Choline is a vitamin-like essential nutrient that serves several important functions in the duck's body.
- It is a metabolic essential for building and maintaining cell structure.
- Choline plays an essential role in fat metabolism in the liver.
- Choline is essential for the formation of acetylcholine, a substance that makes possible the transmission of nerve impulses.
- Choline is a source of labile methyl groups.
Clinical Signs of Choline Deficiency
Clinical signs of choline deficiency in ducks include:
- Reduced growth rate in young, growing duckling.
- Perosis, first characterized by pinpoint hemorrhages about the hock joint, followed by an apparent flattening of the tibiometatarsal joint. Progressively, the Achilles’ tendon slips from its condyles, thus rendering the bird relatively immobile (referred to as 'slipped tendon').
Nutritional Requirements of Choline in Ducks
The choline requirement for growing ducks ranges from 750 to 2,000 mg/kg (341 to 909 mg/lb) of diet. Choline levels are also affected by interactions with other nutrients, such as the amino acid, methionine. When ducklings are methionine deficient, it markedly increases the choline requirements needed for ducks.
Choline Food Sources
All naturally occurring fats contain some choline, and thus, it is supplied by all feeds that contain fat. Egg yolk, germ of cereals, legumes and oilseed meals are good sources of choline. Corn is low in choline, with wheat, barley and oats containing approximately twice as much choline as corn. Canola meal, although three times as rich in total choline as soybean meal, has less bioavailable choline.