DD1996-13: (Supplement) Determination of Livestock Feed Safety of BASF Canada Inc.'s Sethoxydim Tolerant Corn (Zea mays L.) Hybrid DK404SR

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Decision Document 96-13

Issued: 1997-01

Feed Assessment:

This supplement to Decision Document DD96-13 has been prepared to explain the regulatory decision reached under the guidelines Dir95-03 Guidelines for the Assessment of Livestock Feed From Plants with Novel Traits.

The Plant Biotechnology Office (PBO) of the Plant Products Division has evaluated information submitted by BASF Canada Inc. regarding a corn hybrid referred to as DK404SR in the present document. These plants were modified to express tolerance to the herbicide sethoxydim. CFIA has determined that these plants with novel traits do not present altered environmental interactions when compared to currently commercialized corn varieties as explained in decision document DD96-13.

The Feed Section of the Plant Products Division, has evaluated information submitted by BASF Canada Inc. regarding the sethoxydim tolerant corn hybrid DK404SR and has determined that it is substantially equivalent to corn currently approved for use as livestock feed.

Feed use of the corn hybrid DK404SR and its byproducts is therefore authorized. Any other Zea mays lines and intra-specific hybrids derived from the original somaclonal variant may be considered substantially equivalent, provided no inter-specific crosses are performed, provided the intended use is similar and provided it is known that these plants do not display any additional novel traits.

Table of Contents

  1. Brief Identification of the Plants with Novel Traits (PNTs)
  2. Background Information
  3. Nutritional Composition
  4. Anti-Nutritional Factors
  5. Regulatory Decision

I.  Brief Identification of Plant with Novel Traits (PNT)

Designation(s) of the PNT: Corn hybrid DK404SR

Applicant: BASF Canada Inc.

Plant Species: Corn (Zea mays L.)

Novel Traits: Sethoxydim herbicide tolerance

Trait Introduction Method: Selection of a somaclonal variant from embryo culture

Intended Use of PNT: Cultivation as hybrid grain corn for livestock feed and human consumption

II.  Background Information

BASF has developed a corn line tolerant to sethoxydim, the active ingredient of the herbicide POAST, currently registered in Canada as a post-emergence herbicide for the control of various grassy weeds in broadleaf crop plants. This Z. mays hybrid, DK404SR, also referred to as Poast compatible corn, will allow the use of POAST as a post-emergence herbicide on corn, thus providing an alternative for weed control in hybrid corn production.

The original sethoxydim tolerant mutant line was developed by Dekalb Canada Inc., through somaclonal variation of embryo tissue grown under sethoxydim selective pressure. The herbicide tolerant phenotype results from the presence of a gene coding for a modified version of acetyl-CoA-carboxylase, a key enzyme in the fatty acid biosynthesis pathway, such that this enzyme is no longer inactivated by sethoxydim.

BASF Canada Inc. has provided data on the identity of the corn hybrid DK404SR, a description of the modification method and breeding history, data on the role and the activity levels of the modified acetyl-CoA-carboxylase, and on the stability of trait expression. References to scientific publications were also included.

Data to support the suitability of corn hybrid DK404SR as livestock feed was provided. Results from proximate analyses, including crude protein, crude fat, crude fibre, and ash were supplied. Since the mutation conferring herbicide tolerance has affected the herbicide binding site without altering the catalytic properties of the enzyme, data describing the levels of individual fatty acids in the corn hybrid DK404SR was deemed not to be necessary.

For further information and a more detailed description of the novel trait, please refer to decision document DD96-13.

CFIA has reviewed the information submitted by the company in light of the assessment criteria for determining the safety and efficacy of livestock feed as described in Dir95-03 Guidelines for the Assesment of Livestock Feed Derived From Plants with Novel Traits. We have considered :

  • potential impact on livestock and
  • potential impact on livestock nutrition

III.  Nutritional Composition

Analyses of the nutritional composition including protein, oil, fibre and minerals was conducted on the corn hybrid DK404SR and its corresponding non-transformed control at two Canadian locations with four replicates at each site. No differences in oil content, fibre, protein or mineral composition between the novel corn hybrid and the corresponding control were detected. There was a significant effect of location on some nutrients, but no interaction of location and variety. Overall, the nutritional composition of the hybrid line was shown to be substantially equivalent to conventional corn varieties. All values were within the normal observed range for these nutrients in corn. CFIA has determined that hybrid D404SR is substantially equivalent to traditional corn varieties.

IV.  Anti-Nutritional Factors

The parent Zea mays is not known for the production of anti-nutritional factors and the transformation event which produced line D404SR would not be expected to induce their synthesis.

V.  Regulatory Decision

Based on the review of submitted data and information, the Feed Section of the Plant Products Division has concluded that the novel trait does not in itself raise any concerns regarding the safety or nutritional composition of hybrid D404SR. Corn, corn oil, and meal are currently listed in Schedule IV of the Feeds Regulations and are, therefore, approved for use in livestock feeds in Canada. As hybrid corn D404SR has been assessed and found to be substantially equivalent to traditional corn varieties, D404SR and its byproducts are considered to meet present ingredient definitions and are approved for use as livestock feed ingredients in Canada.

Feed use of the corn hybrid DK404SR and its byproducts is therefore authorized. Any other Zea mays lines and intra-specific hybrids derived from the original somaclonal variant may be considered substantially equivalent, provided no inter-specific crosses are performed, provided the intended use is similar and provided it is known that these plants do not display any additional novel traits.

This bulletin is published by the Plant Products Division, Canadian Food Inspection Agency. For further information, please contact the Feed Section at:

Plant Products Division
Food Production and Inspection Branch
59 Camelot Drive, Nepean
Ontario, K1A 0Y9
Tel:  613-225-2342
Fax: 613-992-5219

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