Effect of Feed Additives as Alternatives to In-feed Antimicrobials on Production Performance and Intestinal Clostridium perfringens Counts in Broiler Chickens

Abstract

Numerous non-antibiotic feed additives (alternatives to antibiotics, ATAs) have been marketed, but few have been evaluated under uniform testing conditions modelling commercial flocks. We compared 24 ATA treatments and the ionophorous coccidiostat narasin against a diet without any feed additives. Feed conversion ratio and body weight gain were registered from day 0 to 28 in Ross 308 chickens housed on litter floor. The chickens were challenged with Eimeria spp., and cecal Clostridium perfringens (CP) counts were investigated. Active components from all ATA classes had a positive impact on intestinal health or production performance. Whereas narasin had a strong CP-reducing effect in combination with performance-promoting impact, only two ATA treatments achieved significantly beneficial effects on CP counts as well as feed conversion during the time span following Eimeria challenge. Active components present in these two treatments include a Bacillus subtilis probiotic strain, short- and medium-chain fatty acids and Saccharomyces cerevisiae components. Different ATA classes had beneficial impact during distinct rearing phases and on specific performance targets, suggesting that optimizing combinations and use of active components can make ATAs even more useful tools in broiler rearing without the use of in-feed antimicrobials. Further studies of promising ATAs and ATA combinations are required.

Clostridium perfringens as Foodborne Pathogen in Broiler Production: Pathophysiology and Potential Strategies for Controlling Necrotic Enteritis

“…Its action mechanism is based on altering the permeability of the membrane of microorganisms, causing the leakage of intracellular material. It is difficult to identify its active principle, because there is a variation in growth conditions, climate, harvest, and manufacture, as well as in the biological factors of each plant species [ 142 , 143 ]. Table 8 shows a list of the plants most used for the control of C. perfringens in broilers, as well as a description of the effects caused by the phytogenics tested.…”

“…They can vary considerably in their functionality due to the number of carbon atoms and it they are aliphatic or aromatic. They are natural constituents of animal or plant tissues or products of microbial fermentation [ 143 ].…”

“…Carboxylic acids with an aliphatic chain or fatty acids are classified into short chain fatty acids (SCFAs, 1–5 carbon atoms; C1–C5) and medium chain fatty acids (SCFA, 6–12 carbon atoms; C6–C12). The suggested effects of organic acids are antibacterial activity through pH regulation, changes in the composition of the microbiota, immunomodulatory action, and stimulation of the intestinal mucosa [ 133 , 143 ].…”

“…In addition, they promote changes in the microbiota, have an immunomodulatory action and stimulate the intestinal mucosa. The effects in broilers depend on the base of the organic acid product, dose and type [ 143 , 152 ].…”

Green Tea and Pomegranate Extract Administered During Critical Moments of the Production Cycle Improves Blood Antiradical Activity and Alters Cecal Microbial Ecology of Broiler Chickens

“…In 2006, the European Union banned the use of antimicrobial growth promoters in animal nutrition [1]. This decision led to the result that antimicrobials, other than coccidiostats and histomonostats, were no longer allowed as feed additives [2]. As such, antibiotic alternatives designed to maintain productivity and health became the focus of much research [3,4].…”