Responses in randomised groups of healthy, adult Labrador retrievers fed grain-free diets with high legume inclusion for 30 days display commonalities with dogs with suspected dilated cardiomyopathy

Abstract

Early responses in healthy adult dogs fed grain-free diets with high inclusion of split peas (20%) and lentils (40%) that may lead to canine diet-induced dilated cardiomyopathy (DCM) were investigated. To help understand the clinical relevance of the findings, a survey of electronic health records (EHR) was conducted of dogs with and without suspected DCM for comparison. Control and Test diets were fed to Labrador retriever dogs for 30 days (n = 5 and 6, respectively). Blood and urine samples collected at baseline and days 3, 14 and 28/30 were analyzed for hematology, clinical biochemistry and taurine concentrations. The EHRs of dogs at Banfield® Pet Hospitals in the 2-year period 2018-2019 were surveyed, revealing 420 dogs diagnosed with DCM, which were compared with 420 breed, gender and age-matched healthy control dogs. Compared to baseline values, feeding the Test diet for 28 days caused progressive, significant (p < 0.001) decreases in red blood cell counts (RBC), hematocrit and total hemoglobin by 7.7, 8.3 and 6.3%, respectively, and a 41.8% increase in plasma inorganic phosphate. Commonalities in these parameters were observed in clinical DCM cases. Regarding taurine status, Test dogs transiently increased whole-blood (23.4%) and plasma (47.7%) concentrations on day 14, while taurine:creatinine ratio in fresh urine and taurine in pooled urine were reduced by 77 and 78%, respectively, on day 28/30. Thus grain-free, legume-rich Test diets caused reduced RBC and hyperphosphatemia, findings also indicated in dogs with suspected DCM. Changes in taurine metabolism were indicated. The data will aid in generating hypotheses for future studies.

Effects of a 28-day feeding trial of grain-containing versus pulse-based diets on cardiac function, taurine levels and digestibility in domestic dogs

“…The lack of effect of pulse-based diets on RBCs agrees with a previous 28-day feeding study in Beagles from this group where a high protein pea-containing commercial diet had no effect on RBCs compared to a commercial diet with no pulses [ 42 ]. This differs from the previous Labrador retriever study that observed anemia after feeding pulse-based diets [ 15 ] as well as our previous 7-day study in Beagles using a high protein, pea-based commercial diet where RBCs were within all normal range but lower compared to a pulse-exclusive commercial diet. One would expect that a longer feeding period should have produced a greater effect on RBCs if it is diet-related.…”

“…Total bilirubin and indirect bilirubin were also seen to decrease in the pulse-inclusive diets, the cause for this however remains unknown. The current study in Beagles observed increases in serum phosphorus after feeding the lentil-based diet which agrees with a previous 28-day study in adult Labrador retrievers fed a diet high in both peas and lentils as well as 7-and 28-day studies in Beagles fed a commercial pulse-containing diet [ 15 , 41 , 42 ]. However, in the current study RBC counts were similar after feeding all three lab-made diets.…”

“…Moreover, changing to either grain-inclusive diets without pulses and potatoes or with taurine supplementation have all been reported to improve cardiac function and DCM indicators in dogs, some of which had pre-existing disease and somebreeds with genetic susceptibility [ 9 , 10 , 14 ]. However, another study reported no notable adverse change in blood taurine when healthy Labrador Retrievers were fed a grain-free, pea- and lentil-containing diet for 30 days [ 15 ], while another that fed a vegan, high pea-content diet to healthy dogs of multiple breeds for 12 weeks did report adverse changes consistent with early DCM [ 16 ]. Thus there remains a need for further investigations in this area.…”

Comparison of echocardiography, biomarkers and taurine concentrations in cats eating high- or low-pulse diets

“…12 The present study showed significantly higher median blood phosphorous concentration in the highpulse group compared with the low-pulse group, which mirrors findings of increased phosphorous concentrations after feeding a high pea and lentil diet to healthy Labrador Retrievers for 30 days (despite a lower dietary phosphorus level in the high-pulse vs low-pulse diet). 27 The phosphorus content of the diets eaten by cats enrolled in the study was not analyzed, so it is unclear whether the higher phosphorus concentration is due to the concentration or bioavailability of dietary phosphorus, or to unknown pathophysiologic mechanisms -cardiac or otherwise -that occur with exposure to high-pulse diets. Data are presented as median (interquartile range) *n = 51 (one cat in the low-pulse group did not have this data collected and was therefore excluded from this calculation) † n = 50 (one cat in the low-pulse group did not have these data collected and one cat in the high-pulse group was determined to be an outlier; these cats were therefore excluded from this calculation) ‡ n = 24 (14 cats in the high-pulse group and 14 in the low-pulse group did not have these data collected and were therefore excluded from this calculation) However, it does emphasize the importance of considering diet type and ingredients, as well as blood phosphorus and hematocrit, in future studies of feline heart disease.…”

Correction: Responses in randomised groups of healthy, adult Labrador retrievers fed grain-free diets with high legume inclusion for 30 days display commonalities with dogs with suspected dilated cardiomyopathy

“…Following the publication of the original article [ 1 ], the authors are requesting to update the Competing Interests section. The previous statement “The authors declare that they have no competing interests” needs to be updated to “The authors declare that they have no competing interests.…”