Choline, sometimes referred to as vitamin J, is a saturated quaternary amine often compared to the B vitamins. It is an organic substance classified as an essential nutrient, discovered in 1864 by Andreas Strecker and synthesized two years later. Choline is composed of a series of quaternary ammonium salts that contain the cation N, N, N-trimethylethanolamine, typical of the head of the phosphatidylcholine and sphingomyelin groups, abundant in cell membranes.
Choline performs four main functions in the organism:
- It is an essential metabolite for the construction and maintenance of cellular structure. As a phospholipid component, choline is a structural part of lecithin (phosphatidylcholine), some plasmalogens and sphingomyelins. Lecithin is part of animal cell membranes and lipid transport moieties in cell plasma membranes. Choline, as a phospholipid constituent, is essential for the normal maturation of the cartilage matrix of the bone.
- Choline plays an important role in fat metabolism in the liver, preventing abnormal fat accumulation by promoting lecithin transport or increasing the use of fatty acids in the liver itself. Choline is therefore defined as a “lipotropic” factor due to its ability to act on fat metabolism by decreasing the deposition or accelerating the removal of fat in the liver.
- Choline is essential for the formation of acetylcholine, one of the most important neurotransmitters, responsible for nerve transmission both in the central nervous system and in the peripheral nervous system of many living organisms. Acetylcholine allows the transmission of nerve impulses from presynaptic to postsynaptic fibers of sympathetic and parasympathetic nervous system.
- Choline provides labile methyl groups for the formation of methionine from homocysteine and creatine from guanidinoacetic acid. Methyl groups are essential for the synthesis of purines and pyrimidines used for the production of DNA. Methionine is converted to S- adenosylmethionine, the active methylating agent for many enzymatic methylations.
Choline, unlike most vitamins, can be synthesized by most species although, in many cases, in insufficient quantities or not quickly enough to satisfy the requirements of the animal. The choline requirements for growing poultry range from 750 to 2,000 mg per kg of diet.
The metabolic needs of choline can be provided in two different ways: through the administration of dietary choline, or through the body synthesis of choline using labile methyl groups. For some species, however, body synthesis does not occur fast enough to meet choline requirements to promote rapid growth, thus causing clinical signs of deficiency. Choline doesn’t act as a true vitamin as it is incorporated into phospholipids via cytidine diphosphocholine. Therefore, unlike a typical B vitamin, the choline molecule becomes an integral part of the structural component of the cells of the liver, kidneys or cartilage, preventing the appearance of the typical clinical signs of fatty liver, hemorrhagic kidneys and perosis.
Commercially, the most common source of choline used in animal feed is choline chloride, which comes from chemical synthesis starting from methanol and ammonia (trimethylamine), hydrochloric acid and ethylene oxide. The choline salt is marketed both in solid form at a concentration of 50-70%, and in liquid form at a concentration of 70-75%. In both cases, the maximum content of trimethylamine (TMA) in the final product cannot exceed 300 mg/kg. Once in the intestine, most of the choline chloride will be metabolized by the microflora, and only one third of the salt’s choline will be absorbed by the body, while the rest will be converted into TMA. The TMA produced by bacterial action in the intestine is absorbed and transported by the blood circulation to the tissues, thus affecting the liver metabolism, reducing the activity of the flavin monooxygenase 3.
Choline chloride produces chlorine ions which, at high levels, cause the alteration of the electrolyte balance of the organism and metabolic acidosis. The use of both forms of choline brings with it a number of technical problems when handling it. Powdered choline is highly hygroscopic, therefore susceptible to humidity and temperature, complicating its precise dosage in feed. Moreover, its instability and antagonistic interactions with other vitamins cause the reduction of its absorption and limit its storage and activity time. On the other hand, choline chloride in liquid form is extremely corrosive, thus being a risk for machinery, for its storage and for the safety of those who handle it.
Due to all the drawbacks deriving from the use of synthetic choline, in recent years the poultry industry is introducing the use of choline of natural origin, obtained from extracts of different plants, to be integrated in animal nutrition. Natural choline comes in esterified form as phosphatidylcholine and other phospholipids rich in polyunsaturated fatty acids, such as phosphatidylinositol, phosphatidylethanolamine and phosphatidylserine. The high affinity for intestinal receptors makes vegetable choline highly bioavailable, practically avoiding its transformation into TMA by the microflora. Another important feature is its non-hygroscopicity: unlike solid choline chloride, it does not accumulate water in contact with premixes and feed.
A new presentation of the AdiCholine product, until now in solid-powdered form, now appears on the Spanish market in liquid form, AdiCholine Líquida, thanks to the collaboration of two companies, AdiNature S.L. and Cealvet S.L.u., both committed to safeguarding animal welfare. The formulation of the product is based on the combination of scientifically and carefully selected phytochemicals from plant species authorized for use in animal nutrition, particularly Mangifera, Ocimum sanctum, Withania somnifera, Phyllanthus emblica, Allium sativum and Azadirachta indica.
AdiCholine Líquida, in addition to possessing the fundamental precursor of acetylcholine, the phosphatidylcholine, provides methyl donor groups to the metabolism, thus avoiding the use of methionine to perform this function. The phosphatidylcholine, naturally provided by AdiCholine, improves both liver and intestinal health. At the hepatic level, AdiCholine prevents fatty liver syndrome through the optimization of lipid metabolism which, by emulsifying them into smaller particles, facilitates their transport and absorption. Moreover, the product allows a better defense by hepatocytes against the damages caused by viruses and toxic xenobiotics. At the intestinal level, AdiCholine, in addition to having an anti-inflammatory effect, prevents lesions of the gastrointestinal tract by maintaining its barrier function intact, thanks to phosphatidylcholine, the essential lipid for the formation of the mucosa.
AdiCholine Líquida has all the advantages of natural choline: it is a stable and non-reactive product; it is easy to handle and it isn’t hygroscopic. It is 100% natural and totally harmless as there is no TMA production. AdiCholine is fully compatible with vitamins, amino acids and additives.
The use of AdiCholine Líquida is suitable for feeding birds, pigs, fish, ruminants and pets, with the advantage of reducing the cost of feed thanks to a lower inclusion dose and the replacement of choline chloride. The product also increases the digestibility of nutrients, improves productivity and decreases mortality. In birds, pigs, ruminants and pets, AdiCholine improves intestinal stability and functionality by strengthening the intestinal epithelium and promoting the development of villi; it also prevents the appearance of digestive problems and has a positive impact on the consistency of the feces, decreasing moisture in the litter. In birds, pigs, ruminants and fish, the use of AdiCholine Líquida has a positive effect on the composition of the carcass, in addition to reducing the energy requirements for the basal metabolism, making a greater amount of energy available for growth.
The composition of AdiCholine Líquida, with phospholipids, antioxidants, polyphenols, hepatoprotectors and palatability enhancers, is designed to improve metabolism and promote animal growth. Particularly, the phospholipids, in a minimum concentration of 2%, contribute to the maintenance of the structure of cell membranes; the natural antioxidants (min. 5%) maintain the activity of the extracts and act as a barrier against the oxidation of the active ingredients; while the polyphenols, around 1.2%, preserve the vitamins and minerals of the diet.
Recent studies have tested the effectiveness of AdiCholine on the health and growth of different animal species, particularly broilers, fattening pigs, breeding sows and sea breams.
In 2018, Dr. Antonio Palomo demonstrated that, both in fattening pigs and in breeding sows, the replacement of choline chloride 75% at 250 ppm with AdiCholine at 100 ppm, allows to maintain both zootechnical and reproductive parameters in the farms where these studies were carried out. These results suggest that AdiCholine is a viable alternative to synthetic choline, being much safer and harmless.
In 2018, at the University of Las Palmas de Gran Canarias, it was studied how the replacement of choline chloride with natural choline precursors deriving from AdiCholine maintained the zootechnical performance and nutritional characteristics of sea breams. This was achieved by using 40% fewer natural choline precursors than those normally used for choline chloride. At the hepatic level, the natural precursors of choline, although in a first analysis did not decrease the lipid content of the liver, nevertheless they maintained the correct deposition and morphology of the hepatocytes. In contrast, fish fed a diet enriched with choline chloride had a higher content of intracellular lipids and a loss of membrane integrity.
The Department of Animal Production and Food Sciences of the University of Zaragoza studied the effects of the administration of AdiCholine on broilers, comparing them with those deriving from the use of choline chloride at 60%. The results obtained showed that the replacement of choline chloride at 60% with natural choline increased the digestibility of the feed, obtaining a greater live weight at the end of the study, with a tendency to increase the average daily gains, without however altering the conversion rates. Furthermore, the mortality rate in the group of chickens given the natural choline was 44% lower than in chickens given synthetic choline. AdiCholine’s natural choline is therefore a valid and promising alternative for replacing choline chloride at 60%.
Between 2019 and 2020, the Department of Animal Production and Animal Nutrition of the Complutense University of Madrid conducted a study, led by Dr. Clemente Lopez, with the aim of knowing the effect of some additives related to lipid metabolism in the accumulation of fat in broilers. The results obtained showed statistically significant differences in fat content between the group of chickens given choline chloride and those given AdiCholine, with a difference of 36% or 26% depending on whether it was fresh or dry matter respectively. The study also indicates that although there were no significant differences in the composition of fatty acids between the two groups, there was greater variability in the fat content in the group given choline chloride, indicating possible imbalances or feeding problems.
Field trials carried out by Cealvet and AdiNature demonstrated that for AdiCholine Líquida the blood choline biomarker profiles of 50 days old broilers were equivalent to the replacement rate proposed by the manufacturer (1 kg of AdiCholine : 3,5 kg of choline chloride 60%). More precisely, the percentage of the total content of phospholipids, phosphatidylcholine and choline in the chickens given AdiCholine slightly exceed those of the chickens given choline chloride. In the same study, the liver fat profile also demonstrated the validity of the substitution according to the bioequivalence rate proposed. Finally, the group of birds given AdiCholine Líquida showed more effective mobilization of lipids with less variation leading to animals’ less-dispersive performances.
In conclusion, to improve the performance of the animals, we suggest replacing the synthetic, corrosive, highly reactive choline chloride with AdiCholine, a natural, harmless product, 100% compatible with mixtures and feed.