What are feed additives and why are they vital?

Dear Daktari, Thank you for the informative articles you write in this newspaper. I am a poultry farmer, keeping layers on the outskirts of Eldoret town. Out of curiosity, while buying my feeds at an Agrovet in town, I noticed several products labelled as Probiotics. I was interested in learning more about these products, but unfortunately, the sellers did not explain them to me very well. I would greatly appreciate your support. [Truphena Chebet - Eldoret]
Thank you, Truphena, for reading Smart Harvest and, of course, for your question. What you saw are broadly known as feed additives. Feed additives are common in most animal production systems. Feed additives are ingredients or combinations added to conventional feeds to achieve specific purposes. They are used to improve feed intake, utilisation, or digestibility, to prevent or control certain diseases, and ultimately to enhance the productivity of animals. They include feed coloring agents, enzymes, probiotics, prebiotics, and antioxidants. Feed additives are sometimes classified into two broad categories: nutrient and non-nutrient.

Coccidiostats

Coccidiostats are among the oldest feed additives used in the control and prevention of diseases, especially in poultry. Coccidiostats are chemical products obtained by synthesis or produced by microorganisms, which inhibit the growth of or destroy protozoa. Protozoa are the parasites that cause coccidiosis. Coccidiostats are used in various food-producing animals to prevent, inhibit, and control parasitic protozoa.

Coccidiostats are most extensively employed as food complements in intensively bred species, such as pigs and birds, to maintain animal health and, in some cases, improve feed conversion.

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Enzyme additives

Enzymes are mostly used in the diets of monogastric animals because these animals lack a digestive system that can break down certain feeds. As a result, the nutrients in these feeds are not fully utilized by the animals. Adding enzymes to such feeds helps release the bound nutrients.

Probiotics and Prebiotics

Probiotics are live cultures of microorganisms, while prebiotics are nondigestible functional ingredients that selectively stimulate the growth of favorable bacteria in the gut of the host (acting as food for the good microbes). Probiotics and prebiotics are collectively called symbiotics.

Probiotics and prebiotics act on the microbes in the gut to create a favorable balance. These additives are used to control the growth of beneficial gut microflora, which plays a role in digestion and subsequently improves the digestive process, growth rate, and overall productivity. High populations of beneficial gut microflora suppress the growth of harmful microorganisms through toxin production. This mode of action is advantageous as the world battles antimicrobial resistance, as it greatly reduces the need for antibiotics. 

Antioxidants

Antioxidants are added to feeds to enhance their freshness, increase their shelf life, and improve their palatability. Antioxidants prevent oxidation, which occurs in feeds, especially those rich in fats, subsequently destroying amino acids, and vitamins A, D, and E. Oxidation lowers the quality of feeds. It must be noted that for a long time, antibiotics were also used as feed additives, mainly to act as growth promoters. However, research has linked this practice to the development of antimicrobial resistance.

[Dr Othieno is a veterinary surgeon and the head of communications at FAO-Kenya. The views expressed here are his own]