Equal part mix of mVHH-IgA V2A and V3A in the final feed formulations either secreted from Pichia (Pichia mVHH-IgA feed), or produced in soybean (soybean mVHH-IgA feed) or Arabidopsis (Arabidopsis mVHH-IgA feed) were analyzed as compared to negative control feed without mVHH-IgA. (a) Immunoblot of 10% (w/v) feed suspension extracts which were pre-treated with Endo H. The volume of feed extract loaded corresponds to 1.2 mg of each feed formulation. The densitometric analysis on the ~ 37 kDa band, using the purified Endo H treated Pichia-secreted V2A dilution series as reference standards, corresponded to be 0.0011% for Pichia feed (3.3 mg in 300 gram daily feed), 0.0025% for soybean feed (7.5 mg in 300 gram daily feed) and 0.0013% for Arabidopsis feed (3.9 mg in 300 gram daily feed). (b, c) ELISA titration curves of the 10% (w/v) suspensions of all the experimental feed formulations containing mVHH-IgA (b) without Endo H pre-treatment and (c) with Endo H pre-treatment. In the latter case, the yeast N-glycan mediated inhibition of mVHH-IgA detectability in ELISA is eliminated, resulting in the curves and the endpoint titers as very similar. These analysis were repeated at least twice with similar results.