Authors: Esther Leal Cebrián, Rita Angotzi, Alejandra Godino-Gimeno, Silvia Gregorio, Josep Rotllant, Alfonso Saera-Vila, Juan Fuentes, Jose Miguel Cerdá Reverter

Institutions:

• Instituto de Acuicultura de Torre de la Sal, CSIC, Castelló, Spain
• Sequentia Biotech SL, Carrer Comte d’Urgell 240, Barcelona, Spain

Publication: Red de Bibliotecas y Archivos CSIC

Date: November, 2022

Link: Melanocortinas y su función intestinal en peces

Abstract:

Overexpression of agouti-signalling protein (ASIP) in transgenic zebrafish increases food intake levels and linear growth. A higher feed intake is unnecessary in transgenic fish to enable larger and heavier growth. A plausible explanation may rely on the enhanced feeding efficiency mediated by improved nutrient absorption in transgenic animals. Transcriptomic results suggested that amino acid, monocarboxylates, ionic and vitamin transmembrane transport was substantially modified. Enrichment analysis revealed an inhibition of intestinal lipid metabolism and down-regulation of KEGG pathways related to membrane integrity suggesting an augmented intestinal laxity that may result in enhanced paracellular transport. Electrophysiological experiments showed that asip1 overexpression decrease membrane tissue resistance (Rt), indicating a modification of the intestinal barrier function in ASIP1 transgenic animals. Paracellular permeability was higher in ASIP fish. Both the decrease in Rt and the increase in permeability point to an ASIP1-dependent decrease in the tissue barrier function. Electrogenic amino acid transport was enhanced in transgenic fish providing a strong indication that ASIP1 fish can extract more amino acids from their diet at similar feeding levels. Both transcriptomic and electrophysiological results support that asip1-overexpressing zebrafish display improved nutrient absorption and by extension a higher feed efficiency which explains enhanced growth in the absence of augmented food intake.