Seam breams, Sparus aurata. (Photo: Luis Miguel Bugallo Sánchez)
Mucus protective proteins discovered in sea breams
Monday, June 17, 2013, 02:30 (GMT + 9)
A team of researchers from the National Research Council (CSIC) identified six new proteins that protect the mucus membranes of sea breams (Sparus aurata).
As it was explained by Jaume Pérez, a CSIC research professor and a member of the Institute of Aquaculture Torre de la Sal, Castellón, they studied "the mucin gene expression in various organs of the sea bream, and how they can be altered by changes in the diet or exposure to pathogens."
Mucins are a class of proteins produced by epithelial tissue cells that form the mucus of most animals, and play an important role in the protection against external aggression.
The group found six new mucins: three that are anchored to the cell membrane and three that are secreted.
"The Muc18 predominates in the skin, gills, and stomach; the Muc19 in the esophagus while the Muc13 is found in the whole intestinal tract," explained the researcher.
In addition, he said that in the downstream of the bowel a mucin was found that has no equivalent in mammals and that is responsive to the changes caused by the diet of the fish, which they called I-Muc intestinal mucin.
Meanwhile, the researcher Ariadna Sitjà stated they performed experiments with sea breams that had been fed on diets in which fish oil was replaced by vegetable oils, and found that "the expression of I-Muc was thus significantly reduced."
CSIC researchers also noted that in the sea breams infected by the intestinal parasite Enteromyxum lee there was a sharp decline in all intestinal mucins, especially the I-Muc.
The research results, which were published in the journal Plos One, reflect the intensity and progression of this disease in the sea bream.
"We believe these mucins could be used as diagnostic biomarkers of the impact of infections in fish, and that the I-Muc could have a predictive value of the fish's resilience to various types of enteritis," CSIC experts emphasize.
Since it is a commercially valuable species, which is grown mainly in the Mediterranean region, these findings could be useful to develop new diets and to find additives that improve their intestinal health or reduce the impact of intestinal pathogens.
The study was funded by the European project Advanced Research Initiatives for Nutrition & Aquaculture, the national projects Enteromyx Control and Aquagenomics, and Prometheus programme.
This research was also joined by scientists from the National Institute of Agronomic Research, France.
By Analia Murias