0000000000343671
AUTHOR
Reijo Käkelä
showing 6 related works from this author
High Lipid Content of Prey Fish and n−3 PUFA Peroxidation Impair the Thiamine Status of Feeding-Migrating Atlantic Salmon (Salmo salar) and Is Reflec…
2022
Signs of impaired thiamine (vitamin B1) status in feeding-migrating Atlantic salmon (Salmo salar) were studied in three Baltic Sea areas, which differ in the proportion and nutritional composition of prey fish sprat (Sprattus sprattus) and herring (Clupea harengus). The concentration of n−3 polyunsaturated fatty acids (n−3 PUFAs) increased in salmon with dietary lipids and n−3 PUFAs, and the hepatic peroxidation product malondialdehyde (MDA) concentration increased exponentially with increasing n−3 PUFA and docosahexaenoic acid (DHA, 22:6n−3) concentration, whereas hepatic total thiamine concentration, a sensitive indicator of thiamine status, decreased with th…
Experimental infection of the deer ked (Lipoptena cervi) has no negative effects on the physiology of the captive reindeer (Rangifer tarandus tarandu…
2011
The deer ked (Lipoptena cervi) is a haematophagous parasitic fly of cervids that spread to Finland in the early 1960's. Presently its northern distribution limit lies at approximately 65°N and it is gradually spreading northwards. In Finland the principal host species has been the moose (Alces alces), but the deer ked is about to establish contact with another potential host, the semi-domesticated reindeer (Rangifer tarandus tarandus) causing possible threats to reindeer health and management. The aim of this study was to investigate if the deer ked would have an influence on the welfare of the reindeer. Eighteen adult reindeer were divided into three experimental groups: the control group …
Seasonal changes in European whitefish muscle and invertebrate prey fatty acid composition in a subarctic lake
2019
Ambient light and temperature show extreme seasonal variation in subarctic lakes due to the midnight sun period in summer and cold polar night period in winter. These changes have clear impacts on fish feeding and reproduction cycles, potentially affecting the fatty acid (FA) composition of muscle. Despite extensive research into fish FA over recent decades, we know little about intra‐annual changes of fish FA profile and content. We studied intra‐annual changes in the FA profile (mol%) and content (mg g‐1 dry weight) of sexually mature European whitefish (Coregonus lavaretus) muscle in a large and deep subarctic lake located in northern Fennoscandia. We collected fish, zooplankton, and ben…
Effects of gender, diet, exogenous melatonin and subchronic PCB exposure on plasma immunoglobulin G in mink
2002
Abstract Effects of different fish-based diets (freshwater smelt, Baltic herring, marine herring/cod offal or their mixtures), gender, β-glucan supplement, exogenous melatonin, and PCB exposure (Aroclor 1242®, 1 mg per animal per day in feed) on plasma immunoglobulin G (IgG) in the mink (Mustela vison) were studied. The aims of the study were to find out whether plasma IgG of the mink is affected by the subchronic PCB exposure, and whether biological, nutritional and hormonal effects are large enough to mask the possible IgG response. The concentration of IgG was determined using enzyme-linked immunosorbent assay (ELISA). Sexual dimorphism was detected, the males having higher levels of pla…
The Diapause Lipidomes of Three Closely Related Beetle Species Reveal Mechanisms for Tolerating Energetic and Cold Stress in High-Latitude Seasonal E…
2020
During winter insects face energetic stress driven by lack of food, and thermal stress due to sub-optimal and even lethal temperatures. To survive, most insects living in seasonal environments such as high latitudes, enter diapause, a deep resting stage characterized by a cessation of development, metabolic suppression and increased stress tolerance. The current study explores physiological adaptations related to diapause in three beetle species at high latitudes in Europe. From an ecological perspective, the comparison is interesting since one species (Leptinotarsa decemlineata) is an invasive pest that has recently expanded its range into northern Europe, where a retardation in range expa…
Complementary methods assessing short and long-term prey of a marine top predator ‒ Application to the grey seal-fishery conflict in the Baltic Sea.
2019
The growing grey seal (Halichoerus grypus) population in the Baltic Sea has created conflicts with local fisheries, comparable to similar emerging problems worldwide. Adequate information on the foraging habits is a requirement for responsible management of the seal population. We investigated the applicability of available dietary assessment methods by comparing morphological analysis and DNA metabarcoding of gut contents (short-term diet; n = 129/125 seals, respectively), and tissue chemical markers i.e. fatty acid (FA) profiles of blubber and stable isotopes (SIs) of liver and muscle (mid- or long-term diet; n = 108 seals for the FA and SI markers). The methods provided complementary inf…