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ABSTRACT The aim of this study was to evaluate the performance of Patagonian octopus fed with moist diets formulated with several local feed ingredients. All formulated diets were based on [...]

ABSTRACT Juveniles of the white shrimp Litopenaeus vannamei were kept without food for between 0 to 15 days to evaluate the impact of starvation on physiologic state (oxygen consumption, poststarvation [...]

This study evaluated the effect of biofloc technology (BFT) at 3 (lsBFT) and 35 (hsBFT) practice salinity units (psu) on the zootechnical performance, oxygen consumption, antioxidant activity, and oxidative damage of Litopenaeus setiferus juveniles reared in outdoor tanks. After 90 days, no significant differences were observed in terms of survival (p >.05). The final weight as well as wet weight gain, final biomass, and feeding conversion ratio (FCR) showed higher values for shrimp reared with hsBFT than those reared with lsBFT (p <.05). Compared to that for the hsBFT treatment, high oxygen consumption (VO2) was observed for the lsBFT treatment under fasting and postprandial conditions (p <.05). The activity of the enzymes catalase, superoxide dismutase, and glutathione‐S‐transferase from shrimp muscle did not show significant differences between the treatments (p >.05). Regarding the lipid peroxidation (LPO) and oxidized protein (PO) in muscle samples, no significant differences were observed in LPO, whereas the PO was significantly higher for the lsBFT treatment (p <.05), which was related to higher fasting and postprandial oxygen consumption of the juveniles (p <.05). The adaptation of L. setiferus juveniles reared in BFT at low salinity is relatively weak because of their low growth and excessive oxygen consumption and the oxidative damage (PO) produced. [ABSTRACT FROM AUTHOR]

Carnivorous common snook (Centropomus undecimalis) has potential for aquaculture, but its protein requirement in diet is 500 g kg−1 and the energetic role of lipids in this species has not been explored. Thus, this study investigated the ability of juvenile common snook (8.7 ± 1.2 g) to use dietary lipids as an energy source. The fish were fed four practical diets with two protein levels (400 and 500 g kg−1) associated with two lipid levels (60 and 120 g kg−1) for 12 weeks. Growth performance significantly improved with increasing dietary lipid levels, but no significant difference was observed at the protein level. Fish fed the 400:60 (protein: lipid level) diet exhibited significantly higher feed conversion ratios than those fed 400:120, 500:60 and 500:120 diets, but fish fed the 400:120 diet had significantly higher protein efficiency ratios. Juvenile common snook showed the ability to modulate digestive protease and lipase secretion when dietary protein or lipid levels were modified. The activity of alanine aminotransferase decreased as the dietary lipid level increased (p <.05), while fructose‐1 and 6‐bisphosphatase activities were not significantly affected by dietary protein or lipid levels. Glucose‐6‐phosphate dehydrogenase, 6‐phosphogluconate dehydrogenase and pyruvate kinase activities increased as dietary protein and lipid levels increased (p <.05). The results of this study indicate that an increase in dietary lipid level has a protein‐sparing effect and that the diet containing 400 g kg−1 protein with 120 g kg−1 lipid is suitable for growth and effective protein utilization in common snook. [ABSTRACT FROM AUTHOR]

In a 45‐d experiment, Litopenaeus vannamei was cultured in two treatments, biofloc technology or clear water recirculating aquaculture system, to evaluate the effect on growth and survival, energy balance, and texture of the marketable product. The experimental design consisted of 40 plastic tanks of 54 L (20 tanks per treatment), with a density of 140 organisms/m3 in each culture system. The final body weight, daily growth coefficient, and survival were significantly higher (P < 0.05) in biofloc technology (12.40 g, 5.0%g/d, and 87.1%, respectively) than in the clear water system (7.0 g, 1.4%g/d, and 74.2%). The retained energy and energy content of exuviae were significantly higher for shrimp in the biofloc technology (448.5 ± 36.4 and 22.4 ± 1.8 J/shrimp/d, respectively) than in clear water (246.3 ± 40.9 and 12.3 ± 2.0 J/shrimp/d, respectively). Routine metabolism was significantly higher for the clear water treatment (411.4 ± 123.8 J/shrimp/d). Shear force was higher in the biofloc technology, indicating greater muscle firmness; this matched the gel electrophoresis patterns of the proteins extracted from the muscle tissues. This suggests that biofloc technology could be used not only to improve growth and survival in L. vannamei but also to enhance the final product quality and acceptability in the market. [ABSTRACT FROM AUTHOR]