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

Hofer, R.; Schiemer, F.

doi:10.1007/bf00346492

Cited by 117 publications

(74 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some true herbivores exhibit high proteolytic activity when processing algal food (Horn, 1989;Ojeda & Cáceres, 1995;Johnston & Freeman, 2005), so we expect them to exhibit noticeably lower activity when feeding exclusively on animal food. For example, herbivorous fishes may have intensive proteolytic digestion because their long digestive tracts allow a longer exposure of food to enzymatic action, although the proteolytic activity per volume unit of gut content is clearly lower in herbivores than in omnivores or carnivores (Hofer & Schiemer, 1981). For our study species, thus, the detection of comparable proteolytic activity for algal and animal food would be a first suggestion of an omnivorous habit, provided that animal preys are indeed a regular component of their diet.…”

Section: Introductionmentioning

confidence: 72%

Consumption and digestion of animal food by rocky intertidal herbivores: an evaluation of digestive flexibility and omnivory in three grazing species.

Camus

Cid

Cisterna

et al. 2009

Lat. Am. J. Aquat. Res.

View full text Add to dashboard Cite

ABSTRACT. The ingestion of invertebrates by herbivores on rocky intertidal shores is traditionally considered a casual phenomenon. However, a recent study of 29 species in northern Chile shows that animal consumption is widespread, consistent, and important, suggesting that some of these herbivores may actually be omnivores. Therefore, we examined the capability of three common Chilean herbivores (the key-hole limpets Fissurella limbata and Fissurella picta and the polyplacophoran Chiton granosus) to digest animal food. For each species, we conducted no-choice feeding experiments using artificial foods based on either algal or animal tissue from one of their frequent prey (Ulva rigida, Perumytilus purpuratus). After the feeding trials, we evaluated the total proteolytic activity (availability of free amino acids) in the digestive contents of the species studied and, as a reference, we evaluated this activity in animals obtained directly from the field. We found that all three species were able to eat animal food, and this consumption was not significantly different from that of algal food, suggesting that both foods were not only edible but at least similarly palatable. In addition, we detected comparable levels of proteolytic activity under the three feeding conditions for the three species. No statistical differences were found for C. granosus, but activity was significantly higher with animal food in F. limbata and with algal food in F. picta. Our data show the high digestive flexibility of these species, suggesting their ability for adaptive modulation and the possibility that they are true omnivorous consumers. We discuss the implications of these results for our current view of the structure of rocky intertidal food webs. Keywords: omnivorous, proteolytic, food web, key-hole limpet, polyplacophora, Chile.Consumo y digestión de alimento animal por herbívoros del intermareal rocoso: evaluación de flexibilidad digestiva y omnivoría en tres especies de pastoreadores RESUMEN. La ingestión de invertebrados por herbívoros de costas intermareales rocosas se considera tradicionalmente un fenómeno casual. Sin embargo, un estudio reciente en 29 especies del norte de Chile muestra que el consumo animal es generalizado, consistente e importante, sugiriendo que algunos de estos herbívoros pueden ser realmente omnívoros. Por tanto, se examinó la capacidad de tres herbívoros chilenos comunes para digerir alimento animal: las lapas Fissurella limbata y Fissurella picta, y el poliplacóforo Chiton granosus. Para cada especie, se efectuaron experimentos de alimentación sin elección usando alimentos artificiales basados en tejido animal o algal de algunas de sus presas frecuentes (Ulva rigida, Perumytilus purpuratus). Luego de los ensayos de alimentación se evaluó la actividad proteolítica total (disponibilidad de aminoácidos libres) en sus contenidos digestivos, y como referencia, se determinó la actividad en animales obtenidos directamente desde condiciones de terreno. Se encontró que las tres especies fueron capaces de come...

show abstract

Section: Introductionmentioning

confidence: 72%

Consumption and digestion of animal food by rocky intertidal herbivores: an evaluation of digestive flexibility and omnivory in three grazing species.

Camus

Cid

Cisterna

et al. 2009

Lat. Am. J. Aquat. Res.

View full text Add to dashboard Cite

show abstract

“…The use of proteolytic enzyme specific activities, such as trypsin and activity ratio of trypsin and chymotrypsin (T/C ratio), for predicting growth in aquatic species have been reported 8,15 . For carbohydrate digestion, amylase activity and the A/T ratio, which is used as indicator of metabolic flexibility to utilize carbohydrateprotein 31 , appeared to be indicative of FCR in the experiments. The significant increase in amylase specific activity in turtles fed by diet 3 might be due to the high amount of available carbohydrate in the fish pellet diet (36%), while the other carbohydrate contents of feed constituents were 24% in fresh feed containing minced fresh fish and vegetable, and 29% in fresh feed containing minced fish fillet, vegetable, and fish pellet diet.…”

Section: Specific Activity Of Faecal Digestive Enzymes In Relation Tomentioning

confidence: 92%

Faecal characteristics as markers of Chelonia mydas feeding

Thongprajukaew¹,

Kanghae²,

Kittiwattanawong³

2016

ScienceAsia

View full text Add to dashboard Cite

ABSTRACT:Faecal sampling can provide an unobtrusive monitoring of feed utilization. We demonstrate that faecal digestive enzymes and physicochemical characteristics correlate with the feed conversion efficiency in green turtle (Chelonia mydas). The 10-day-old juvenile turtles (25.4 ± 1.3 g body weight) were fed with either fresh feed containing minced fresh fish and vegetable (diet 1); fresh feed containing minced fish fillet, vegetable and fish pellet diet (diet 2); or only fish pellet diet (diet 3) for four months in a completely randomized design (3 treatments × 3 replicates × 10 subjects per replication). Analysis of faecal digestive enzymes (pepsin, trypsin, amylase, and activity ratio of amylase to trypsin) based on colorimetric determinations of specific activity suggested that carbohydrate digestion is a key indicator for feed utilization efficiency in terms of intake and conversion ratio. Physicochemical characteristics to enhance enzymatic hydrolysis, namely, microstructure (scanning electron microscope), thermal transition properties (differential scanning calorimeter), and relative crystallinity (X-ray diffractometer) indicate that the faeces of turtles fed with diet 3 provide a superior feed utilization efficiency. The observed faecal characteristics varied in response to different diets over the duration of the experiments. Thus analysis of faecal digestive enzymes and physicochemical characteristics appear to provide useful unobtrusively sampled indicators for determining feed utilization and can be applied in studies of nutritional status in endangered species without conflicting ethical standards.

show abstract

“…Therefore, a higher ratio in females probably indicates better growth capacity and food utilization compared to males. For carbohydrates, the A/T ratio was used as an effective marker to understand feeding habits (Hofer and Schiemer 1981;Gambao-Delgado et al 2003). The significantly higher ratio in males might indicate better carbohydrate utilization or stronger omnivorous feeding habits than females.…”

Section: Specific Activity Of Digestive Enzymesmentioning

confidence: 99%

Effects of sex on characteristics and expression levels of digestive enzymes in the adult guppy Poecilia reticulata

Thongprajukaew

Kovitvadhi

2013

Zool. Stud.

View full text Add to dashboard Cite

Background: Characteristics (pH 2 to 12 and temperature of 25°C to 80°C) and expression levels of the main digestive enzymes, including amylase, lipase, total protease, trypsin, and chymotrypsin, were investigated in adult male and female guppies Poecilia reticulata. A completely randomized design was used during this experiment. Results: Digestive enzyme studies indicated that sex had a direct effect on characteristic profiles (n = 3) and expression levels (n = 10) of all digestive enzymes. The most suitable conditions for studying digestive enzymes in general were pH 2 at 50°C for acidic amylase, pH 7 at 55°C for neutral amylase, pH 11 at 50°C for alkaline amylase, pH 7 at 30°C to 35°C for lipase, pH 2 at 55°C for acidic protease, pH 9 at 45°C for alkaline protease, pH 8 at 50°C for trypsin, and pH 9 at 50°C for chymotrypsin, regardless of sex. Specific activities of amylase, total protease, trypsin, and chymotrypsin were higher in females than males (p < 0.001), while the specific activity of lipase was higher in males than females. These findings were correlated with the higher growth capacity of females than males (except for lipase), as indicated by differences in body weight (p < 0.001), length (p < 0.001), and the activity ratio of trypsin (T) to chymotrypsin (C), i.e., the T/C ratio (p < 0.007).

show abstract

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

Cited by 117 publications

References 15 publications

Consumption and digestion of animal food by rocky intertidal herbivores: an evaluation of digestive flexibility and omnivory in three grazing species.

Consumption and digestion of animal food by rocky intertidal herbivores: an evaluation of digestive flexibility and omnivory in three grazing species.

Faecal characteristics as markers of Chelonia mydas feeding

Effects of sex on characteristics and expression levels of digestive enzymes in the adult guppy Poecilia reticulata

Contact Info

Product

Resources

About