不同摄食状态下南方鲇幼鱼肠道黏液细胞的量化分析

量化分析了南方鲇(Silurus meridionalis)幼鱼在正常摄食节律下摄食前(S0d)、摄食后64 h(S0d-64h)、饥饿16d(S16d)、饥饿32 d(S32d)以及饥饿后首次恢复摄食64 h(S16d-64h,S32d-64h)肠道各类型黏液细胞的反应特征。结果发现,摄食后肠道各部位黏液细胞总数均有一定程度减少,其中前肠减少最为显著(P<0.05);中肠和后肠II型黏液细胞数量显著减少(P<0.05),中肠的III型黏液细胞数量显著增多(P<0.05);肠腔中黏液增多,黏液细胞呈空泡结构。S16d组和S16d-64h组前肠和中肠的I型细胞数量显著减少(P<0.05),III型细胞数量显著增多(P<0.05)。S32d组和S32d-64h组前肠各类型细胞数量以及黏液细胞总数变化不明显(P>0.05);中肠的II型细胞数量显著增多(P<0.05),IV型细胞数量显著减少(P<0.05);饥饿和恢复摄食后肠各类型黏液细胞数目变化不明显(P>0.05)。研究表明,南方鲇幼鱼肠道黏液细胞的摄食反应明显;饥饿胁迫以及恢复摄食后肠道黏液细胞的反应特征与肠道各段的生理功能相适应;面对营养胁迫时,肠道前段能迅速调节黏液细胞的数目,而后肠基本不变,可能是该鱼应对营养缺乏的保护性适应机制。

Changes in the number of intestinal mucous cells of juvenile southern catfish Silurus meridionalis following feeding, starvation, and refeeding

Abstract: We evaluated the effects of feeding, starvation, and re-feeding on the number of mucous cells in the intestinal mucosa in juvenile southern catfish (Silurus meridionalis). The total number of mucous cells tended to decrease throughout all intestinal segments in the S0d-64h group, but the decrease was only significant in the proximal intestinal segment (P<0.05). The number of type II cells decreased significantly in both the mid intestinal segment and the distal intestinal segment (P<0.05), whereas the number of type III cells increased significantly in the mid intestinal segment (P<0.05). Feeding induces secretion from the mucous cells, resulting in more mucous in the intestinal lumen and vesicles of the mucous cells. There was no significant change in the total number of mucous cells across all intestinal segments, but there were type-specific changes in the number of mucous cells. There was a significant decrease in the number of type I cells and a significant increase in the number of type III cells in the proximal and mid intestinal segments in both the 16 day starvation group and post-refeeding 64 hour group. Conversely, there was an increase in the number of type II cells and a decrease in type IV cells in the mid intestinal segment in the 32 day starvation group and the postfeeding 64 hour group. There was no change in any of the mucosal cell types in the distal intestinal segment following starvation and refeeding. Our results suggest that feeding has an effect on the number of intestinal mucous cells in southern catfish. The segment specific regulation of mucous cells is likely correlated to the differing functions of each segment. The regulation of different types of mucous cells in both the proximal and mid intestinal segments may be a protective adaptation to low food availability.