Effects of dietary camelina, flaxseed, and canola oil supplementation on transepidermal water loss, skin and coat health parameters, and plasma prostaglandin E2, glycosaminoglycan, and nitric oxide concentrations in healthy adult horses.

Camelina oil is derived from a low-input, high-yield crop and, in comparison to many other dietary fat sources currently used in equine diets, provides a greater amount of α-linolenic acid [ALA; (n-3)], than linoleic acid [LA; (n-6)]. However, no research exists assessing the effects of feeding camelina oil to horses in contrast to other commonly used oils. The objective of this study was to compare the effect of supplementing camelina oil to that of flaxseed and canola oil supplementation, on outcomes related to skin and coat health in horses. Thirty adult horses [23 mares, 7 geldings; 14.9 years ± 5.3 years; 544 ± 66 kg body weight (BW) (Mean ± SD)] underwent a 4-week wash-in period consuming hay and sunflower oil. Following the wash-in period, horses were blocked by location, age, and BW, and assigned to one of three treatment oils for 16 weeks (370 mg oil/kg BW): camelina (CAM), canola (OLA), or flaxseed (FLX) oil. Blood samples were collected and plasma prostaglandin E2 (PGE2; ELISA), nitric oxide (NO; Griess Reaction), and glycosaminoglycan (GAG; DMMB) concentrations were measured on weeks 0 (n=30), 14 (n=24), and 16 (n=30). On weeks 0, 2, 4, 8, and 16, transepidermal water loss (TEWL) was measured pre- and post-acetone application using a VapoMeter (n=26), and a 5-point-Likert scale was used to assess skin and coat characteristics on the side and rump of the horses (n=30). All data were analyzed with repeated measures ANOVA using PROC GLIMMIX in SAS. Independent of treatment, coat color and quality increased from baseline. There were no differences in the outcomes assessed between the horses supplemented camelina oil and those supplemented canola or flaxseed oil. These results suggest that independent of treatment, all oil supplements improved coat colour and quality in horses. This provides indication that camelina oil is comparable to existing plant-based oil supplements in supporting skin and coat health and inflammation in horses.