Function of the intestinal immune system and biogenic amines

The lamina propria layer of the intestinal wall is the richest place in the body for plasmocytes (plasma cells)

Plasmocytes produce immunoglobulins. The intestinal flora stimulates the development of the intestinal immune system. Without normal intestinal flora, immunity is reduced, macrophages show reduced activity and lymphatic tissue is underdeveloped.

A fourfold defence system suppresses and displaces pathogenic bacteria in response to the antigenic load of the intestinal lumen

The system consists of four components. The intestinal immune system cannot fight off biogenic amines that are produced from free Amino acids are formed. It consists of four defence systems: the microbial, humoral, anatomical and cellular defence systems. The four-element defence system is primarily a defence against cellular elements and offers protection against antigenic microbial protein compounds. These barriers are ineffective against toxic, non-antigenic compounds (biogenic amines, microtoxins).

Local immunostimulation in the intestine

Local immune stimulation takes place in the intestine. The cell wall of bacteria, including the beneficial Intestinal bacteriacontains two important immunobiologically active components: Peptidoglycan (PG) in Gram-negative and Gram-positive bacteria and lipopolysaccharide (LPS) in the cell wall of Gram-negative bacteria. LPS has a 1000-fold higher immunobiological activity. 

The Immune system normally functions at a basic level. Specific protection only develops after an appropriate antigenic response. The LPS and PG stimulators from the gut flora are continuously required for the proper development and readiness of the immune system and to maintain health. The entry of LPS into the bloodstream in small amounts is beneficial to the host. It leads to a general stimulation of the immune system and an improved cellular defence.

By-products of fermentation (e.g. amino acids, sodium glutamate, by-products of fermentation of other food additives): 

• Threonine amino acid → E. amino acid → fermented by Corynebacterium glutamicum bacteria 
• Sodium glutamate → fermented by Corynebacterium glutamicum bacteria 

When large quantities of LPS enter the bloodstream, they trigger an acute systemic immune reaction. This leads to a general inflammatory process.

Biogenic amines in feed for farm animals

As a result of the globalised feed industry, new feed ingredients have been introduced into piglet feed over the last decade and a half. As a result, piglets come into contact with substances that were not previously contained in their feed. In 2010, the global pharmaceutical, food and feed sectors produced over 100 million tonnes of fermented amino acids and artificial food additives and their fermentation by-products. Today, the animal feed industry uses fermented amino acids and artificial flavour enhancers and their by-products as raw materials.

The by-products of the fermentation industry are also used as pig, fattening and sow feed. These are a common feature of these processes. In addition to the main product, fermentation processes also produce various intermediate products such as free amino acids, di- and polypeptides and biogenic amines. The by-products are particularly critical. They contain billions of dead bacterial bodies of the fermenting bacteria contained in the feed materials. The bacterium E. coli, for example, ferments the artificially produced amino acid threonine.

Biogenic amines (BA) are formed by the decarboxylation of amino acids

There are exogenous (supplied with the feed) and endogenous (produced in the animal) biogenic amines. These are involved in the fine regulation of the body and are known as tissue hormones. Biogenic amines are neurotransmitters that are involved in the transmission of stimuli. Their quantity in the body is fixed and regulated. Any other quantity raises unexplained toxicological problems.

Biogenic amines are obtained from amino acids by oxidative decarboxylation:

• Arginine - Agmatin, Putrescin
• Hisztidin - Histamine
• Lizin - Cadaverine
• Methionine - Spermine és spermidine
• Ornitine - Putrescine
• Phenylalanine - Phenylethylamine
• Tryptophan - triptamine, serotonin
• Tirozine - Tiramine

The presence of large quantities of biogenic amines in the blood puts a strain on the liver. The liver can only partially detoxify the amines, which leads to a variety of liver problems. Biogenic amines are direct cellular and neurotoxins and paralyse the autonomic nerves that innervate the vascular network.