The European Food Safety Authority (EFSA), in an opinion published this week, said the additive - a mixture of dolomite plus magnesite and magnesium-phyllosilicates (MMDM) - is safe in complete feed for dairy cows, piglets and pigs for fattening at a maximum concentration of 20,000 mg/kg.
But the Authority's FEEDAP panel was unable to determine the safety of the product, branded as Fluidol, in complete feed for other livestock species - a finding in keeping with its conclusions on the additive in January 2016.
Fluidol is intended to be used as a technological additive, an anti-caking agent, in premixtures and feedstuffs, with no minimum and maximum content. However, IMI FABI has suggested use levels of 5,000 to 20,000 mg/kg.
Following the publication of that January 2016 opinion, the EU Commission said the Italian developer could submit complementary information in order to complete the assessment on the safety and to, potentially, allow a revision of Authority's findings.
But EFSA said IMI FABI only sent it its analysis of the 2016 FEEDAP opinion, and did not deliver any new data on the additive.
"We followed the recommended procedures in that regard," Mario Mondonico, a spokesperson for the R&D department at IMI FABI, told us. He also said the company was evaluating next steps.
Interpretation of the science
The most recent opinion includes the analysis submitted by IMI FABI supporting its request for authorization of the additive for all livestock species and EFSA's counter arguments.
In its earlier assessment of the safety of the product, the FEEDAP Panel assessed three tolerance studies - one with piglets, a trial on broilers and another with dairy cows.
IMI FABI raised the following arguments in relation to those findings:
In the study with dairy cows, the producer said:
- The absence of replicates for feed intake (owing the difficulties to register individual feed intake with cows) does not impair the validity of the study, since for tolerance the primary outcome should be milk production.
- Diets should be considered equivalent only if they are isocaloric and isonitrogenous, without considerations to the type and the amount of the ingredients included in the formulation. The diets are also considered equivalent if the outcome is an equal ratio dry matter (DM) intake/milk yield (kg/day), without consideration to the absolute milk yield.
- Dairy and meat-producing ruminants share the same digestive system, have the same physiology, and the feed formulation for meat-producing animals is not too far from the one for dairy animals. Therefore, any conclusion drawn for dairy cows can be applied to other ruminants (i.e. cattle for fattening).
In response, among other remarks, the FEEDAP panel noted: "Any extrapolation of results from one animal species or category carries a certain degree of uncertainty. This uncertainty is considered to be reduced by the requirement for a (wide) margin of safety of the safe use level of the test item. This margin of safety could not be derived from the cow study; consequently any extrapolation is not possible."
On the study related to broilers, IMI FABI claimed: "Although the differences in feed-to-gain ratio are significantly different, they are minimal, and are to be attributed to unbalanced diet formulation."
The panel said that, in its previous opinion, it had concluded that "no safe level of MDMM for chickens for fattening could be identified since feed-to-gain ratio was higher in all treated groups compared to control. With [an] increasing amount of MDMM, feed-to-gain ratio increased related to the dose of the test item.
"The applicant proposed to use a system in which only certain levels of impairment would allow a conclusion on adverse effects. A scientific assessment uses, generally, for this decision statistical parameters; a significant difference is taken as a difference to be considered.
"Feed-to-gain ratio was significantly affected in a dose-dependent manner, with even the lowest dose (2% MDMM in the diet) showing a significant difference. In case of dose-related changes, the difference (even if small or not statistically significant) observed at the lowest dose is of concern."
And the FEEDAP panel said it did not see any reason to modify its former position on the additive.
The latest opinion can be read here.