Modification of the terms of authorisation regarding the maximum inclusion level of Maxiban® G160 (narasin and nicarbazin) for chickens for fattening

Safety and efficacy of a feed additive consisting of lasalocid A sodium and nicarbazin (Nilablend™ 200G) for chickens for fattening (Zoetis Belgium SA)

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the coccidiostat Nilablend™ 200G containing lasalocid A sodium and nicarbazin. Nilablend™ 200G is not safe for chickens for fattening at the proposed maximum use level of 50 mg lasalocid A sodium + 50 mg nicarbazin/kg complete feed. Concurrent administration of Nilablend™ 200G (containing lasalocid A sodium) with tiamulin and certain other medicinal substances should be avoided. Lasalocid A sodium has antimicrobial activity against Gram-positive bacterial species while many Enterobacteriaceae are naturally resistant. Induction of resistance and/or cross-resistance was not observed in experimental conditions. No information on the interactions of nicarbazin with feed materials, other approved additives or medicinal products have been provided. No data were submitted on the microbiological safety of nicarbazin. The toxicological package for lasalocid A sodium and nicarbazin identified no observed adverse effect levels (NOAELs) that could be the basis for setting health-based guidance values (e.g. an acceptable daily intake (ADI)). The Panel concluded that a concern for the genotoxicity of nicarbazin in Nilablend™ 200G cannot be excluded and that clarification on the mechanism of action of the test items would be needed. Therefore, the FEEDAP Panel is not in the position to establish an ADI for DNC on which to base the assessment of consumer safety. Nilablend™ 200G is considered toxic by inhalation, corrosive and irritant to eyes, slightly irritant to the skin but not a skin sensitiser. Inhalation exposure is considered a risk to persons handling the additive. The FEEDAP Panel cannot conclude on the safety of Nilablend™ 200G for the environment due to a possible risk for aquatic compartment (freshwater) for DNC. The efficacy of Nilablend® 200G was demonstrated.

Sensitive Lateral Flow Immunoassay for the Residues of Imidocarb in Milk and Beef Samples

Based on the successful derivation of a hapten, we prepared and optimized a murine monoclonal antibody against imidocarb, with an IC₅₀ of 2.22 ng/mL and a limit of detection (LOD) of 0.45 ng/mL. Cross-experiment results showed that the cross-over rate for 4,4'-dinitrocarbanilide was 18.12%, and the cross-reactivity with other analogues when using the ic ELISA was less than 0.1%. We used the developed ic-ELISA to detect the addition and recovery of imidocarb in milk and beef samples, and values were 86.0-93.5 and 84.5-101.2%, respectively. The preparation of an immunochromatographic test strip based on gold nanoparticles was used for the rapid identification of imidocarb in milk and beef samples. When assessed by the naked eye, the visual LOD for imidocarb in milk and beef samples was 5 and 10 ng/mL, and the cut-off values were 20 and 50 ng/mL, respectively. Because of its high sensitivity, specificity, and simplicity, the test strip can be used for on-site testing and rapid screening of imidocarb in food samples.

Revisiting the Economic Impacts of Eimeria and Its Control in European Intensive Broiler Systems With a Recursive Modeling Approach

Ionophore compounds active against Eimeria species are widely used in intensive broiler systems and have formed the backbone of coccidiosis control for almost 50 years. Producers, however, are under pressure to reduce ionophore use due to consumer concerns over antimicrobial usage in food animals, and antimicrobial resistance. Moreover, current vaccines against Eimeria are commonly considered to be less cost-effective in intensive broiler systems, especially in Europe where attenuated live vaccines are used. An economic assessment of the impact of Eimeria and the disease coccidiosis, including the cost implications of different efficacies of control, is therefore timely to provide evidence for industry and policy development. A mechanistic model of broiler production under varying infection and control states was used to construct a dataset from which system productivity can be measured. Coccidiosis impact increased rapidly as control efficacy decreased. In the total absence of control, median impact was found to maximize at between €2.55 and €2.97 in lost production per meter squared of broiler house over a 33 day growing period. Coccidiosis remains a major risk to intensive broiler systems and the model developed allows investigation of issues related to coccidiosis control, antimicrobial use and the development of antimicrobial resistance.

Impact of coccidiostat and phytase supplementation on gut microbiota composition and phytate degradation in broiler chickens

BACKGROUND

There is good evidence for a substantial endogenous phytase activity originating from the epithelial tissue or the microbiota resident in the digestive tract of broiler chickens. However, ionophore coccidiostats, which are frequently used as feed additives in broiler diets to prevent coccidiosis, might affect the bacterial composition and the abundance of phytase producers in the gastrointestinal tract. The aim of the present study was to investigate whether supplementation of a frequently used mixture of the coccidiostats Narasin and Nicarbazin alone or together with a phytase affects microbiota composition of the digestive tract of broiler chickens, characteristics of phytate breakdown in crop and terminal ileum, and precaecal phosphorus and crude protein digestibility.

RESULTS

Large differences in the microbial composition and diversity were detected between the treatments with and without coccidiostat supplementation. Disappearance of myo-inositol 1,2,3,4,5,6-hexakis(dihydrogen phosphate) (InsP6) in the digestive tract, precaecal P digestibility, inorganic P in blood serum, and the concentration of inositol phosphate isomers in the crop and ileum digesta were significantly affected by phytase supplementation, but not by coccidiostat supplementation. Crude protein digestibility was increased by coccidiostat supplementation when more phosphate was available. Neither microbial abundance and diversity nor any other trait measured at the end of the experiment was affected by coccidiostat when it was only supplemented from day 1 to 10 of age.

CONCLUSIONS

The coccidiostats used herein had large effects on overall microbiota composition of the digestive tract. The coccidiostats did not seem to affect endogenous or exogenous phytase activity up to the terminal ileum of broiler chickens. The effects of phytase on growth, phosphorus digestibility, and myo-inositol release were not altered by the presence of the coccidiostats. The effects of phytase and coccidiostats on nutrient digestibility can be of significant relevance for phosphorus and protein-reduced feeding concepts if confirmed in further experiments.