Productive performance of rainbow trout in cages under different feeding strategies

Abstract

Slight improvements in the feeding efficiency can be translated in an important diminution of the production costs and feed waste that would alter the water quality. With the objective of determine the optimal daily ration during the season of greater growth and study the effect of ration on the corporal condition and dispersion of weight statures under the conditions of an commercial aqua farm, the growth of 15 000 trouts under 3 treatments was evaluated during 4 weeks: feeding to satiety (J1), growth ration (J2) and maintenance ration (J3). The total length, corporal weight and corporal condition factor differed significantly with the applied treatment, resulting in all cases J1>J2>J3. The J1 group (153.9 ± 4.12 g) demonstrated the greater dispersion of weight statures, with respect to J2 (110.5 ± 2.74 g) and J3 (75.1 ± 1.94 g). An oscillating feeding behavior, with variations from 1 to 3% of a day for another one, has been observed in J1. The relation between the specific growth rate (SGR) and the daily ration (r) fit to a quadratic function, SGR=(-0.26.R2)+(2.64.R)-3.06. On the other hand, the relation between the feed conversion ratio FCA and the SGR fit to the function CA=(0.35.SGR2)-(1.83.SGR)+3.48. The optimal R was 2.9%. However, were not significant differences for global FCA between J1 (1.32 ± 0.08) and J2 (1.13. ± 0.14). Therefore, satiety feeding would be the best option during the summer when the temperature is optimal for the growth.