Alternative performance enhancers are intended to have a positive influence on the organism with regard to performance and health. These 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). [3] .
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, thereby achieving positive health effects." [1] .
Prebiotic additives such as carbohydrates, polysaccharides, oligosaccharides, disaccharides, short-chain sugar alcohols (β-glucans, mannan oligosaccharides from the yeast cell wall) are used in the animal feed industry. [2] .
The principle behind prebiotic products is not the body's own digestion for energy production, but rather that the substances are selectively metabolized undigested in the gut by microorganisms and used as their own energy source. Gut microbes break down ingested carbohydrates into the short-chain fatty acids acetate, butyrate, and propionate. These short-chain fatty acids theoretically lead to a decrease in pH in the gut, thereby inhibiting harmful microorganisms. [3] .
Besides promoting beneficial microorganisms, some undesirable microorganisms can also metabolize prebiotics. Therefore, the desired theoretical effect is not always achieved. Studies in salmonids have shown a reduction in mortality rates when feeding them β-glucans. [4] .
Scientific sources:
[1] Wilson, RP (1991): Handbook of Nutrient Requirements of Finfish. CRC press. Boston, p. 35.
[2] Schäperclaus, W. & Lukowicz, MV (1998): Textbook of Pond Management. 4th revised edition. Parey. Berlin, pp. 51–209.
[3] REGULATION (EC) No 1831/2003 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 22 September 2003 on additives for use in animal nutrition.
