Effects Of Zearalenone On Ghrelin,PCNA And Hsp70 Expression In The Small Intestine Of Post-weaning Piglets

Zearalenone( ZEN) is a Fusarium estrogenic toxin produced by fungi, with widespreading pollution in China breeding industry. And the pig has the most sensitivity among livestocks. Previous research on ZEN is mainly about its impact on the porcine reproductive system. Considering the fact that ZEN is mainly metabolized in the intestine cell, we come up with the idea of studying the ZEN effects on intestine. To be specific, we test the distribution and expresison of ghrelin, PCNA and Hsp70 in duodenum, jejunum and ileum. Ghrelin can promotes digestion and absorption, PCNA is an important indicator of cell proliferation, and Hsp70 is an important protein responded to various stress conditons. Therefore, we can assess the ZEN effects on the physiology function of the post-weaning pig, including the endocrine, digestion and absorption in testine.This experiment select 20 female weaned and crossbred piglets(Duke×Landrace×Yorkshire), 28 d, average weight of 8.74±0.26 kg, were divided randomly into two groups that the control group and the ZEN treated group. Both the control group and the ZEN treated group all has 10 piglets, without significant difference on initial body weights between two groups(P>0.05). Control group piglets was fed with basal diet, while ZEN treated group piglets were fed with basal dietary with added ZEN(1.04 mg / kg). The experiment includes 7d pre-trial period and then 35 d test period. After that, the piglets were slaughted and the small intestine samples were collected. In this experiment, HE staining indicated the intestinal histological structure, the SABC immunohistochemistry indicated the distribution of ghrelin, PCNA and Hsp70 in the small intestine, and at the same time, ghrelin, PCNA and Hsp70 mRNA relative expression level in the small intestine of weaned piglets was detected by real-time quantitative RT-PCR.The experiment results showed that ZEN can change the histological structure of intestinal tissue, the intestinal development was inhibited. Duodenum, jejunum and ileum villus were stunted, the length of the jejunum villus were significantly reduced(P < 0.01), the ileum villus became shorter, thicker, and its villus amount became decreased with branches intactness broken. However, the lymphoid nodules amout in the submucosa of ileum were increased. By means of immunohistochemistry staining, we found that ghrelin positive reaction in the small intestine was mainly located in the villus epithelial cells in all three sections of the intestine, although most of intestinal glands showed weakly positive reaction. After ZEN added, positive reaction in the duodenum and jejunum was weakened, the ghrelin positive reaction in the villi epithelial showed positive staining weakened, IOD was decreased(P < 0.01), while IOD of positive reaction in the ileum showed increase(P < 0.01). The PCNA positive reaction in the small intestine mainly located in epithelium that basal part of the villus, intestinal gland and Peyer's patches. After ZEN added, PCNA positive reaction in all three sections of the intestine was weakened, total IOD of the intestine all same showed decreased(P < 0.01). Hsp70 positive reaction in the small intestine mainly located in the villus epithelial cells, intestinal gland cells and neuronal cells of muscular layer. After ZEN added, positive reaction in each section of the intestine were all enhanced, total IOD of the intestine all same showed increased(P < 0.01). The mRNA relative expression of three protein were generally consistent with the immunohistochemistry results.Summary: After ZEN added, weaning piglets could weaken the abibility to digestion and absorption of the intestine by reducing the secretion of ghrelin. Meanwhile, the small intestine would reduce cell division with the shortened intestine villi and the less branches to resist ZEN. The small intestine villi length is shortened, reducing the number of branches and incomplete development of resistance to change is the result of the body physiological response ZEN, and the increased Hsp70 synthesis helped the anti-ZEN response.