Morphological and histochemical study of intestine in wild and reared European eel (Anguilla anguilla L.)

Abstract

Diet-related differences between the ratio of intestine length to body size and the enzymatic activity in the intestinal tract of wild and reared European eel (Anguilla anguilla L.) were studied. Compared with reared eel, wild eel showed significantly shorter relative intestine length. For the purpose of histochemical examination, different parts (anterior, middle and posterior) of intestine proper were used. Activities of non-specific esterase, alkaline and acid phosphatase, and aminopeptidase were examined in each segment. All enzymes were present in the intestines of both wild and reared European eel. Fish from both groups showed similar enzyme distribution within the enterocytes, but distribution and intensity of enzyme activity along the intestine vary depending on the group. Generally, reared European eel showed highest enzymatic activity and wider distribution of enzymes throughout all parts of the intestine. These results suggest that different diets could be one of the reasons for observed changes.

Histochemical distribution of four types of enzymes and mucous cells in the gastrointestinal tract of reared half‐smooth tongue sole Cynoglossus semilaevis

“…Histochemical analysis of various gastrointestinal tissues of C. semilaevis revealed moderate NSE activity in the stomach, in contrast to a robust activity in the intestine with nonsignificant differences between the anterior and posterior intestinal segments. This finding is similar to that of farmed A. anguilla (Kužir et al , ). Variations in NSE activity of different regions of the intestinal tract, however, are indicative of unequal NSE hydrolysis processes for carboxylic esters, which has also be observed in D. vulgaris (Gajger et al , ).…”

“…NSE is a major hydrolase that is involved in the digestion of glycerol esters of fatty acids in most vertebrates, including fish. In the present study, NSE was identified mainly in the cytoplasm of stomach epithelial cells and intestinal enterocytes and similar findings have been observed in M. merluccius (Kozarić et al , ), A. anguilla (Kužir et al , ), D. vulgaris (Gajger et al , ) and pacu Piaractus mesopotamicus (Holmberg 1887) (Moretti et al , ). Other studies have localized NSE activity to lysosomes and endoplasmic reticuli, as well as in other organelles such as the Golgi apparatuses and mitochondria (Ben & Li, ).…”

“…The higher ALP activity in the anterior intestine indicates that the anterior region of the intestine plays a major role in nutrient absorption than the posterior region (Tengjaroenkul et al , ). These observations have also been reported in A. anguilla (Kužir et al , ) and D. vulgaris (Gajger et al , ). Changes in ALP activity between the stomach and intestine may also be indicative of functional differentiation in food digestion and nutrient absorption.…”

“…ACP is a ubiquitous lysosomal enzyme that hydrolyses organic phosphates at an acidic pH. In the intestinal tract of C. semilaevis , the fact that ACP was localized in the supranuclear parts of enterocytes is in agreement with the results in hake Merluccius merluccius (L. 1758) (Kozarić et al , ), sea ruffe Sebastiscus marmoratus (Cuvier 1829) (Shi et al , ), European eel Anguilla anguilla (L. 1758) (Kužir et al , ) and the common two‐banded sea bream Diplodus vulgaris (Geoffroy Saint‐Hilaire 1817) (Gajger et al , ). The activity of ACP observed in the lamina propria apparently coincided with the presence of pinocytotic processes.…”

AKTIVITAS PROTEASE DAN AMILASE PADA IKAN SIDAT <em>Anguilla bicolor</em> McClelland)

“…Fenomena keberadaan dan distribusi aktivitas protease pada saluran digesti ikan sidat juga dilaporkan pada penelitian sebelumnya seperti pada spesies Anguilla rostrata (Wang, 2007), Anguilla anguilla (Caruso et al, 2008;Kužir et al, 2012), dan Anguilla japonica (Murashita et al, 2013;Lin et al, 2015). Protease terdistribusi sepanjang saluran digesti yaitu lambung, hepatopankreas dan instetine (usus).…”