title: Role of peptidases of the intestinal microflora and prey in temperature adaptations of the digestive system in planktivorous and benthivorous fish.
abstract: Many fish enzymatic systems possess limited adaptations to low temperature; however, little data are available to judge whether enzymes of fish prey and intestinal microbiota can mitigate this deficiency. In this study, the activity of serine peptidases (casein-lytic, mainly trypsin and hemoglobin-lytic, mainly chymotrypsin) of intestinal mucosa, chyme and intestinal microflora in four species of planktivorous (blue bream) and benthivorous (roach, crucian carp, perch) was investigated across a wide temperature range (0-70 °C) to identify adaptations to low temperature. At 0 °C, the relative activity of peptidases of intestinal mucosa (<13%) and usually intestinal microflora (5-12.6%) is considerably less than that of chyme peptidases (up to 40% of maximal activity). The level of peptidase relative activity in crucian carp intestinal microflora was 45% of maximal activity. The shape of t°-function curves of chyme peptidase also differs in fish from different biotopes. Fish from the littoral group are characterized by a higher degree of adaptation of chyme casein-lytic peptidases to functioning at low temperatures as compared to fish from the pelagic group. The role of intestinal microbiota and prey peptidases in digestive system adaptations of planktivorous and benthivorous fish to low temperatures is discussed.
authors.affiliation: I.D.Papanin Institute for Biology of Inland Waters RAS, PO Box 152742, Borok, Yaroslavl, Russia. vkuzmina@ibiw.yaroslavl.ru.|FSBEI HPE Yaroslavl State Agricultural Academy, PO Box 150042, Yaroslavl, Russia. vkuzmina@ibiw.yaroslavl.ru.
authors.forename: V V
authors.initials: VV
authors.lastname: Kuz'mina
authors.affiliation: FSBEI HPE Yaroslavl State Agricultural Academy, PO Box 150042, Yaroslavl, Russia.
authors.forename: E G
authors.initials: EG
authors.lastname: Skvortsova
authors.affiliation: I.D.Papanin Institute for Biology of Inland Waters RAS, PO Box 152742, Borok, Yaroslavl, Russia.|FSBEI HPE Yaroslavl State Agricultural Academy, PO Box 150042, Yaroslavl, Russia.
authors.forename: M V
authors.initials: MV
authors.lastname: Shalygin
authors.affiliation: Natural Resources Research Institute, University of Minnesota Duluth, Miller Trunk Highway, PO Box 5013, Duluth, MN, USA.
authors.forename: K E
authors.initials: KE
authors.lastname: Kovalenko
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D002918:Chymotrypsin / Q000378:metabolism; D003080:Cold Temperature; D003530:Cyprinidae / Q000502:physiology*; D005766:Gastrointestinal Contents / Q000201:enzymology; D000069196:Gastrointestinal Microbiome; D007413:Intestinal Mucosa / Q000201:enzymology*; D010447:Peptide Hydrolases / Q000378:metabolism*; D010471:Perches / Q000502:physiology*; D014357:Trypsin / Q000378:metabolism
chemical_list: D010447:Peptide Hydrolases; D002918:Chymotrypsin; D014357:Trypsin
keywords: Benthivorous fish; Chyme; Intestinal microflora; Intestine; Mucosa; Peptidases; Planktivorous