Grain-free diets tend to have greater inclusions of pulses in contrast to grain-based diets. In 2018 the Food and Drug Administration (FDA) released a statement that grain-free diets may be related to the development of canine dilated cardiomyopathy (DCM). However, all dog foods met regulatory minimums for nutrient inclusion recommended by the Association of American Feed Controls Official (AAFCO). In some FDA case reports, but not all, dogs diagnosed with DCM also had low concentrations of plasma or whole blood taurine, as such we hypothesized that feeding these diets will result in reduced taurine status from baseline measures. The objective of this study was to determine the effects of feeding a grain-free diet to large breed dogs on taurine status and overall health. Eight Labrador Retrievers (4 males, 4 females; Four Rivers Kennel, MO) were individually housed and fed a commercial complete and balanced grain-free diet (Acana Pork and Squash formula; APS) for 26 wk. Fasted blood samples were collected prior to the start of the trial (baseline; wk 0), at wk 13 and wk 26 for analyses of blood chemistry, hematology, plasma amino acids (AA), and whole blood taurine. Urine was collected by free catch at wk 0 and 26 for taurine and creatinine analyses. Fresh fecal samples were collected at wk 0 and 26 for bile acid analyses. Data were analyzed using the GLIMMIX procedure with repeated measures in SAS (v. 9.4). Plasma His, Met, Trp, and taurine and whole blood taurine concentrations increased over the course of the study (P < 0.05). Urinary taurine to creatinine ratio was not affected by diet (P>0.05). Fecal bile acid excretion increased after 26 wk of feeding APS to dogs. Despite the higher fecal excretion of bile acids, plasma and whole blood taurine increased over the 26-wk feeding study. These data suggest the feeding APS, a grain-free diet, over a 26-wk period improved taurine status in Labrador Retrievers and is not the basis for incidence of DCM for dogs fed APS. Other factors that may contribute to the etiology of DCM should be explored.

The aim of this experiment was to evaluate the effect of undenatured type II collagen supplementation on inflammation and cartilage degeneration after exercise in healthy dogs. Forty healthy Labrador Retrievers (20 male/20 female; Range 5-12yrs; Avg 8yrs) were sorted into two groups: undenatured type II collagen group receiving 40mg UC-II (10mg Collagen Type II/Min. 3% Undenatured Type II Collagen; Lonza Consumer Health, Inc.) and placebo group receiving 40mg maltodextrin daily by capsule. After 2-weeks loading, all dogs began an 11-week endurance exercise regimen consisting of two weekly runs, starting at 5km and increasing incrementally to 8km, with one final 16km run. Blood samples were collected at baseline, pre and post first 5km run, and pre and post 16km run. Activity per kilometer was greater in male undenatured type II collagen vs male placebo over all runs (P=0.004), and average moving speed was greater in all undenatured type II collagen dogs compared with placebo over all runs (P<0.001). Hematology analysis indicated that during the first insult, undenatured type II collagen dogs had a greater lymphocyte count (P<0.001) and lymphocyte percentage (P=0.001) vs placebo dogs. Undenatured type II collagen dogs had a lesser neutrophil percentage (P=0.042) and neutrophil to lymphocyte ratios (P=0.001) compared to placebo dogs. For the final insult, undenatured type II collagen dogs had greater lymphocyte percentage (P=0.013) and lesser mean corpuscular hemoglobin concentration (P=0.043) compared with placebo dogs. Both groups had significant changes between timepoints for several hematological parameters. Biomarker IL-6 was lesser in undenatured type II collagen dogs compared with placebo at post 5km (P=0.037). Cartilage oligomeric matrix protein (COMP) was lesser in undenatured type II collagen dogs at post 16km (P=0.023), and only the placebo dogs had a significant increase in COMP from pre to post 16km (P=0.021). In summary, Labrador Retrievers supplemented with undenatured type II collagen had decreased inflammation and cartilage degeneration compared with non-supplemented dogs during exercise.

The primary goal was to investigate the effects of l-carnitine on fuel efficiency, as an antioxidant, and for muscle recovery in Labrador retrievers. Dogs were split into two groups, with one group being supplemented with 250 mg/d of Carniking™ l-carnitine powder. Two experiments (Expt 1 and Expt 2) were performed over a 2-year period which included running programmes, activity monitoring, body composition scans and evaluation of recovery using biomarkers. Each experiment differed slightly in dog number and design: fifty-six v. forty dogs; one endurance and two sprint runs per week v. two endurance runs; and differing blood collection time points. All dogs were fed a low-carnitine diet in which a fixed amount was offered based on maintaining the minimum starting weight. Results from Expt 1 found that the carnitine dogs produced approximately 4000 more activity points per km compared with the control group during sprint (P = 0·052) and endurance runs (P = 0·0001). Male carnitine dogs produced half the creatine phosphokinase (CPK) following exercise compared with male control dogs (P = 0·05). Carnitine dogs had lower myoglobin at 6·69 ng/ml following intensive exercise compared with controls at 24·02 ng/ml (P = 0·0295). Total antioxidant capacity (TAC) and thiobarbituric acid reactive substance (TBARS) results were not considered significant. In Expt 2, body composition scans indicated that the carnitine group gained more total tissue mass while controls lost tissue mass (P = 0·0006) and also gained lean mass while the control group lost lean mass (P < 0·0001). Carnitine dogs had lower CPK secretion at 23·06 v. control at 28·37 mU/ml 24 h after post-run (P = 0·003). Myoglobin levels were lower in carnitine v. control dogs both 1 h post-run (P = 0·0157; 23·83 v. 37·91 ng/ml) and 24 h post-run (P = 0·0189; 6·25 v.13·5 ng/ml). TAC indicated more antioxidant activity in carnitine dogs at 0·16 mm v. control at 0·13 mm (P = 0·0496). TBARS were also significantly lower in carnitine dogs both pre-run (P = 0·0013; 15·36 v. 23·42 µm) and 1 h post-run (P = 0·056; 16·45 v. 20·65 µm). Supplementing l-carnitine in the form of Carniking™ had positive benefits in Labrador retrievers for activity intensity, body composition, muscle recovery and oxidative capacity.

The aim of this experiment was to evaluate the effect of undenatured type II collagen supplementation on inflammation and pain using gait analysis and industry-accepted pain and mobility questionnaires during an exercise regimen in healthy dogs. Forty healthy Labrador Retrievers (20 male/20 female; Range: 5-12yrs) were sorted into two groups: undenatured type II collagen group receiving 40mg UC-II product (10mg total collagen and ≥3% undenatured type II collagen) and placebo group receiving 40mg maltodextrin daily by capsule. After 2wks loading, all dogs began an 11wk endurance exercise regimen consisting of two weekly runs, starting at 5km and increasingly incrementally to 8km, with one final 16km run. Gait analysis was performed at baseline; before, 24h and 48h after the first 5km run; and before, 24h and 48h after the final 16km run. Gait analysis was calculated to obtain a Four Rivers Kennel (FRK) Inflammation Index score. Dogs were scored according to the Liverpool Osteoarthritis in Dogs (LOAD) and Canine Brief Pain Inventory (CBPI) assessments at baseline, before and after the first 5km run, and before and after the final 16km run. On the LOAD questionnaire, undenatured type II collagen group had improved “how active is the dog” (P=0.03) and less “stiffness after a lie down” (P=0.041) compared with placebo at pre 5km. Undenatured type II collagen appeared to mitigate the development of pain after exercise compared with placebo, as related to the CPBI assessment. Undenatured type II collagen dogs had lower “pain at worst” pre 5km (P=0.021), “pain at least” post 5km (P=0.015), “pain at average” post 5km (P=0.046), and “pain as it is now” post 16km (P=0.006) compared with placebo dogs. Undenatured type II collagen was more effective than placebo at mitigating inflammation on gait analysis per the FRK Inflammation Index. Undenatured type II collagen dogs had a 6.42 lower FRK Inflammation Index score at 24h post 5km (P=0.032) and 6.3 lower score at 24h post 16km (P=0.029), indicating the mitigation of inflammation on gait analysis. When considering the change between timepoints, undenatured type II collagen had a lower increase in FRK Inflammation scores compared with placebo for baseline to pre 5km (p&lt;0.001), pre 16km to 24h post 16km (P=0.028), and pre 16km to 48h post 16km (P=0.027). Undenatured type II collagen supplemented Labrador Retrievers improved pain assessment variables and improved FRK Inflammation Index on gait analysis.

The objective of this trial was to develop an index system to identify inflammation in Labrador Retrievers using a pressure walkway system. Gait analysis data can be difficult to interpret between treatment groups or for identifying low grade inflammation. To calculate the Total Inflammation Index™, the distance away from the ideal score was calculated for four parameters for each dog, including gait lameness score, total pressure index, step/stride ratio, and hind reach. These values were equally weighted and added together to produce the Total Inflammation Index™. For validation, the Total Inflammation Index™ values were compared to biomarker data for inflammation including cartilage oligomeric matrix protein, interleukin-6, creatine kinase, and c-reactive protein. Forty Labrador Retrievers (20 male/20 female) were used in this trial. All dogs were passed over the pressure walkway (Gait4Dogs; CIR Systems, Inc) to obtain gait analysis at baseline, 24h prior to the first 5km run, 24h after the first 5km run, 24h prior to the final 16km run, and 24h after the final 16km run. All biomarkers and the Total Inflammation Index™ were both significantly lower at the pre-exercise timepoints and elevated after post-exercise timepoints (P &lt; 0.01). The Total Inflammation Index™ had significant correlation between timepoints and all biomarkers, including cartilage oligomeric matrix protein (P &lt; 0.01), interleukin-6 (P &lt; 0.05), creatine kinase (P &lt; 0.01), and c-reactive protein (P &lt; 0.05). The Total Inflammation Index™ appears to be a valid assay to evaluate generalized inflammation in Labrador Retrievers, and is in agreement with inflammatory biomarker values.