Effects of dietary supplementation of DL-methionine or 2-hydroxy-4-(methylthio)-butanoic acid on food intake, nutrient digestibility, nitrogen balance, and urinary and blood metabolites in healthy, growing dogs.

The aim of this study was to evaluate effects on nutritional responses of supplemental DL-methionine and 2-hydroxy-4-(methylthio) butanoic acid (HMTBA) in a commercial-type diet in growing dogs. A nitrogen balance study was conducted as a randomized complete block design using 30 Pointer puppies (72-d-old; 5.5 kg). A corn and poultry byproduct meal based diet was supplemented with 0.1 or 0.2% DL-methionine or HMTBA on an equimolar basis. Organic matter and gross energy tended (p < 0.10) to be less digestible by dogs fed the 0.1% HMTBA diet compared with the 0.2% DL-methionine diet, but other nutrients were unaffected. Postprandial urinary calcium tended (p < 0.10) to be lower for the basal and HMTBA treatments. Fecal ammonia tended (p < 0.10) to be lower for the 0.1% HMTBA diet than for the 0.2% DL-methionine diet. At the levels tested, DL-methionine and HMTBA appear to act similarly when included in a corn and poultry by-product meal diet fed to young dogs.