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A life-cycle assessment was conducted during semi-intensive and super-intensive commercial cultivation of marine shrimp from December 2011 to June 2012, considering all phases from the preparation of the nursery to harvesting of the shrimp, to determine the carbon footprints of each process. Inputs and outputs associated to the production of 1 kg of shrimp were evaluated using the CML-1A baseline method, V3.01 EU25, with Software SimaPro ® 8.0.2, to identify the factors of impact that are most relevant to the category global warming, measured in kg of CO 2 eq. The grow-out phase contributed the most to the final results in super-intensive culture, which had a higher carbon footprint, 47.9967 kg of CO 2 eq., which was 1.0042 kg of CO 2 eq. in the semi-intensive culture. The most important impacting factor is the use of electrical energy, which is required to maintain dissolved oxygen and the biofloc particles in suspension in the super-intensive culture and for movement of large volumes of water in the semi-intensive system.

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The objective of this study was to evaluate the effect of different stocking densities and the presence/absence of two artificial substrates on water quality and production rates of marine shrimp in a biofloc shrimp nursery culture. Two experiments were performed: different stocking densities with mosquito netting substrate and the presence/absence of polyestertype substrate. The first experiment lasted 38 days, and shrimp at an initial weight of 0.013±0.010 g were stocked in 24 tanks. The second experiment lasted 35 days, and shrimp at an initial weight of 0.037±0.002 g were stocked in six tanks. Weekly biometric measurements were performed to adjust the amount of feed. Suspended solids were higher at a density of 6000 PL m −3 and mosquito netting substrate. Final weight and specific growth rate were higher in treatments with mosquito netting substrate. However, survival was significantly lower with this substrate. Yield was significantly higher at a density of 6000 PL m −3. Polyester-type substrate had no significant effect on production rates or variables of water quality. However, this substrate could reduce the production of sludge. The results indicate that it is possible to culture shrimp in nursery stage up to 6000 PL m −3 in a biofloc system.

This study aimed to evaluate the production of phenolic compounds, antioxidant activity and growth performance of Sarcocornia ambigua exposed to different periods of continuous irrigation in an aquaponics system with Litopenaeus vannamei reared in a biofloc technology (BFT) system, in addition to possible effects on shrimp growth performance, nitrogen recovery and water quality. Four treatments were evaluated as follows: 6, 12, 18 and 24 h of continuous irrigation per day, all set up in triplicate.Plants from the 12 and 24 h of irrigation treatments exhibited significantly higher values of phenolic compounds, 48.4 ± 1.8 and 47.7 ± 1.6 mg Gallic acid equivalent (GAE) 100 g −1 FW (fresh weight), respectively, when compared with the 6 and 18 h treatments, 42.6 ± 1.1 and 42.6 ± 1.3 mg GAE 100 g −1 FW, respectively (p < 0.05).Antioxidant activity also differed significantly between treatments (p < 0.05). The highest concentrations were found in treatments of 12 and 24 h of irrigation, which presented 41.3 ± 0.6 and 42.7 ± 0.8 μmol Trolox Equivalent Antioxidant Capacity (TEAC) 100 g −1 FW, respectively. For treatments of 6 and 18 h of irrigation, the concentrations were 29.9 ± 0.8 and 31.1 ± 1.5 μmol TEAC 100 g −1 FW. No significant differences between treatments were observed for plant and shrimp growth performance (p ≥ 0.05). There was also no significant effect of the different irrigation periods on water quality (p ≥ 0.05). The overall mean nitrogen recovery was 29.3% for all treatments. In conclusion, S. ambigua cultivated under 12 and 24 h of continuous irrigation exhibited higher production of bioactive compounds and antioxidant activity.

Soybean molasses was evaluated as a partial replacement for sugarcane molasses as a carbon source for biofloc development in the superintensive culture of Pacific white shrimp (Litopenaeus vannamei). A 50-day study was conducted with juvenile (3.2 g) shrimp stocked in 16 800 L tanks at a stocking density of 250 shrimp m À3 . Control of total ammonia concentration was performed by the addition of combined mixtures of soybean and sugarcane molasses to the culture water. Three different molasses treatments were evaluated using different soybean-to-sugarcane molasses ratios: 15-85%, 38-62% and 60-40% respectively. The control group was treated only with sugarcane molasses. Water quality, chlorophyll a concentration, heterotrophic bacterial load, Vibrio spp. concentration and zootechnical indexes were all evaluated. Total ammonia concentration was controlled by heterotrophic and chemotrophic pathways. Biofloc formation, as quantified by measuring the total suspended solids, was not altered. The Vibrio spp. concentration showed a significant reduction in treatments with soybean-to-sugarcane molasses ratios of 38-62% and 60-40%. All combined mixtures of soybean and sugarcane molasses could maintain water quality and productivity in the superintensive culture of L. vannamei using the biofloc system. Thus, the potential use of a residue from agroindustry as a carbon source in a biofloc culture is demonstrated.