Opinion of the Scientific Panel on Additives and Products or Substances used in Animal Feed on the safety and the bioavailability of product L-Histidine monohydrochloride monohydrate for salmonids

The product contains 74 % of the essential amino acid L-Histidine and is to be used in supplementing salmon feed. It is an essential amino acid also for fish, and has been shown to prevent cataracts under practical farming conditions. L-Histidine monohydrochloride monohydrate is obtained by fermentation of an isolated strain of Escherichia coli (ATCC-21318) derived by conventional mutation. The product is isolated from the fermentation broth, purified, including an ion-exchange procedure and therefore impurities from organic sources are not expected, de-colourized, concentrated, crystallized and dried. The European Food Safety Authority (EFSA) received a request from the Commission to evaluate the safety of the product for salmonids, the worker, the user, the consumer and the environment and to assess the product’s bioavailability in order to add the product to the Annex of Council Directive 82/471/EC. With regard to bioavailability, studies on Atlantic salmon were performed using production parameter and muscle concentration of histidine as criteria. Based on muscle concentration data FEEDAP Panel concludes that the bioavailability of histidine from LHistidine monohydrochloride monohydrate is as high as that of histidine from natural sources. There is limited scientific information on the use of excess dietary crystalline histidine in salmonids. However, a six month study on Atlantic salmon with dietary His levels up to 1.7 % (approximately two times higher than the dietary requirement of histidine for protein synthesis, but at about the recommended level for feeding practices), showed no adverse effects on fish growth or health. EFSA’s FEEDAP Panel considers that since the product is an essential amino acid, potential safety concerns are expected to be primarily associated with the production method and the resulting purity of L-Histidine monohydrochloride monohydrate. It is not considered that the use of L-histidine in animal feed will increase human intake of that amino acid, and on the basis of the data available and considering the high degree of purity of L-Histidine monohydrochloride monohydrate obtained using a multistep physico-chemical purification process, the FEEDAP Panel does not expect a risk for the consumer. Specific studies concerning worker/user safety are not submitted, but due to the experience of the long term use of comparable products as food supplements and cosmetics ingredients, specific risks are not expected. However, workers and users should wear protective clothes as recommended by the applicant. The FEEDAP Panel concludes that the use of the product will not adversely influence the environment.