Effects of dietary protein:lipid ratio on genes implicated in somatic growth, lipid metabolism and food intake in pejerrey fry (Odontesthes bonariensis).

BERTUCCI JI; BLANCO AM; UNNIAPPAN S; NAVARRO JC; CANOSA LF

Buenos Aires

Congreso; Reunion conjunta de sociedades de biociencia; 2017

Sociedades de Biociencias de Argentina

Abstract: Pejerrey is a freshwaterfish from south America with potential as an aquaculture specie. With the majorgoal to develop its aquaculture, the aim of this study was to determine thebest protein:lipid ratio of diets to achieve higher growth rates in first stagesof development. To do this, pejerrey fry (30 days after hatching) were dividedin three groups, each one fed per 60 days with an experimental diet containingone of the following protein (P):lipid (L) ratios: 40% P ? 12% L (Diet 40P12L);40% P ? 20% L (Diet 40P20L); 50% P ? 12% L (Diet 50P12L) and 50% P ? 20% L (Diet50P20L). After trial, RNA from head, trunk and tail were collected to analyzethe gene expression of components from the GH-IGF axis. Also, the geneexpression from the enzyme ∆6-desaturase (involved inlipid metabolism) and from the anorexigenic peptide nesfatin-1 were measured. Fryfed with diets 40P12L and 50P12L showed the highest somatic growth and highestgrowth hormone (gh) gene expression.The total amount of PUFAs from the sere n-6 was higher in group fed on diet50P20L. The ∆6-desaturase geneexpression was higher in head of those fry fed on diet 40P12L. The expressionlevels of nucb2/nesfatin-1 and gh in head, and of nucb2/nesfatin-1 and the ghr-Iand ghr-II in body follow the samepatterns. In conclusion, diets with 12% of lipids produces the higher frygrowth compared to those diets containing 20%. Comparing diets with 12% oflipid content, the higher percent of proteins (50%) generates the highergrowth-rates. In these groups, mRNA expression from GH-IGF axis could berelated with the promotion of somatic growth. The different expression patternsof nucb2/nesfatin-1 in head and bodyof pejerrey fry seems to indicate some effect not only related to food intakeregulation.