Growth, immunological and physiological parameters of white shrimp Litopenaeus vannamei reared at different salinity levels (1, 10, 15, 25 and 35 g/L) at stocking density of 214 shrimp/m3 were ...examined at 1, 30 and 63 days. Results showed that the total haemocyte count (THC) of shrimp decreased with time at all salinity levels, indicating a potential reduction in the resistance of shrimp against pathogens, since a low value of THC indicates a perturbation of the immune system. Glucose and protein values observed in the haemolymph throughout the study indicate that shrimp adapted well to low salinities (1, 10 and 15 g/L). Although of those shrimp reared at 10 g/L only 83.3% survived, at this salinity, shrimp depicted a higher glucose concentration in haemolymph at the beginning and end of the study.
The aim of this study was to evaluate the effect of light limitation on the water quality, bacterial counts and performance of Litopenaeus vannamei postlarvae reared with biofloc at low salinity ...(≈9 g L−1). Two treatments were designed: T1 = culture with natural sunlight and T2 = culture in darkness. After 28 days, in both treatments, the final weight of shrimp was over 0.6 g with a specific growth rate over 7.4% d−1, and a survival rate over 70%. In both treatments, Vibrio sp. concentration presented low values (culture with natural sunlight = 0.1 to 9.9 × 102 CFU mL−1, culture in darkness = 0.4 to 11.7 × 102 CFU mL−1) and Bacillus sp. had high values (culture with natural sunlight = 0.7 to 66.0 × 104 CFU mL−1, culture in darkness = 0.7 to 65.8 × 104 CFU mL−1). All water quality parameters remained within the ranges suitable for shrimp culture, except for alkalinity during the first stage of the study. Although in some sampling periods some significant differences were found in bacterial counts and water quality parameters, shrimp productive performance under culture with biofloc at low salinity was not affected significantly by light limitation.
The algae Ulva lactuca and Gracilaria parvispora are abundant in the Gulf of California, rich in nutrients, and may be used as a source of protein in balanced diets for shrimp. This study tests ...whether their meal, as a partial inclusion in diets for juvenile Litopenaeus vannamei, is feasible. Percentages of inclusion were 5, 10, and 15 %. Results showed that final weight, weight gain, and specific growth rate varied significantly among diets (P < 0.05). There were significant differences in growth among the trials of amount of inclusion of meal when using U. lactuca (P < 0.05), and no significant differences among the trials when using G. parvispora (P > 0.05). In general, better results were obtained when using G. parvispora compared with U. lactuca. When compared to the control diet (without inclusion), diets that included 10 and 15 % U. lactuca meal yielded a significantly lower growth (P < 0.05), but no significant differences were detected when using U. lactuca 5 % meal (P > 0.05), suggesting the feasibility of inclusion to this limited percentage. No significant differences were detected between the control and the three treatments with G. parvispora, suggesting the possibility of using higher percentages of inclusion. We conclude that both seaweeds may be used as a component in preparing feed for juvenile L. vannamei.
This research aims to evaluate the effect of molasses as a source of organic carbon on the growth and lipid profile of Dunaliella salina cultivated under different light regimes to determine its ...strategy and potential use to produce biodiesel. Two sources of nutrients (F/2 medium, F/2; molasses, M) and two light conditions (12 h light: 12 h darkness, 12L:12D) conformed four treatments (F/2 12L:12D, F/2 D, M 12L:12D, and MD) that were investigated with three replicates each. The concentration of microalgae produced by the groups under light conditions was more than double that of those grown in darkness. The highest biomass produced (46.91 ± 6.47 g L-1) was obtained in the F/2 medium with 12L:12D treatment, while the lowest (18.99 ± 0.78 g L-1) was in the M 12L:12D group. Regardless of the culture conditions, the lipids were mainly composed of the C16:0 and C18 fatty acids. The use of molasses as a culture medium produced the highest amount of C18:1, regardless of the light regime. Molasses promoted the highest production of fatty acids methyl esters. Depending on the culture medium, D. salina cells showed different percentages of saturated (SFA), monounsaturated (MFA), and polyunsaturated (PUFA) fatty acids. The highest amount of saturated fatty acids was obtained in F/2 12L:12D. The highest amount of polyunsaturated fatty acids was presented in the mixotrophic culture (molasses and light). The cultures grown with molasses were rich in monounsaturated fatty acids. An inexpensive industrial by-product, Cane molasses could be a low-cost feedstock for biodiesel in cultivating D. salina.
The effect of stocking density and water exchange was evaluated on growth performance of
Litopenaeus vannamei
postlarvae (PL), reared in a biofloc-based system at the nursery level and exposed to ...short-term low-high salinity stress. A bioassay was conducted with four treatments in triplicate:
T
1
= 8500 postlarvae/m
3
without water exchange,
T
2
= 16,500 postlarvae/m
3
without water exchange,
T
3
= 8500 postlarvae/m
3
with 50% water exchange per week, and
T
4
= 16,500 postlarvae/m
3
with 50% water exchange per week. At 0 (PL′22), 15 (PL′37), 30 (PL′52), and 45 (PL′67) days of culture, a group of shrimp from each treatment was exposed to acute stress by low (27 to 2‰) and high (27 to 60‰) salinity. After 45 days, the water exchange rate and water exchange rate × stocking density interaction affected shrimp survival, but shrimp growth was affected only by stocking density. The mean weight of shrimp in the treatments with the lowest stocking density was higher than that with the highest stocking density, independently from the water exchange rate. In the salinity stress tests, shrimp survival was affected by the interaction between the salinity stress tests and treatments. Generally, shrimp showed a greater tolerance when subjected to low salinity (27 to 2‰). In the culture with biofloc at the nursery level, it was confirmed that
L. vannamei
shrimp improve their tolerance to a sudden low salinity endpoint; a directly proportional relationship of survival with ontogenetic development in low and high salinity was determined.
The effects of reducing feeding rate and molasses on water quality, growth, and gene expression of Litopenaeus vannamei were evaluated in a super intensive system with zero water exchange. A bioassay ...of 35 days (0,75 ± 0,22 g, 36 shrimp tank-1, 450 shrimp m-3) with treatments in triplicate was performed: I) 100% commercial feed (control group) with water exchange; II) 100% commercial feed without water exchange; III) 100% commercial feed + Bacillus licheniformis BCR 4-3 + molasses without water exchange; IV) 90% commercial feed + B. licheniformis BCR 4-3 + molasses without water exchange, and V) 80% commercial feed + B. licheniformis BCR 4-3 + molasses without water exchange. Shrimp survival, weight, nitrogenous wastes, settleable solids (SS), and the relative expression (RT-qPCR) of stress and digestive genes were determined. Shrimp survival was 100% in all treatments. The reduced diet, bioflocs, and bacilli did not affect shrimp growth. The culture conditions reduced nitrogenous wastes and modulated mRNA expression of trypsin, chymotrypsin, and heat shock protein 70. Reduced feed ration can help to maintain water quality and lower costs in intensive shrimp cultures with bioflocs.
The aim of this study was to investigate the effects of organic (molasses) and inorganic (Nutrilake®) fertilization on plankton, water quality, and shrimp Litopenaeus vannamei performance reared in ...zero-discharge tanks and ponds. The findings showed that in tanks, the organic fertilization induced highest survival and production, and low total ammonia-N concentration; however, this effect was not observed in the ponds. In both tanks and ponds, the inorganic fertilization increased nitrogen levels. The phytoplankton abundance increased in both tanks/ponds with the fertilization treatments. Shrimp production in the tanks and ponds fertilized almost doubled compared with unfertilized treatments.
The aim of this study was to investigate the effects of organic (molasses) and inorganic (Nutrilake® ) fertilization on plankton, water quality, and shrimp Litopenaeus vannamei performance reared in ...zero-discharge tanks and ponds. The findings showed that in tanks, the organic fertilization induced highest survival and production, and low total ammonia-N concentration; however, this effect was not observed in the ponds. In both tanks and ponds, the inorganic fertilization increased nitrogen levels. The phytoplankton abundance increased in both tanks/ponds with the fertilization treatments. Shrimp production in the tanks and ponds fertilized almost doubled compared with unfertilized treatments.
A search is performed for the central exclusive production of pairs of charmonia produced in proton-proton collisions. Using data corresponding to an integrated luminosity of collected at ...centre-of-mass energies of 7 and 8 TeV, and pairs are observed, which have been produced in the absence of any other activity inside the LHCb acceptance that is sensitive to charged particles in the pseudorapidity ranges and . Searches are also performed for pairs of P-wave charmonia and limits are set on their production. The cross-sections for these processes, where the dimeson system has a rapidity between 2.0 and 4.5, are measured to be where the upper limits are set at the 90% confidence level. The measured and cross-sections are consistent with theoretical expectations.
During the COVID-19 crisis it was necessary to generate a specific care network and reconvert operating rooms to attend emergency and high-acuity patients undergoing complex surgery. The aim of this ...study is to classify postoperative complications and mortality and to assess the impact that the COVID-19 pandemic may have had on the results.
this is a non-inferiority retrospective observational study. Two different groups of surgical patients were created: Pre-pandemic COVID and Pandemic COVID. Severity of illness was rated according to the Diagnosis-related Groups (DRG) score. Comparisons were made between groups and between DRG severity score-matched samples. Non-inferiority was set at up to 10 % difference for grade III to V complications according to the Clavien-Dindo classification, and up to 2 % difference in mortality.
A total of 1649 patients in the PreCOVID group and 763 patients in the COVID group were analysed; 371 patients were matched for DRG severity score 3-4 (236 preCOVID and 135 COVID). No differences were found in relation to re-operation (22.5 % vs. 21.5 %) or late admission to critical care unit (5.1 % vs. 4.5 %). Clavien grade III to V complications occurred in 107 patients (45.3 %) in the PreCOVID group and in 56 patients (41.5 %) in the COVID group, and mortality was 12.7 % and 12.6 %, respectively. During the pandemic, 3 % of patients tested positive for Covid-19 on PCR: 12 patients undergoing elective surgery and 11 emergency surgery; there were 5 deaths, 3 of which were due to respiratory failure following Covid-19-induced pneumonia.
Although this study has some limitations, it has shown the non-inferiority of surgical outcomes during the COVID pandemic, and indicates that resuming elective surgery is safe.
Clinicaltrials.gov identifier: NCT04780594 .
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