Betaine has a positive effect on the gut of weaned piglets, but is often forgotten when considering possible supplements to support gut health or reduce problems associated with weaning diarrhea. Adding betaine as a functional nutrient to feed can affect animals in a variety of ways.
First, betaine has a very potent methyl group donor ability, primarily in animal liver. Due to the transfer of unstable methyl groups, the synthesis of various compounds such as methionine, carnitine and creatine is enhanced. Thus, betaine affects the protein, lipid and energy metabolism of animals, thereby beneficially changing the composition of the carcass.
Secondly, betaine can be added to feed as a protective organic penetrant. Betaine acts as an osmoprotectant, helping cells throughout the body maintain fluid balance and cellular activity, especially during periods of stress. A well-known example is the beneficial effect of betaine on animals suffering from heat stress.
Various beneficial effects on animal performance have been described as a result of betaine supplementation in anhydrous or hydrochloride form. This article will focus on the many possibilities for using betaine as a feed additive to support gut health in weaned piglets.
Several betaine studies have reported the effects of betaine on nutrient digestibility in the ileum and colon of pigs. Repeated observations of increased fiber digestibility in the ileum (crude fiber or neutral and acid detergent fiber) suggest that betaine stimulates bacterial fermentation in the small intestine because enterocytes do not produce fiber-degrading enzymes. Fibrous plant parts contain nutrients that can be released when microbial fibers decompose. Thus, an improvement in the digestibility of dry matter and crude ash was also observed. At the level of the entire gastrointestinal tract, piglets fed a diet of 800 mg betaine/kg showed improved digestibility of crude protein (+6.4%) and dry matter (+4.2%). Additionally, another study found that the apparent overall digestibility of crude protein (+3.7%) and ether extract (+6.7%) was improved with betaine supplementation at 1250 mg/kg.
One possible reason for the observed increase in nutrient absorption is the effect of betaine on enzyme production. A recent in vivo study on the effects of betaine supplementation in weaned piglets assessed the activity of digestive enzymes (amylase, maltase, lipase, trypsin and chymotrypsin) in the digesta (Fig. 1). The activity of all enzymes increased, with the exception of maltase, and the effect of betaine was more pronounced at a dose of 2500 mg betaine/kg feed than at a dose of 1250 mg/kg feed. Increased activity may result from increased enzyme production, but may also result from increased catalytic efficiency of the enzymes. In vitro experiments have shown that trypsin and amylase activities are inhibited by creating high osmotic pressure through the addition of NaCl. In this experiment, addition of betaine at various concentrations restored the inhibitory effect of NaCl and improved enzyme activity. However, when no sodium chloride was added to the buffer solution, the betaine inclusion complex had no effect on enzyme activity at lower concentrations, but exhibited an inhibitory effect at relatively high concentrations.
Improved growth performance and feed conversion rates have been reported in pigs fed dietary betaine, as well as improved digestibility. Adding betaine to pig diets also reduces the animal's energy requirements. The hypothesis for this observed effect is that when betaine is available to maintain intracellular osmotic pressure, the need for ion pumps (a process that requires energy) is reduced. Thus, in situations where energy intake is limited, the effect of betaine supplementation is expected to be greater by increasing growth rather than by maintaining energy requirements.
Epithelial cells of the intestinal wall must cope with the highly variable osmotic conditions created by the contents of the intestinal lumen during the digestion of nutrients. At the same time, these intestinal epithelial cells are essential for controlling the exchange of water and various nutrients between the intestinal lumen and plasma. To protect cells from these harsh conditions, betaine is an important organic penetrant. If you look at the concentration of betaine in various tissues, you can see that intestinal tissue has fairly high levels of betaine. Additionally, it has been noted that these levels may be influenced by dietary betaine concentrations. Well-balanced cells will have better proliferative capacity and good stability. In summary, the researchers found that increasing betaine levels in piglets increased the height of duodenal villi and the depth of ileal crypts, and the villi became more uniform.
In another study, an increase in villous height without an effect on crypt depth could be observed in the duodenum, jejunum, and ileum. The protective effect of betaine on intestinal structure may be more important in specific (osmotic) diseases, as observed in broiler chickens with coccidia.
The intestinal barrier is primarily composed of epithelial cells that are attached to each other through tight junction proteins. The integrity of this barrier is essential to prevent the entry of harmful substances and pathogenic bacteria that could otherwise cause inflammation. In pigs, negative effects on the intestinal barrier are thought to be a result of feed contamination with mycotoxins or one of the negative effects of heat stress.
To measure the effect on the barrier effect, cell lines are often tested in vitro by measuring transepithelial electrical resistance (TEER). Improvements in TEER have been observed in numerous in vitro experiments due to the use of betaine. TEER decreases when cells are exposed to high temperatures (42°C) (Figure 2). Addition of betaine to the growth medium of these heated cells counteracted the decrease in TEER, indicating improved thermotolerance. In addition, in vivo studies in piglets revealed increased expression of tight junction proteins (occludin, claudin1 and zonula occlusions-1) in the jejunal tissue of animals receiving betaine at a dose of 1250 mg/kg compared to the control group. In addition, diamine oxidase activity, a marker of intestinal mucosal damage, was significantly reduced in the plasma of these pigs, indicating a stronger intestinal barrier. When betaine was added to the diet of finishing pigs, the increase in intestinal tensile strength was measured at slaughter.
Recently, several studies have linked betaine to the antioxidant system and described a reduction in free radicals, a reduction in malondialdehyde (MDA) levels, and an increase in glutathione peroxidase (GSH-Px) activity. A recent study in piglets showed that GSH-Px activity in the jejunum was increased, whereas dietary betaine had no effect on MDA.
Not only does betaine act as an osmoprotectant in animals, but various bacteria can accumulate betaine through de novo synthesis or transport from the environment. There is evidence that betaine may have a positive effect on the bacterial flora of the gastrointestinal tract of weaned piglets. The total number of ileal bacteria increased, especially bifidobacteria and lactobacilli. In addition, lower numbers of Enterobacteriaceae were detected in the stool.
The last observed effect of betaine on gut health in weaned piglets was a reduction in the incidence of diarrhea. This effect may be dose dependent: dietary supplementation with betaine at a dose of 2500 mg/kg was more effective in reducing the incidence of diarrhea than betaine at a dose of 1250 mg/kg. However, weaner piglet performance was similar at both supplementation levels. Other researchers have shown lower rates of diarrhea and morbidity in weaned piglets when supplemented with 800 mg/kg betaine.
Interestingly, betaine hydrochloride has potential acidifying effects as a source of betaine. In medicine, betaine hydrochloride supplements are often used in combination with pepsin to help people with stomach and digestive problems. In this case, betaine hydrochloride serves as a safe source of hydrochloric acid. Although there is no information available regarding this property when betaine hydrochloride is included in piglet feed, it may be important. It is known that in weaned piglets the gastric pH can be relatively high (pH > 4), thereby interfering with the activation of the pepsin protein-degrading enzyme in its precursor pepsinogen. Optimal protein digestion is important not only so that animals can take full advantage of this nutrient. In addition, poorly digested protein can lead to unnecessary proliferation of opportunistic pathogens and worsen the problem of post-weaning diarrhea. Betaine has a low pKa value of approximately 1.8, which causes betaine hydrochloride to dissociate when ingested, resulting in gastric acidification. This temporary re-acidification has been observed in preliminary human studies and in canine studies. Dogs previously treated with acid reducers experienced a dramatic decrease in gastric pH from approximately pH 7 to pH 2 after a single dose of 750 mg or 1500 mg of betaine hydrochloride. However, in control dogs that did not receive the drug, gastric pH decreased significantly. Approximately 2, regardless of betaine HCl intake.
Betaine has a positive effect on the intestinal health of weaned piglets. This literature review highlights the various capabilities of betaine to support nutrient digestion and absorption, improve physical defense barriers, influence the microbiota and enhance defense in piglets. References available upon request, contact Lien Vande Maele, maele@orffa.com