Scientific Opinion on the safety and efficacy of Lenziaren (iron, aqua carbonate hydroxyl oxo starch sucrose complex) as a feed additive for cats

The additive Lenziaren is a polynuclear Fe(III) starch/saccharose complex intended to be used in food for adult cats to reduce phosphate absorption in the gastrointestinal tract in order to prevent chronic kidney disease. The recommended minimum and maximum levels are 0.25 g and 1.0 g per cat per day, equivalent to 5 000 and 20 000 mg/kg feed, respectively. The FEEDAP Panel considers that Lenziaren is safe for adult cats at the maximum recommended dose. However, the consequences of chronic exposure have not been investigated. The additive is not genotoxic. No adverse effects were seen in a repeat-dose toxicity study in mice. Lenziaren had no adverse effects on reproduction and development at dose levels that were not toxic to the mother. A no observed adverse effect level (NOAEL) of 500 mg/kg body weight (bw) per day was identified for Lenziaren on the basis of maternal toxicity (diarrhoea and reduced body weight gain), which was seen in rabbits at an oral dose of 1 000 mg/kg bw per day or greater. Similar effects were seen in rats, dogs and monkeys at higher doses in repeat-dose toxicity studies. No NOAELs were identified in these studies. Lenziaren is not regarded as an irritant to skin or eyes or as a skin sensitiser. Although some inhalation exposure is possible, it is not expected to be harmful to those exposed as a result of handling the additive. Based on the results of three in vivo efficacy studies, the FEEDAP Panel concludes that Lenziaren has the potential to be efficacious in cats at the highest recommended dose of 1 g/cat per day (equivalent to 20 000 mg/kg feed). However, the FEEDAP Panel has some reservations regarding the value of its long-term use in healthy cats. The Panel concludes that there is a need for a post-market monitoring plan.