Longitudinal assessment of taurine and amino acid concentrations in dogs fed a green lentil diet

Abstract

A recent association between the inclusion of pulses in canine diets and taurine deficiency has become a prevalent issue in the pet food industry. Although dogs do not currently have a nutritional requirement for taurine, taurine deficiencies that do occur can result in serious health issues, such as dilated cardiomyopathy. The objective of this study was to determine the circulating concentrations of plasma and whole blood taurine, indispensable and dispensable amino acid concentrations in the plasma, and taurine and creatinine concentrations in the urine of adult dogs fed a green lentil diet. Twelve adult, intact, female beagles were randomly assigned to a diet containing 45% green lentils (GLD) or a poultry byproduct meal diet (CON) for 90 d. Fresh urine samples were collected every 30 d and analyzed for taurine and creatinine concentrations. A blood sample was also collected every 30 d and analyzed for amino acids including taurine. Animal procedures were approved by the University of Illinois Institutional Animal Care and Use Committee. All diets were formulated to meet or exceed the nutrient requirements for adult dogs at maintenance. The concentrations of taurine in the plasma and whole blood showed no differences (P > 0.05) between dietary treatments or across time points. Similarly, no differences (P > 0.05) in plasma methionine concentrations were observed between treatments or across time points. A treatment effect (P < 0.05) showed dogs fed GLD had higher total primary fecal bile acid excretion compared with dogs fed CON. The differential abundance of fecal microbial communities showed Firmicutes as the predominant phyla in dogs fed both GLD and CON, with Bacteroidaceae, Erysipelotrichaceae, and Lactobacillaceae as predominant families in dogs fed GLD. The α-diversity of dogs fed GLD (P < 0.05) was lower than in dogs fed CON. These data suggest that the inclusion of 45% green lentil in extruded diets does not lower whole blood and plasma taurine concentrations during a 90-d period and is appropriate for use in a complete and balanced formulation for dogs.

Keywords: canine; dilated cardiomyopathy; plant protein; pulse; taurine.

Figure 1.

Food intake of dogs fed green lentil or poultry byproduct meal diets. Abbreviations: CON, poultry byproduct meal control; GLD, green lentil diet.

Figure 2.

Whole blood taurine concentrations of dogs fed green lentil or poultry byproduct meal diets. Dashed line indicates minimum taurine concentration (150 nmol/mL) where deficiency is not observed. Abbreviations: CON, poultry byproduct meal control; GLD, green lentil diet.

Figure 3.

Plasma taurine concentration of dogs fed green lentils or poultry byproduct meal diets. Dashed line indicates minimum taurine concentration (40 nmol/mL) where deficiency is not observed. Abbreviations: CON, poultry byproduct meal control; GLD, green lentil diet.

Figure 4.

Plasma methionine concentration of dogs fed green lentil or poultry byproduct meal diets. Dashed line indicates mean canine plasma methionine concentration (57 nmol/mL) in healthy dogs. Abbreviations: CON, poultry byproduct meal control; GLD, green lentil diet.

Figure 5.

Fecal microbial composition at the phyla level of dogs fed either green lentil or poultry byproduct meal diets. Abbreviations: CON, poultry byproduct meal control; GLD, green lentil diet.

Figure 6.

Fecal microbial composition at the family level of dogs fed either green lentil or poultry byproduct meal diets. Abbreviations: CON, poultry byproduct meal control; GLD, green lentil diet.

Figure 7.

Fecal microbial composition at the genera level of dogs fed green lentil or poultry byproduct diets. Abbreviations: CON, poultry byproduct meal control; GLD, green lentil diet.

Figure 8.

Fecal microbial α-diversity of dogs fed either green lentil or poultry byproduct meal diets. Abbreviations: CON, poultry byproduct meal control; GLD, green lentil diet.

Figure 9.

Principal component analyses of weighted (A) and unweighted (B) distances of fecal microbial communities of dogs fed green lentil or poultry byproduct meal diets. Abbreviations: CON, poultry byproduct meal control; GLD, green lentil diet; NMDS, nonmetric multidimensional scaling.

Figure 10.

Canonical correspondence analysis (CCA) of taxa abundance constrained by bile acid and taurine metabolic variables. Abbreviations: CON, poultry byproduct meal control; GLD, green lentil diet; WB, whole blood.