The effects of a plant-based and a plant- and marine-based n-3 oil supplement on behavioural reactivity, heart rate variability, and plasma fatty acid profile in young healthy horses.

The study investigates the impact of oil supplements sourced from plants and marine life on the behavioural reactions, heart rate variability, and plasma fatty acid profile of young, healthy horses. The research does not find any significant reduction in reactivity with the supplement doses used in the study.

Introduction and Objectives

• This research was primarily motivated by a concern for horse welfare and safety. Excessive behavioural reactivity in horses can pose risks to animals and their handlers.
• Previous studies have suggested positive benefits of dietary fat replacing sugar on horse behaviour. Moreover, certain fatty acids (namely eicosapentaenoic (EPA) and docosahexaenoic acid (DHA)) have been found to improve negative behaviours in humans and rodents.
• This study aimed to assess the effects of camelina oil, which is rich in α-linolenic acid (ALA), and a mix of camelina and algal oil, enriched in ALA, EPA, and DHA, on horses’ behaviour, heart rate variability, and plasma fatty acid profile. The effects were compared with a negative control group.

Methodology

• The study involved 34 horses aged between 7 months and 6 years, owned by clients of the researchers.
• The horses were exposed to a novel object test (NOT), which is a test of behaviour, both before and after a period of supplementation with one of the two types of oil or no oil (control).
• The behaviours of the horses were recorded and analyzed by designated software, and blood samples were obtained to evaluate their plasma fatty acid profiles.
• Additionally, electrocardiograms (ECGs) were conducted at various stages to assess heart rate and heart rate variability.

Results

• The results showed a notably greater amount of DHA and a reduced n-6:n-3 ratio in the algal group compared to the camelina-only and control groups. However, the ALA and EPA levels did not greatly differ across the groups.
• There was a significant rise in maximum heart rate and a key heart rate variability parameter during the NOT compared to baseline and recovery. This suggests that the horses experienced acute stress during this period.
• Two specific behaviours, bucking and backing, were marginally reduced in the camelina group compared to the control, but there was no significant difference between these groups and the algal group.
• All other measured behaviours, heart rate, and heart rate variability parameters were not dramatically different across the supplement feeding groups.

Conclusions and Further Research

• The study concludes that while the NOT successfully induced acute stress in the horses, the dosages of camelina oil or the mix of camelina and algal oil did not significantly decrease reactivity within the horse sample.
• The researchers call for further investigation into how specifics fatty acids may affect horse behaviour and heart rate variability, particularly in horses that are known to be highly reactive.