Objective—To determine the pharmacokinetics of DL-α-lipoic acid in dogs when administered at 3 dosages via 3 methods of delivery.
Animals—27 clinically normal Beagles.
Procedures—In a 3 × 3 factorial Latin square design, 3 dosages (2.5, 12.5, and 25 mg/kg) of DL-α-lipoic acid were administered orally in a capsule form and provided without a meal, in a capsule form and provided with a meal, and as an ingredient included in an extruded dog food. Food was withheld for 12 hours prior to DL-α-lipoic acid administration. Blood samples were collected before (0 minutes) and at 15, 30, 45, 60, and 120 minutes after administration. Plasma concentrations of DL-α-lipoic acid were determined via high-performance liquid chromatography. A generalized linear models procedure was used to evaluate the effects of method of delivery and dosage. Noncompartmental analysis was used to determine pharmacokinetic parameters of DL-α-lipoic acid. Nonparametric tests were used to detect significant differences between pharmacokinetic parameters among treatment groups.
Results—A significant effect of dosage was observed regardless of delivery method. Method of delivery also significantly affected plasma concentrations of DL-α-lipoic acid, with extruded foods resulting in lowest concentration for each dosage administered. Maximum plasma concentration was significantly affected by method of delivery at each dosage administered. Other significant changes in pharmacokinetic parameters were variable and dependent on dosage and method of delivery.
Conclusions and Clinical Relevance—Values for pharmacokinetic parameters of orally administered DL-α-lipoic acid may differ significantly when there are changes in dosage, method of administration, and fed status.
Objective—To evaluate plasma taurine concentrations
(PTC), whole blood taurine concentrations
(WBTC), and echocardiographic findings in dogs fed 1
of 3 protein-restricted diets that varied in fat and L-carnitine
Animals—17 healthy Beagles.
Design—Baseline PTC and WBTC were determined,
and echocardiography was performed in all dogs consuming
a maintenance diet. Dogs were then fed 1 of
3 protein-restricted diets for 48 months: a low-fat (LF)
diet, a high-fat and L-carnitine supplemented (HF + C)
diet, or a high-fat (HF) diet. All diets contained methionine
and cystine concentrations at or above recommended
Association of American Feed Control
Officials (AAFCO) minimum requirements.
Echocardiographic findings, PTC, and WBTC were
evaluated every 6 months.
Results—The PTC and WBTC were not significantly
different among the 3 groups after 12 months. All
groups had significant decreases in WBTC from baseline
concentrations, and the HF group also had a significant
decrease in PTC. One dog with PT and WBT
deficiency developed dilated cardiomyopathy (DCM).
Taurine supplementation resulted in significant
improvement in cardiac function. Another dog with
decreased WBTC developed changes compatible
with early DCM.
Conclusion and Clinical Relevance—Results
revealed that dogs fed protein-restricted diets can
develop decreased taurine concentrations; therefore,
protein-restricted diets should be supplemented with
taurine. Dietary methionine and cystine concentrations
at or above AAFCO recommended minimum
requirements did not prevent decreased taurine concentrations.
The possibility exists that AAFCO recommended
minimum requirements are not adequate for
dogs consuming protein-restricted diets. Our results
also revealed that, similar to cats, dogs can develop
DCM secondary to taurine deficiency, and taurine supplementation
can result in substantial improvement in
cardiac function. (Am J Vet Res 2001;62:1616–1623)
Objective—To determine an optimal window for determining peak flatulence and evaluate the effects of oligosaccharides and supplemental β-mannanase in soybean meal–based diets on nutrient availability and flatulence.
Procedures—Dogs were used in a 2 × 3 factorial arrangement of treatments in a 6 × 6 Latin square experiment to evaluate the digestibility, flatulence, and fecal odor metabolites of low-oligosaccharide low-phytate soybean meal (LLM), conventional soybean meal (SBM), and poultry by-product (PBP) meal diets with or without supplemental β-mannanase (5 g/kg).
Results—Enzyme supplementation had no effect on total tract dry matter (DM), nitrogen digestibility, or digestible energy; however, differences between protein sources did exist for total tract DM digestibility and digestible energy. The PBP meal had higher DM digestibility and digestible energy (mean, 0.913 and 4,255 cal/g), compared with soy-based diets (mean, 0.870 and 4,049 cal/g). No differences were detected for any treatment regardless of protein source or addition of supplemental enzyme for any flatulence components analyzed. No differences were detected for all fecal odor metabolites regardless of addition of supplemental enzyme; however, differences between protein sources were detected. The PBP meal had lower concentrations of carboxylic acids and esters and higher concentrations of heterocycles, phenols, thio and sulfides, ketones, alcohols, and indoles than LLM and SBM.
Conclusions and Clinical Relevance—Diets containing < 22.4 g of stachyose/kg and < 2 g of raffinose/kg did not alter digestibility or increase flatulence in dogs.
Objective—To evaluate the effect of high- and lowprotein
diets with or without tryptophan supplementation
on behavior of dogs with dominance aggression,
territorial aggression, and hyperactivity.
Design—Prospective crossover study.
Animals—11 dogs with dominance aggression, 11
dogs with territorial aggression, and 11 dogs with
Procedure—In each group, 4 diets were fed for 1
week each in random order with a transition period of
not < 3 days between each diet. Two diets had low
protein content (approximately 18%), and 2 diets had
high protein content (approximately 30%). Two of the
diets (1 low-protein and 1 high-protein) were supplemented
with tryptophan. Owners scored their dog's
behavior daily by use of customized behavioral score
sheets. Mean weekly values of 5 behavioral measures
and serum concentrations of serotonin and
tryptophan were determined at the end of each
Results—For dominance aggression, behavioral
scores were highest in dogs fed unsupplemented
high-protein rations. Tryptophan-supplemented low-protein
diets were associated with significantly lower
behavioral scores than low-protein diets without tryptophan
Conclusions and Clinical Relevance—For dogs with
dominance aggression, the addition of tryptophan to
high-protein diets or change to a low-protein diet may
reduce aggression. For dogs with territorial aggression,
tryptophan supplementation of a low-protein
diet may be helpful in reducing aggression. (J Am Vet
Med Assoc 2000;217:504–508)