Zinc (II) betaine complex

In the current application an authorisation is sought under Article 4(1) for zinc (II) betaine complex under the category/ functional group (3b) "nutritional additives"/"compounds of trace elements", according to the classification system of Annex I of Regulation (EC) No 1831/2003. Specifically, the authorisation is sought for the use of the feed additive for dogs, cats, milk replacers for calves, suckling and weaned piglets, sows, rabbits, salmonids, all fish other than salmonids and other species and categories.

According to the Applicant, the feed additive is a solid preparation of Zinc (II) betaine complex containing minimum of 20 % (w/w) of zinc and minimum of 41 % (w/w) of betaine and 9 to 12 % (w/w) of sulphur corresponding to 27 to 36 % (w/w) of sulfate.

The feed additive is intended to be incorporated into premixtures and feedingstuffs with the following proposed maximum levels of total zinc in feedingstuffs: 200 mg/kg for dogs and cats; 180 mg/kg for salmonids and milk replacers for calves; 150 mg/kg for piglets, sows, rabbits and all fish other than salmonids; and 120 mg/kg for other species and categories. The proposed levels are in agreement with the Commission Implementing Regulation (EU) 2016/1095.

For the quantification of total zinc in the feed additive, premixtures and feedingstuffs the Applicant proposed the internationally recognised ring-trial validated EN 15621 method based on inductively coupled plasma-atomic emission spectrometry (ICP-AES). In addition, the EN 15510 method based on ICP-AES and the European Union (EU) method based on atomic absorption spectrometry (AAS), which was further ring-trial validated by the UK Food Standards Agency (FSA), have been previously evaluated and recommended by the EURL in the frame of the Zinc group dossiers (including FAD-2010-0059; FAD-2010-0063; FAD-2010-0072; FAD-2010-0142; FAD-2010-0228). The EURL is also aware of two ring-trial validated methods, namely: ISO 6869 based on AAS and EN 17053 based on inductively coupled plasma-mass spectrometry (ICP-MS).

Based on the available method performance characteristics, the EURL recommends for official control the above mentioned five ring-trial validated methods: (i) EN 15621, EN 15510 and ISO 6869 for the quantification of total zinc in the feed additive, premixtures and feedingstuffs; (ii) the EN 17053 for the quantification of total zinc in premixtures and feedingstuffs; and (iii) the EU method for the quantification of total zinc in feedingstuffs.

For the quantification of betaine in the feed additive the Applicant submitted the official method of International Commission for Uniform Methods of Sugar Analysis (ICUMSA) based on high performance liquid chromatography with refraction index detection (HPLC-RI) which is dedicated for the determination of betaine in beet molasses. The Applicant performed batch-to-batch analysis of 5 samples of the feed additive using the above mentioned HPLC-RI method and a relative standard deviation for repeatability (RSD_r) of 0.9 % was derived for an average betaine content of 42 % (w/w).

Based on the available data, the EURL recommends for official control the above mentioned method based on HPLC-RI for the quantification of betaine content in the feed additive.

For the quantification of sulphur and sulfate content in the feed additive the Applicant proposed no methods for official control. However, several batches of the feed additive have been analysed for sulphur and sulfate content by using the above mentioned ring-trial validated EN 15621 method. The standard deviation for repeatability (RSD_r) of 3.1 % was obtained for the average sulphur content of 10.8 % (w/w), which corresponds to sulfate content of 32.5 % (w/w).

Based on the performance profile, the EURL recommends for official control the EN 15621 method for the quantification of sulphur and sulfate content in the feed additive.

For proving the formation of zinc (II) betaine complex, the Applicant applied a qualitative method based on powder X-ray diffraction (XRD). Based on the available data, the EURL considers that this method is suitable for proving the complex formation between zinc and betaine.

Further testing or validation of the methods to be performed through the consortium of National Reference Laboratories as specified by Article 10 (Commission Regulation (EC) No 378/2005, as last amended by Regulation (EU) 2015/1761) is not considered necessary.

Recommended Method

as of:

- Commission Implementing Regulation (EU) 2024/265

For the quantification of total zinc in the feed additive:

• Inductively coupled plasma-atomic emission spectrometry, ICP-AES (EN 15621 or EN 15510) 

  or

• Atomic absorption spectrometry, AAS (ISO 6869)

For the quantification of total zinc in premixtures:

• Inductively coupled plasma-atomic emission spectrometry, ICP-AES (EN 15621 or EN 15510) 

  or

• Atomic absorption spectrometry, AAS (ISO 6869) 

  or

• Inductively coupled plasma-mass spectrometry, ICP-MS (EN 17053)

For the quantification of total zinc in compound feed:

• Inductively coupled plasma-atomic emission spectrometry, ICP-AES (EN 15621 or EN 15510) 

  or

• Atomic absorption spectrometry, AAS (Commission Regulation (EC) No 152/2009 (Annex IV-C) or ISO 6869)

  or

• Inductively coupled plasma-mass spectrometry, ICP-MS (EN 17053)

For the quantification of betaine in the feed additive:

• High performance liquid chromatography with refraction index detection (HPLC-RI)

For the quantification of sulphur and sulfate in the feed additive:

• Inductively coupled plasma-atomic emission spectrometry, ICP-AES (EN 15621)

Proof of complex formation between zinc, betaine and sulfate: 

• Powder X-ray diffraction (XRD)