ABSTRACT This study determined the apparent digestibility for crude protein (ACPD) and essential aminoacids (AEAAD) of ingredients for Litopenaeus vannamei fed diets containing soy protein concentrate (SPC), corn gluten meal (CGM), poultry byproduct meal (PBM), meat and bone meal (MBM), hydrolyzed feather meal (HFM), spray-dried blood meal (DBM), tilapia byproduct meal (TBM), Brazilian marine fish meal (BFM), salmon byproduct meal (SLM), and krill meal (KRM). Digestibility was estimated using chromic oxide as a marker in a reference (REF) mixture. Shrimp of 6-8 g body weight were reared over three separate experimental stages lasting 29-30 days each. Shrimp survival exceeded 96% and was unaffected by test ingredient. The ACPD ranged from 66.7% for a diet containing DBM to 84.2% for the REF diet. Higher ACPD were observed for aquatic compared with plant and terrestrial animal byproducts. Aside from SPC (79.3%), ACPD for CGM was low at 47.5%. Among terrestrial animal byproducts, ACPD was higher for MBM compared with PBM, DBM, and HFM (71.2, 62.8, 48.6, and 45.9%, respectively). With the exception of BFM (59.7%), ACPD for all other aquatic proteins was high (KRM, 84.3%; TBM, 83.3%; SLM, 78.9%). Aquatic proteins have higher crude protein (CP) and essential aminoacid (EAA) digestibility for shrimp. Ingredients SLM, SPC, TBM, and KRM are preferable in feeds for the whiteleg shrimp since they carry a high CP and EAA content (>600 g kg−1) combined with ADC near or in excess of 80%.

ABSTRACT This study was conducted to evaluate the effect of rice byproducts on water quality, microbial community, and growth performance of L. vannamei juveniles. Shrimp of 0.98±0.10 g body weight (BW) were reared in 49 tanks of 1.5 m3 under 127 animals m−2 for 77 days. Rice bran, rice grits, and rice hulls were mixed into five different fertilizers varying their fiber content (90, 110, 150, 200, and 250 g kg−1) and compared against sugarcane molasses (MO) and unfertilized tanks (UNF). Rice byproducts and MO were applied in water three times a week at a fixed rate of 4.5 g m−3. Water salinity, pH, temperature, and dissolved oxygen reached 43±2 g L−1, 8.03±0.32, 30.2±0.90 °C, and 5.03±0.53 mg L−1, respectively. Settleable solids (SS) were higher in tanks fertilized with rice byproducts (from 2.5±1.0 to 3.1±1.1 mL L−1) and MO (3.4±1.0 mL L−1). Total ammonia nitrogen (0.19±0.09 mg L−1), nitrite (5.97±2.04 mg L−1), and nitrate (1.29±0.48 mg L−1) were kept low without any significant differences among treatments. The concentration of heterotrophic bacteria and fungi was significantly higher in rice byproducts compared with MO. Water fertilization had no effect on final shrimp survival (85.5±9.5%), weekly growth (0.72±0.11 g), and feed conversion ratio (1.59±0.10). Tanks treated with rice byproducts, except with 90 g kg−1 fiber, resulted in a higher final shrimp BW (from 9.04±1.56 to 9.52±1.89 g) compared with MO (8.75±2.14 g) and UNF (7.74±1.48 g). Gained yield and feed intake were significantly higher for tanks treated with rice byproducts than with UNF. A mix of rice byproducts can be equally or more effective as carbon sources to shrimp culture than MO.

ABSTRACT A 10-week study was conducted to evaluate the effect of feed allowance and graded levels of dietary methionine (Met) on growth performance of Litopenaeus vannamei. Juvenile shrimp of 1.83±0.14 g were stocked in 42 outdoor green-water tanks of 1 m3 under 120 shrimp m−2. Animals were fed under two feed allowances, regular and 30% in excess. Five diets with 30 g kg−1 fishmeal were designed to contain 318±2 g kg−1 crude protein and a minimum amount of protein-bound Met. To achieve graded levels of dietary Met, a control diet with 4.6 g kg−1 Met or 8.9 g kg−1 methionine + cysteine (M+C) was supplemented with 1.2, 2.2, 3.2, and 4.2 g kg−1 of DL-methionyl-DL-methionine to result in total dietary Met of 5.6, 6.9, 7.9, and 9.2 g kg−1 (10.0, 11.2, 12.1, and 13.5 g kg−1 M+C, respectively). A final survival of 86.5±3.6% was reached with no significant influence from feed allowance or dietary Met. Feed inputs significantly affected apparent feed intake, weekly shrimp growth, final body weight (BW), and gained yield. Larger meals and a higher dietary Met had no impact on feed conversion ratio. There was a significant interaction between feed allowance and Met over shrimp BW. By feeding animals in excess, BW was enhanced at 6.9 g kg−1 Met. A dietary Met of 7.9 g kg−1 was required to achieve a maximum BW under a regular feed allowance. Thus, shrimp required less amounts of dietary Met to maximize BW when higher feed inputs were delivered. Our findings demonstrate a sparing effect of dietary Met for L. vannamei when a higher feed allowance is adopted. Shrimp farmers should consider adjusting feed allowance to dietary Met to maximize shrimp growth performance and yield.

RESUMO A geração de efluentes e o custo com a alimentação do camarão são os principais desafios enfrentados pela carcinicultura. Uma solução conjunta para ambos os problemas é a produção de bioflocos em um sistema de lodo ativado para tratamento de efluentes. Neste trabalho, o afluente ao sistema estudado era composto pelas águas residuais do cultivo de camarão suplementadas com ureia e melaço de cana-de-açúcar. Os resultados mostraram que a remoção média de demanda química de oxigênio foi de 71% e a produção média de bioflocos no reator foi de aproximadamente 1,5 g.L-1. A adição de melaço ao afluente contribuiu para o aumento da quantidade e da diversidade de microrganismos benéficos para a produção de camarão. Houve remoção de amônia e nitrificação confirmada pelo balanço de massa. Portanto, a utilização do sistema de lodos ativados é uma alternativa viável e ambientalmente adequada para produzir bioflocos e tratar efluentes de cultivo de camarão.

ABSTRACT The release of wastewater and the shrimp feed cost are the main challenges faced by the shrimp farming industry. An alternative solution to both problems is biofloc production in a unit external to the farm, in an activated sludge system for effluent treatment. The treatment system’s influent was composed of the shrimp farm wastewater supplemented with urea and sugarcane molasses. The results show that the average removal of chemical oxygen demand was 71% and the average biofloc production in the reactor was approximately 1.5g.L-1. Adding molasses to the influent contributed to the increase in the quantity and diversity of existing microorganisms that are beneficial to cultured shrimp. The mass balance of nitrogen compounds confirmed that nitrification occurred in the system. Therefore, the use of the activated sludge system is a viable and environmentally suitable alternative to produce bioflocs and shrimp farming effluent treatment.

ABSTRACT This study investigated the effect of dietary amino acid composition from proteins alternative to fishmeal on the growth performance of the common snook, Centropomus undecimalis. Fish of 10.79±0.71 g (n = 150) were stocked in 15 shaded outdoor tanks of 1 m3. The basal diet contained 643.4 g kg−1 salmon byproduct meal (SML) and 200.0 g kg−1 soy protein concentrate (SPC). Two other diets replaced 39 and 29% of the SML with poultry byproduct meal (PBM, 170.1 g kg−1) and SPC (334.9 g kg−1), respectively. Fish were fed twice daily for 84 days under 32±1 g L−1 water salinity and 27.3±0.9 °C temperature. Final survival (99.5±2.6%) was unaffected by dietary treatment. Snook grew slower (0.24±0.03 and 0.27±0.04 vs 0.35±0.06 g day−1) and achieved the lowest body weight (31.1±6.62 and 33.3±10.20 vs 40.4±13.18 g) and the highest feed conversion ratio (3.69±0.29 and 3.11±0.51 vs 2.33±0.34) when fed SPC and basal diets compared with PBM, respectively. Retention of dietary crude protein varied from 36 to 38% for fish fed the basal and SPC diets, but exceeded 51% in fish fed PBM. Results indicate a greater ability of the common snook to gain weight and increase retention of nutrients when dietary protein is of terrestrial animal origin. Dietary protein from PBM yields a more balanced dietary amino acid composition relative to fish muscle, but possibly in excess of the species requirements.

The present study compared the bioavailability of crude protein and lipid from biofloc meals generated with an activated sludge system using two water sources: wastewater from shrimp experimental culture (BFL-W) and, artificially, using clean seawater (BFL-C). The sludge system operated by chemical and organic fertilization three times per week. Sampling of bioflocs occurred every two days during 81 days. To evaluate digestibility, each type of biofloc meal was incorporated into a reference diet (REF) at 300 g/kg. Another diet acted as a negative control (NEG) by using fish waste meal. The apparent digestibility of bioflocs was estimated by the indirect method using chromic oxide (Cr2O3) as the inert marker at 10 g/kg of the diet. Juvenile L. vannamei of 5.09±0.79 g (n = 440) were stocked at 10 shrimp/tank in 44 tanks of 61 L each that operated under a water recirculating regime. Biofloc meals contained a high ash content (591.0-649.2 g/kg) combined with a low crude protein content (95.9-137.3 g/kg). After 26 days, shrimp achieved a final survival of 93.2±0.8% and a biomass gain of 37.1±1.8 g/tank. Final shrimp body weight ranged from 9.01±0.15 to 9.45±0.13 g. The apparent digestibility coefficient (ADC) of crude protein in the biofloc produced from BFL-W, BFL-C and fish waste meal (NEG) reached 26.0, 25.7, and 64.1%, respectively. Similarly, the lipid ADC was 78.9, 67.9, and 85.8%, respectively. This study indicated that biofloc meals had a low protein availability for L. vannamei. However, although low levels of lipid were present, it proved to be available for the species. The dietary inclusion of biofloc meal appears to have a growth-promoting effect on shrimp, which may be associated with trace minerals, or other nutrients not identified in this study.

This study determined the efficacy of a β-1,3/1,6-glucan source on the survival, growth, and immunological responses of Litopenaeusvannamei challenged with infectious myonecrosis virus (IMNV). The work was conducted in 20 tanks of 500 L with clear water with constant recirculation and aeration. Shrimp weighing 2.6±0.4 g were stocked at 100 animals/m2 and reared for 10 weeks. Viral challenge occurred through oral administration of IMNV positive extract (1.82 £ × 103 copies of IMNV/µL RNA) during three consecutive days, twice a day. One treatment and three controls, with five replicatetanks each, were used, as follows: Com - commercial diet fed to non-challenged shrimp (NCS); Ref - lab-manufactured basal diet, deprived of β-1,3/1,6- glucan fed to NCS; IMNV-Ref - basal diet fed to IMNV-challenged shrimp; and, IMNV-BetG - basal diet with 1,000 mg/kg of a β-1,3/1,6-glucan. Per os challenge began on the 29th day of rearing (4.93-g to 6.92-g shrimp). Shrimp were effectively contaminated with IMNV. Animals were highly susceptible to IMNV four weeks after the first day of infection when mortality peaked. Shrimp in the Com treatment (69.5±12.7%) reached the highest survival, but it did not differ from the Ref group (57.9±9.21%). Shrimp under the IMNV-Ref treatment achieved the lowest survival (23.2±5.76%). Survival for IMNV-BetG (48.1±8.53%) was significantly higher than IMNV-Ref, and similar to the Ref group. Total hemocyte count was significantly affected by treatment and hemolymph sampling time, while serum protein concentration and phenoloxidase activity did not change. Addition of 1,000 mg/kg of β-1,3/1,6-glucan in a diet for L. vannamei enhances shrimp survival when orally exposed to IMNV. No signs of immunological fatigue or detriment in growth are detected when the species is continually exposed to this diet.