279. Effects of A Dietary Polyphenol Blend At 0.02% and 0.04% On Oxidation, Inflammation, Macronutrient Utilization, and Concentrations of Fecal Short and Branched Chain Fatty Acids in Healthy Adult Male Cats.

Abstract Polyphenols are plant secondary metabolites known for their antioxidant, anti-inflammatory and anti-microbial properties. While the benefits of dietary polyphenols are well documented in humans and livestock, feline-specific data remain limited despite cats' increased susceptibility to oxidative stress and the pet food industry's growing interest in plant-derived functional ingredients. Therefore, the objectives of this study were to evaluate: 1) feed acceptance in cats given a dietary conifer bark polyphenol blend (BOREOX®) supplemented at 0.02% (Trmt1) or 0.04% (Trmt2) of the diet compared with 0.2% or 0.4% of the diet, and 2) the effects of Trmt1 and Trmt 2 compared to a control (CR; no supplement) on total antioxidant capacity (TAC), nitric oxide (NO), serum vitamin E, serum amyloid A (SAA), indirect calorimetry measures, and fecal short-chain (SCFA) and branched-chain fatty acids (BCFA). Twelve healthy adult neutered male cats (5-6 years, 4.40±0.395kg) were allotted to three groups balanced by body weight, then assigned to dietary treatments in a 3x3 Latin square with 28-day periods. On d0-1 of each period, Trmt1 and Trmt2 received BOREOX® at 0.2% and 0.4% of the diet, respectively. On d2-27, Trmt1 and Trmt2 received 0.02% and 0.04% respectively. On d27, 24h indirect calorimetry was performed prior to the collection of fecal samples and blood via saphenous venipuncture. Descriptive statistics were performed for SAA. All other data were analyzed in SAS using PROC GLIMMIX, with treatment as the fixed effect, cat and period as random effects. Orthogonal contrasts were applied for blood and fecal outcomes. Feed intake and indirect calorimetry measures were analyzed as repeated measures, with treatment, time and their interaction as fixed effects. SAA (0-3.2mg/L) remained within typical reference ranges, with 89% being below the limit of detection. Serum vitamin E, NO, and TAC had no linear or quadratic trends or treatment effects (p > 0.05). Energy expenditure and respiratory quotient had no treatment or treatment-by-time effects (p > 0.05). On d0-1 feed intake was lowest in Trmt2 (73.9g/day; p < 0.01) compared Trmt1 (129.7g/day; p < 0.01) and the CR (167.2g/day; p < 0.1); but remained unchanged from d2-27 (p > 0.05). Trmt2 had greater fecal valerate (p = 0.04) and propionate (p = 0.04) compared to Trmt1, but not the CR. Fecal butyrate (p = 0.08), isovalerate (p = 0.09), isobutyrate (p = 0.08), and 2-methylbutyrate (p = 0.08) tended to be greater in Trmt2 than Trmt1, but not the CR. Therefore, Trmt1 decreased overall gut fermentation activity, decreasing SCFA and BCFA production compared to Trmt2 and the CR. Overall, BOREOX® supplementation altered the colonic environment without altering whole-body metabolism, markers of oxidative stress, or inflammation in healthy adult cats without an external challenge. Future research should assess polyphenol supplementation at 0.02%-0.04% on the microbiome and in cats experiencing higher oxidative stress, such as senior or obese cats.