Body site matters: an evaluation and application of a novel histological methodology on the quantification of mucous cells in the skin of Atlantic salmon, Salmo salar L.

Abstract

Mucous cell size and distribution were investigated in the skin of five salmon using a novel stereology-based methodology: one (48 cm) fish to test 15 tissue treatment combinations on measures of cell area and density on the dorsolateral region and, using the most suitable treatment, we mapped mucous cell differences between body regions on four (52 cm) salmon, comprising a male and a female on each of two diets. The section site, decalcification, embedding medium and plane of sectioning all impacted significantly on mucous cell size, whereas mucous cell density is more robust. There were highly significant differences in both mucosal density and mean mucous cell size depending on body site: the dorsolateral skin of the four salmon had significantly denser (about 8% of skin area) and larger (mean about 160 μm(2)) mucous cells, whereas the lowest mean density (about 4%) and smallest mean area (115 μm(2)) were found on the head. We found that 100 random measurements may be sufficient to distinguish differences >7 μm(2) in mean mucous cell areas. The results further suggest that salmon exhibit a dynamic repeatable pattern of mucous cell development influenced by sex, diet and possibly strain and season.

Microbial ecology of Atlantic salmon, Salmo salar, hatcheries: impacts of the built environment on fish mucosal microbiota

“…Elevated skin mucous cell numbers are generally reflective of healthy fish whereas depleted mucosal cells may indicate a recent mucosal discharge due to stress or disease (63, 64). Mucosal cell numbers however, can also be influenced by the sampling location on the fish body, sex, diet, and age or development stage, thus care must be taken when interpreting results (31, 65, 66). In our study, skin and gill mucosal cell numbers were elevated in both RAS systems compared to the FT suggesting that RAS fish may have been more healthy or less stressed.…”

Stress response of Salmo salar (Linnaeus 1758) facing low abundance infestation of Caligus rogercresseyi (Boxshall & Bravo 2000), an object in the tank, and handling

“…Slicing was performed in tangential sections of 5 μm, running almost parallel to the epidermal stratifications, which are not planar (Pittman et al . ). Sections were stained with haematoxylin–periodic acid–Schiff (PAS) staining.…”

“…All samples were dehydrated in an increasing gradient of alcohols, cleared in xylene and embedded in paraffin. Slicing was performed in tangential sections of 5 lm, running almost parallel to the epidermal stratifications, which are not planar (Pittman et al 2013). Sections were stained with haematoxylin-periodic acid-Schiff (PAS) staining.…”

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

“…These properties of mucus have mainly been ascribed to the mucin molecules. However, Atlantic salmon mucins had not been isolated previously, and the knowledge of their biochemical characteristics in this species is scarce and mainly based on histological staining and lectin binding techniques (39)(40)(41)(42). We used isopycnic density gradient centrifugation to isolate mucins on the basis of their characteristic densities.…”