Pet Nutrition
Beta-glucans in dog food
Dr A C Beynen
was professor of
veterinary nutrition
at the Faculty
of Veterinary
Medicine, Utrecht
University, Th e
Netherlands in the
period of 1993-2007.
Beta-glucans are water-soluble plant fi bers, comprising chains
of up to 2000 glucose units in so-called beta form. Glucose is a
simple sugar, existing in solution as mixture of alpha and beta
rings. The glucose building blocks of beta-glucans are joined
by one of three linkage types. Beta-glucan constructions can
differ as to linkage pattern, spatial structure and functionality.
Cellulose is a water-insoluble beta-glucan with only one
linkage type; this plant fi ber is not discussed here.
Corn, rice, barley, wheat and oat contain different amounts
of similarly linked beta-glucans. Another type of beta-glucans
is found in baker’s yeast. The fi ve cereal grains and yeast are
commonly used as petfood ingredient. Dog-food labels rarely
highlight the beta-glucans in whole cereals and yeast. In
contrast, added concentrates of beta-glucans, isolated from
the outer layer of baker’s yeast, are reputed to strengthen dog’s
immune system.
Free beta-glucans are recognized by immune cells in the
intestinal wall. As a result, certain specialized cells may
more effi ciently capture and disarm harmful bacteria and
viruses, while others produce more offensive antibodies. Such
immunostimulation has been shown in dogs challenged with
foreign substances (antigens), while ingesting purifi ed beta-
glucans derived from yeast or oyster mushroom. The amount
ingested was equivalent to 0.08 % in dry food. Similar diet
intervention also relieved symptoms in dogs with infl ammation
in joints, skin or bowel.
40
In dogs, food with added, purifi ed beta-glucans can stimulate
the immune response elicited by antigens. The risk, if any,
of overstimulation is unknown. There is no evidence that
extra intake of beta-glucans, as purifi ed additives, prevents
development of diseases in dogs. Nevertheless, beta-glucans
did ameliorate infl ammatory diseases.
Creature Companion | February - March 2019 • Vol. XII • Issue 2 • Noida