Effect of oral or injectable supplementation with cobalamin in dogs with hypocobalaminemia caused by chronic enteropathy or exocrine pancreatic insufficiency

Cobalamin is a cofactor for 2 important enzymes involved in the maintenance of cellular function in mammals. The cobalamin dogs obtain through diet must be combined with intrinsic factor (IF) to be absorbed in the ileus by specific receptors. Exocrine pancreatic insufficiency (EPI) is a frequent cause of hypocobalaminemia in dogs since the exocrine pancreas is the major source of IF. Another common cause is chronic small intestinal disease since there is a reduction in the expression of receptors needed to for cobalamin absorption, which consequently leads to low levels of this compound.

It is important that clinicians evaluate cobalamin levels in dogs with chronic enteropathy (CE) or EPI since low levels are considered as a negative prognostic factor. Methylmalonic acid (MMA) is a better marker of cellular cobalamin status since it accumulates when the level of cobalamin is abnormally low. Nevertheless, this compound can also be affected by renal diseases or enzymatic deficiencies. Therefore, cobalamin serum level below reference interval is considered hypocobalaminemia and this in association with an increase in MMA levels is considered cobalamin deficiency.

Several clinicians recommend supplementation when there is hypocobalaminemia regardless of underlying cause. Currently, injectable supplementation is the most frequently used; however, recent reports suggest that oral supplementation can be equally effective in normalizing serum cobalamin concentrations in dogs with CE or EPI.

The goal of this study was to evaluate the effectiveness of oral or injectable supplementation with cobalamin in normalizing not only its serum concentrations but also MMA in dogs suffering from hypocobalaminemia due to CE or EPI.

Forty-six dogs were included in the present study. They were divided into two groups – 27 diagnosed with CE and the remaining 19 with EPI. Each dog was randomly distributed to one of 3 groups: injectable or oral supplementation only with cobalamin and a third where folate oral supplementation was also added to the oral cobalamin. Thirteen dogs with CE and 9 with EPI received oral supplements whilst the remaining received injections.

Through the results obtained with this study, after rechecks, authors were able to conclude that both forms of supplementation where effective in normalizing cobalamin concentrations in dogs with altered values due to either of the underlying etiologies. In the case of dogs with CE, both supplementations where effective in also reducing MMA concentrations; however, in dogs with EPI, only the oral supplementation was able to favorably change those values.

Despite favorable results, this study did have several limitations – manner of diagnosis of dogs with CE; lack of diet control and cobalamin intake through this route and each dog received different treatments for the underlying cause of hypocobalaminemia.

Chang, C-H, Lidbury, JA, Suchodolski, JS, Steiner, JM. Effect of oral or injectable supplementation with cobalamin in dogs with hypocobalaminemia caused by chronic enteropathy or exocrine pancreatic insufficiency. J Vet Intern Med. 2022; 1- 15.
Doi: 10.1111/jvim.16528