Genetically modified corn has been approved as an animal feed in several countries, but information about the fate of genetically modified DNA and protein in vivo is insufficient. Genetically modified corn Bt11 is developed by inserting a recombinant DNA sequence encoding insecticidal Cry1Ab protein from Bacillus thuringiensis subsp. kurstaki. We examined the presence of corn intrinsic and recombinant cry1Ab gene by PCR, and the Cry1Ab protein by immunological tests in the gastrointestinal contents of five genetically modified corn Bt11-fed and five nongenetically modified corn-fed pigs. Fragments of corn zein (242 bp), invertase (226 bp) and of ribulose-1,5-bisphosphate carboxylase/ oxygenase genes (1,028 bp) were detected in the gastrointestinal contents of both Bt11 and nongenetically modified corn-fed pigs. Fragments of recombinant cry1Ab gene (110 bp and 437 bp) were detected in the gastrointestinal contents of the Bt11-fed pigs but not in the control pigs. Neither corn intrinsic nor cry1Ab gene fragments were detected in the peripheral blood by PCR. The gastrointestinal contents were positive for Cry1Ab protein by ELISA, immunochromatography, and immunoblot; however, these methods did not work for blood and precluded conclusions about any potential absorption of the protein. These results suggest that ingested corn DNA and Cry1Ab protein were not totally degraded in the gastrointestinal tract, as shown by their presence in a form detectable by PCR or immunological tests.

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The concentration of interleukin-6 (IL-6), alpha1-acid glycoprotein (alpha1-AG), and corticosterone (CORT) was investigated chronologically (0 h to 14 d) in the sera of 2-wk-old specific-pathogen-free chicks inoculated with Escherichia coli lipopolysaccharide (LPS). In the LPS group the IL-6 level was elevated from 1 h to 2 d and was the highest at 3 h. From 4 to 14 d the IL-6 level was low in the LPS group. In the PBS group, IL-6 was not detected except a mild increase from 1 h to 6 h. In the LPS group, the alpha1-AG level increased from 6 h to 4 d, and the peak was 2 d. In the PBS group the alpha1-AG level was always low. The CORT level in the LPS group was higher than that of PBS group at 1 h. This study suggests that E. coli LPS may elevate serum IL-6 and CORT, and that IL-6 and CORT may increase the alpha1-AG level in the chicks.

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ABSTRACT. Reproductive failure associated with porcine circovirus type 2 (PCV2) was observed in a farm, and a weak-born 8-day-old piglet was examined pathologically. Focal to locally extensive lesions, including infiltration of macrophages and lymphocytes, fibrosis and degeneration of the myocardium were observed in the heart. PCV2 antigens and nucleic acids were detected in degenerated cardiomyocytes and macrophages infiltrating the heart by immunohistochemical staining and in situ hybridization. Depletion of lymphocytes with occasional infiltration of multinucleated giant cells was seen in the lymphoid organs and PCV2 antigens were demonstrated in histiocytic cells. Crystalline arrays of viral particles were observed in infiltrated macrophages in the heart and, rarely, in cardiomyocytes by electron microscopy. Although myocarditis is a common finding in aborted or stillborn piglets in reproductive failure due to PCV2, it was also observed in the 8-day-old piglet with PCV2 association. KEY WORDS: myocarditis, porcine circovirus type 2, reproductive failure.J. Vet. Med. Sci. 67 (7): [735][736][737][738] 2005 Porcine circovirus type 2 (PCV2) is known as the causative agent for postweaning multisystemic wasting syndrome (PMWS), which is characterized by wasting or unthriftiness, dyspnea and jaundice [11,20]. PCV2 was also related to porcine dermatitis and nephropathy syndrome (PDNS) and reproductive failure [7,12,17,23]. Several reports suggested that nonsuppurative myocarditis is a common microscopic finding in PCV2-infected fetuses [17,19,23]. In this report, we focus on a weak-born piglet that died at 8 days old in a chain of PCV2-associated reproductive failure.The herd was a 177-sow, farrow-to-finish operation and was kept under good hygienic conditions. Reproductive failure including mummified fetuses and late-term dead fetuses occurred on the farm from June to August, 2001. The gilts had been vaccinated for Japanese encephalitis virus (JEV), porcine parvovirus (PPV) and Bordetella bronchiseptica. The herd was free from classical swine fever (CSF), Aujeszky's disease (AD) and porcine reproductive and respiratory syndrome (PRRS). PMWS and PDNS had been never found on the farm before the occurrence of reproductive failure.One gilt in the farm farrowed seven dead fetuses including autolyzed fetuses and one weak-born piglet. This piglet died at 8 days old and was necropsied for etiology. Mild to moderate enlargement of the superficial lymph nodes was observed at the necropsy. Tissue samples were fixed in 10% neutral buffered formalin, routinely paraffin-embedded and sectioned at 4 µm for hematoxylin and eosin stain, Masson trichrome stain (MT), phosphotungstic acid hematoxylin stain (PTAH), immunohistochemical staining (IHC) [9] and in situ hybridization (ISH) for PCV2. For ISH, sections were deparaffinized and pretreated by 40 µg/ml proteinase K solution at 37°C for 20 min and 0.2 M HCl at room temperature for 10 min. PCR product (primer pair; 5'-A G A A G G G T T G G G G G A T T G T A T G -3 ' a n d 5 ' -GG...

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The presence of maize intrinsic and recombinant cry1Ab genes in the gastrointestinal (GI) contents, peripheral blood mononuclear cells (PBMC), and visceral organs of calves fed genetically modified Bt11 maize was examined by PCR in a subchronic 90-day performance study. Samples were collected from six Japanese Black/Holstein calves fed Bt11 maize and from six calves fed non-Bt maize. Fragments of maize zein (Ze1), invertase, chloroplast, and cry1Ab were detected inconsistently in the rumen fluid and rectal contents 5 and 18 h after feeding. The chloroplast DNA fragments of ribulose-1,5-bisphosphate carboxylase/oxygenase and tRNA were detected inconsistently in the PBMC, the visceral organs, and the longissimus muscle, while the cry1Ab gene was never detected in PBMC or in the visceral organs. These results suggest that feed-derived maize DNA was mostly degraded in the GI tract but that fragmented DNA was detectable in the GI contents as a possible source of transfer to calf tissues. These results also suggest that the recombinant cry1Ab genes were not transferred to the PBMC and tissues of calves fed Bt11 maize.