What is feed grade Tributyrin？
The molecular formula of tributyrin is C15H26O6 and its molecular weight is 302.37. Transparent oily liquid, colorless, odorless, insoluble in water, easily soluble in organic solvents. pH is neutral, non-toxic, non-corrosive, no moisture absorption, excellent stability. Excess n-butyric acid was synthesized by an esterification process with glycerol, the catalyst involved. Purification process to remove impurities such as water, free butyric acid, glycerol, and catalyst. In the gut, tributyrin is released slowly and in steps by specific lipases as they move along the chyme. Triglyceride, a feed additive in the intestinal health category, can be used on all animals, feeds, and farming sites. With the strong development of the feed industry, it is very difficult to rely on natural extraction, so it needs artificial fermentation synthesis. Synthetic tributyrin has high purity and can be controlled. Even if there are impurities that can be artificially controlled, the detection is very clear, and can quickly increase the yield.
Special line production equipment is the safest. Dedicated personnel and equipment are very mature in the use and operation of technology so that mistakes can be avoided and the probability of additives being contaminated can be greatly reduced.
Butyric acid is a four-carbon short-chain fatty acid, which is a natural organic acid. It has a PH of less than 7 and has a peculiar stench. Butyric acid is involved in a variety of physiological reactions in the body, so butyric acid is a very important molecule for life activities and health. There are three main sources of butyric acid. The first is the consumption of butter, cheese, etc. The second is the chemical plant through the petrochemical raw materials extraction production. The third is endogenous butyric acid, a probiotic bacteria in the gut that ferments fiber in the gut to make butyric acid.
What are short-chain fatty acids and their role in animal farming？
Short-chain fatty acids (SCFAs), also known as volatile fatty acids (VFAs), are important metabolites of post-gut microbiota fermentation and are also key signaling molecules to study the interaction between gut microbiota and the body. It is a general term for a group of organic fatty acids composed of 1 to 6 carbon atoms. Common SCFAs include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, and isovaleric acid. At present, SCFAs have been approved by the EU as chicken feed additives, which can partially replace antibiotics.
Formation, transport, absorption and metabolism of SCFAs
The hindgut is an important production site of short-chain fatty acids in animals, and anaerobic flora (such as Bacteroidetes, Firmicutes, etc.) can use undigested dietary fibers (mainly carbohydrates) to ferment and produce SCFAs. Different bacterial groups can ferment different metabolites, mainly acetic acid, propionic acid, and butyric acid, which account for more than 95% of the whole SCFAs. Most of the SCFAs in the intestinal lumen are weak acids in the form of free anions, which are the main components of anions in the hindgut and can be rapidly absorbed by the intestinal mucosa. Most of the SCFAs in the intestinal lumen are weak acids in the form of free anions, which are the main components of anions in the hindgut and can be rapidly absorbed by the intestinal mucosa. SCFAs enter cells mainly in three different ways: the first is direct diffusion through the intercellular space; the second is through the H+-dependent way of monocarboxylate transporter 1 (MCT1/SLC16A1) and sodium-coupled monocarboxylate in intestinal epithelial cells. Acid transporter 1 (SMCT1/SLC5A8) co-transports SCFAs in a Na+-coupled manner; the third is by activating cell surface G protein-coupled receptors (GPCRs): GPR41 (also known as free fatty acid receptor 3, FFAR3), GPR43 (also known as free fatty acid receptor 2, FFAR2) and GPR109A, promote the transport of SCFAs in cells. The hindgut has the highest availability of butyric acid in SCFAs, and only a small amount of butyric acid can penetrate the intestinal mucosal epithelial cells and enter the portal vein. In contrast, acetate and propionate enter the liver for metabolism mainly through the portal vein. In the liver, the metabolic pathways of acetate, propionate, and butyrate are different: acetate is mainly involved in the synthesis of long-chain fatty acids, glutamine, glutamate, and β-hydroxybutyrate; propionate is mainly used as a gluconeogenesis substrate; Acids are mainly involved in gluconeogenesis, ketone body formation, and triacylglycerol synthesis, and indirectly affect carbohydrate and lipid metabolism.
The physiological role of SCFAs
- Maintain the integrity of the intestinal mucosal barrier
The intestinal mucosal barrier is mainly composed of a single layer of columnar epithelial cells, intercellular tight junctions, a mucus layer on the cell surface, and a biofilm. The integrity of the intestinal mucosal barrier is the first line of defense against harmful substances (such as pathogenic bacteria) from invading the body. When the barrier structure is damaged, intestinal permeability will increase, and harmful substances will more easily enter the bloodstream, resulting in decreased immunity and inflammation reaction occurs. Studies have found that SCFAs can not only regulate the secretion of mucus and antimicrobial peptides in the distal intestine of chickens but also enhance the integrity of the intestinal mucosal barrier by maintaining an environment conducive to the survival of intestinal commensal bacteria and controlling the growth of pathogenic bacteria.
- Promote intestinal epithelial cell proliferation and differentiation
SCFAs are an important energy source for intestinal cells. Acetate, propionate, and butyrate in the intestine can be absorbed by epithelial cells, and play an important role in promoting the proliferation and differentiation of intestinal epithelial cells and inducing the functional maturation of intestinal epithelial cells. Studies have shown that SCFAs in the hindgut can significantly reduce intestinal mucosal atrophy and promote the growth and development of intestinal mucosa, while the reduction of SCFAs content can inhibit the proliferation of intestinal epithelial cells. Butyrate, the main product of fermentation by avian gut microbes, is absorbed by enterocytes via passive diffusion, promoting intestinal villi growth and cell turnover. The exogenous addition of sodium butyrate can promote the proliferation and differentiation of broiler intestinal epithelial cells to improve intestinal morphology. Intestinal butyrate can provide energy for colonic epithelial cells and promote epithelial cell proliferation.
- Involved in intestinal immune regulation
The metabolite SCFAs produced by the fermentation of intestinal flora can not only strengthen the intestinal mucosal barrier but also directly participate in the regulation of intestinal immunity to maintain intestinal health. SCFAs mainly regulates intestinal immune function in the following two ways: First, activate GPCRs (GPR41, GPR43, and GPR109A), of which GPR41 and GPR43 are mainly expressed in enteroendocrine L cells and are activated by acetate, propionate, and butyrate, etc., GPR109A is mainly expressed in colonic epithelial cells (macrophages and dendritic cells) and is activated by butyrate. Second, direct inhibition of the activity of histone deacetylases (HDACs), especially butyrate and propionate, selectively inhibits the activity of HDAC1 and HDAC2. GPCRs play an important role in SCFAs regulating immune response, maintaining intestinal immune homeostasis, and treating enteritis. SCFAs increase the production of cytokines and chemokines by activating GPR41 and GPR43 signaling pathways, thereby reducing the occurrence of goat appendicitis. Butyrate and propionate can inhibit the expression of tumor necrosis factor-α (TNF-α) and nitric oxide synthase (NOS) in lipopolysaccharide (LPS)-mediated NF-kB signaling pathway by binding to GPR41, GPR43 and GPR109A. expression and play a role in intestinal immunity.
Application of SCFAs in Broiler Production
Growth performance is the most direct indicator to reflect the nutritional status of broilers. SCFAs can have a positive effect on poultry growth performance as a feed additive. The addition of SCFAs to the feed can significantly increase the feed intake, body gain, and pancreas weight of broilers, and increase the activities of various digestive enzymes, thereby improving the growth performance of broilers. The addition of butyric acid to the diet can significantly increase the carcass yield and breast meat yield of broilers to improve animal performance. The differences in the growth performance of SCFAs may be related to their addition methods (coating, powder, drinking water, diet), the combination, ratio, and dosage of different SCFAs. The specific application and effect research needs further exploration.
Effects of SCFAs on the gut health of broilers
Intestinal health plays a very important role in broiler body digestion and absorption of nutrients, maintenance of homeostasis, and resistance to various diseases. When intestinal health is damaged, it will lead to the imbalance of intestinal flora and damage to the intestinal barrier, which will lead to intestinal diseases, such as necrotizing enteritis, coccidiosis, etc., which seriously damage the intestinal health of broilers. Therefore, maintaining the intestinal health of chickens is an important way to improve broilers’ performance. Dietary supplementation of short-chain fatty acids can improve host immunity and disease resistance. Adding SCFAs to the drinking water of broilers can inhibit the colonization of Escherichia coli in the cecal chyme of broilers, and has a good effect on improving the histological morphology of broiler intestines. Studies have shown that butyric acid can induce the expression of antibacterial host defense peptide (HDP) genes in chickens, improve broilers’ resistance to pathogens, and reduce the risk of intestinal diseases caused by Salmonella.
