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Pyridoxine (Vitamin B6) in dog and cat diets

A short guide to the role of Pyridoxine (Vitamin B6) in dog and cat nutrition.

Pyridoxine (Vitamin B6)

It belongs to the water-soluble vitamins and is responsible for the metabolism of proteins and amino acids (transamination, decarboxylation). It takes part in the production of red blood cells, supports immunity and creates neurotransmitters, including serotonin and dopamine [1]. A simple rule applies: the more protein in the diet, the greater the requirement for B6 [3]. Because BARF is by nature high-protein, B6 is in it in constant use. It is sensitive to high temperature.

Where it's found: Brewer's yeast, raw muscle meat (especially poultry, pork, beef), hearts, liver and fish. Poultry and rabbit are by far the best sources — beef is distinctly poorer.

Deficiency: Rare with a raw diet. It results in microcytic anaemia (small, pale blood cells), neurological disorders and calcium oxalate stones (oxalate) in the bladder, which cannot be dissolved by diet [3]. A low result in the calculator is usually not a reason for supplementation, but a signal of a faulty recipe: too little muscle meat, too much bone and fat, or a diet based mainly on beef without supplementation with poultry.

Excess: Because it is a water-soluble vitamin, its excess is efficiently excreted in the urine. Only gigantic, long-term synthetic doses can damage peripheral nerves [2].

Species difference cat–dog

The cat, as an obligate carnivore, constantly catabolises protein — it cannot "switch off" these enzymes even when fasting — so it uninterruptedly uses up B6 as their coenzyme. That is why it has a higher requirement and a smaller safety margin: the NRC standard (RA) is about 0.625 mg B6/1000 kcal ME in the cat versus about 0.375 mg in the dog [1]. Paradoxically, a very lean, high-protein diet raises this consumption even more. See also Protein.

Sources

  1. National Research Council (2006). Nutrient Requirements of Dogs and Cats — Chapter 6, Water-Soluble Vitamins. National Academies Press. https://nap.nationalacademies.org/catalog/10668/nutrient-requirements-of-dogs-and-cats
  2. Hand MS, Thatcher CD, Remillard RL, Roudebush P, Novotny BJ (2010). Small Animal Clinical Nutrition, 5th Edition. https://www.markmorrisinstitute.org/sacn5.html
  3. Bai SC, Sampson DA, Morris JG, Rogers QR (1989). Vitamin B6 deficiency and oxalate nephrocalcinosis in the cat. Am J Vet Res. https://pubmed.ncbi.nlm.nih.gov/2695960/
  4. Kocaturk M et al. (2024). Factors influencing vitamin B6 status in domestic cats. Scientific Reports. https://doi.org/10.1038/s41598-024-52367-y
  5. FEDIAF (2021). Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs. https://europeanpetfood.org/self-regulation/nutritional-guidelines/