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Copper (Cu) is widely used in the swine industry to improve the growth performance of pigs. However, high doses of copper will induce cell damage and toxicity. The aim of this study was to evaluate toxicity, bioavailability, and effects on metabolic processes of varying copper sources using porcine intestinal epithelial cells (IPEC-J2) as a model. The IPEC-J2 were treated with two doses (30 and 120 &mu, M) of CuSO4, Cu Glycine (Cu-Gly), and Cu proteinate (Cu-Pro) for 10 h, respectively. Cell damage and cellular copper metabolism were measured by the changes in cell viability, copper uptake, oxidative stress biomarkers, and gene/protein expression levels. The results showed that cell viability and ratio of reduced and oxidized glutathione (GSH/GSSG) decreased significantly in all treatment groups, intracellular copper content increased significantly in all treatment groups, total superoxide dismutase (SOD) activity increased significantly in the 120 &mu, M exposed groups, SOD1 protein expression levels were significantly upregulated in 30 &mu, M Cu-Pro, 120 &mu, M Cu-Gly, and 120 &mu, M Cu-Pro treatment groups, intracellular reactive oxygen species (ROS) generation and malondialdehyde (MDA) content increased significantly in 30 &mu, M treatment groups and 120 &mu, M CuSO4 treatment group. CTR1 and ATP7A gene expression were significantly downregulated in the 120 &mu, M exposed groups. While upregulation of ATOX1 expression was observed in the presence of 120 &mu, M Cu-Gly and Cu-Pro. ASCT2 gene expression was significantly upregulated after 120 &mu, M Cu-Glycine and CuSO4 exposure, and PepT1 gene expression was significantly upregulated after Cu-Pro exposure. In addition, CTR1 protein expression level decreased after 120 &mu, M CuSO4 and Cu-Gly exposure. PepT1 protein expression level was only upregulated after 120 &mu, M Cu-Pro exposure. These findings indicated that extra copper supplementation can induce intestinal epithelial cell injury, and different forms of copper may have differing effects on cell metabolism.

Lectin is one of the major anti-nutritional factors in soybeans and inhibits digestion of dietary protein. Here, an absolute quantification method was developed to detect lectin using synthetic peptide 183TTSWDLANNK192 as reference standard and corresponding isotope labeled peptide TTSWDLANNK (Alanine-13C3,15N) as internal standard to normalize results. After the ground soybeans and soy products were defatted with n-hexane and extracted with extraction buffer, the crude protein extract was digested on filter membrane by trypsin. Further, the enzymatic hydrolysis peptides were quantified using liquid chromatography-tandem mass spectrometry. The synthetic reference peptide showed a detection limit of 0.27 ng/mL and a linear relationship in the range of 3.2–1000 ng/mL (r2 > 0.997). Correspondingly, the detect limit of lectin in soybean samples was 35.5 μg/g. The results showed that the recoveries of the lectin in spiked samples ranged from 80.9% to 108.7% with intra-day precisions (% CV) less than 9%. The method was successfully used to evaluate lectin levels in hundreds of soybean seeds from different varieties and soy products from different soybean processing techniques. Furthermore, the method may provide a potential application as a general method for the ultrasensitive detection of various protein anti-nutritional factors in food.

Background:Soy isoflavones, such as genistein and daidzein, are bioflavonoids found in soy products that are able to interact with various hormones such as estrogen. Epidemiological studies reveal a proper level of isoflavones in diet can prevent many diseases like cancers or diabetes. Therefore, it is important to study the biotransformation and xenobiotic metabolism of soy isoflavones.Methods:A systematic review of published studies was carried out to investigate the characterization of isoflavones and their metabolites, sample pretreatment and quantitative analysis of isoflavones, and the influence of soy isoflavones on drug and xenobiotic metabolism.Results:Aglycones with weak estrogen-like activities are the biologically active forms of the soy isoflavones in mammals. The most recent advances including extraction, purification and detection of isoflavones in soybean and soy products are discussed. The effects of soy isoflavones on drug and xenobiotic metabolism involve in regulation of phase I cytochrome P450 (CYPs) enzyme and phase I detoxifying enzymes expression and activity. At the molecular level, soy isoflavones have proved capable of estrogenic/antiestrogenic with tissue-selective, anti-cancer, antiobesity, anti-oxidation, and tyrosine kinase inhibition activities.Conclusion:This review summarized different aspects of soy isoflavones and their molecular mechanisms of pharmacological action on xenobiotic, which demonstrated that soy isoflavones can decrease the incidence of many diseases and benefit for human health. However, since the lack of clinical research for evaluation of the proper dosage of intake of soy isoflavones in diet or adjunctive therapy, there is a need for further studies on the selection of doses, biomedical applications and adverse effects of isoflavones for human health.