223. Long-term Feeding of a Fresh-frozen Diet Supports Canine Health and Reduces Biological Ages.

Abstract Fresh-frozen diets are a rapidly emerging sector of the pet food market. Due to their novelty, there is a lack of data concerning health outcomes from extended feeding. To better understand the long-term health implications of fresh-frozen diets, a 6 month long feeding trial was conducted to assess general dog health, blood inflammatory markers, blood and urine advanced glycation end products (AGEs), and urine relative supersaturation (RSS). Labrador Retrievers between 3.9 and 4.3 years of age were randomly assigned to consume either a chicken based fresh-frozen diet (Fresh, n = 8) or a chicken based commercial dry extruded kibble (Kibble, n = 8) at levels to meet maintenance requirements. Veterinary wellness exams were performed prior to diet transition and at 182 days of feeding. Skin and coat quality was assessed on days 0, 91, and 182 with qualitative questionnaires focusing on alopecia, glossiness, greasiness, softness, scaliness, and overall quality. Blood samples collected on days 0, 91, and 182 were analyzed for hematology, serum chemistries, N-carboxymethyl-lysine (CML) and N-carboxyethyl-lysine (CEL) AGEs, and inflammatory markers interleukin-6 (IL-6) and c-reactive protein (CRP). Urine was collected on dogs fed the fresh diets for specific gravity-adjusted AGEs (days 0, 91, and 182) and RSS (days 0,182). Dogs were deemed healthy by vet examination at the end of the study and blood counts and serum chemistries remained within acceptable ranges. Albumin, white blood cells, and neutrophils increased (P < 0.01), and alkaline phosphatase and hemoglobin decreased (P < 0.01) from baseline, but all remained within healthy reference ranges. The fresh diet did not affect perceived skin and coat quality (P ≥ 0.16), but glossiness increased and scaliness decreased from baseline across all dogs (P = 0.03). Urine CEL and CML decreased after 6 months of consuming the fresh diet (P ≤ 0.01). There were significant treatment*time interactions for blood CML and total AGEs (P ≤ 0.04), with concentrations decreasing in the Fresh group. The fresh-frozen food had lower concentrations of CML and total AGEs (CML + CEL) on a dry matter basis than the extruded kibble (P ≤ 0.04). Urine RSS for calcium oxalate and struvite decreased after 6 months of feeding and values suggested undersaturation by end of study (P ≤ 0.05). Inflammatory markers c-reactive protein and IL-6 did not differ between treatments or by treatment over time (P ≥ 0.24), but there were minor increases at the 6-month mark across both diets for CRP (P = 0.01) and IL-6 (P = 0.06). A fresh-frozen diet was able to support canine health over the course of 6 months. These diets may also contribute to reduced circulating AGEs, which could have implications for long-term health, particularly potential to promote healthy aging and combat chronic diseases.