Soybean plants containing the event DP-3Ø5423-1 were generated by introducing the gm-fad2-1 gene fragment and the gm-hra gene. The endogenous fatty acid desaturase-2 enzyme (FAD2-1) is highly expressed in the developing soybean seed especially during the period of oil deposition and is responsible for the conversion of oleic acid to linoleic acid. Transcription of the gm-fad2-1 gene fragment suppresses endogenous FAD2-1 resulting in higher levels of oleic acid and reduced levels of linoleic acid, linolenic acid, and to a lesser extent palmitic acid in the seed. The aim of this study was to evaluate the nutrient composition of high-oleic transgenic full-fat soybean meal (FFSBM; DP-3Ø5423-1) and near isoline non-transgenic control FFSBM, and also assess their feeding effects on mRNA abundance of immune response and fatty acid metabolism markers in broilers. Prior to trial initiation, proximate, fatty acid and amino acid analyses of these FFSBMs were determined and no differences were observed except for fatty acid composition. As expected, transgenic FFSBM contained a substantially higher proportion of oleic acid (C18:1; 76.37%) and lower proportion of linoleic and linolenic acids (18:2; 6.44%, C18:3; 2.03%) compared to the control FFSBM (C18:1; 18.17%, C18:2; 52.25%, C18:3: 10.58%). A total of 480 day-of-hatch chicks (Ross 308) were randomly allocated to 24 floor pens in a 2×2 factorial arrangement that included diet and gender (6 pens/group). Birds were fed isocaloric and isonitrogenous diets containing 20% of either DP-3Ø5423-1 or control FFSBM for 35 days. On d 35, two birds from each replicate were selected based on average pen BW. Spleen and liver tissue samples were excised to assess the mRNA abundance of immune response and fatty acid metabolism related genes, respectively. Data were subjected to a 2-way ANOVA using the GLM procedure of JMP (Pro13). There was no main effect of diet or gender on mRNA abundance of IL-1β, IL-2, IL-6, IL-12b, IFNγ, TNF-α, and NF-κB. Liver malic enzyme 1 (ME1) mRNA level was significantly lower in birds fed transgenic FFSBM diets. However, dietary treatment had no significant impact on ACCα, FAS, MTTP, SREBF, PPARα, PPARγ, and AMPK mRNA levels in the liver.
In conclusion, our results showed that genetically modified DP-3Ø5423-1 soybean is nutritionally equivalent to non-transgenic near-isoline counterpart with a comparable genetic background as evidenced by feed analyses except for fatty acid composition. Furthermore, transgenic FFSBM has no adverse effect on mRNA abundance of cytokines, transcription factors, and liver fatty acid metabolism markers.