Intestinal morphology of the wild atlantic salmon (Salmo salar)

Abstract

The worldwide-industrialized production of Atlantic salmon (Salmo salar) has increased dramatically during the last decades, followed by diseases related to the on-going domestication process as a growing concern. Even though the gastrointestinal tract seems to be a target for different disorders in farmed fish, a description of the normal intestinal status in healthy, wild salmon is warranted. Here, we provide such information in addition to suggesting a referable anatomical standardization for the intestine. In this study, two groups of wild Atlantic salmon were investigated, consisting of post smolts on feed caught in the sea and of sexually mature, starved individuals sampled from a river. The two groups represent different stages in the anadromous salmon life cycle, which also are part of the production cycle of farmed salmon. Selected regions of gastrointestinal tract were subjected to morphological investigations including immunohistochemical, scanning electron microscopic, and morphometric analyses. A morphology-based nomenclature was established, defining the cardiac part of the stomach and five different regions of the Atlantic salmon intestine, including pyloric caeca, first segment of the mid-intestine with pyloric caeca, first segment of the mid-intestine posterior to pyloric caeca, second segment of the mid-intestine and posterior intestinal segment. In each of the above described regions, for both groups of fish, morphometrical measurements and regional histological investigations were performed with regards to magnitude and direction of mucosal folding as well as the composition of the intestinal wall. Additionally, immunohistochemistry showing cells positive for cytokeratins, α-actin and proliferating cell nuclear antigen, in addition to alkaline phosphatase reactivity in the segments is presented.

Gut morphology of diploid and triploid Atlantic salmon (Salmo salar L.)

“…This is in agreement with findings for Atlantic cod (Peruzzi et al 2013). The numbers of pyloric caeca of farmed diploid salmon (range 50-62) found in our study overlap those reported for wild fish (range 55-75) (Løkka et al 2013). …”

“…With regard to Atlantic salmon, gut morphology of wild, diploid fish has been described (Løkka et al 2013), but information about the digestive system of farmed triploids is lacking.…”

Transcriptional Characterization of the T Cell Population within the Salmonid Interbranchial Lymphoid Tissue

“…During the sampling procedure, macroscopic examination was performed, and pathological manifestations were registered. Samples were conserved in RNAlater and were collected from the second segment of midintestine (16), hereafter referred to as intestine, midkidney, and gills. In addition, gill samples designated for laser-capture microdissection were snap-frozen in liquid nitrogen for subsequent cryosectioning.…”

Aeromonas salmonicida Binds Differentially to Mucins Isolated from Skin and Intestinal Regions of Atlantic Salmon in an N -Acetylneuraminic Acid-Dependent Manner

“…Measurement of the surface area of pyloric ceca is less feasible, as the high number of ceca makes surface measurement very time-consuming and the lengthy handling time would severely lower the quality of the preparations. Furthermore, to our knowledge, there is no correlation between surface area of pyloric ceca and body weight as proposed for the skin, mainly due to the high individual variation in the numbers of ceca (31). Instead, the mucins of the pyloric ceca are expressed per unit of weight of the organ.…”