Spring 2025 www.pigchamp.com 15 Natural choline sources occur at meaningful levels in most feed ingredients; which is the main reason why choline is not considered to be a vitamin in the classic sense. That said, the feed industry has learned from experience that there are certainly many feeding conditions where choline becomes inadequate for optimum animal health and performance, which is why target choline levels are considered in several stages of swine production. Choline (and related metabolites) has three broad physiological roles in the animal: 1. Building and maintaining cellular structures; 2. Mobilizing and metabolizing lipids in support of liver function, and; 3. Neurotransmission maintenance. Choline flows quickly through the animal system and is metabolically altered for specific biological purposes by oxidation, phosphorylation, and acetylation pathways (Chen et al., 2024). Choline naturally occurs in various bulk ingredients, such as soybean meal, primarily in the form of phosphatidylcholine. Why do we Feed it? There are, of course, several production benefits associated with choline supplementation, particularly in sows and piglets. Choline supplementation in sows has been shown to increase sow litter size, improve conception rate, and lead to more live-born and weaned piglets (K-State Animal Science, 2022). The use of choline supplementation in gestating and lactating diets has a positive influence on sow milk composition, bodily choline concentrations, and piglet performance (Mudd et al., 2016; Getty and Dilger, 2015). Choline is often not included as a supplement to the animals in the grow/finish phase, as choline requirements are met by intrinsic (natural) choline forms from bulk ingredients. However, supplementation of choline during this phase has been shown to positively alter the gut microbiota and can lead to improvements in body weight gain (Jiao et al., 2018; Xie et al., 2023). Classic choline deficiency signs are not common in swine production systems, as most requirements are met by well-formulated diets with external choline chloride supplementation. However, with the omission of supplemental choline or a possible choline antagonist, signs of choline deficiency can include reduced growth and reproductive performance, as well as increased fat accumulation around the liver and miss-formation of cartilage and tendons. Choline Recommendations According to the NRC (National Research Council) in 2012, choline requirements are 600-1,250 ppm (parts per million) in gestation and lactating sows diets and 400-600 ppm in starter, grower, and finisher diets. Practical diets that are high in intrinsic choline can often meet the pig’s requirements for choline. In piglets, the choline requirement is met through milk. Pigs are also able to meet some of their dietary choline needs through internal conversion of the amino acid methionine. While most of the US-based diets theoretically have enough intrinsic choline to meet requirements, the uniform bioavailability of the feed choline is questionable. Unfortunately, little research work has been done examining choline bioavailability in common feedstuffs, and the research that has been completed was published over 25 years ago. Previous work done by the NRC in 1994 shows that soybean meal has a choline level of around 2,300 mg/kg (the amount in milligrams that is present per kilogram of an individual’s body weight), and DDGS (distillers dried grains with solubles—this is a co-product of ethanol production that is widely used as a feed ingredient) has a choline level of around 2,100 mg/kg, with almost all of that being in the form of phosphatidylcholine. In the past 25 years, there have been numerous changes to how we feed pigs, along with advancements in pig genetics, and how ingredients are processed and sourced. It is uncertain whether past research properly represents the current status of intrinsic choline supply and bioavailability. AN ESSENTIAL NUTRIENT WITH NEW PERSPECTIVES CholineWhile pigs can synthesize some choline, dietary supplementation is often necessary to meet their physiological needs. Jordyn Studer, Poultry Technical Service Specialist, Barentz North America
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