The B Complex

This range of vitamins is necessary for a healthy nervous system.
Cats need almost twice as much of these vitamins as dogs do for proper absorption of nutrients throughout the body.
These vitamins require each other to work and so are taken in the B-complex unit, with occasional additions of the other single B vitamins.
Mouth, eyes, skin, gastrointestinal tract, and reproductive organs are B deficiency disease sites, as well as behavior, intelligence, and brain and nerve functions.
Stress depletes the B vitamins, as it does vitamin C, and so does extremely cold weather.
The individual B vitamins known to be of primary use for pets are listed in the following sections.
Vitamin B-1 (Thiamine)

A major issue for cats, as supermarket cat foods may not provide enough of it.
Results of this deficiency are brain damage, seizures, and loss of movement control, potentially leading to death.
Treatment with the vitamin by injection effects full recovery within 24 hours.
Many cat breeders supplement with B vitamins, and B-1 also helps hyperactivity, internal muscle weakness, flea resistance, appetite, learning ability, and intelligence.
Cats that eat fish and cats or dogs on supermarket pet foods are more likely to be thiamine deficient.
In dogs, B-1 deficiency signs are lack of appetite, vomiting, unsteadiness, and spasticity of the hind legs.
Dogs also respond to B-1 as a flea repellant.
A tablespoon of brewer's yeast contains 1.25 mg of B-1, but some pets are allergic to yeast and it should not be used on cats during urologic (FUS) attacks; a B-complex-50 from the health food store contains 50 mg and may be bought yeast free cheaply.
Vitamin B-2 (Riboflavin)

A B-2 deficiency may lead to cataracts in both dogs and cats.
Bloodshot eyes and conjunctivitis are often deficiency symptoms.
This vitamin is necessary for red blood cell formation, antibody production, food metabolism, and growth.
Riboflavin prevents birth defects and dandruff.
Vitamin B-3 (Niacin)

B-3 deficiency may cause black tongue in dogs which is the equivalent to human pellagra.
Niacin is an immense help in controlling seizures and reducing behavioral problems.
It reduces cholesterol levels, improves blood circulation, and aids in central nervous system functioning.
In cats, niacin deficiency signs are mouth ulcers; thick, foul smelling saliva that drools; weight loss and lack of appetite; and weakness and apathy, finally leading to death from respiratory disease.
Raw meat and brewers yeast are good niacin sources; cooking destroys many B-complex vitamins.
Because of the hot flush effect, niacin is usually given only as part of the full B-complex or as niacinamide.
Cats need more of it than dogs.
Vitamin B-5 (Pantothenic Acid)

B-5 adds to animals' (and humans') longevity.
It is important for good immune system and adrenal function, and vitamin and food utilization.
It is essential in fighting allergies, inflammations, asthma, and infections.
Vitamin C and B-5 together are highly important for skin diseases and allergies in both cats and dogs.
The presence of allergies or infections is considered a B-5 deficiency symptom.
It also helps animals to combat stress, reduce depression, and ease anxiety.
Vitamin B-6 (Pyridoxine)

B-6 deficiency symptoms include failure to grow and thrive, epilepsy, anemia, water retention, and kidney stones or kidney damage in dogs and cats.
Its deficiency is also implicated in artery disease, cancer, arthritis, asthma, and allergies in pets and people.
B-6 is essential for the metabolism of protein (and more protein is often needed by cats than by dogs).
It is required in the utilization of some minerals for a healthy nervous system, red blood cell production, good brain function, and a strong immune system.
Vitamin B-9 (Folic Acid)

B-9 deficiency results in reproductive problems, birth defects when the mother is deficient, weight loss and anemia, erratic appetite, low energy, seizures, eye discharge, depression and anxiety, as well as decreased immune function in both cats and dogs.
Red blood cell formation, DNA synthesis, and protein metabolism depend on this vitamin.

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Vitamin B-12 (Cobalamin)

B-12 deficiency in humans results in anemia that, if left untreated, leads to death; dogs can also suffer from B-12 deficiency anemia, but how much they (or cats) actually require is unknown.
Supplementing pregnant females with vitamin B-12 results in stronger, larger, and healthier young, with better disease resistance.
This vitamin prevents nerve damage, aids fertility, and promotes normal growth and development.
It is necessary for normal digestion and proper food absorption; raw liver is the best animal food source.
Biotin

Biotin deficiency results in hair loss and in hair and skin disorders in cats and dogs, but the exact requirements for it are unknown in both.
This B vitamin is essential for thyroid and adrenal health, strong nervous systems and nerve tissue, healthy reproduction, normal sweat glands and bone marrow, and healthy skin.
It is necessary for utilization of fat, proteins, and carbohydrates in the body.
Biotin is a cure for dogs that eat their feces; they may be looking for this vitamin, which is produced to some extent in the intestines. Raw egg whites contain an enzyme that depletes biotin. For this reason, eggs fed to pets should be cooked to deactivate this enzyme.

Any harmful effects with regards to over consumption of Vitamin B complex? Will it make the dog anxious and have seizures? Do we need to include it in our Neapolitan Mastiff care.