Dietary Choline: A Story Beyond Fatty Liver

Choline. Choline has been identified as a required nutrient for many species including humans, chicks, and pigs. Choline is found in low concentrations in most feeds, ranging from 0.04% in corn silage and alfalfa hay to 0.3% in protein sources such as soybean meal and cottonseed meal (DM basis). Its low concentrations in feeds are indicative of the low amounts required by livestock (e.g. 3 g/day for a lactating sow). Although the bovine requirement for choline has yet to be established, the supplementation of choline to dairy cows in transition usually improves milk production and often aids in the reduction of fat in the liver. However, in order for choline to be absorbed in the small intestine of ruminants, the choline must have some protection from degradation by ruminal microbes which degrade dietary choline to methane and acetic acid. Several ruminally-protected choline (RPC) products are being marketed commercially to the dairy industry across the world. ReaShure (Balchem Corp., New Hampton, NY) is such a product containing approximately 25% choline chloride. In 16 experiments published since 2003, dairy cows supplemented with an RPC product starting in late gestation (~ 3 weeks prepartum) and continuing into lactation produced an average of 4.4 lb/day more milk or fat-corrected milk compared with cows not supplemented with RPC. Fourteen of the 16 studies reported a numerical increase and 10 reported a statistically significant increase in milk due to RPC supplementation. The need for choline by nonruminants is increased during pregnancy and lactation because of the dam’s transport of choline to the fetus during pregnancy and into the milk (Zeisel, 2011). This may well be true for ruminant animals as well.