Alternatives to antibiotics for livestock feed

Development of new products to replace the subtherapeutic use of antibiotics and alternatives to the coccidiostatics currently used in farm livestock food.

The prohibition or withdrawal of the use of certain growth promoting substances, either antibiotics (tylosin, virginamicin, zinc bacitracin and spiramycin; July 1999), coccidiostat (Ipronidazol, dinitolmide and aprinocin; September 1999; metilclorpindol, methtylbenzoquate, amprolium, ethopabate, dimetridazol and nicarbazin; November 2001) or other compounds (quinoxalines-n-dioxide carbadox and olaquindox; August 1999) implies changes in the productive systems of pig and poultry, and results in a need to find alternatives which permit the productive levels to be maintained without reducing the performance or affecting the health of the livestock. Furthermore, these alternative products must fulfil the requirements of the productive sector (maintaining or improving the health conditions in farms without affecting their performance) as well as consumers (without any significant deviation in the costs which would be reflected in the final product, use of 'natural products', etc.). Although studies on the origin of the resistance in stocks of pathogen microorganisms for human beings are not definitive, the use of antibiotics at sub-therapeutical levels in the diet of farm animals has been considered a hazardous practice. It is a common practice (a recent study in the E.U. showed that 1/3 of the total antibiotics used in livestock is used as a growth factor) to which efficient alternatives must be found. In the case of coccidiosis, the use of coccidiostat products is a common practice in farms in order to avoid resistances. However, this will no longer be possible for some species (quails, guinea fowls) as from 15 May 2002, as the use of only one coccidiotic product will be allowed. Therefore, there is a need to find valid alternatives to regulate and limit the incidence of coccidiosis in farms. The main positive effect of these forbidden substances is the maintenance of the microbiological balance and the integrity and normal development of the digestive system, which permits the proper digestion and absorption of nutrients. In the digestive system of poultry and pigs there are saprophyte microbes in a dynamic balance, which consist of bifidobacteriae and lactobacilae as the main 'positive' agents, and enterobacteriae, clostridiae, coli or spirochetes as 'possibly pathogen' organisms. A loss of balance in these microbes provokes diarrhoea, reduces ingestion and the digestive performance of the nutrients, and reduces the productive rates, finally requiring the use of systematic therapeutical treatments. In order to maintain the balance of intestinal flora, we must act on one or many of the following aspects: a) reducing the contaminating ability of the environment, and especially the fodder; b) increasing the digestibility of the nutrients to reduce the non-digested matter available as a substrate for the maintenance and growth of the microflora; c) interfering the microbiotic metabolic rutes for the assimilation of these nutrients in order to avoid their growth; and d) encouraging the availability of nutrients for microflora categorised as 'positive'. Among the nutritional supplements capable of reducing the effect of the suppression of antibiotics and coccidiostatics used as promoters, there are a number of alternatives: a) acidogenic (inorganic and organic); b) plant extracts (essential oils and other chemical substances of different natures with specific functions related to an 'inmunomodulating' effect); c) prebiotics; d) enzymatic preparations; and e) probiotics. The research in the present project will be focussed on the characteristics of the use of: a) acidogenics (inorganic and organic); b) plant extracts (essential oils and other chemical substances of different natures with specific functions related to an 'inmunomodulating' effect); c) prebiotics; and d) enzymatic preparations. Acidogenic compounds and plant extracts can modify the characteristics of the environment, making it difficult for pathogen microorganisms to settle and grow, either in the fodder or in the gastro-intestinal system. In a more generic sense, enzymes also make it difficult for pathogen microorganisms to develop, as they dramatically reduce the substrate available for their growth. Prebiotic refers to those compounds which favour the development of non-pathogen microorgranisms which are usually found in the gastro-intestinal systems of livestock, and compete efficiently with pathogen microorganisms, thus preventing them from settling in and colonising the digestive system. The goal of this project is to develop products as a substitute to the sub-therapeutical use of antibiotics and to find valid alternatives to the coccidiostatics currently used in livestock food. We aim to determine the efficiency of these products separately and to discover possible synergies among them. Keywords: farm animals, animal husbandry, medicinal plants.
Start date: 
Project Duration: 
Project costs: 
2 660 000.00€
Technological Area: 
Virus, Virology, Vaccines/ Antiobiotics / Bacteriology
Market Area: 
Animal Husbandry

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