Monitoring of verotoxigenic Escherichia coli (VTEC) and identification of human pathogenic VTEC types 1 Scientific Opinion of the Panel on Biological Hazards

The effect of formic acid and 2 plant extracts on performance traits, apparent ileal digestibility (AID), intestine mucosa morphology, and meat yield of broilers was studied in a 49-d experiment. There were 6 treatments: a negative control diet without additives (control); 10 ppm of avilamycin; 5,000 of formic acid; 10,000 ppm of formic acid; 200 ppm of plant extract based on a blend of oregano, cinnamon, and pepper essential oil; and 5,000 ppm of hydroalcoholic plant extract from sage, thyme, and rosemary leaves. A total of 312 Ross chicks were distributed into 24 groups of 13 in each, comprising 4 replicates per treatment. The performance data revealed significantly better FCR in all the supplemented diets except for the 5,000 ppm of hydroalcoholic plant extract diet. All additives improved AID of nutrients. Both acidifier inclusion levels improved villus height, and the group fed the 10,000 ppm of formic acid diet also had the greatest crypt depth; however, villus surface area was not influenced. Meat yield was not affected. It was concluded that the diets with 5,000 and 10,000 ppm of formic acid, and with 200 ppm of plant extract based on a blend of oregano, cinnamon, and pepper essential oils were similar to avilamycin and were beneficial for improving growth traits and nutrient AID. Furthermore, a positive effect of formic acid on intestine mucosa was observed. This experiment involved a small sample, so the additives that showed beneficial effects should be further studied in commercial farms.

Effect of Formic Acid and Plant Extracts on Growth, Nutrient Digestibility, Intestine Mucosa Morphology, and Meat Yield of Broilers

Concerns have been raised in recent years regarding co-selection for antibiotic resistance among bacteria exposed to biocides used as disinfectants, antiseptics and preservatives, and to heavy metals (particularly copper and zinc) used as growth promoters and therapeutic agents for some livestock species. There is indeed experimental and observational evidence that exposure to these non-antibiotic antimicrobial agents can induce or select for bacterial adaptations that result in decreased susceptibility to one or more antibiotics. This may occur via cellular mechanisms that are protective across multiple classes of antimicrobial agents or by selection of genetic determinants for resistance to non-antibiotic agents that are linked to genes for antibiotic resistance. There may also be relevant effects of these antimicrobial agents on bacterial community structure and via non-specific mechanisms such as mobilization of genetic elements or mutagenesis. Notably, some co-selective adaptations have adverse effects on fitness in the absence of a continued selective pressure. The present review examines the evidence for the significance of these phenomena, particularly in respect of bacterial zoonotic agents that commonly occur in livestock and that may be transmitted, directly or via the food chain, to human populations.

Co-Selection of Resistance to Antibiotics, Biocides and Heavy Metals, and Its Relevance to Foodborne Pathogens

Implications of butyrate and its derivatives for gut health and animal production

In recent years, there has been an increase in the use of organic acids as substitutes for antibiotic growth promoters because of the fear of antibiotic resistance and the implications for human health. Organic acids and their salts have been used in poultry diets and drinking water for decades and seem to elicit a positive response in growth performance. An important objective of dietary acidification is the inhibition of intestinal bacteria competing with the host for available nutrients, and a reduction of possible toxic bacterial metabolites resulting in the improvement of nutrient digestibility, thereby ameliorating the performance of birds and enhancing the specific and non-specific immunity in poultry. Literature shows that short-chain fatty acids, medium-chain fatty acids and other organic acids have more or less pronounced antimicrobial activity, depending on both the concentration of the acid and the bacterial species that is exposed to the acid. The possible mechanisms contributing to t...

M. Antongiovanni

Papers

Effect of butyric acid on the performance and carcass yield of broiler chickens