Improved understanding of longevity is important in the care of our canine companions. Environmental influences such as living conditions, health care, exercise and nutrition can potentially impact longevity. Eukanuba is committed to understanding the potential impact of nutrition on ageing in companion dogs.
In 2004 Eukanuba initiated a 10 year feeding study to evaluate aging and longevity in dogs when continuously fed a diet based upon a Eukanuba nutrition matrix. This summary reports results from one of the two cohorts – cohort 1, which comprises 39 adult Labrador retrievers (12 males and 27 females, mean age 6.7 years at the beginning of the study). The cohort 2 study is not yet completed and therefore is not included in this analysis.
The dogs were placed on a diet (the Eukanuba study diet) based upon a Eukanuba nutrition matrix comprised of nutritional technologies believed to enhance the health and wellness of adult and senior dogs (Table 2), and with and without a specialized carbohydrate hypothesized to mimic calorie restriction. The Eukanuba formulation incorporated primary use of animal-based protein sources, a particular ratio of omega-6 and omega-3 fatty acids, multi-source carbohydrate blend, enriched antioxidant levels, specialized fiber blend, L-carnitine, and a dental tartar reducing agent.
The daily food allowance for each dog was based on the amount of food needed to maintain each dog within an optimal body condition range. Throughout the study body weight was measured weekly and body condition score (BCS) was evaluated quarterly by qualified graders using a five point scale. The daily food allowances were set for each dog and did not change unless warranted by a change in their quarterly BCS. Each dog’s daily food allowance was adjusted accordingly to maintain their BCS between 2 and 4, with 3 representing the ideal.
1Study diet was formulated to represent a Eukanuba based dry dog food appropriate for adult and senior dogs.
2 Chicken by-product meal
5Supplemental chromium in the form of chromium piccolinate was originally part of the diet. It was removed from the diet after 31 months.
6 A specialized carbohydrate (<0.10%) was included in the diet matrix for 19 of the dogs
7Nutrient composition is actual laboratory analytical results expressed on as-fed basis
9Ratio of dietary omega-6 fatty acids and omega-3 fatty acids
Dogs were single or double housed in indoor pens connected to outdoor runs. They had free access to their outside runs throughout the day. Additionally, all dogs received daily socialization with a qualified welfare specialist and supervised daily outside exercise (minimum of 30 minutes) in exercise yards with a compatible social group of three to six dogs. The exercise yards contained enrichment devices such as agility course apparatus, wading pools, a variety of dog toys, and shaded areas.
The general health and overall condition of each dog was monitored daily. A comprehensive physical examination was performed annually and a blood sample was collected every six months for standard clinical assessments (serum chemistry, complete blood count and thyroid function). Dental examinations were completed annually and dental cleaning was performed as deemed necessary by the supervising veterinarian. Annual fecal examination for intestinal parasites and blood tests for heartworm were performed. All dogs received monthly heartworm prevention, monthly flea/tick prevention and annual vaccinations. Medical conditions were treated by the supervising veterinarian using standard veterinary protocols; however, cancer and severe or life threatening conditions were managed individually by the veterinary care team based on the dog’s quality of life assessment.
Whole-body composition measures of lean mass, fat, bone mineral density, and bone mineral content were obtained prior to the start of the study and then annually using dual-energy x-ray absorptiometry (DXA). Frailty and quality of life assessments were made on a regular basis to evaluate each dog’s overall quality of life. Quality of life assessments were performed by care takers, veterinary technicians, and the supervising veterinarian using a 10-point Likert scale ratings to assess food/water intake (hunger/thirst), pain/discomfort, mobility, hygiene, happiness, and number of “good days”.
No significant differences in the measured parameters were detected between dogs that received the Eukanuba study diet with the nutritional additive and dogs fed the Eukanuba study diet without the nutritional additive. The results have therefore been pooled for this analysis.
At the time of writing, one dog continues in the study. The age of death of the 38 deceased dogs ranged from 9.7 to 17.9 years. The median age at death was 14.1.
Three longevity categories were defined on the basis of age of death: short lived, long lived and exceptionally long lived. There were no significant differences in food intake or intake per unit of body weight between these three longevity categories. This would be expected considering the daily food allowance was tightly controlled based on quarterly BCS assessments. There were also no statistically significant differences in BCS over time between the longevity categories. Whole-body fat (g) increased in each category to age 13 but the increase was significantly slower for the long lived dogs than the typical dogs. In addition, the rate of increase in percentage body fat over time was slower for the dogs living long and exceptionally long lives as also was loss of percentage lean tissue over time .
Environmental factors, such as nutrition, husbandry and housing can impact successful aging and longevity. The present study was the first to incorporate Eukanuba’s nutritional components into a single formula and investigate whole-body health, wellness, aging and longevity in dogs fed this as the sole source of nutrition over an extended period of time.
Key nutritional components in the Eukanuba diet matrix used in the study that are believed to benefit canine health and wellness include: