Halophyte plants native to Brazil: phenolic compounds, pigments, antioxidant activity and use in marine shrimp feeding (Litopenaeus vannamei Boone, 1931)
The objective of this thesis was to evaluate the effects of irrigation with saline water on the growth, productivity and chemical composition of the biomass of a selected group of six Brazilian halophytes, in addition to testing their antioxidant and nutritional potential in the diet of the marine shrimp Litopenaeus vannamei. In order to characterize the chemical composition of the selected halophytes, the extraction of phenolic compounds assisted by ultrasound was optimized (extraction time and ultrasonic power) by central composite planning using biomass of the marine asparagus Salicornia neei grown with shrimp effluent (chapter I). The optimal conditions (315 W for 30 minutes), also applied to other halophytes, soybean meal and rice, resulted in an increase of up to 30% in the content of phenolic compounds extracted.In Chapter II, it was verified that the phenolic compounds of halophytes showed a profile of phenolic acids and of the flavonoid quercetin diversified, but all species showed high antioxidant activity. However, some characteristics inherent to halophytes (such as raising metal content) may favor the pro-oxidant behavior of plant extracts. In Chapter III, it was determined that two new genotypes (BTH1 and BTH2) of S. neei showed high tolerance to salt stress (up to 769 mM NaCl) and different chromatic responses and production of bioactive metabolites against photo-oxidative stress generated by salinity. The BTH2 genotype showed a higher performance, content (and diversity) of phenolic acids and antioxidant capacity than BTH1 when produced in the field with shrimp effluents.Chapter IV shows that the insertion of the biomass of the BTH2 genotype of marine asparagus (S. neei) in the diet of juveniles of L. vannamei does not affect the survival and zootechnical performance of animals. Additionally, the insertion of up to 30% of S. neei reduced the levels of lipid peroxidation and changed the color (tending to red and yellow) of the shrimp meat. In general, the Brazilian halophytes studied have great potential to be used in food and in the health products of animals and men. This potential was particularly demonstrated by the BTH2 genotype of S. neei, which demonstrated high productivity with saline aquaculture effluent.