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OMNIGEN-AF® SUPPLEMENTATION INCLUSION RATE INDEPENDENTLY PROMOTES IMMUNE FUNCTION IN A RAT MODEL
Feeding OmniGen-AF® (OG; Prince Agri Products, Inc., Quincy, IL), a branded proprietary product, supports immune function in many domestic animals. Targeted profiling of immune-associated genes in whole blood is an established methodology to evaluate the efficacy of feed additives with immune-altering properties. We hypothesized that higher daily inclusion rate of OG than 0.5% may be required to optimize immune function. The objective of this study was to evaluate the effect of dietary OG inclusion rate (0.5% vs. 1.0%) on the expression profile of immune-associated genes. Male CD rats (5/treatment) weighing 180-200 grams had ad libitum access to a diet with 0 (control), 0.5 (1×), or 1% (2×) of OmniGen-AF® for 28 days. At the end of the feeding period, whole blood was collected. RNA was purified from whole blood samples and used to generate cDNA that acted as template in the Rat Innate and Adaptive Immune Responses RT2 Profiler PCR array (SABiosciences). Using PROC GLM, we compared cDNA abundance of immune-associated genes between control and supplemented groups (0.5 or 1%) with a P < 0.05 cut-off value for significance. Of the 79 immune-associated genes that were expressed above the detection limit in all samples, 16 (7 up-regulated) and 13 genes (8 up-regulated) were altered by 0.5% and 1% OG supplementation, most of which (11 with 6 up-regulated) were altered at both OG inclusion rates. Genes that were up-regulated at both rates include IL13 (0.5%: +3.16, 1%: +3.70 fold-change), IL5 (0.5%: +2.64, 1%: +2.62), Irak1 (0.5%: +2.50, 1%: +1.98), Nod2 (0.5%: +1.83, 1%: +2.02), IFNa1 (0.5%: +1.81, 1%: +2.10), and Cd80 (0.5%: +1.77, 1%: +2.47). Genes that were down-regulated at both inclusion rates include TLR3 (0.5%: -2.22, 1%: -2.39), CxCL10 (0.5%: -2.19, 1%: -2.26), STAT1 (0.5%: -2.07, 1%: -1.99), STAT3 (0.5%: -2.05, 1%: -1.92), and NFκb1 (0.5%: -1.84, 1%: -1.75). In conclusion, our results suggest that OG supplementation promotes immune function through various pathways including pathogen recognition, adaptive immune cell activation, and various transcription factors, independent of dietary inclusion rate.
Keywords:
Gene Profiling, Immunity, OmniGen-AF