Effect of diets containing tuna head hydrolysates on the survival and growth of shrimp Penaeus vannamei.

摘要

A feeding trial was conducted to evaluate the effect of the supplementation of hydrolysates from tuna head on the survival and growth of Penaeus vannamei. To this end, a feeding trial was performed on eleven groups of shrimps of average weight 4.34 g. Every group was distributed into three tanks (30 shrimps per tank of 150 L) and was fed with one of the following eleven diets, all of them containing 40% crude protein: one diet containing tuna head meal as the principal protein source, which was used as control diet; nine diets formulated by replacing 50% tuna head meal by fish protein hydrolysates (FPH), and finally one commercial diet chosen as a reference. FPH were obtained by hydrolysis of tuna head during 2, 3 or 6 h and ulterior centrifugation in order to recover an aqueous fraction containing soluble protein and a solid sludge. 9 different diets were formulated according to the origin of the FPH: three diets DS2, DS3 and DS6 containing the soluble protein powders (dry extract from the aqueous fraction) recovered after 2, 3 and 6 h of hydrolysis, respectively; 3 diets supplemented with insoluble protein powers DI2, DI3, DI6 (obtained after drying the solid sludge) and 3 diets containing a mixture of both soluble and insoluble protein powers DM2, DM3, DM6. After 6 weeks of experiment, the survival, gain weight, feed conversion ratio and protein efficiency ratio were compared between the different groups. The present study showed that the diets supplemented with soluble protein powders (DS2, DS3 and DS6), as well as one containing insoluble protein powder (DI2) from the hydrolysis of tuna head improved significantly the four zootechnical parameters studied. On the contrary, the survival rates and growth performances for the groups fed with the diets containing a mixture of protein powders were not significantly different or even lower compared to the control and the commercial diets. It was concluded that fraction separation after hydrolysis had a positive effect on the zootechnical performance of the formulated diets.