161 Dietary oxidized protein result in growth and histology differences in pigs

Rendered by-products are common feedstuffs in diets. During processing, these sources have potential to become oxidized. While most research on oxidative stress has focused on dietary oxidized lipids, little research has been done in dietary oxidized proteins and the potential to induce oxidative stress. Recent studies have shown consumption of dietary oxidized proteins resulted in shifts in oxidative status. The objective of this study was to determine the effects of dietary oxidized protein on oxidative stress in pigs as a model for canines. Fifty-six, 3 weeks old pigs (5.55 ± 0.71 Kg) were fed 4 dietary treatments each varying in dietary oxidized protein. Each treatment was fed the same diet, with the exception of the degree of oxidation in chicken by-product meal which was included in the diet at 23 percent to represent typical inclusion levels of a companion animal diet. Oxidation was induced by 2 levels of heating and 2 levels of antioxidants (mixed tocopherol), in a 2 x 2 factorial design. A significant antioxidant effect was observed in villi height (P-value < 0.05) where pigs fed diets without antioxidant had increased villi height (674 μm) compared to those fed diets with antioxidants (576 μm). Additionally, pigs fed diets without antioxidant had significantly greater villi:crypt (3.22) compared to those fed diets with antioxidants (2.84 ; P-value < 0.05). Additionally, feed efficiency measured by gain:feed, was significantly decreased in pigs fed heated protein (0.65) compared to not heated (0.69; P-value < 0.05). Results from this study are consistent with previous studies (Dibner, et al., 1996). Future studies should examine the effects of feeding oxidized proteins in regard to oxidative status, such as markers of protein, lipid, DNA, and antioxidative enzyme damage. In conclusion, dietary oxidized protein can reduce feed efficiency in pigs.

Spiroplasma eriocheiris Enters Drosophila Schneider 2 Cells and Relies on Clathrin-Mediated Endocytosis and Macropinocytosis

ABSTRACT Spiroplasma eriocheiris causes great economic losses in the crustacean aquaculture industry. However, the mechanism of S. eriocheiris infecting host cells has been poorly studied. We established a Spiroplasma-infected Drosophila Schneider 2 (S2) cell model and investigated its pathogenic mechanism. First, S. eriocheiris induced S2 cell apoptosis and necrosis, seriously decreased cell viability, and increased the production of intracellular reactive oxygen species. Further research showed that S. eriocheiris can invade S2 cells, and the number of copies of intracellular spiroplasmas is sharply increased by 12 h postinfection. In addition, S. eriocheiris can cause S2 cells to form typical inclusion bodies and exhibit large vacuoles. Second, S. eriocheiris is internalized into S2 cells and strongly inhibited through blocking clathrin-mediated endocytosis using chlorpromazine and dynasore. Inhibitors of macropinocytosis, protein kinase C and myosin II, cause a significant reduction in S. eriocheiris in S2 cells. In contrast, disruption of cellular cholesterol by methyl-β-cyclodextrin and nystatin has no effect on S. eriocheiris infection. These results suggest that the entry of S. eriocheiris into S2 cells relies on clathrin-dependent endocytosis and macropinocytosis, but not via the caveola-mediated endocytic pathway. In addition, the intracellular numbers of S. eriocheiris are dramatically reduced after S2 cells are treated with cytoskeleton-depolymerizing agents, including nocodazole and cytochalasin B. Thus, cellular infection by S. eriocheiris is related to microtubules and actin filaments. This research successfully shows for the first time that S. eriocheiris can invade Drosophila S2 cells and provides a process for S. eriocheiris infection.

Canine distemper virus infection with secondary Bordetella bronchiseptica pneumonia in dogs

Canine distemper virus infection and secondary Bordetella bronchiseptica pneumonia are described in mongrel dogs. Canine distemper was characterised by nonsuppurative demyelinating encephalitis with typical inclusion bodies in astrocytes. B. bronchiseptica was isolated from areas of purulent bronchopneumonia.

DEMONSTRATION OF THE SEQUENTIAL DEVELOPMENT OF VACCINIAL ANTIGENS AND VIRUS IN INFECTED CELLS: OBSERVATIONS WITH CYTOCHEMICAL AND DIFFERENTIAL FLUORESCENT PROCEDURES

Virus-induced alterations in vaccinia virus-infected HeLa cells have been followed by immunofluorescent and cytochemical techniques. In a time sequence study, infected cells show an early increase in cytoplasmic RNA content, followed by appearance of centers of viral DNA synthesis in the cytoplasm. The centers of synthesis were detected at 4 hours post infection, with the acridine orange fluorochrome stain as compared to 6 hours with Feulgen and methyl green-pyronin stains. Marginal fragmentation of the inclusion bodies was seen at 8 to 10 hours post infection, and appears to coincide with the first increase in cell-associated virus. With the immunofluorescent technique, it was found that the LS antigen of the virus can be detected at about 4 hours post infection. This is followed at 5 to 6 hours post infection by the appearance of the NP antigen. Both antigens are found only in the cytoplasm, and precede the appearance of the infective particle. The HA antigen, a by-product of virus-cell interaction, is not seen until about 10 hours post infection; that is, several hours after the appearance of both the LS and NP antigens, and only after the appearance of mature virus. The successful application of the use of two immune sera, each labeled with a different fluorescent dye for the simultaneous visualization of two antigens within a cell, is reported. Using this technique, the sites of LS and NP antigen synthesis, were easily differentiated. The intimate mixing of the two antigens at a later stage appears to coincide with the fragmentation of the inclusion body and the first detectable increase in cell-associated virus. The evidence obtained strongly suggests that the typical inclusion body observed in vaccinia-infected cells is composed mainly of the NP antigen.

INTRACELLULAR FORMS OF POX VIRUSES AS SHOWN BY THE ELECTRON MICROSCOPE (VACCINIA, ECTROMELIA, MOLLUSCUM CONTAGIOSUM)

The intracellular development of three pox viruses has been studied with the electron microscope using thin sections of infected tissue. Cells infected with vaccinia, ectromelia, and molluscum contagiosum viruses all form developmental bodies preliminary to the production of mature virus. Developmental bodies, believed to be virus precursors, are round to oval, slightly larger than mature virus particles, less dense to electrons, and have a more varied morphology. It is suggested as a working hypothesis that the process of maturation of a virus particle takes place as follows. In the earliest form the developmental bodies appear as hollow spheres, imbedded in a very dense cytoplasmic mass constituting an inclusion body, or in a less dense matrix near the nucleus in cells without typical inclusion bodies. The spheres become filled with a homogeneous material of low electron density. A small, dense granule appears in each developmental body and grows in size at the expense of the low density material. Following growth of the granule, particles are found with the dimensions of mature virus and having complex internal structure resembling bars or dumbells. Mature virus is ovoid and very dense to electrons. An "empty" interior may be found within its thick walls.