Effect of starvation on the type and distribution of mucus cells in the digestive tract of the yellow drum Nibea albiflora (Richardson, 1846)

Abstract

Effects of starvation on the type and distribution of mucus cells in the digestive tract of Nibea albiflora were evaluated by Alcian Blue/Periodic acid-Schiffs staining (AB-PAS). The experimental fishes were divided into four groups. Control group (S0) was fed with formulated diets to satiation twice a day during the experiment. The other three groups were deprived of feed for 10 (S10), 20 (S20), and 30 (S30) days. Results showed that the total number of mucus cells in the oropharyngeal cavity decreased significantly during the experiment, while no significant differences were observed in the hindgut. In S10 fishes, mucus cells in oesophagus decreased initially and then stabilised, whereas the total number of mucus cells in the foregut decreased significantly (p<0.05). Type I, II and IV mucus cells significantly decreased in all parts of the digestive tract of starved fishes (p<0.05). Type IV mucus cells were the most severely affected cells which even disappeared in the digestive tract after ten days of starvation. However, type III mucus cells containing mainly neutral substances increased significantly during starvation stress (p<0.05).