Slide 1: Understanding Choline: An Overlooked Nutrient in Pigs and Chickens
Understanding Choline: An Overlooked Nutrient in Pigs and Chickens Ryan N. Dilger, PhD University of Illinois at Urbana‐Champaign Department of Animal Sciences Division of Nutritional Sciences Neuroscience Program Balchem Real Science Lecture Series, February 23, 2021
Slide 2: Outline
Understanding Choline Choline C5H14NO+ 104.1708 g/mol Discovered by Adolph Strecker in 1862 as isolated from pig and ox bile (‘chole’ in Greek) • Choline functions and metabolism Outline • Clinical signs of deficiency • Feedstuff concentrations and relative bioavailability • Pigs vs. chickens: requi
Slide 3: Defining Choline
Defining Choline • 2‐hydroxyethyl‐trimethyl‐ammonium salt • Quasi‐vitamin (high concentrations, de novo synthesis) and conditionally essential nutrient • Defined as an essential nutrient for humans in 1998 (Institute of Medicine, IOM) • Choline‐containing metabolites and derivatives critical for mul
Slide 4: Forms of Choline
Forms of Choline Water‐soluble forms • Reach the liver via portal circulation Lipid‐soluble forms • Packaged into chylomicrons and transported via lymphatic system Blue‐dotted box denotes choline (per se) as incorporated into other forms Wiedeman et al., 2018; Nutrients 10, 1513
Slide 5: Choline Functions
Choline Functions • Cellular maintenance and growth across all life‐stages – Neurotransmission (sphingomyelin, acetylcholine) – Membrane synthesis (component of phospholipids, especially PC) – Lipid transport (lipoprotein synthesis) – One‐carbon metabolism (betaine)
Slide 6: Choline Metabolism
Choline Metabolism (ACh) Microbial Oxidation fermentation (irreversible) BHMT Choline serves critical (50% of remethylation) (PCh) functions in neuronal Met development, lipid Cytidine diphosphate (CDP)‐choline pathway Cycle metabolism, and epigenetics Methyl donation (hundreds of methyl transferase
Slide 7: Choline Metabolism
Choline Metabolism • Dietary free choline is preferentially used for biosynthesis of acetylcholine (Ach) and phosphatidylcholine (PC) • PC is most abundant choline form in the body – 70% of total hepatic PC synthesized via CDP‐choline pathway – Less efficient synthesis from PE via 3 methyl‐transfer
Slide 8: Clinical Signs of Choline Deficiency
Clinical Signs of Choline Deficiency • Reduced growth and reproductive performance • Hepatic lipid accumulation • Tissue development abnormalities – Bone/cartilage formation, neural tube closure, cognitive function – Perosis (chondrodystrophy) in broiler chickens is the classic choline deficiency si
Slide 9: Dietary Sources of Choline
Dietary Sources of Choline • Ingested form depends on species and physiological stage • Animals transition from water‐soluble forms (milk/egg yolk) to lipid‐soluble forms (oilseed meals) with age • Enriched sources are those of animal origin (eggs, meat, liver), but oilseed meals also contain (PC; a
Slide 10: Choline-containing Feedstuffs
Choline‐containing Feedstuffs Poultry NRC 3000 Corn Commercial supplements Corn DDGS • Choline chloride Total concentration, 2500 Wheat Soybean Meal mg/kg (as-is) 2000 • Dry (50‐70% purity) 1500 • Liquid (70‐75% purity) 1000 • Choline bitartrate, citrate 500 Plant‐based ingredients 0 Choline Betaine
Slide 11: Relative Bioavailability (RBV)
Relative Bioavailability (RBV) • Few measures of bioavailability exist in the literature • Broiler model using SPI‐based diet containing 2‐amino‐2‐ methyl‐1‐propanol (inhibits de novo choline synthesis) • RBV estimates Canola meal • Soybean meal: 77‐90% • Analyzed total choline: > 6,000 mg/kg • Cano
Slide 12: Choline/Betaine Interrelationship
Choline/Betaine Interrelationship • Choline provides labile methyl groups via betaine 2‐step oxidation (irreversible) • Betaine remethylates Hcy to Met, with SAM serving as the donor to hundreds of Choline Betaine (N‐trimethylethanolamine) (N‐trimethylglycine) methyltransferase reactions • Betaine d
Slide 13: Choline-sparing Effect of Betaine
Choline‐sparing Effect of Betaine Theory: First 2 functions of choline will be satisfied at Weight Gain 50% of the total choline requirement Total choline reqt. satisfied Predicted outcome: PC and ACh No betaine response reqt. satisfied until PC and ACh functions satisfied Dietary Choline
Slide 14: Choline-sparing Effect of Betaine
Choline‐sparing Effect of Betaine • Choline‐free purified diet containing adequate methionine • Betaine could NOT spare choline in a choline‐free diet • Preformed dietary choline is required to satisfy the ACh and 116/229 = 51% PC functions (50% of total choline requirement) • Betaine was able to sa
Slide 15: Choline in Poultry Nutrition
Choline in Poultry Nutrition • Relatively high dietary requirement for preformed choline – Lacking in hepatic PEMT capacity, so de novo synthesis is low – Relatively high choline oxidase activity favors betaine formation • Betaine serves as a potent osmolyte to counteract toxic effects of uric acid
Slide 16: Choline Requirements in Poultry
Choline Requirements in Poultry • Diets high in protein (but not Met alone) increase the dietary choline requirement, possibly through enhanced degradation • PEMT activity increases with age; challenging to create a choline deficiency after birds are 8 weeks post‐hatch • Total choline requirements (
Slide 17: Choline Requirements in Pigs
Choline Requirements in Pigs • Lower dietary requirement compared with chickens due to efficient de novo choline synthesis • Sufficient choline can be obtained via milk and practical diets • No growth benefits in pigs consuming corn‐SBM‐based diets, where methionine can completely spare choline • To
Slide 18: Choline in Sow Nutrition
Choline in Sow Nutrition • Some evidence that higher choline may benefit reproductive performance of sows (Stockland and Blaylock, 1974) – Increased conception rate, increased total born alive • Choline intake during gestation/lactation influences: – Sow’s milk composition (choline, amino acids, fat
Slide 19: Perinatal Choline Status in Sows
Perinatal Choline Status in Sows Plasma Milk CA CD CA CD CA CD CA CD CA CD Gestation Lactation Lactation d0 d7 d 18 d 65 d 19 CA, choline‐adequate; CD, choline‐deficient Mudd et al., 2016; J. Nutr. 146, 2216
Slide 20: Perinatal Choline Status in Pigs
Perinatal Choline Status in Pigs Liver Weight Prenatal / Postnatal Liver Lipid Content Getty and Dilger, 2015; PLoS ONE 10(7): e0133500
Slide 21: Perinatal Choline and Metabolomics in Pigs
Perinatal Choline and Metabolomics in Pigs Total Choline Free Choline Prenatal / Postnatal • Plasma metabolomics suggest stark changes to choline‐related Betaine Methionine metabolites • Amino acid, lipid, and carbohydrate metabolism altered • Liver health biomarkers elevated in postnatal CD pigs Ge
Slide 22: Conclusions
Conclusions • Choline is a ‘pervasive’ nutrient due crucial metabolic roles • Species‐specific metabolic idiosyncrasies drive requirements • Analytical data for choline‐related compounds is lacking • Bioavailability and metabolic kinetics vary by choline form • Potential for choline deficiency remai
Slide 23: Questions?
Questions? Ryan N. Dilger, PhD rdilger2@illinois.edu Ph: (217) 333‐2006 http://go.illinois.edu/RNDilgerLab