| This study was conducted to investigate the effectiveness of nanometer silicate additive (CDAA) to adsorb dietary cadmium of growing pigs (Duroc X Landrace X Yorkshine) on the basis of better adsorptive capacity of CDAA in vitro, and approach the protection of CDAA against adverse effects of cadmium on growth performance, apparent digestibility of nutrients, cadmium residues in tissues, endocrine function, immune index and meat color.One hundred and ninety two crossbred barrows with an average initial body weight of 27.6 ?.44 kg were randomly allotted to two supplementation of cadmium (0 and 10.0 mg/kg; control and T2) (as CdCl2) and two levels of CDAA (0 and 0.5%; T1 and T3) in a 2x2 factorial arrangement of treatments. Each group was fed corn-soybean basal diets and consisted of three pens (replications) of sixteen pigs(sex balanced). The feeding experiment lasted for eight-three days after seven days of adaptation period. At the beginning of the adaptation period, a blood sample was drawn from the anterior vena cava of two pigs from each pen(sex balanced). The blood sample from a same pig in each pen was taken every sixteen days. Ten days before ending of the feeding trial, digestion experiment was conducted by the method of total fecal collection. The 24 pigs(sex balanced) were kept in individual pens and given their respective experimental diets. At the end of the feeding trial, four pigs from each pen were randomly selected based on similar body weight and slaughtered. Blood and organ samples were collected and determined for cadmium residues, meat color, iron, copper and zinc retention in tissues, immune index, serum hormone, antioxidation capacity and biochemical index in serum and urine. The main results as follows:The determination of cadmium residues in tissues showed that muscle, liver and renal cortex of control were 0.076, 0.87, 1.49 mg/kg, respectively, and beyond the standards of European Union on foods. When 0.5% CDAA was added to basal diet, cadmium retentions in these organs were 0.02,0.34,0.62mg/kg, respectively, and reach the international standards(EU standards) which permit cadmium residues in muscle, liverand kidney were 0.05,05,1.0mg/kg, respectively. Cadmium retentions in these organs of T1 decreased by 73.7% (p<0.05), 60.9% (p<0.05), 61.0% (p<0.05), respectively, compared to control. The corresponding contents in T3 decreased by 69.9% (p<0.05), 75.9% (p<0.05), 76.4% (p<0.05), respectively. Cadmium retentions in renal medulla, immune organs, brain, ovary, and other organs were lower than control, respectively (p<0.05), and cadmium residues in these organs of T3 were lower than those in T2, respectively (p<0.05).The results of determination of cadmium concentrations in gastrointestinal contents showed that cadmium retentions in jejunum, ileum, cecum, forepart colon, distal colon and feces of T1 and T3 increased significantly compared with control and T2, respectively(p<0.05).The results of feeding trial showed that ADG in T2 decreased by 18.6% compared to control (p<0.05), and that in T3 improved by 14.6% compared with T2 (p<0.05). F/G in T2 increased by 17.8% compared to control (p<0.05) and that in T3 decreased by 13.2% compared with T2 (p<0.05). There was no difference on ADG and F/G between Tl and control (p>0.05).The apparent digestibility of nutrients showed that the digestibility of dry matter and crude protein decreased by 12.5% (p<0.05), 12.2% (p<0.05), respectively, compared to control. Those in T3 improved by 11.2% (p<0.05), 10.6% (p<0.05) respectively compared with T2. There was no difference in the apparent digestibility among pigs of other treatments. There were no effects of CDAA and cadmium on digestibility of EE, Ca, P (p>0.05).The analysis of iron, copper and zinc retentions in tissues showed that, tissue iron contents of T2 were significantly lower than that of the control(p<0.05), and these in T3 were significantly higher than that of T2(p<0.05). There was no effect of CDAA added to basal diet on iron retention(p>0.05). Pigs that received the diet contai...
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