Studies On Effectiveness Of Nano-silicate (PBAA) In Eliminating Feed Lead And Its Mechanism In Pigs

PBAA were used to study the effects of eliminating feed lead and its mechanism of applied effects in pigs in vitro and the effect of adsorbing of lead using Caco-2 cell model in vivo.In vitro trial, to determine the effects of PBAA and Pb on toxicity of Caco-2 cell in different times, PBAA and Pb were set as 0.02%, 0.1%, 0.5% and 5mg/L, 10 mg/L, 20mg/L, 40mg/L, 80mg/L concentration grads in cell culture, each concentration included three replicates, respectively. To detect the effect of PBAA and Pb on gene expression of DMT1, three groups of 0mg/L, 5mg/L Pb, 5mg/L Pb+0.5%PBAA in cell culture were set and each had three replicates. In animals trial, 96 growing pigs (Duroc × Landrac × Yorkshine) which weighed about 33kg were selected and allotted to four groups by weight and sex, each of which included 3 replicates of eight pigs. The group received the same basal diet, supplemented with 0, 0.5%PBAA, 10.0mg/kg lead and 10.0mg/kg lead+0.5%PBAA. All pigs were given adequate diets and free access to water. On finishing the feeding experiment, 12 pigs were picked out by similar body weight from each group respectively to be slaughtered at the local abattoir and the samples were collected for laboratory analysis. The main results are as follows.The results of cell culture trial showed different concentration PBAA have no difference on cell proliferation rate in different time (p>0.05). 40 and 80mg/L lead significantly reduced cell proliferation rate and damage the cellular morphology in time-dose dependent manner. When simultaneously supplementation of lead and PBAA, cell proliferation rate and cellular morphology of Caco-2 cell hold normal. In addition, lead evidently decreased DMT1 mRNA abundance in intestinal epithelia, while simultaneously supplemented lead and PBAA to cell culture, DMT1 mRNA abundance in intestinal epithelia had no effect compared to control group (p>0.05), increased by 81.82% (p<0.01) compared with the group of adding lead.The results of feeding trial indicated that ADG, ADFI in 10mg/kg Pb exposed group decreased by 11.10% (P<0.05), 3.13% (p<0.05), F/G increased by 9.06% (p<0.05) compared to control. ADG, ADFI in 10mg/kg Pb+0.5%PBAA adding groupincreased by 10.60% (p<0.05), 2.30% (p<0.05). F/G reduced by 7.42% (p<0.05) compared to 1 Omg/kg Pb adding group.The effects of PBAN on the accumulation of lead in organs showed that the accumulation of lead in muscle, liver, kidney of supplemented with 0.5% PBAN only were lower than the standards of European Union on foods, respectively. The Pb contents in blood, heart, spleen, pancreas, lung, brain, bone and hair decreased by 59J2%(p0.05). In addition, Pb exposure significantly elevated SUN, GOT, GPT levels in serum (p<0.05), decreased serum Ca, P, -SH and ALK levels (p<0.05). After supplemented PBAA to diet, above those indexes in serum were improved (p<0.05).The determination of trace element in tissues indicated that pigs fed the diet adding lOmk/kg Pb only had lower iron, Ca, Zn, Cu concentrations in liver, kidney, long bone than those of control (p<0.05), which were improved significantly by PBAA supplemented to the diet (p<0.05).From transmission electron micrographs of liver, it was showed that lead damaged the structure and morphology of liver cell, which were improved significantly by PBAA supplemented to the diet.The overall results suggest that PBAA as a heavy metals Pb adsorbent in animal's diets imply a potential protective role against lead toxicities. It can adsorb effectively Pb in animal's feed, interdict lead accumulation in animal's body, significantly reduced the residues in organs and tissues, safeguard the safety of animal products. At the same time, PBAA can evidently improve growth performance.