Removal of Mercury(Hg(Ⅱ)) from Seaweed Extracts by Electrodialysis and Process Optimization Using Response Surface Methodology

In this work,response surface methodology(RSM)was employed to model and optimize electrodialysis process for mercury(Hg(II))removal from seaweed extracts.Box-Behnken design(BBD)was utilized to evaluate the effects and the interaction of influential variables such as operating voltage,influent flow rate,initial concentration of Hg(II)on the removal rate of Hg(II).The developed regression model for removal rate response was validated by analysis of variance,and presented a good agreement of the experimental data with the quadratic equation with high value coefficient of determination value(R2=0.9913,RAdj 2=0.9678).The optimum operating parameters were determined as 7.17V operating voltage,72.54L h−1 influent flow rate and 5.04mgL−1 initial concentration of mercury.Hg(II)removal rate of 76.45%was acquired under the optimum conditions,which showed good agreement with model-predicted(75.81%)result.The results revealed that electrodialysis can be considered as a promising strategy for removal of Hg(II)from seaweed extracts.

Potential of a fucoidan-rich Ascophyllum nodosum extract to reduce Salmonella shedding and improve gastrointestinal health in weaned pigs naturally infected with Salmonella

Background:Dietary supplementation with a fucoidan-rich Ascophyllum nodosum extract(ANE),possessing an in vitro anti-Salmonella Typhimurium activity could be a promising on-farm strategy to control Salmonella infection in pigs.The objectives of this study were to:1)evaluate the anti-S.Typhimurium activity of ANE(containing 46.6%fucoidan,18.6%laminarin,10.7%mannitol,4.6%alginate)in vitro,and;2)compare the effects of dietary supplementation with ANE and Zinc oxide(ZnO)on growth performance,Salmonella shedding and selected gut parameters in naturally infected pigs.This was established post-weaning(newly weaned pig experiment)and following regrouping of post-weaned pigs and experimental re-infection with S.Typhimurium(challenge experiment).Results:In the in vitro assay,increasing ANE concentrations led to a linear reduction in S.Typhimurium counts(P<0.05).In the newly weaned pig experiment(12 replicates/treatment),high ANE supplementation increased gain to feed ratio,similar to ZnO supplementation,and reduced faecal Salmonella counts on d 21 compared to the low ANE and control groups(P<0.05).The challenge experiment included thirty-six pigs from the previous experiment that remained on their original dietary treatments(control and high ANE groups with the latter being renamed to ANE group)apart from the ZnO group which transitioned onto a control diet on d 21(ZnO-residual group).These dietary treatments had no effect on performance,faecal scores,Salmonella shedding or colonic and caecal Salmonella counts(P>0.05).ANE supplementation decreased the Enterobacteriaceae counts compared to the control.Enterobacteriaceae counts were also reduced in the ZnO-residual group compared to the control(P<0.05).ANE supplementation decreased the expression of interleukin 22 and transforming growth factor beta 1 in the ileum compared to the control(P<0.05).Conclusions:ANE supplementation was associated with some beneficial changes in the composition of the colonic microbiota,Salmonella shedding,and the expression of inflammatory genes associated with persistent Salmonella infection.