Proteolytic activity in the digestive tract of several species of fish with different feeding habits

Oecologia ◽  
1981 ◽  
Vol 48 (3) ◽  
pp. 342-345 ◽  
Author(s):  
R. Hofer ◽  
F. Schiemer
2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Bhaskara Canan ◽  
Wallace Silva do Nascimento ◽  
Naisandra Bezerra da Silva ◽  
Sathyabama Chellappa

This study investigated the morphohistology of the digestive tract and the mean intestinal coefficient of the damsel fishStegastes fuscuscaptured from the tidal pools of Northeastern Brazil. The wall of the digestive tract ofS. fuscusis composed of the tunica mucosa, tunica muscularis, and tunica serosa. The esophagus is short with sphincter and thick distensible wall with longitudinally folded mucosa. Mucous glands are predominant, and the muscular layer of the esophagus presented striated fibers all along its extension. The transition region close to the stomach shows plain and striated muscular fibers. Between the stomach and intestine, there are three pyloric caeca. The intestine is long and thin with four folds around the stomach. The anterior intestine presents folds similar to those of pyloric caeca. The estimated mean intestinal coefficient and characteristics of the digestive system ofS. fuscuspresent morphological adequacy for both herbivorous and omnivorous feeding habits.


Author(s):  
Grace Madanire-Moyo ◽  
Annemariè Avenant-Oldewage

Cestodes are parasitic flatworms that live in the digestive tract of vertebrates as adults and often in the liver, muscle, haemocoel, mesentery and brain of various animals as larval stages. To identify the cestodes infecting Clarias gariepinus Burchell, 1822 (sharptooth catfish) in the Vaal Dam, a total of 45 host specimens were collected with the aid of gill nets between October 2011, January and April 2012. The fish were sacrificed and examined for cestode parasites. Two adult cestodes, Tetracampos ciliotheca Wedl, 1861 (prevalence 86.7%, mean intensity = 15, n = 45) and Proteocephalus glanduligerus (Janicki, 1928) (prevalence 51.1%, mean intensity = 5, n = 45) were found in the intestines of the catfish. Both T. ciliotheca and P. glanduligerus are new locality records. There were statistically insignificant differences in the infection of the male and female C. gariepinu. Fish with standard length ranging from 40 cm – 54 cm (≥ 3 years) had the highest prevalence and mean intensity while those ranging from 10 cm – 24 cm (< 1 year) had the lowest prevalence and mean intensity for both cestodes. The study highlights the importance of changing feeding habits of C. gariepinus with age on the prevalence and mean intensity of the two gastrointestinal cestode parasites.


1956 ◽  
Vol 33 (2) ◽  
pp. 311-324
Author(s):  
R. H. DADD

1. In Tenebrio secretion of protease occurs spontaneously after moult and adult emergence, and in response to feeding in the active larva and mature adult. Damp cellulose powder or water are effective in increasing secretion in the adult. 2. Since little enzyme is accumulated in the epithelial tissue when the total midgut enzyme is greatly increased, it is inferred that synthesis and discharge are interdependent. When synthesis (as indicated by comparatively high tissue enzyme) is accelerated, growth of the midgut epithelium occurs. 3. In starved Dytiscus protease is accumulated in the midgut tissue. Within one hour of feeding it is largely discharged into the crop. Protease recurs in the midgut tissue in a few hours, but remains low so long as the crop contains undigested material. When the crop is empty, discharge ceases and enzyme is again accumulated in the epithelium. Thus the process of discharge appears to be independent of synthesis. 4. The secretory mechanisms of Tenebrio and Dytiscus are discussed in relation to their feeding habits.


2015 ◽  
Vol 87 (2) ◽  
pp. 867-878 ◽  
Author(s):  
Marcella L. Dos Santos ◽  
Fábio P. Arantes ◽  
Kleber B. Santiago ◽  
José E. Dos Santos

The digestive tracts of 44 specimens of Schizodon knerii were studied using anatomical, histological and histochemical techniques. The mouth has terminal position, the lip epithelium is squamous stratified with mucous, claviform cells and taste buds, teeth have an incisive form and the tongue has a stratified squamous epithelium with mucous cells and taste buds. The oropharynx cavity is formed by gill apparatus and pharyngeal teeth. The oesophagus presented pleated mucosa, a stratified squamous epithelium with mucous cells, oesophageal glands and taste buds. The stomach presented cardiac, fundic and pyloric regions, simple prismatic epithelium with tubular glands, with none in the pyloric region. The intestine contains 11-15 pyloric caeca, a simple prismatic epithelium with brush border, goblet cells and lymphocytes. Mucosal cells, oesophageal glands and goblet cells reacted positively to PAS, amylase + PAS, Ab pH 2.5 and Ab pH 0.5. Gastric prismatic cells reacted positively to PAS, amylase + PAS, but only those in the pyloric region reacted positively to Ab pH 2.5 and Ab pH 0.5. The results improve the understanding of the anatomy of S. knerii feeding habits and the presence of mucosubstances in the epithelium, highlights the importance of glycoproteins for passing food through the digestive tract.


2001 ◽  
Vol 79 (6) ◽  
pp. 1120-1124 ◽  
Author(s):  
Klaus Jaffe ◽  
Flavio H Caetano ◽  
Pedro Sánchez ◽  
Jose V Hernández ◽  
Leonardo Caraballo ◽  
...  

Ants in the tribe Cephalotini are exceptional in that they maintain microorganisms in their digestive tract. To understand what these microorganisms mean to the ants, we observed the feeding habits of Cephalotes pusillus and Cephalotes atratus, finding that in nature they feed on extrafloral nectars, homopteran secretions, and bird droppings. Feeding the antibiotic kanamycin to colonies of C. pusillus in the laboratory kills them. Ants desiccate or starve rather than feed on liquids to which the antibiotics gentamycin and netilmycin have been added, but feed and survive on liquids containing nystatin, penicillin, and ampicillin. We identified over 10 microorganisms from the intestine of C. pusillus with different antibiotic-resistance patterns. The bacteria are from the genera Corynebacterium, Brevibacterium, Sphingobacterium, Ochrobactrum, Myroides, Brevundimonas, Alcaligenes, Stenotrophomonas, Moraxella, and Pseudomonas. We hypothesize that the microorganisms provide nutrients to the ants by synthesizing amino acids from carbohydrates and nitrates. We do not know whether the ants collect the bacteria from the environment, but they transmit them to their young. They culture them in their digestive tract, eventually feeding on them.


2021 ◽  
Vol 64 (2) ◽  
pp. 173-179
Author(s):  
Sanjeet Debnath ◽  
Surjya Kumar Saikia

Two teleosts (Rohu, Labeo rohita and Koi, Anabas testudineus), both with contrasting feeding habits (herbivorous versus carnivorous) were studied for amylase and protease activity concerning different regions of their digestive tracts. Significant differences in enzymatic activity across different regions of the digestive tracts were observed. Rohu, with three equal regions of the stomachless gut, showed the highest amylolytic activity at the posterior digestive tract but the highest proteolytic activity is limited to mid region. Contrary to such observation, Koi with three distinct regions of the digestive tract (stomach, pyloric caeca and intestine), the pyloric caeca exhibited the highest specific activity for both amylase and total protease. The optimum pH and temperature conditions were determined concerning the activity for both amylase and protease.


Author(s):  
Elena Nikolaevna Kashinskaya ◽  
Evgeniy Petrovich Simonov ◽  
Mikhail Maryanovich Solovyev

This paper presents the current state of research on the intestinal microbiota of fish of different ecological groups from water bodies of West and East Siberia. The present study focused on the gut bacterial diversity of 16 species/forms of fish (due to intricate taxonomical position of whitefish from Teletskoye Lake) inhabiting Chany Lake (Novosibirsk oblast), Teletskoye Lake (Altai Republic), Baikal Lake and other water bodies of East Siberia using molecular genetic methods. The analysis of the conducted studies shows the main features of gut bacterial communities in the digestive tract of fish and to better understand the features of the functioning of aquatic ecosystems in Siberia. In all studied fish (except for Lena grayling and Baikal omul), regardless of their habitat, taxonomy, digestive system structure (presence or absence of stomach and pyloric caeca) and feeding habits, bacteria of all four phyla (Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria) were found among the dominants. Such differences can also be explained by sample preparation techniques before sequencing that researchers may apply. Also, the uncultivated microbiota such as Pseudoalteromonadaceae (Lake Chany), Comamonadaceae and Bacillaceae (whitefish from Lake Teletskoye) and Rhodobacteraceae (Baikal omul and whitefish) were often found among the dominant bacterial taxa in the digestive tract of the most studied fish. Moreover, the data focused on the structure of gut bacterial community of fish will be useful for the development of aquaculture industry in the region, since the information makes it possible to identify pathogenic, opportunistic, and probiotic bacteria in aquatic ecosystems.


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