Data Evaluation Record - The study was conducted to compare the performance of male broiler chickens fed transgenic Bt Cry9C insecticidal, glufosinate resistant corn (CBH351) with a standard commercially available corn hybrid MRID: 44734306

Date: 11/10/99

Reviewer: Zig Vaituzis, Senior Scientist,
Microbial Pesticides Branch Biopesticides and Pollution Prevention Division (7511C)

Secondary Review by: Mike Mendelsohn Microbiologist,
Microbial Pesticides Branch, Biopesticides and Pollution Prevention Division (7511C)

STUDY TYPE: The study was conducted to compare the performance of male broiler chickens fed transgenic Bt Cry9C insecticidal, glufosinate resistant corn (CBH351) with a standard commercially available corn hybrid.

EPA GUIDELINES NUMBER: Not applicable. This is not a required study.

CITATION: Leeson, S. (1998) The effect of corn hybrid CBH351 on the growth of male broiler chickens. Department of Animal and poultry Science, Arkell Research Farms, University of Guelph, Guelph, Ontario, N1G 2W1 Canada. Lab project Id Number C-2-98. April 20,1998.

MRID: 44734306

DP BARCODE: D252310

CASE: 290730

PETITION #: 9F05050

CHEMICAL/BIOL#: 006466 Bacillus thuringiensis subsp. tolworthi Cry9C protein

COMPANY/SPONSOR: (Submitter) AgrEvo USA Company, Little Falls Centre One, 2711 Centerville Rd.,Wilmington, De 199808.

TEST MATERIAL: Bacillus thuringiensis subsp. tolworthi Cry9C insecticidal, glufosinate resistant corn (event CBH351)

REVIEW CONCLUSION: This is not a required study and the results are inconclusive. Small differences were seen with the CBH351 test groups as compared to the the non-CBH351 test groups. Increased feed intake during the starter period, an increase in bird weight, and greater breast meat yield were observed. However, it is not possible to make an independent assessment of the significance of the data without an analysis of the bird feed for the presence of Cry9C protein.

RECOMMENDATIONS: None. This is not a required study and the results are inconclusive.

MATERIALS & METHODS:

Test birds

Three hundred and sixty commercial strain Ross x Ross male broiler chickens obtained at (one) day of age were weighed and randomly distributed to 2 treatment groups, replicated 6 times, with 30 birds per replicate. The replicates were randomized over 12 floor pens each measuring 1.8 x 2.4 m. and cared for according to the guidelines of the Canadian Council on Animal Care. The birds were reared on 1 of 2 diets (Bt- and Bt+ corn respectively, supplied by AgrEvo). The birds were fed starter diets to day 17 (57% corn as determined from raw data) , grower diets to day 31 (61% corn as determined from raw data) and finisher diets to day 42 (66% corn as determined from raw data).

Test conditions:

The birds were maintained at a brooding temperature of 32^oC for 5 days, with the temperature being gradually reduced to 22^o C by day 33. The report states that constant lighting was used throughout the study, however, the supplied raw data show light periods diminishing from 23 hrs to 12 hrs at day 6, back to 18 hrs at day 14, then to 23 hrs at day 20 to end of study (day 42). Relative humidity was not reported.

Sampling:

Feed intake and body weights were recorded at 17, 31 and 42 days. Mortality was recorded as it occurred.

Observations:

The study was conducted from January 20, 1998 thru March 3, 1999. At day 42, eight randomly selected birds from each pen were sacrificed and the abdominal fat pad and the right and left breast meat were removed and weighed. No comments on the condition or appearance of the birds are given.

STATISTICAL METHODS

The data were considered by the T-test appropriate to 2 levels of treatment. Significance was accepted at P <0.05.

REPORTED RESULTS

The 31 and 42 day (and 0-42 day) body weights of the birds fed Bt Cry9C, glufosinate resistant corn diets are significantly greater than the birds fed the control corn diet, and the body weight gain measured between days 17 and 31 is also significantly greater for the test birds. The actual difference in body weights was less than 3%. Feed intake for the Bt corn was significantly higher during the starter period (0-17 day). The reported mortality was 3.89% in the control group and 6.11% in the Bt corn group (not significantly different). Post mortem examination revealed a greater breast meat yield (<5%) for Bt fed birds. The feed intake/body weight ratios and percent mortality were unaffected by the source of corn in the diets. Carcass weight and abdominal fat pad and breast meat yield as a percent of carcass weight were also unaffected by the source of corn in the diet.

STUDY AUTHOR'S CONCLUSIONS

Bt Cry9C, glufosinate resistant corn (CBH351) diets are comparable in feeding value to the non-Bt corn hybrid. Actual body weight and breast meat yield was significantly different (<5% for all characteristics evaluated). Therefore in nutritive value CBH351 corn is at least equivalent to the commercial hybrid and did not adversely effect the feeding and growth of the male broiler population used in this study.

QUALITY ASSURANCE MEASURES

No Quality Assurance statement is included with the study report.

DISCUSSION

This was not a required study. In general the testing was conducted by acceptable procedures, and shows no significant mortality or acute effects from the consumption of Cry9C containing corn. However, analytical measurements were not performed as part of this study to verify the homogeneity, stability or concentrations of the test substance in the test bird diet. This is a substantial deficiency, since small, but significant, differences were seen between the two test groups. Without the analysis of the bird diet it is not possible to make an independent assessment that the noted effects are due to CBH351 corn on the test birds.

The submitted data do show an effect on the feed intake during the starter period, a delayed effect on bird weight and a greater breast meat yield. A verification of the presence of Cry9C in the test diet is essential to determine which treatment group data are a result of Bt in corn.

It is necessary to have the diet analysis data to assess the significance of the reported results.

ADEQUACY OF STUDY

Validation category: Not useful for avian diet effects assessment.
Rationale: The submitter does not claim GLP compliance, no Quality Assurance statement is included with the study report, and the report lacks analysis for the presence of Cry9C in the test diet.

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