Results suggest that 25% restriction in food intake increased median life span and delayed the onset of signs of chronic disease in these dogs.

This report reviews decade two of the lifetime diet restriction study of the dog. Labrador retrievers (n 48) were paired at age 6 weeks by sex and weight within each of seven litters, and assigned randomly within the pair to control-feeding (CF) or 25 % diet restriction (DR). Feeding began at age 8 weeks. The same diet was fed to all dogs; only the quantity differed. Major lifetime observations included 1·8 years longer median lifespan among diet-restricted dogs, with delayed onset of late life diseases, especially osteoarthritis. Long-term DR did not negatively affect skeletal maturation, structure or metabolism. Among all dogs, high static fat mass and declining lean body mass predicted death, most strongly at 1 year prior. Fat mass above 25 % was associated with increasing insulin resistance, which independently predicted lifespan and chronic diseases. Metabolizable energy requirement/lean body mass most accurately explained energy metabolism due to diet restriction; diet-restricted dogs required 17 % less energy to maintain each lean kilogram. Metabonomics-based urine metabolite trajectories reflected DR-related differences, suggesting that signals from gut microbiota may be involved in the DR longevity and health responses. Independent of feeding group, increased hazard of earlier death was associated with lower lymphoproliferative responses to phytohaemagglutinin, concanavalin A, and pokeweed mitogen; lower total lymphocytes, T-cells, CD4 and CD8 cells; lower CD8 percentages and higher B-cell percentages. When diet group was taken into account, PWM responses and cell counts and percentages remained predictive of earlier death.Diet restriction: Dog: Ageing: Longevity During 1987, a diet restriction study of domestic dogs (Canis lupus familiaris) was initiated with a hypothesis that 25 % diet restriction would decrease hip joint laxity and osteoarthritis (OA) in a dog breed that is genetically susceptible to obesity and OA (1) .At 24 months, the experiment was extended for the lifetimes of the dogs. The original experimental design was continued with the added hypothesis that 25 % diet restriction (DR) for lifetime would result in increased longevity and improved overall health of DR dogs, compared to pair-mate control-fed (CF) dogs. The last dog died in mid-2001, at age 14·5 years. The database of physiological observations from this study is large and diverse, and earlier communications have occurred over an elapsed time of about 15 years. This report reviews the key findings of the second decade of this work and presents our view of the most important inter-species comparative observations. Overview of general methods Study designLabrador retrievers (n 48) were paired at age 6 weeks by sex and body weight within each of seven litters, and then were assigned randomly within the pair to CF or 25 % DR. Beginning at age 8 weeks, each CF dog was given the dry, extruded diet ad libitum, and each DR pair-mate was given 75 % of the amount of food that its CF pair-mate had consumed the previous day. Each feeding g...

Assessment of the selenium status of livestock is an important aspect of production medicine, but variations in reported values between laboratories and between methods may be > 30%. Reliable interpretations require considerable experience with an assay and an extensive database from field and research case samples of a variety of species. The Michigan State University Animal Health Diagnostic Laboratory (MSU-ADHL) has offered Se analyses by acid-digestion and fluorometric detection since 1982. This laboratory expects serum Se values (nanograms per milliliter) of livestock to increase gradually with age from starting ranges for neonates of 50 to 80 for calves and sheep and 70 to 90 for foals and pigs. Expected or "normal" values for the adults are in the ranges of 70 to 100 for cattle, 120 to 150 for sheep, 130 to 160 for horses, and 180 to 220 for swine. Normal liver Se concentrations are considered to range between 1.2 and 2.0 micrograms/g on a dry weight basis, regardless of the species or age. Based on samples submitted to MSU-AHDL between September 1990 and August 1991, contemporary feeding practices in the Michigan area resulted in mean serum Se values (nanograms per milliliter) of 75 +/- 19 for adult Holsteins, 170 +/- 27 for adult swine (mixed breeds), and 137 +/- 30 for adult race horses. Within that period of time, two field cases of Se toxicity were diagnosed. One involved feeder pigs with a recorded high serum Se value of 1,525 ng/mL due to a commercial premix manufacturing error.(ABSTRACT TRUNCATED AT 250 WORDS)

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