Effect of dietary polyunsaturated fatty acid and related nutrients on plasma lipids, and skin and hair coat condition in canines

by Hester, Shaleah Lynnae

A study was performed to investigate the effect of diet modifications on skin and hair coat condition in canines. The study included 24 normal adult dogs fed a baseline diet (Ol'Roy[trademark]), during an acclimation period of 12 wk (Phase I). Nine female Beagles and 15 male Hound mix-breed dogs were used. For the next 12 wk (Phase II) the dogs were divided into three groups and fed one of three specially formulated diets. They contained similar ingredients and had similar nutrient profiles except for the following differences: Diet A contained lower but adequate amounts of dietary zinc and linoleic acid than diet B. Diet C was similar to B with respect to zinc and linoleic acid but contained more ?-linolenic acid. An evaluation panel conducted skin and hair coat condition scoring on wk 0, 4, 7, and 12 (Phase I) and wk 14, 16, 19, and 24 (Phase II). The panel evaluated the dogs for glossiness, softness, scale, greasiness, and overall condition. Transepidermal water loss (TEWL) and skin hydration (HYDR) assessments were determined on wk 3, 7, and 11 (Phase I) and wk 11, 12, 15, 19, and 23 (Phase II) using a Tewameter[trademark] and Corneometer[trademark] respectively.

Blood samples were collected on d 0, 5, 8, 16, 28, 56, and 84. Profiles of plasma phospholipid fatty acids were determined at each collection period. Serum zinc concentrations were analyzed on wk 12, 14, and 24. The hypothesis was that a diet containing increased LA, ALA, and zinc concentrations (diet C) would show improvements of skin and hair coat condition in dogs compared to the other diets. All three test diets caused significant improvements compared to Ol'Roy[trademark]. Diet B caused more improvement than diet A in both subjective and objective assessments of skin and hair coat. Based on mean values diet B is better to be fed to dogs that need to improve skin hydration and diet C should be fed to dogs that need to decrease TEWL. Diet C not only led to improvements in skin and hair coat condition, but also provided additional benefit by producing less pro-inflammatory conditions in the skin.