Towards a mechanism-based approach for the prediction of nongenotoxic carcinogenic potential of agrochemicals.

Chemical substances are subjected to assessment of genotoxic and carcinogenic effects before being marketed to protect man and the environment from health risks. For agrochemicals, the long-term rodent carcinogenicity study is currently required from a regulatory perspective. Although it is the current mainstay for the detection of nongenotoxic carcinogens, carcinogenicity studies are shown to have prominent weaknesses and are subject to ethical and scientific debate. A transition toward a mechanism-based weight-of-evidence approach is considered a requirement to enhance the prediction of carcinogenic potential for environmental (agro)chemicals. The resulting approach should make optimal use of innovative (computational) tools and be less animal demanding. To identify the various mode of actions (MOAs) underlying the nongenotoxic carcinogenic potential of agrochemicals, we conducted an extensive analysis of 411 unique agrochemicals that have been evaluated for carcinogenicity by the United States Environmental Protection Agency (US EPA) and the European Chemicals Agency (ECHA). About one-third of these substances could be categorized as nongenotoxic carcinogens with an average of approximately two tumor types per substance, observed in a variety of organs. For two-third of the tumor cases, an underlying MOA (network) could be identified. This analysis demonstrates that a limited set of MOA (networks) is underlying nongenotoxic carcinogenicity of agrochemicals, illustrating that the transition toward a MOA-driven approach appears manageable. Ultimately the approach should cover relevant MOAs and its associated key events; this will also facilitate the evaluation of the human relevance. This manuscript describes the results of the analysis while identifying knowledge gaps and necessities to achieve a mechanism-based weight-of-evidence approach.

A comprehensive view on mechanistic approaches for cancer risk assessment of non-genotoxic agrochemicals.

Currently the only methods for non-genotoxic carcinogenic hazard assessment accepted by most regulatory authorities are lifetime carcinogenicity studies. However, these involve the use of large numbers of animals and the relevance of their predictive power and results has been scientifically challenged. With increased availability of innovative test methods and enhanced understanding of carcinogenic processes, it is believed that tumour formation can now be better predicted using mechanistic information. A workshop organised by the European Partnership on Alternative Approaches to Animal Testing brought together experts to discuss an alternative, mechanism-based approach for cancer risk assessment of agrochemicals. Data from a toolbox of test methods for detecting modes of action (MOAs) underlying non-genotoxic carcinogenicity are combined with information from subchronic toxicity studies in a weight-of-evidence approach to identify carcinogenic potential of a test substance. The workshop included interactive sessions to discuss the approach using case studies. These showed that fine-tuning is needed, to build confidence in the proposed approach, to ensure scientific correctness, and to address different regulatory needs. This novel approach was considered realistic, and its regulatory acceptance and implementation can be facilitated in the coming years through continued dialogue between all stakeholders and building confidence in alternative approaches.

Is current risk assessment of non-genotoxic carcinogens protective?

Non-genotoxic carcinogens (NGTXCs) do not cause direct DNA damage but induce cancer via other mechanisms. In risk assessment of chemicals and pharmaceuticals, carcinogenic risks are determined using carcinogenicity studies in rodents. With the aim to reduce animal testing, REACH legislation states that carcinogenicity studies are only allowed when specific concerns are present; risk assessment of compounds that are potentially carcinogenic by a non-genotoxic mode of action is usually based on subchronic toxicity studies. Health-based guidance values (HBGVs) of NGTXCs may therefore be based on data from carcinogenicity or subchronic toxicity studies depending on the legal framework that applies. HBGVs are usually derived from No-Observed-Adverse-Effect-Levels (NOAELs). Here, we investigate whether current risk assessment of NGTXCs based on NOAELs is protective against cancer. To answer this question, we estimated Benchmark doses (BMDs) for carcinogenicity data of 44 known NGTXCs. These BMDs were compared to the NOAELs derived from the same carcinogenicity studies, as well as to the NOAELs derived from the associated subchronic studies. The results lead to two main conclusions. First, a NOAEL derived from a subchronic study is similar to a NOAEL based on cancer effects from a carcinogenicity study, supporting the current practice in REACH. Second, both the subchronic and cancer NOAELs are, on average, associated with a cancer risk of around 1% in rodents. This implies that for those chemicals that are potentially carcinogenic in humans, current risk assessment of NGTXCs may not be completely protective against cancer. Our results call for a broader discussion within the scientific community, followed by discussions among risk assessors, policy makers, and other stakeholders as to whether or not the potential cancer risk levels that appear to be associated with currently derived HBGVs of NGXTCs are acceptable.

Integrating in vitro data and physiologically based kinetic (PBK) modelling to assess the in vivo potential developmental toxicity of a series of phenols.

Toxicity outcomes derived in vitro do not always reflect in vivo toxicity values, which was previously observed for a series of phenols tested in the embryonic stem cell test (EST). Translation of in vitro data to the in vivo situation is therefore an important, but still limiting step for the use of in vitro toxicity outcomes in the safety assessment of chemicals. The aim of the present study was to translate in vitro embryotoxicity data for a series of phenols to in vivo developmental toxic potency values for the rat by physiologically based kinetic (PBK) modelling-based reverse dosimetry. To this purpose, PBK models were developed for each of the phenols. The models were parameterised with in vitro-derived values defining metabolism and transport of the compounds across the intestinal and placental barrier and with in silico predictions and data from the literature. Using PBK-based reverse dosimetry, in vitro concentration-response curves from the EST were translated into in vivo dose-response curves from which points of departure (PoDs) were derived. The predicted PoDs differed less than 3.6-fold from PoDs derived from in vivo toxicity data for the phenols available in the literature. Moreover, the in vitro PBK-based reverse dosimetry approach could overcome the large disparity that was observed previously between the in vitro and the in vivo relative potency of the series of phenols. In conclusion, this study shows another proof-of-principle that the in vitro PBK approach is a promising strategy for non-animal-based safety assessment of chemicals.

The Isolated Chicken Eye test to replace the Draize test in rabbits.

In 1944, Draize et al., published a paper entitled "Methods for the study of irritation and toxicity of substances applied topically to the skin and mucous membranes". The Organization for Economic Co-operation and Development published their first guideline on eye irritation in 1981, using rabbits. In the early eighties the development of alternative non-animal tests to replace the Draize eye test started. The first attempts to validate alternative tests for eye irritation were considered to be relatively simple by comparing in vitro and in vivo irritation index scores. In the early nineteen-eighties, we introduced the use of isolated eyes as an alternative test for the Draize eye irritation test. What was expected to be a process of several years, however, turned out to be a decades spanning process still not fully completed. For a large part, this can be attributed to the nature of the in vivo test in rabbits, which is more complicated and compromised than originally believed. This paper describes, most chronologically, the development, performance, validation and application of the Isolated Eye Test and, in broader perspective, the international validation and acceptance of this alternative test by regulatory authorities and agencies.

An integrative test strategy for cancer hazard identification.

Assessment of genotoxic and carcinogenic potential is considered one of the basic requirements when evaluating possible human health risks associated with exposure to chemicals. Test strategies currently in place focus primarily on identifying genotoxic potential due to the strong association between the accumulation of genetic damage and cancer. Using genotoxicity assays to predict carcinogenic potential has the significant drawback that risks from non-genotoxic carcinogens remain largely undetected unless carcinogenicity studies are performed. Furthermore, test systems already developed to reduce animal use are not easily accepted and implemented by either industries or regulators. This manuscript reviews the test methods for cancer hazard identification that have been adopted by the regulatory authorities, and discusses the most promising alternative methods that have been developed to date. Based on these findings, a generally applicable tiered test strategy is proposed that can be considered capable of detecting both genotoxic as well as non-genotoxic carcinogens and will improve understanding of the underlying mode of action. Finally, strengths and weaknesses of this new integrative test strategy for cancer hazard identification are presented.

Prediction of carcinogenic potential of chemicals using repeated-dose (13-week) toxicity data.

Sub-chronic toxicity studies of 163 non-genotoxic chemicals were evaluated in order to predict the tumour outcome of 24-month rat carcinogenicity studies obtained from the EFSA and ToxRef databases. Hundred eleven of the 148 chemicals that did not induce putative preneoplastic lesions in the sub-chronic study also did not induce tumours in the carcinogenicity study (True Negatives). Cellular hypertrophy appeared to be an unreliable predictor of carcinogenicity. The negative predictivity, the measure of the compounds evaluated that did not show any putative preneoplastic lesion in de sub-chronic studies and were negative in the carcinogenicity studies, was 75%, whereas the sensitivity, a measure of the sub-chronic study to predict a positive carcinogenicity outcome was only 5%. The specificity, the accuracy of the sub-chronic study to correctly identify non-carcinogens was 90%. When the chemicals which induced tumours generally considered not relevant for humans (33 out of 37 False Negatives) are classified as True Negatives, the negative predictivity amounts to 97%. Overall, the results of this retrospective study support the concept that chemicals showing no histopathological risk factors for neoplasia in a sub-chronic study in rats may be considered non-carcinogenic and do not require further testing in a carcinogenicity study.

Predicting individual responses to pravastatin using a physiologically based kinetic model for plasma cholesterol concentrations.

We used a previously developed physiologically based kinetic (PBK) model to analyze the effect of individual variations in metabolism and transport of cholesterol on pravastatin response. The PBK model is based on kinetic expressions for 21 reactions that interconnect eight different body cholesterol pools including plasma HDL and non-HDL cholesterol. A pravastatin pharmacokinetic model was constructed and the simulated hepatic pravastatin concentration was used to modulate the reaction rate constant of hepatic free cholesterol synthesis in the PBK model. The integrated model was then used to predict plasma cholesterol concentrations as a function of pravastatin dose. Predicted versus observed values at 40 mg/d pravastatin were 15 versus 22 % reduction of total plasma cholesterol, and 10 versus 5.6 % increase of HDL cholesterol. A population of 7,609 virtual subjects was generated using a Monte Carlo approach, and the response to a 40 mg/d pravastatin dose was simulated for each subject. Linear regression analysis of the pravastatin response in this virtual population showed that hepatic and peripheral cholesterol synthesis had the largest regression coefficients for the non-HDL-C response. However, the modeling also showed that these processes alone did not suffice to predict non-HDL-C response to pravastatin, contradicting the hypothesis that people with high cholesterol synthesis rates are good statin responders. In conclusion, we have developed a PBK model that is able to accurately describe the effect of pravastatin treatment on plasma cholesterol concentrations and can be used to provide insight in the mechanisms behind individual variation in statin response.

Risk assessment of feed components of botanical origin - Approaches taken in the European Union.

In view of a continuous trend in replacing synthetic feed additives and especially flavouring compounds by botanical preparations, different aspects of the safety evaluations of plants and plant-derived preparations and components in feed are discussed. This includes risk assessment approaches developed by the European Food Safety Authority (EFSA) for phytotoxins regarding unintentional exposure of target animals and of consumers to animal derived food via carry-over from feed. Relevant regulatory frameworks for feed additives and feed contaminants in the European Union are summarised and the essentials of existing guidelines used in the safety evaluation of botanicals and their preparations and components in feed are outlined. The examples presented illustrate how the safety of the botanicals, their preparations and components present in feed is assessed. An outlook on possible future developments in risk assessment by applying new in vitro and in silico methodologies is given.

Assessment of the feed additive consisting of l-cystine for all animal species for the renewal of its authorisation (Bretagne Chimie Fine [BCF Life Sciences]).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the assessment of the application for the renewal of the authorisation of l-cystine as nutritional feed additive. The additive is authorised for use in all animal species (3c391). The applicant has provided evidence that the additive currently in the market complies with the existing conditions of authorisation. The EFSA Panel on Additives and Products or Substances used in Animal Feed concluded that the use of the feed additive in animal nutrition remains safe for the target species, the consumers and the environment. As regards the safety for the user, l-cystine is not an irritant to skin or eyes and is not a skin sensitiser. Exposure by inhalation of persons handling the additive cannot be excluded. The present application for the renewal of the authorisation does not include any modification proposal that would have an impact on the efficacy of the additive and therefore there is no need for reassessing the efficacy.

Efficacy of a feed additive consisting of endo-1,4-beta-xylanase and endo-1,3(4)-beta-glucanase produced with Talaromyces versatilis IMI 378536 and DSM 26702 (ROVABIO® ADVANCE) for weaned piglets (Adisseo France SAS).

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 efficacy of ROVABIO® ADVANCE (liquid and solid) which contains endo-1,4-beta-xylanase and endo-1,3(4)-beta-glucanase produced with Talaromyces versatilis IMI 378536 and DSM 26702 as a zootechnical feed additive for weaned piglets at the recommended use level of 1800 U xylanase and 1250 U glucanase per kg feed. In a previous assessment, three long-term trials in weaned piglets were submitted. Two of them were considered to support the efficacy of the additive while a third trial was not further considered due to the large number of veterinary treatments applied. A new trial was provided to support the efficacy of the additive, but it did not show a significant improvement of the performance parameters at the minimum recommended use level. Due to the lack of sufficient data, the FEEDAP Panel is not in the position to conclude on the efficacy of the additive for the target species.

Safety of the feed additive consisting of endo-1,4-ß-xylanase (produced with Trichoderma reesei CBS 143953), subtilisin (produced with Bacillus subtilis CBS 143946) and α-amylase (produced with Bacillus amyloliquefaciens CBS 143954) (Avizyme® 1505) for all poultry species (Danisco (UK) Ltd.).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety of the feed additive consisting of endo-1,4-ß-xylanase (produced with Trichoderma reesei CBS 143953), subtilisin (produced with Bacillus subtilis CBS 143946) and α-amylase (produced with Bacillus amyloliquefaciens CBS 143954) (Avizyme® 1505) as a zootechnical feed additive for all poultry species. The additive is authorised in feed for chickens and turkeys for fattening, ducks and laying hens. In 2020, the FEEDAP Panel issued an opinion for the renewal of the authorisation of the additive for the species/categories for which there is an authorisation, a reduction of the minimum recommended level in turkeys for fattening and the extension of use to all poultry species. In that assessment, the Panel could not conclude on the safety of the additive due to uncertainties on the characterisation of the production strains and the possible presence of their viable cells and DNA in the final product. Moreover, limitations were identified in the xylanase specifications and xylanase method of analysis. The applicant submitted information to address the limitations previously identified. The Panel concluded that the additive is safe for the target species under the proposed conditions of use. The use of Avizyme® 1505 in animal nutrition is considered safe for the consumer and the environment. The additive is a mild irritant to skin and eyes; it is not a dermal sensitiser but should be considered a respiratory sensitiser. The additive is efficacious in ducks at 75 U endo-1,4-ß-xylanase, 1000 U subtilisin and 100 U α-amylase/kg of complete feed. In other poultry species for fattening (including turkeys), reared for breeding and reared for laying, the additive is efficacious at 187.5 U endo-1,4-ß-xylanase, 2500 U subtilisin and 250 U α-amylase per kg of complete feed and at 300 U endo-1,4-ß-xylanase, 4000 U subtilisin and 400 U α-amylase per kg of complete feed for all poultry species for laying (except for ducks).

Safety and efficacy of a feed additive consisting of an essential oil derived from the leaves of Cymbopogon nardus (L.) Rendle (citronella oil) for use in all animal species (FEFANA asbl).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of citronella oil obtained from the leaves of Cymbopogon nardus (L.) Rendle, when used as a sensory additive for all animal species. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) concluded that citronella oil from C. nardus is of low concern for long-living and reproductive animals at the use levels in complete feed of 3.5 mg/kg for laying hens and rabbits, 6 mg/kg for sows and dairy cows, 9.5 mg/kg for sheep/goats and horses, 2.0 mg/kg for cats and 10 mg/kg for dogs. For short-living animals (species for fattening), the additive was considered of no concern at concentrations of 18 mg/kg in chickens for fattening, 24 mg/kg in turkeys for fattening, 20 mg/kg for piglets, pigs for fattening, veal calves (milk replacer), cattle for fattening, sheep/goats for meat production, horses for meat production and rabbits for meat production, and 30 mg/kg for salmonids. The conclusions were extrapolated to physiologically related minor species. For any other species, the additive is considered of low concern at 2.0 mg/kg complete feed. The use of citronella oil in animal feed is expected to be of no concern for the consumers and for the environment. The essential oil under assessment should be considered as irritant to skin and eyes and as a dermal sensitiser. When handling the essential oil, exposure of unprotected users to methyleugenol may occur. Therefore, to reduce the risk, the exposure of the users should be minimised. Since the leaves of C. nardus and its preparations were recognised to flavour food and its function in feed would be essentially the same as that in food, no further demonstration of efficacy was considered necessary.

Assessment of the feed additive consisting of endo-1,4-beta-xylanase (produced with Trichoderma reesei MUCL 49755) and endo-1,3(4)-beta-glucanase (produced with T. reesei MUCL 49754) (AveMix® XG 10) for laying hens and minor poultry species for fattening and laying for the renewal of its authorisation (AVEVE BV).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the assessment of the feed additive consisting of endo-1,4-beta-xylanase (produced with Trichoderma reesei MUCL 49755) and endo-1,3(4)-beta-glucanase (produced with T. reesei MUCL 49754) (AveMix® XG 10/AveMix® XG 10 L) for the renewal of its authorisation as a zootechnical feed additive for laying hens and minor poultry species for fattening and laying. The applicant declared a change in the carrier material used in AveMix® XG 10 from soybean meal to calcium carbonate + wheat flour or calcium carbonate + sepiolite. The applicant provided evidence that the additive AveMix® XG 10 with calcium carbonate + wheat flour and AveMix® XG 10 L comply with the conditions of the authorisation. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) noted that no data were submitted to support compliance of the formulation of AveMix® XG 10 with calcium carbonate + sepiolite with the conditions of the authorisation. The FEEDAP Panel concluded that both formulations of the additive (powder and liquid) remain safe for laying hens and minor poultry species for fattening and laying, consumers and the environment. AveMix® XG 10 formulated with calcium carbonate + sepiolite and AveMix® XG 10 L are not irritant to skin and eyes. No conclusions on the irritation potential of AveMix® XG 10 formulated with calcium carbonate + wheat flour could be drawn. The additive in both formulations is considered a respiratory and skin sensitiser. There was no need for assessing the efficacy of the additive in the context of the renewal of the authorisation.

Scientific opinion on the characterisation of Ensifer adhaerens CGMCC 19596 used in the production of the feed additive consisting of vitamin B12 (cyanocobalamin) for all animal species (Hebei Huarong Pharmaceutical Co., ltd.).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the characterisation of the feed additive consisting of vitamin B12 (cyanocobalamin) produced by fermentation with Ensifer adhaerens (CGMCC 19596). The additive is intended to be used as a nutritional additive for all animal species. In a previous opinion, the FEEDAP Panel could not conclude on the characterisation of the production strain, due to uncertainties on whether the production strain E. adhaerens CGMCC 19596 was genetically modified. However, since viable cells and DNA were not detected in the product, the FEEDAP Panel concluded that vitamin B12 (cyanocobalamin), produced with E. adhaerens CGMCC 19596 would not raise safety concerns as regards the production strain. In the present submission, the applicant provided supplementary information regarding the origin and history of modifications of the strain. Based on the data provided, the FEEDAP Panel concluded on the characterisation of the production strain E. adhaerens CGMCC 19596, which can be considered not to be genetically modified.

Safety of a feed additive consisting of sepiolite for all animal species (Sepiol S.A. and Tolsa S.A.).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety of sepiolite as a technological feed additive for all animal species. In 2022, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) delivered an Opinion on the safety and efficacy of the same additive. The Panel concluded that sepiolite used as a feed additive is safe for the consumers and the environment, and efficacious as a thickener-suspending agent, binder and anticaking agent in feed for all animal species under the proposed conditions of use. The additive was not considered an eye or skin irritant. However, it was considered a respiratory irritant, a respiratory and dermal sensitiser; owing to the dusting potential and its silica content, the additive was considered a risk by inhalation. Regarding the target species, in the previous Opinion, the Panel concluded on the safety of the additive for dairy ruminants. However, no conclusion could be drawn for all other species/categories. Based on the tolerance studies in chickens for fattening, weaned piglets and trout evaluated in the current assessment, and the one in dairy cows previously assessed, the Panel concluded that the inclusion of sepiolite at the maximum recommended level of 20,000 mg/kg complete feed is safe for all animal species.

Assessment of the feed additive consisting of endo-1,4-beta-xylanase (produced with Trichoderma reesei MUCL 49755) and endo-1,3(4)-beta-glucanase (produced with T. reesei MUCL 49754) (AveMix® XG 10) for weaned piglets for the renewal of its authorisation and for its extension of use to suckling piglets (AVEVE BV).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of the feed additive consisting of endo-1,4-beta-xylanase (produced with Trichoderma reesei MUCL 49755) and endo-1,3(4)-beta-glucanase (produced with T. reesei MUCL 49754) (AveMix® XG 10/AveMix® XG 10 L) as a zootechnical feed additive for weaned and suckling piglets. The additive is already authorised for use in weaned piglets. This scientific opinion concerns the request for the renewal of the authorisation of the additive for weaned piglets and the extension of use to suckling piglets. The applicant declared a change in the carrier material used in AveMix® XG 10 from soybean meal to calcium carbonate + wheat flour or calcium carbonate + sepiolite. The applicant provided evidence that the additive AveMix® XG 10 with calcium carbonate + wheat flour and AveMix® XG 10 L comply with the conditions of the authorisation. The EFSA Panel on Additives and Products or Substances used in Animal FEED (FEEDAP) noted that no data were submitted to support compliance of the formulation of AveMix® XG 10 with calcium carbonate + sepiolite with the conditions of the authorisation. The FEEDAP Panel concluded that both formulations of the additive (powder and liquid) remain safe for the target species, consumers and the environment, and that the extension of use to suckling piglets would not affect these conclusions. AveMix® XG 10 formulated with calcium carbonate + sepiolite and AveMix® XG 10 L are not irritant to skin and eyes. No conclusions on the irritation potential of AveMix® XG 10 formulated with calcium carbonate + wheat flour could be drawn. The additive in all its formulations is considered a respiratory and skin sensitiser. There was no need for assessing the efficacy of the additive in the context of the renewal of the authorisation for weaned piglets. The Panel concluded that the additive is efficacious in suckling piglets at 4000 XU and 900 BGU/kg complete feed.

Consumer safety of feed additives containing selenium.

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety for the consumer of products from animals fed diets with feed additives containing selenium as an active substance. Based on the limited data set available and the several uncertainties, the FEEDAP Panel concluded that the use of organic selenium at the currently maximum authorised use level of 0.2 mg supplemented selenium from organic sources/kg complete feed (within a maximum of 0.5 mg total selenium/kg complete feed) leads to an exceedance of the UL for all the population categories (except elderly and very elderly), suggesting a concern for consumer safety. It was not possible to conclude on the safety of the currently maximum use level of 0.5 mg total selenium/kg complete feed for all consumer categories. Additional data from studies specifically designed to measure deposition of selenium in tissues and products from animal origin resulting from the use of the different sources of selenium would be required to perform a proper risk assessment.

Animal dietary exposure in the risk assessment of contaminants in feed.

EFSA performs dietary exposure assessments for food-producing and non-food-producing animals to deliver risk assessment for mandates on the presence of contaminants in feed. The CONTAM and FEEDAP Panels identified the need to update the animal dietary exposure assessment model used in those assessments in CONTAM Scientific Opinions since 2011 in cases where insufficient occurrence data are available on species specific compound feeds. The Panels proposed in this statement a series of model diets based on groups of feed materials with the possibility to use different feed materials in their formulation. The Panels considered that the currently proposed model diets cover the need of the CONTAM Panel to assess the dietary exposure of animals to contaminants in feed.

Safety and efficacy of a feed additive consisting of sodium ferrocyanide and potassium ferrocyanide for all animal species (Eusalt a.i.s.b.l.).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of sodium ferrocyanide and potassium ferrocyanide as technological feed additives for all animal species. In its previous opinion on the safety and efficacy of the additives, the FEEDAP Panel concluded that the use of sodium ferrocyanide and potassium ferrocyanide is safe, when added to sodium chloride at a maximum content of 80 mg ferrocyanide anions (anhydrous)/kg for turkeys for fattening and laying hens and other laying/breeding birds, all porcine species and categories, all ruminant species and categories, rabbits, horses, salmonids and other minor fin fish, dogs and cats. However, the Panel could not conclude on the safety of the additives for chickens for fattening and other poultry species for fattening or reared for laying/breeding other than turkeys, and for all species/categories other than the above listed. In the current assessment, the applicant is proposing a maximum content of 60 mg ferrocyanide anions (anhydrous)/kg sodium chloride for chickens for fattening and other poultry species (except turkeys) for fattening or reared for laying/breeding and for all species/categories other than the listed above. The FEEDAP Panel concluded that sodium ferrocyanide and potassium ferrocyanide are safe at a maximum content of 80 mg ferrocyanide anions (anhydrous)/kg sodium chloride for: turkeys for fattening and reared for breeding, laying hens and other laying/breeding birds, all porcine species, all ruminant species, rabbits, equines, salmonids and minor fin fish, dogs and cats. The Panel concluded also that a maximum content of 60 mg ferrocyanide anions (anhydrous)/kg sodium chloride is safe for chickens for fattening and minor poultry species for fattening or reared for laying/breeding and all other animal species.