5. Conclusions
The present study showed that the diets supplied 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 both growth and the survival rates of shrimps, as well as
the feed conversion ratio and the protein efficiency ratio. On the contrary,
the incorporation of the mixtures of protein powder did not improve
the survival and growth of shrimp, compared with the control.
The results demonstrated that the hydrolysis of the tuna heads and
the ulterior separation of the resulting fractions by centrifugation
had a positive effect on the survival and growth of shrimps, compared
to the traditional feeding with fish meal. Further research is needed in
order to develop a commercial diet containing fish hydrolysates. The
scaling up of the procedure described above requires that all the operational
variables controlling the hydrolysis be optimized in order
to assure the quality standards of a product intended to shrimp feeding
while limiting the operation costs associated (i.e. energy consumption,
time of hydrolysis, etc.).