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Feeding studies were conducted with rats and broiler chickens to assess the safety and nutrition of maize grain containing event DP-Ø23211-2 (DP23211), a newly developed trait-pyramid product for corn rootworm management. Diets containing 50% ground maize grain from DP23211, non-transgenic control, or non-transgenic reference hybrids (P0928, P0993, and P1105) were fed to Crl:CD®(SD) rats for 90 days. Ross 708 broilers were fed phase diets containing up to 67% maize grain from each source for 42 days. Body weight, gain, and feed conversion were determined for comparisons between animals fed DP23211 and control diets in each study. Additional measures included clinical and neurobehavioral evaluations, ophthalmology, clinical pathology, organ weights, and gross and microscopic pathology for rats, and carcass parts and select organ yields for broilers. Reference groups were included to determine if any observed significant differences between DP23211 and control groups were likely due to natural variation. No diet-related effects on mortality or evaluation measures were observed between animal fed diets produced with DP23211 maize grain and animal fed diets produced with control maize grain. These studies show that maize grain containing event DP-Ø23211-2 is as safe and nutritious as non-transgenic maize grains when fed in nutritionally adequate diets. The results are consistent with previously published studies, providing further demonstration of the absence of hazards from edible-fraction consumption of genetically modified plants.

Saccharomyces cerevisiae genetically engineered to enhance butanol production will be used in a manufacturing process similar to that of fuel ethanol production, including co-production of distillers products for animal feed. A poultry feeding trial was conducted with simulated isobutanol-derived dried distillers grains with solubles (bDDGS), comprising non-fermentable corn solids and heat-inactivated Butamax modified yeast (BMY), to determine potential health effects. Simulated dried distillers grains were produced in 2 variants: bDDGS containing 10% (B10) or 50% (B50) BMY. The BMY concentrations were selected based on a conservative estimate from ethanol-derived distillers grains (eDDGS) approximating 2.5 and 12-fold margins of exposure. The B10 and B50 DDGS were evaluated in a 42-day feeding trial using male Ross 708 broiler chickens fed diets containing eDDGS, B50 DDGS, or B10 DDGS without or with isobutanol, 2,3-butanediol, and isobutyric acid metabolites each at target concentrations of 2 (B10-2), 5 (B10-5), or 10 (B10-10) times the anticipated specification limit in the commercial product. Diets were fed (n = 50 broilers/treatment) in 3 phases: starter phase with 8% DDGS and grower and finisher phases each with 15% DDGS. No statistically significant differences or diet-related effects on mortality, clinical pathology, or organ weights, and no microscopic observations associated with consumption of diets containing B10, B50, or B10 supplemented with metabolites at any targeted exposure level were observed. A lower (P < 0.05) mean absolute bursa of Fabricius weight in the B10-10 group compared to the B10 group was considered to be within the range of biological variability. A non-significant trend toward lower weight, gains, and feed intake, and higher feed:gain ratio was observed in the B10-10 group, and was considered a non-adverse palatability effect of consuming high concentrations of metabolites. These results demonstrate that consumption of phase diets containing simulated DDGS from a novel isobutanol production process was well-tolerated.

Two broiler chick experiments were conducted to evaluate four basal diets for iron bioassay suitability. The test basal diets, identified according to their principal ingredients and iron content, were: (1) starch-skim milk—15 p.p.m., (2) degerminated corn-skim milk—18 p.p.m., (3) degerminated corn-fish meal-isolated soy—45 p.p.m., and (4) degerminated corn-fish meal-dehulled soy—59 p.p.m. Significant differences between an iron source with known low availability (ferric oxide) and a highly available iron source (ferrous sulfate) were not detected with the degerminated corn-fish meal-isolated soy or the degerminated corn-fish meal-dehulled soy diets. Likewise, there were no significant differences found between supplemental iron levels, 10 and 20 p.p.m. The corn-skim milk and starch-skim milk diets were both found to be satisfactory for iron bioassays. However, the sample size needed to estimate the population mean was almost twice as great for the starch-skim milk fed groups than was needed for the corn-skim milk fed groups which indicates the corn-skim milk diet obtained greater sensitivity in testing iron sources and levels. Mortality was excessively high in the starch-skim milk fed group. Ferrous sulfate was superior to ferric oxide as a source of iron.

A total of 1110 broiler cockerels were used in three experiments to determine the availability of iron and copper from various sources. A skim milk basal diet was fed in each experiment using chicks maintained in battery brooders beginning at one day of age. Four organic iron compounds (sequestered iron A 1 and ferric choline chloride 2 in Experiment 1 and sequestered iron B and C 1 in Experiment 2), ferrous sulfate and ferric oxide were the test iron compounds used in Experiments 1 and 2. Added dietary iron levels furnished by the test compounds were 10 and 20 p.p.m. (Experiment 1) and 5 and 10 p.p.m. (Experiment 2). The test copper compounds fed in Experiment 3 were added to furnish 1 and 2 p.p.m. copper using cupric sulfate, cuprous oxide and cuprous iodide. No consistent differences in hemoglobin content, hematocrit (packed cell volume), chick weight and mortality were observed between ferrous sulfate and the four organic iron compounds; however, these compounds were significantly superior to ferric oxide. Hemoglobin content, hematocrit and liver copper content were significantly increased when cupric sulfate was fed as compared to results obtained with cuprous iodide or cuprous oxide. Increased chick weight gain and decreased mortality were observed with chicks fed cupric sulfate or cuprous iodide as compared to those fed cuprous oxide. Chick availability values for ferric oxide (71 and 82%) were approximately three-quarters that of ferrous sulfate. The organic sources of iron gave high availability values (91–131%), although ferric choline chloride was not as available to the chick as the sequestered iron compounds (93–131%) as determined by regression analysis method and relative biological availability. Cuprous iodide and cuprous oxide have essentially equal availability, but the availability of these copper sources is only three-quarters that of cupric sulfate.

Four experiments were conducted using a total of 1480 broiler strain cockerels to determine the effect of particle size and source of calcium on chick weight and tibia ash. The particle sizes of the test calcium sources obtained from oyster shell and limestone were defined as 6–8, 16–20, 40–50, 100–140, and 270–Pan on a passed-retained basis using the U.S.B.S. sieve series. Non-screened samples of oyster shell, limestone and a mined marine source were also tested. No consistent differences in growth rate and percent tibia ash were observed between oyster shell and limestone when the particle size of these supplements was equal. Increased weight gains were obtained with the medium and fine particle sizes (U.S.B.S. 16–Pan) as compared to the larger sizes (U.S.B.S. 6–8). Tibia ash was significantly increased when the particle size of the calcium supplement was medium (U.S.B.S. 40–50) as compared to the ash values obtained by feeding either the smallest (U.S.B.S. 270–Pan) or largest (U.S.B.S. 6–8) particle sizes. Screen analyses of commercial limestone, oyster shell and the mined marine calcium source revealed that the commercial oyster shell was a larger sized material than either limestone or the mined marine source tested in this study. Increased tibia ash was obtained by feeding the commercial oyster shell product which verifies the need for a medium particle size (16–50) in the chick’s diet. These data indicate calcium utilization by the chick is dependent upon the particle size of the calcium supplement. It appears desirable to use a medium to fine (U.S.B.S. 16–Pan) particle size calcium supplement in chick diets when considering both chick weight and percent tibia ash.