ABSTRACT
OBJECTIVE: Cage rearing has critical implications for the laying duck industry because it is convenient for feeding and management. However, caging stress is a type of chronic stress that induces maladaptation. Environmental stress responses have been extensively studied, but no detailed information is available about the comprehensive changes in plasma metabolites at different stages of caging stress in ducks. We designed this experiment to analyze the effects of caging stress on performance parameters and oxidative stress indexes in ducks. METHODS: Liquid chromatography tandem mass spectrometry (LC/MS-MS) was used to determine the changes in metabolites in duck plasma at 5 (CR5), 10 (CR10), and 15 (CR15) days after cage rearing and traditional breeding (TB). The associated pathways of differentially altered metabolites were analyzed using Kyoto encyclopedia of genes and genomes (KEGG) database. RESULTS: The results of this study indicate that caging stress decreased performance parameters, and the plasma total superoxide dismutase levels were increased in the CR10 group compared with the other groups. In addition, 1,431 metabolites were detected. Compared with the TB group, 134, 381, and 190 differentially produced metabolites were identified in the CR5, CR10, and CR15 groups, respectively. The results of principal component analysis (PCA) show that the selected components sufficiently distinguish the TB group and CR10 group. KEGG analysis results revealed that the differentially altered metabolites in duck plasma from the CR5 and TB groups were mainly associated with ovarian steroidogenesis, biosynthesis of unsaturated fatty acids, and phenylalanine metabolism. CONCLUSION: In this study, the production performance, blood indexes, number of metabolites and PCA were compared to determine effect of the caging stress stage on ducks. We inferred from the experimental results that caging-stressed ducks were in the sensitive phase in the first 5 days after caging, caging for approximately 10 days was an important transition phase, and then the duck continually adapted.
ABSTRACT
OBJECTIVE: The oxidative stress status and changes of chicken ovary tissue after shading were studied, to determine the mechanism of the effect of shading on follicular development. METHODS: Twenty healthy laying hens (40 weeks old) with uniform body weight and the same laying rate were randomly divided into two groups (the shading group and normal light group). In the shading group, the cage was covered to reduce the light intensity inside the cage to 0 without affecting ventilation or food intake. The normal lighting group received no additional treatment. After 7 days of shading, oxidative stress related indicators and gene expression were detected. RESULTS: Analysis of paraffin and ultrathin sections showed that apoptosis of ovarian granulosa cells (GCs) increased significantly after light shading. Enzyme linked immunosorbent assay results revealed that the levels of total antioxidant capacity, malondialdehyde, superoxide dismutase (SOD), glutathione, catalase (CAT), and other substances in the sera, livers, ovaries, and follicular GCs of laying hens increased significantly after shading for 7 days; and reactive oxygen species (ROS) levels in the livers of laying hens also increased significantly. ROS in the serum, ovarian and GCs also increased. After shading for 7 days, the levels of 8-hydroxy-2 deoxyguanosine in the sera and ovarian tissues of laying hens increased significantly. Cell counting kit-8 detection showed that the proliferation activity of GCs in layer follicles decreased after shading for 7 days; the expression level of the anti-apoptotic gene B-cell lymphoma-2 in ovarian tissue and follicular GCs was significantly reduced, and the expression levels of pro-apoptotic caspase 3 (casp3), and SOD, glutathione peroxidase 2 (GPX2), and CAT were all significantly increased. CONCLUSION: Oxidative stress induced by shading light has a serious inhibitory effect on follicular development during reproduction in laying hens.
ABSTRACT
Intestinal epithelial cells (IECs) not only have an absorption function but also act as a physical barrier between the body and the intestinal bacterial flora. Damage to IECs leads to the breakdown of this barrier and has negative effects on animal health. Intestinal epithelial damage is frequently associated with long-term acute stress, such as increased temperature and new stress management models. The intestinal epithelial damage caused by environmental stress has been linked to oxidative stress. Until now, the effects of intestinal epithelial antioxidant activity from feed additives and treatments could be tested in ducks only in vivo because of the lack of in vitro cell culture systems. In this study, we describe our protocol for the easy isolation and culture of IECs from the small intestine of duck embryos. Immunofluorescence was used for the cytological identification of IECs. In addition, IEC marker genes (IAP and CDH1) could also be detected in cultured cells. And cell status assessments were performed, and cell proliferation viability was analyzed by CCK-8 assay. Furthermore, we constructed an oxidative stress model to be used to research the oxidative stress response mechanism, and drugs acting on the cell signal transduction pathway. In conclusion, we have developed an effective and rapid protocol for obtaining duck primary IECs and constructed an oxidative stress model. These IECs exhibit features consistent with epithelial cells and could be used to explore the physiological mechanisms of oxidative stress ex vivo.
