Cría de juveniles de tenca ("Tinca tinca L.")dietas compuestas y alternativas para una acuicultura sostenible

Resum

With the aim of advancing in the formulation and ellaboration of a specific and sustainable diet for juvenile tench, the effects of fishmeal and fish oil replacement with alternative sources of protein and lipids on their survival, growth and body composition were evaluated. For this, four 90-day experiments were carried out with four-month-old tench juveniles. Considering previous results of our research team and considering a possible deficiency of methionine and arginine as a limiting factor to increase the inclusion levels of soybean and pea protein concentrate in the diets, two experiments were carried out where the effects of supplementation with both essential amino acids. In both cases, the tench juveniles had a high tolerance to the inclusion of both, soybean protein concentrate (up to 383 g kg-1 diet) and pea (up to 487 g kg-1 diet), without negative effects on survival and growth. Methionine was the main limiting amino acid and its minimum requirements for tench juveniles can be estimated at 10 g kg-1 of diet, making supplementation of this amino acid unnecessary over that amount. Regarding the effects on body composition, the inclusion of both protein concentrates determined a significant reduction in lipid content in the diets, which was reflected in the decrease in body fat content of tench juveniles. In the other two experiments, the fish oil was replaced by a mixture of vegetable oils or by camelina oil, verifying in both cases that the total substitution did not affect the survival or growth of tench juveniles. Regarding body composition, juveniles fed diets that did not contain fish oil showed a significant decrease in body lipid content. No significant differences were found in the total content of saturated, monounsaturated, and polyunsaturated fatty acids among tench juveniles fed diets where fish oil was partially or totally replaced by vegetable oils. The highest/best values of the nutritional index polyunsaturated fatty acids / saturated fatty acids corresponding to the body analysis of the juvenile tench, were obtained with the diets with total replacement of fish oil by a mixture of vegetable oils or camelina oil, 0.86 and 0.92, respectively. The results obtained in this provide valuable information to achieve specific free fishmeal and fish oil diets for juvenile tench.