Salmo salar

This study compares the digestibility of a series of lupin and soybean protein products when fed to either rainbow trout or Atlantic salmon. The test ingredients in the study, from one of two key grain resources (lupins: Lupinus angustifolius and soybeans), represented various levels of processing of each grain in order to increase the protein content of the meals. A reference ingredient of enzymatically hydrolyzed casein (EHC) was also included in the study. The rainbow trout (266 F 18 g) were housed in freshwater tanks (250 l, salinity < 1x, 22.1 F 1.8 jC) and acclimated to the diets for 6 days before faecal collection commenced. The Atlantic salmon (66 F 10 g) were housed in similar freshwater tanks (250 l, salinity < 1x, 15 jC) and acclimated to the diets for at least 6 days before faecal collection commenced. Faeces were collected from each fish species using settlement collection methods. The digestibility of organic matter, phosphorus, energy and nitrogen 0044-8486/$ -see front matter D Aquaculture 237 333 -346 was assessed using the diet-substitution method, with each test ingredient included in the diet at 30%. Several differences were observed between the two fish species in their capacity to digest nutrients and energy from each of the products. Organic matter and energy digestibility of each of the ingredients was largely reflective of the protein content of each ingredient. Protein digestibilities were generally consistent between the two fish species with only lupin kernel meal having a significantly higher digestibility when fed to Atlantic salmon than rainbow trout and the soybean protein concentrate a significantly lower digestibility. Although limited differences in protein digestibility were noted among the ingredients when fed to rainbow trout, more substantial differences were noted when the same ingredients were fed to Atlantic salmon. The digestible energy value of the range of products examined was generally higher in Atlantic salmon than rainbow trout. A clear difference between the two fish species was their capacity to digest phosphorus from the ingredients, with several of the plant protein ingredients showing differences in phosphorus digestibility between the two fish species. Generally, both series of grain products have excellent potential as feed ingredients for either of these species. However, the digestive capacity of Atlantic salmon appears to more positively respond to the absence of dietary non-starch polysaccharide content than that of rainbow trout. D

The distribution and excretion of arsenobetaine in fish were investigated using whole body autoradiography and liquid scintillation counting. A single dose of synthesised [ 14 C]arsenobetaine was orally administered to Atlantic salmon, Salmo salar L., and Atlantic cod, Gadus morhua L. Arsenobetaine was distributed to most organs within both species. Nevertheless, there were species differences in tissue distribution and excretory pattern. The highest level of arsenobetaine in Atlantic salmon was present in muscle tissue, while high levels of arsenobetaine were found in both muscle and liver (including gall bladder) from Atlantic cod. The results suggest that the major route of excretion was via urine, which seemed to be more important in Atlantic cod than in Atlantic salmon. Elimination of arsenobetaine via bile appeared to be negligible in both species.

Long-term variation in Atlantic salmon (Salmo salar) stocks was analyzed in two Barents Sea rivers, the Teno and Näätämöjoki, that represent the northernmost distribution area of the species. In contrast to most of the North Atlantic area, these rivers are among a group of northern salmon rivers that, despite wide annual variation in catches, demonstrate no consistent trend for declining abundance. Variations in abundance were generally synchronous for the total catch and numbers of 1-sea-winter (1SW) and 2SW salmon during period of 1972-2003. Part of the variation observed in catches could be related to ocean climate conditions as the mean seawater temperature in July during the year of smoltification for the Kola section of the Barents Sea was significantly related to numbers of 1SW, 2SW, and 3SW salmon in the large River Teno. In contrast, NAO (North Atlantic Oscillation) indices were not related to salmon catches. The latest increase (1999)(2000)(2001) in salmon catches in these rivers reflects both temporarily improved oceanic conditions and past management measures affecting offshore, coastal, and river fisheries.

Although the inclusion of genetically modified (GM) plants in diets fed to fish is a contentious issue, there are few empirical data. The present study addressed nutritional value and potential risks of four maize types (two traditional and two GM maize varieties) and two soy types (one traditional and one Roundup Ready Ò soy) included at moderate levels in diets fed to Atlantic salmon parr (initial mean weight ± SD; 0.21 ± 0.02 g) during the first 8 months of feeding (March to October), which included the parr-smolt transformation. The GM-maize varieties [Dekalb 1 (D1) and Pioneer 1 (P1)] were hybrids of traditional maize variants [Dekalb 2 (D2) and Pioneer 2 (P2)] and the GM maize MON810 Ò . Four maize diets, two soy diets and one Standard fishmeal-based diet were formulated and fed to fish in triplicate. The maize diets were formulated with 121 g kg )1 GM maize (P1 and D1) or 121 g kg )1 of the traditional untransformed line (nGM-maize, P2 and D2) and the soy diets were formulated with 125 g kg )1 GM soy or 125 g kg )1 of the traditional untransformed line (nGM-soy), all of equivalent nutrient composition. All diets supported good growth and showed no evidence of diet-related mortality. Based on samplings every 6th week, growth was within the normal range and at conclusion of the study body weight did not differ among any of the treatments (range 101-116 g). Besides minor differences on heptatosomatic index (HSI), plasma triacylglycerol (TAG) values and thermal growth coefficient (TGC), body composition, relative organ weights, plasma nutrient concentrations and enzyme activities did not vary among treatments at any sampling. The present findings indicate that the inclusion of GM plants at the given level in salmonid diets poses little, or no, adverse risk to the health of first feeding Atlantic salmon parr and promote normal growth. The paper presents the production related data of this feeding study. Results regarding structure and function of intestinal segments and intestinal organs are presented in Sanden et al.

Toll-like receptors (TLRs) are involved in the innate immune response against microbial pathogens in vertebrates and insects. The extracellular region of a TLR recognizes pathogen-associated molecules, while the intracellular region initiates the signaling pathway leading to immune response. Membrane-bound TLRs have been found in most vertebrates, but few soluble forms have been reported. A novel transcript corresponding to a portion of a soluble TLR was identified in liver of infected Atlantic salmon. The complete coding sequence of this TLR was obtained and BLASTN analysis showed the highest sequence identity to a recently described full-length cDNA sequence of a soluble TLR5 from rainbow trout (GenBank Accession No.: AB062504). The deduced protein is 40% identical to the mammalian counterpart of the leucine-rich repeat (LRR)/LRR-like motifs of TLR5. Based on the structure of human TLRs, it contains 21 LRRs with conserved LxxLxLxxNx*xx*xxxxFxxL pattern. Since TLR5 is essential for the recognition of bacterial flagellins, we hypothesize that flagellin and perhaps some other pathogen-derived factors from Aeromonas salmonicida bind to this soluble TLR through an unknown binding domain within the LRR. #

This study investigates the effect of different smolt production strategies on vertebral morphology (radiology), composition (mineral content) and mechanical strength (load-deformation testing) in Atlantic salmon (Salmo salar). Rapid-growing underyearling (0+) smolt were compared with slower-growing yearling (1+) smolt and a reference group of wild smolt (w). The underyearling and yearling smolt were transferred to seawater in October 2002 and May 2003, respectively. The underyearling smolt were reared under continuous light and the yearling smolt under natural light during the first twelve weeks in seawater, at ambient temperatures. Thus, the underyearling smolt hit seawater at 13°C and were reared at 10-13°C during the early seawater phase, whereas the yearling smolt hit seawater at 7°C and were reared at 7-10°C during the early seawater phase. All groups displayed increased longitudinal growth (up to 9% increase in relative length) of the caudal vertebrae during parr-smolt transformation. However, at transfer to seawater, the underyearling smolt had significantly lower vertebral mineral content (0+ 44%, 1+ 47%, w 50%) and higher incidence of deformed vertebrae (0+ 1.5%, 1+ 0%, w 0%), and at twelve weeks after transfer to seawater significantly lower vertebral mineral content (0+ 36%, 1+ 41%, w 43%), yield-load (0+ 6492 g, 1+ 8797 g, w 9150 g) and stiffness (0+ 7578 g/mm, 1+ 15,161 g/mm, w 20,523 g/mm), and significantly higher incidence of deformed vertebrae (0+ 2.5%, 1+ 0.3%, w 0%). There was a significant correlation between the mineral content and mechanical properties of the vertebrae. The underyearling smolt had significantly elevated plasma concentrations of total Ca, and P and Ca 2+ during the parr-smolt transformation and in the early seawater phase.

White muscle high-energy phosphate levels showed that the bleeding procedure applied during slaughter of Atlantic salmon (Salmo salar) did not overshadow the total pre-slaughter handling stress. The energy status of the muscle seemed to increase as a result of bleeding and the bleeding per se did not have adverse effects on flesh freshness resulting from excessive handling stress. The time for onset of rigor mortis and rigor strength were clearly related to the initial stress level and the rate of ATP depletion. The onset of rigor in stressed fish occurred about one day earlier compared with rested fish and the stressed fish also became stiffer.

Crossing experiment of sea-ranched Atlantic salmon (Salmo salar) was used to study the factors behind marine survival and precocious maturity of the offspring. The compared smolt groups differed in their parental rearing history (wild or reared), and also in their parental age at maturity. The length and potential precocious maturity of the smolts at the time of release was recorded. Altogether, about 18 400 externally tagged smolts, derived from different crossing groups, were released into the estuary of the River Kemijoki, in the northern Baltic Sea, in 1986 and 1988. The total tag recovery rate was 15% for both year-classes. The results showed that the rearing history of the parents had a significant influence on both the survival and the precocious maturation of the offspring. Reared parents produced on average faster growing offspring than the wild parents. Precocious maturation reduced marine survival of the offspring in the first hatchery generation, but not anymore in the second hatchery generation. The marine survival of both immature and mature smolts generally improved with increasing smolt size, but still the large precocious males (over 21 cm) had the best survival. Maternal and paternal age at maturity and their interactions had also a significant influence on the survival and precocious maturation of the progenies. The increasing maternal and paternal age at maturity had opposite effects on precocious maturation rate of the offspring. Decreasing maternal age and increasing paternal age both increased the proportion of precocious males among the offspring. The survival of the precocious male offspring of old females (3 sea-winter) and young males (1 sea-winter) surpassed all other offspring groups. The proportion of these precocious males was, however, low consisting only 2% of all offspring. Maternal sea age was more important than maternal rearing history in determining marine survival and precocious maturation of the offspring. Survival was higher and precocious maturation was less frequent for the progenies of older females compared to those of young females. The results as a whole suggest that an increased number of hatchery generations do not necessarily reduce the marine survival of sea-ranched Atlantic salmon, but hatchery rearing may generate selection, which causes significant genetic changes in life history traits, even in one hatchery generation.

Among the species in the family Salmonidae, those represented by the genera Salmo, Salvelinus, and Oncorhynchus (subfamily Salmoninae) are the most studied. Here, various aspects of phenotypic and life-history variation of Atlantic salmon Salmo salar L., brown trout Salmo trutta L., and Arctic charr Salvelinus alpinus (L.) are reviewed. While many strategies and tactics are commonly used by these species, there are also differences in their ecology and population dynamics that result in a variety of interesting and diverse topics that are challenging for future research. Atlantic salmon display considerable phenotypic plasticity and variability in life-history characters ranging from fully freshwater resident forms, where females can mature at approximately 10 cm in length, to anadromous populations characterised by 3-5 sea-winter (5SW) salmon. Even within simple 1SW populations, 20 or more spawning life-history types can be identified. Juveniles in freshwater can use both fluvial and lacustrine habitats for rearing, and while most smolts migrate to sea during the spring, fall migrations occur in some populations. At sea, some salmon undertake extensive oceanic migrations while other populations stay within the geographical confines of areas such as the Baltic Sea. At the other extreme are those that reside in estuaries and return to freshwater to spawn after spending only a few months at sea. The review of information on the diversity of life-history forms is related to conservation aspects associated with Atlantic salmon populations and current trends in abundance and survival. Brown trout is indigenous to Europe, North Africa and western Asia, but was introduced into at least 24 countries outside Europe and now has a world-wide distribution. It exploits both fresh and salt waters for feeding and spawning (brackish), and populations are often partially migratory. One part of the population leaves and feeds elsewhere, while another part stays as residents. In large, complex systems, the species is polymorphic with different size morphs in the various parts of the habitat. Brown trout feed close to the surface and near shore, but large individuals may move far offshore. The species exhibits ontogenetic niche shifts partly related to size and partly to developmental rate. They switch when the amount of surplus energy available for growth becomes small with fast growers being younger and smaller fish than slow growers. Brown trout is an opportunistic carnivore, but individuals specialise at least temporarily on particular food items; insect larvae are important for the young in Dempson and O'Connell reviewed the Atlantic salmon, Jonsson and Jonsson the brown trout and Amundsen and Klemetsen the Arctic charr. Mortensen initiated the review and gave constructive criticism to the manuscript.

In this study, we present a promising method of computer vision-based quality grading of whole Atlantic salmon (Salmo salar). Using computer vision, it was possible to differentiate among different quality grades of Atlantic salmon based on the external geometrical information contained in the fish images. Initially, before the image acquisition, the fish were subjectively graded and labeled into grading classes by a qualified human inspector in the processing plant. Prior to classification, the salmon images were segmented into binary images, and then feature extraction was performed on the geometrical parameters of the fish from the grading classes. The classification algorithm was a threshold-based classifier, which was designed using linear discriminant analysis. The performance of the classifier was tested by using the leave-one-out cross-validation method, and the classification results showed a good agreement between the classification done by human inspectors and by the computer vision. The computer vision-based method classified correctly 90% of the salmon from the data set as compared with the classification by human inspector. Overall, it was shown that computer vision can be used as a powerful tool to grade Atlantic salmon into quality grades in a fast and nondestructive manner by a relatively simple classifier algorithm. The low cost of implementation of today&amp;amp;amp;#39;s advanced computer vision solutions makes this method feasible for industrial purposes in fish plants as it can replace manual labor, on which grading tasks still rely.