Microbial biomass (MB) produced by different industries is thought to be a beneficial supplement in fish feed due to high contents of antioxidants and pigments.However, little is known about their impact on fish health. In this experiment, 960 tilapia (26.84 AE 1.03 g) were fed one of eight experimental diets-a control diet with no MB (C), a control diet with vitamin E (VE) and six diets with three types of MB at two concentrations (0.25% and 0.5%): Rubrivivax gelatinosus (RG25 and RG50), Spirulina platensis (SP25 and SP50) and Saccharomyces cerevisiae (SC25 and SC50). Adding MB to diets decreased plasma total oxidant status, malonaldehyde and leucocyte respiratory burst; increased the total antioxidant status; and did not affect the blood biochemical parameters. In flesh, the use of the MB lowered the thiobarbituric acid-reactive substances and increased redness (except for SC) and carotenoid deposition (except SC25). So, it was concluded that the use of the MB provided an antioxidant effect in tilapia blood plasma, decreased lipid oxidation and increased pigmentation and carotenoid deposition in the fish flesh, without imparting a negative impact on the animals' health. K E Y W O R D Sbiochemical analysis, carotenoids, colour, leucocyte respiratory burst, lipid oxidation, TBARS

No abstract

The proteins recovered by ultrafiltration (UF) represent a co-product of fish industrialization and can be used as a protein ingredient in the fortification of food formulations. The objective of this study was to evaluate the quality of surimi fishburger elaborated with the proteins recovered by UF from the wastewater generated in the production of surimi. The water generated in the washing operations of trims of farmed tilapia (Oreochromis niloticus) were filtered in a 30 kDa polyethersulfone membrane. The recovered proteins were dehydrated in spray dryer and added at 5 and 10% into fishburgers made with tilapia surimi. The fishburgers were evaluated for proximal composition, cooking yield, sensory parameters and acceptability. The incorporation of proteins into the fishburgers improved the sensory aspects of the final product and provided greater acceptability while maintaining the same manufacturing yield. The addition of 10% of the recovered proteins increased the nutritional value of surimi fishburgers. Practical Application:The recovery of proteins from surimi wastewaters reduces organic matter, makes the production process more profitable and less aggressive to environment and, in addition, provides a protein-rich ingredient that may find use in food industry. The use of this protein concentrate in food products like surimi increases nutritional quality and productivity and so may reach consumers and producers demands.

Materials and methods 2.1 Surimi processing Cuttings of tilapia fillets (Oreochromis niloticus) resulting from filleting were ground and subjected to three successive