no significant effect | #9 |
diet supplemented with a predominantly saturated vegetable oil | no change | haematological parameters | exercising Thoroughbred horses | no significant effect | no significant effect | #10 |
diet supplemented with a predominantly unsaturated vegetable oil | increase | cholesterol and triglycerides | exercising Thoroughbred horses | P < 0.05 | significant effect | #11 |
diet supplemented with a predominantly saturated vegetable oil | increase | cholesterol and triglycerides | exercising Thoroughbred horses | P < 0.05 | significant effect | #12 |
diet supplemented with a predominantly unsaturated vegetable oil | increase | linoleic acid in the cholesterol ester and phospholipid classes | exercising Thoroughbred horses | P < 0.05 | slightly, but significantly higher concentrations | #13 |
diet supplemented with a predominantly saturated vegetable oil | increase | total resting plasma fatty acid content | exercising Thoroughbred horses | P < 0.05 | significantly higher | #14 |
diet supplemented with a predominantly unsaturated vegetable oil | no change | apparent coat condition or hoof appearance | exercising Thoroughbred horses | no adverse effects | no apparent adverse effects | #15 |
diet supplemented with a predominantly saturated vegetable oil | no change | apparent coat condition or hoof appearance | exercising Thoroughbred horses | no adverse effects | no apparent adverse effects | #16 |
diet supplemented with a predominantly unsaturated vegetable oil | increase | grease score | exercising Thoroughbred horses | apparent increase | apparent increase | #17 |
diet supplemented with a predominantly saturated vegetable oil | increase | grease score | exercising Thoroughbred horses | apparent increase | apparent increase | #18 |
This study looked at the effect of feeding diets supplemented with either a predominantly saturated or unsaturated vegetable oil over a prolonged period to exercising horses. Eight Thoroughbred horses were assigned to 2 diet treatments and for 10 months were fed Timothy hay and oats, together with a fortified sweet feed supplemented with either a predominantly unsaturated (Un) or a saturated (S) vegetable oil so that approximately 19% DE (Digestible Energy) came from dietary fat and approximately 12% from either the Un or S source (AC). An increased amount of Un or S fortified sweet feed, replacing the oats, was then fed for a further 6 months (HF) so that approximately 27% DE came from fat and approximately 20% from the Un or S vegetable oil. Standardised incremental treadmill exercise (8-12 m/s) tests (STEP) and duplicate oral glucose tolerance tests (TOL) were carried out after 3, 6 and 9 months of the AC diet and after 3 and 6 months on the HF diet. There was no significant effect of dietary treatment or when the tests were undertaken (time) on the insulin or lactate responses to the STEP tests. Overall there was a significant (P < 0.05) effect of time and treatment on the glucose response, but there was no difference between treatments at the first and last tests or between the results for these tests or between the endAC and endHF tests. No significant effect of treatment or time was seen on the TOL glucose response (% change from Time '0') although there was a trend for the glucose concentrations to be lower and the insulin responses higher (nonsignificant) in the S treatment group. No significant effect of treatment on haematological parameters, monitored monthly, was found. Total protein and gamma glutamyl transferase remained within the normal range throughout. There was a significant effect of treatment (P < 0.05) on cholesterol and triglycerides with higher concentrations in the S group from the first (1 month) sample. Linoleic acid was the main fatty acid in all the 4 plasma lipid classes with slightly, but significant (P < 0.05), higher concentrations in Un for the cholesterol ester and phospholipid classes. There was no effect of time. Overall, the total resting plasma fatty acid content was significantly higher (P < 0.05) with S at the sample points (endAC and endHF). No adverse effects of feeding either diet on apparent coat condition or hoof appearance were seen apart from an apparent increase in the grease score. Many of the parameters assessed showed significant improvements with time (P < 0.05). In conclusion, no apparent adverse effects of feeding a diet supplemented with either an unsaturated or saturated vegetable oil for 6 months at approximately 20% DE after 10 months at approximately 12% DE were identified and there were no apparent disadvantages of feeding a saturated vegetable oil supplemented diet compared with an unsaturated one.