Growth Of Litopenaeus Vannamei Research Articles

Effect of ionic adjustment frequency in low-salinity water on zootechnical performance, water quality and mineral composition of Litopenaeus vannamei in a synbiotic nursery system

Ions are important for shrimp metabolic processes and can affect their growth. However, little is known about the need to supplement the major ions to maintain an adequate Ca:Mg:K ratio for shrimp as well as how often these ratios should be adjusted during a culture cycle using low-salinity water so that shrimp growth is not affected. The aim of this study was to evaluate the effect of ionic adjustment frequencies in low-salinity water in a synbiotic nursery system and verify its effects on Litopenaeus vannamei growth, water quality, and mineral composition of microbial flocs and shrimp. The experiment was carried out for 40 days, with a density of 2000 post-larvae m−3. The following treatments were tested, in triplicate: SW (seawater - salinity 31 g L−1); SWD (seawater diluted to a salinity of 2.3 g L−1); 1IA (ionic adjustment to achieve Ca:Mg:K ratio of 1:3:1 only on day 1 - salinity 2.3 g L−1); 2IA (ionic adjustment to achieve Ca:Mg:K ratio of 1:3:1 on day 1 and day 20 - salinity 2.3 g L−1); and 3IA (ionic adjustment to achieve Ca:Mg:K ratio of 1:3:1 on day 1, day 10, and day 20 - salinity 2.3 g L−1). Shrimp were fed four times a day with a 45% protein diet. The synbiotic fertilization protocol used a powder blend of Bacillus subtilis, B. licheniformis, Pseudomonas sp., and instant dry biological yeast (Saccharomyces cerevisiae) every 3 days. Nitrogen compounds remained within the recommended levels (TAN = 0.66 mg L−1, NO2−-N = 0.52 mg L−1, NO3−-N = 1.91 mg L−1) for L. vannamei reared in low-salinity water. Mean weight (1.14 to 1.18 g), survival (88.61 to 94.44%) and yield (2.10 to 2.15 kg m−3) were not significantly different in low-salinity treatments but were higher than those found in SW treatment (mean weight = 1.02 g; survival = 84.72%; and yield = 1.73 kg m−3). Mineral concentration in microbial floc and shrimp biomass did not differ among the frequencies tested, only differing when compared to SW treatment. To evaluate the juvenile's resistance, an ammonia stress test was performed during 96 h, obtaining 100% survival for all treatments. According to the results, L. vannamei juveniles can be produced in diluted seawater (salinity 2.3 g L−1, Ca2+ = 38.0 mg L−1, Mg2+ = 96.0 mg L−1, K+ = 48.3 mg L−1, total alkalinity = 92.33 mg CaCO3 L−1, total hardness = 490.13 mg CaCO3 L−1, Ca:Mg:K ratio 1:2.5:1.3) without ionic adjustments and without water exchange for 40 days in the nursery phase using a synbiotic system without affecting production performance.

Effects of reducing dietary fishmeal with yeast supplementations on Litopenaeus vannamei growth, immune response and disease resistance against Vibrio harveyi

The aim of this experiment was to investigate the effects of reducing dietary fishmeal (FM) with yeast culture (SYC) supplementation on growth, immune response, intestinal microbiota, intestinal morphology, and disease resistance of Litopenaeus vannamei. A total of 480 shrimps with an average initial body weight of 0.35 ± 0.002 g were randomly distributed into twelve tanks. Three isonitrogenous (40.00 crude protein) and isolipidic (8.00 crude lipids) diets with yeast culture supplementing fishmeal were formulated. The groups were divided into two (2) namely control group and experimental groups. The formulations of the groups were control (0 %, without yeast culture) and the experiment groups (SYC) [(1 % of yeast culture), and (2 % of yeast culture)]. Each diet was delivered in four replicate per treatment group. The results indicate significant improvement on the growth indices (specific growth rate, weight gain rate, survival rate and lower feed conversion ratio) with yeast culture treatment group after 56 days feeding trials (P < 0.05). Total hemolymph protein, superoxide dismutase, catalase, alkaline phosphatase, acid phosphatase, lysozyme and phenoxidase were enhanced but low aspartate aminotransferase, alanine aminotransferase, and glucose were observed in shrimp fed yeast culture diets (P < 0.05). The SYC groups showed insignificant differences in hemolymph cholesterol and triglyceride. Proteobacteria, Bacteroidetes, and Actinobacteria were the dominant bacteria found in all the SYC groups. At the genus level, Vibrio was significantly decreased (P < 0.05) in 2 % yeast culture diets supplemented group whereas the beneficial bacteria Pseudoalteromonas was significantly enhanced. Moreover, intestinal villus length and width in shrimps fed yeast culture diets were improved (P < 0.05). Dietary yeast culture supplementation can improve growth, intestinal health, immune response, and resistance against Vibrio harveyi infections in L. vannamei.

The Role of Bacillus amyloliquefaciens on Litopenaeus vannamei During the Maturation of a Biofloc System

Biofloc technology is a sustainable aquaculture production system which uses microorganisms to maintain water quality and to increase productivity. In this system, probiotics can enhance the positive effects of bioflocs on the cultured species. The objective of this research is to study the role of the probiotic bacterium Bacillus amyloliquefaciens during the formation of a biofloc system for the culture of Litopenaeus vannamei. Two doses of probiotic were assayed and applied directly to the water. The experiment was developed in nine tanks distributed as follows: Three control tanks with no probiotic, three tanks with a probiotic dose of 103 cfu/mL, and three tanks with a dose of 104 cfu/mL. Water quality, microbial activity, growth parameters and the immune system state of shrimps were monitored throughout the maturation process. The results indicate a positive effect upon the shrimp immune system throughout the study period, where specifically there was an increase in granular hemocytes in the shrimp hemolymph. During the immature biofloc phase, granular hemocytes were 5% higher in tanks supplemented with the probiotic. During the mature biofloc phase, granular hemocytes were 7% higher in those same tanks. During the maturation of the biofloc, environmental conditions are more unfavorable for shrimp growth, due to the accumulation of nitrites. So, the effect of the probiotic is especially important during this stage when the shrimp are stressed and are more vulnerable to diseases. However, the effects on microbial activity, water quality and Litopenaeus vannamei growth did not increase the benefits of the biofloc system.

Effect of Ca2+, Mg2+and salinity on survival, growth and shrimp taste ofLitopenaeus vannamei

Salinity, calcium and magnesium play key roles in the survival and growth of Litopenaeus van-namei. In the present study, two experiments were conducted to test the effect of salinity, calcium and magnesium on survival, growth and flavor of the shrimp, L. vannamei. The first experiment designed using the Taguchi method with three factors (Ca2+, Mg2+ and salinity), each with 7 levels (L49), was run for 60 days to analyze the independent role of Ca2+, Mg2+ and salinity on the survival, growth and flavor of L. vannamei. Additionally, a L8 test of three factors, each with two levels, was conducted to analyze the in-teraction of Ca2+, Mg2+ and salinity on the survival, growth and flavor of L. vannamei. The results showed that Ca2+, Mg2+ and salinity significantly affect the survival and flavor amino acids of L. vannamei, and Ca2+ and Mg2+ significantly influence the growth. The highest survival rate was observed at Ca2+ of 100 mg/L and 400 mg/L, Mg2+ of 1200 mg/L, and salinity of 10; The growth did not significantly change at Ca2+ of≥200 mg/L, and Mg2+ of ≥300 mg/L. The highest length and weight gains were found at Ca2+ of 100 mg/L, Mg2+ of 150 mg/L and salinity of 10-20; The content of flavor amino acids increased with the increase of Ca2+, Mg2+ and salinity, and the highest content of flavor amino acids occurred at Ca2+ of 400 mg/L, Mg2+ of 750 mg/L, and salinity of 20 and 35. Low salinity and concentration of Ca2+, Mg2+ signifi-cantly reduced the growth and survival of the shrimp. The interaction between Ca2+ and Mg2+ was signifi-cant on survival and daily weight gain of the shrimp, and the combined effect of Ca2+ and salinity was sig-nificant on survival of the shrimp. However, the interaction between Mg2+ and salinity was not significant on any of the three parameters.