Betaine offers benefits
in poultry diets
Taking a fresh look at betaine, not only as a methyl group donor in metabolism,
but also its roles in carcass quality and in ameliorating the effects of heat stress.
Betaine, also named
trimethylglycyne, N,N,N-trimethylglycine, oxyneurine
or glycine betaine, is an amino acid
derivate with three reactive methyl
groups (CH ) and a bipolar structure
3
(Figure 1). Widely found in nature,
betaine can be synthesised by several
Figure 1: Molecular structure
of betaine
CH
3
CH N+ CH COO
32
CH
3
CH H NO : 117.15
5 11 2
Nutreco Poultry Nutrition Group
Experimental facilities for broilers at Nutreco’s research centre
plants (sugar beet roots and legumes) the methylation of DNA, RNA to the This may be because choline must
and micro-organisms (both Gram- synthesis of carnitine and creatine. be oxidised to betaine via betaine
positive and Gram-negative bacteria). Several groups of researchers aldehyde and because oxidation
The molecular weight of betaine is have demonstrated the choline- and occurs in the mitochondria and
117.5. It is soluble in water, partly methionine-sparing properties of betaine has to be transported to the
soluble in methanol and almost betaine in methylation reactions. cytosol to act as a methyl donor.
insoluble in organic solvents. Choline, apart from methyl group Contradictory results have
Betaine has been used in broiler source, participates in the synthesis been reported regarding the use
nutrition for more than 60 years, of phospholipids, cell membranes of betaine to replace methionine
mainly as a methyl group donor, and and in the nerve impulse as part in its function as essential amino
for its osmoprotecting (osmolyte) of acetylcholine, which is required acid. The methionine-sparing
properties. Lately, also an effect by poultry for many processes like effect of betaine may be related
of betaine in the metabolism crop emptying and heart function. to the health status of the animal
of lipids has been reported. Animals have a specific dietary (coccidia challenge) and to the
choline requirement per se. It cysteine levels in the feed.
has been established that betaine can substitute 25% of the dietary Betaine in lipid metabolism
choline requirement, as long as Betaine can donate methyl groups
Choline, betaine and methionine the choline requirement is met. to form carnitine via S-adenosyl-
are the most important sources of Excessive homocysteine methionine. The transport of long-
methyl groups. Methyl groups must concentrations in the feed adversely chain fatty acids across the inner
be provided through the diet as affect the growth of chickens. It membrane of mitochondria and the
vertebrates are unable to synthesise seems that betaine is more efficient normal rate of oxidation is dependent
them. They are involved in many than choline in re-methylation on carnitine. Carnitine deficiency
important pathways ranging from of homocysteine to methionine. impairs fatty acid oxidation. Choline
Betaine as a methyl
group donor
