Alternative Health Promoters

Alternative health promoters

Alternative performance enhancers are intended to have a positive effect on the organism in terms of performance and health. Performance enhancers include probiotics, prebiotics, enzymes, organic acids/salts and essential herbs. They can be found under the additional categories of sensory and zootechnical additives (REGULATION (EC) No. 1831/2003) ^[1] .

Probiotics

Probiotics are defined as living microorganisms that reach the intestines in sufficient quantities in an active form and thereby have positive health effects ^[1] . One difficulty in using probiotics is their survival. Many do not survive the extrusion process (which is intended to preserve the food) and must be administered afterwards. It is difficult for the consumer to judge whether the probiotics reach the koi in a sufficiently living form.

Thus, the feed does not contain microbial metabolites, as is the case with antibiotics, but rather the microorganisms themselves. The mechanisms of action are diverse and cannot be examined in detail. They are based, among other things, on the displacement of the undesirable microorganisms, on competition for available nutrients or on the inhibition of the undesirable microorganisms by metabolic metabolites. For the most part, microorganisms are responsible for immune stimulation and the direct activation of immune cells ^[2] .

In animal nutrition, microorganism genera such as Saccharomyces, Enterococcus faecium, Streptococcus infantarius, Bacillus subtilis, B. licheniformis, B. cereus var. toyoi, Lactobacillus rhamno-sus, L. casei, L. plantarum, L. farciminis, Paediococcus acidilactici and yeasts of the genus Saccharomyces cerevisiae are most commonly used ^{[2, 3]} .

The metabolic products released by the probiotic bacteria are mainly organic acids, lactate, volatile fatty acids and enzymes. Some metabolic metabolites have been shown to have an antimicrobial effect. For example, lactobacilli produce bacteriocins and plasmid-encoded proteins that can inhibit the growth of other bacteria ^[2] . In a scientific study on trout, consumption of Lactobacillus rhamnosus after 30 days of testing resulted in a significantly increased activity of phagocytosis (absorbing dead microorganisms) and leukocytes (fighting incompatible substances such as pathogens) ^[4] .

Prebiotics

According to the Federal Institute for Consumer Health Protection and Veterinary Medicine, prebiotics are “specific indigestible substances that promote the growth of selective bifidobacteria and possibly other microorganisms in the intestine and thereby achieve positive health effects” ^[1] .

Prebiotic additives such as carbohydrates, polysaccharides, oligosaccharides, disaccharides, short-chain sugar alcohols (β-glucans, mannanoligosaccharides from the yeast cell wall) are used in the feed industry ^[2] .

The principle of prebiotic products is not the body’s own digestion to provide energy, but rather the substances are selectively metabolized undigested in the intestine by microorganisms and used as their own energy source. Intestinal microbes break down ingested carbohydrates into the short-chain fatty acids acetate, butyrate and propionate. These short-chain fatty acids theoretically lead to a reduction in the pH in the intestine, which inhibits negative microorganisms ^[3] .

In addition to promoting desirable microorganisms, some undesirable microorganisms can also metabolize prebiotics. As a result, the desired theoretical effect is not always achieved. Studies on salmonids have shown a reduction in mortality when β-glucans were fed ^[4] .

Organic acids and their salts

For centuries, companies in the food industry have used organic acids to preserve food and feed (silage, yoghurt, sauerkraut, etc.). Organic acids and essential oils are considered to be beneficial to health and have antimicrobial properties ^[1] .

Organic acids were once used for preservation to protect feed from spoilage. Now they are used in animal nutrition to lower the pH value in the digestive tract. The most common acids include propionic acid, butyric acid, sorbic acid, acetic acid, succinic acid, benzene acid, lactic acid, formic acid, citric acid and fumaric acid ^[1] .

The use of organic acids in cases of diarrhea is mainly used in young monogastric animals, i.e. piglets. Since gastric acid production is not yet fully developed and the number of microbes in the digestive tract is still relatively low, the use of acids can lower the pH value and protect the intestine from bacterial infection (E. coli bacteria). Improved protein digestion can also be ensured ^[2] .

Humic acids (peat) have always been used in aquaristics and pond farming to improve the health of fish. They can stimulate the body’s own cellular defenses in fish ^{[3, 4]} . It has been proven that feeding humic acids can reduce the residence time of toxic lead and cadmium in the organism ^[5] .

Enzymes

Enzymes are used in animal nutrition to utilize food components that the organism itself is not capable of.

Not all animals are fully capable of independently synthesizing the enzymes required to process certain nutrients. By adding the necessary enzymes, the energy and nutrient supply for growth can be significantly improved. Amylases, for example, are used to break down starch and phytases are used to utilize phosphorus from plant sources.

Secondary plant ingredients

Secondary plant ingredients use the health-promoting, anti-parasitic, anti-inflammatory or antibacterial properties of medicinal plants to combat health problems. According to Regulation (EC) No. 1831/2003, these are classified in the categories of sensory and/or zootechnical additives. The legal differentiation between phytotherapeutic agents and feed additives (phytoadditives) is difficult to consider.

Phytotherapeutics are medicinal products that are made from whole plants or plant extracts ^[1] . Since phytotherapeutics consist of the same components as a phytoadditive (subject only to Regulation (EC) 1831/2003), the problem here is that they are subject to the Medicines Act.

One approach to getting around this problem is to divide the substances according to the amount used. This involves taking in phytoadditives in nutritionally significant quantities. The most common secondary plant substances include the groups of bitter substances, pungent substances, essential oils, phenolic oils, saponins, alkaloids, glycosinolates, mucilaginosa and tannins ^[2] . In terms of their chemical structure alone, secondary plant ingredients have an inhomogeneous structure, to which a variety of effects and mechanisms of action can be attributed. Unlike conventional medicines, the effect is not only due to a single active ingredient, but to the interactions of several substances involved ^[1] . Secondary plant ingredients have different effects on the organism, which can be described as anti-inflammatory, antiseptic, antiviral, immune system stabilizing, appetite stimulating, antiparasitic ^{[3, 4, 5]} .

In a 13-week feeding trial of Nile tilapia (Oreochromis niloticus) with oregano (Origanum vulgare), an oregano concentration of 1% resulted in a significant improvement in daily gain, relative and specific growth rate, and feed utilization ^[6] .