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Penaeus spp. are the most cultivated type of shrimp because they have rapid growth and good adaptation to farming conditions. Due to diseases that result in high mortality and a decreased product quality, the cultivation of these shrimp globally, and in Cuba in particular, comes with the risk of significant financial losses. This study examined the effect of fructooligosaccharide (FOS, 1-kestose) on the growth and immune response of shrimp, as well as the multitude of Vibrio spp. and Pseudomonas spp. in Penaeus vannamei post-larvae under culture conditions. Fructooligosaccharide was applied in a completely randomized manner at a concentration of 0.4%, in both experimental groups with seventeen tanks each. In the results of this investigation, animals of greater weight (control 6.8 ± 0.2 mg; FOS 9.5 ± 0.3 mg; p < 0.001), length (control 1.1 ± 0.1 mm; FOS 1.3 ± 0.1 mm; p < 0.001), and survival (control 61.7% (95% CI of median 54.2–70.0); FOS 76.6% (95% CI of median 72.1–84.2); p < 0.001) were obtained when administered FOS relative to the control. An increase in the activity of proteases (p < 0.001), enzymes of the innate immune system such as phenoloxidase (p < 0.001), and lysozymes (p < 0.001) was observed, as well as an increase in the number of lectins (p < 0.001). Changes in the microbiota could be observed, with a reduction in Vibrio spp. and Pseudomonas spp. (control 2.4 × 103 ± 0.5 × 103; FOS 1.1 × 102 ± 0.3 × 102; p < 0.001). FOS improves the quality of the post-larvae of P. vannamei as reflected in the length, weight, and survival of the animals. Moreover, FOS stimulates the P. vannamei immune system through the enzymatic activities of phenoloxidase, lysozyme, and a number of lectins. The reduction in the population load of Vibrio spp. and Pseudomonas spp. might be a consequence of the improvement in the quality and immune system of P. vannamei. [ABSTRACT FROM AUTHOR]

This study examined the effects of Bacillus licheniformis strain CIGBC-232, isolated from the gut of shrimp Litopenaeus vannamei and having antagonistic activity against Vibrio harveyi, on the immunity and larval quality of L. vannamei at various ontogenetic stages, in two separate experiments: (1) PL2 to PL17 exposed to the strain CIGBC-232 under laboratory conditions (2) zoea I to PL8 exposed to the strain CIGBC-232 and EPICIN 3W probiotics under farming conditions. The first experiment showed that phenoloxidase, peroxidase and superoxide dismutase activities were improved in animals grown with CIGBC-232 compared to the untreated control. In tests, the resistance to osmotic stress was also enhanced. During the second experiment, animals treated with CIGBC-232 exhibited significant ( P < 0.05) increases in phenoloxidase activity (30-40% higher in zoea I- II, mysis II- III and PL 2-7) and in the respiratory burst (30% higher from PL 2 to 7) as compared to those animals that received EPICIN 3W. There was no significant difference in the lectins and agglutinins (except in PL1, 6 and 7), in peroxidase and superoxide dismutase activities, in the resistance to osmotic stress, nor in the survival rate among treatments. CIGBC-232 treatment was able to reduce, the level of presumptive Vibrio spp. with respect to EPICIN 3W treatment in the tank water as well as in animals. At the end of both experiments, the growth of shrimp, i.e. weight and length was increased by CIGBC-232 treatment. This study showed the probiotic effect of CIGBC-232, which appeared to have a better probiotic performance than EPICIN 3W treatment. [ABSTRACT FROM AUTHOR]

Abstract: To date, little is known about the immune system during early ontogeny for crustaceans with high commercial value, such as white shrimp (Litopenaeus vannamei). The aim of this study was to characterize several immunological parameters during ontogeny (from eggs to early postlarvae) of L. vannamei under farming conditions. Phenoloxidase activity showed the highest peak 3.6±0.4×10−2 U μg−1 at the first nauplius stage, followed by a continuous decrease until dropping to 14% of the peak value in early postlarval (PL) stages. Superoxide dismutase activity reached the highest peak 9.9±0.3×10−3 Uμg−1 after metamorphosis to the protozoea stage, then to half that value after metamorphosis to mysis stage and kept dropping until reaching a minimum of 0.5±0.4×10−3 Uμg−1 in PL stages. In larval stages peroxidase activity showed a maximum of 2.5±0.4×10−6 Uμg−1 after metamorphosis to mysis, and a gradual increase was observed in PL stages until attaining the highest value 4.6±0.8×10−6 Uμg−1. Generation of superoxide anion showed a progressive increase after spawning in an evident relationship with growth, reaching the highest value of 7.0±0.4×10−6 Uμg−1 in PL-7. To our knowledge, this is the first study that characterizes immunological parameters through the first stages of ontogeny of L. vannamei under farming conditions. [Copyright &y& Elsevier]

Abstract: Tilapia growth hormone (GH) was used to determine the presence of a presumed protein with GH receptor-like function in the hepatopancreas of shrimp L. vannamei and to evaluate its effect on growth of L. vannamei postlarvae. The receptor assay was performed using brush border membrane vesicles (BBMV) from the hepatopancreas of L. vannamei and the affinity constant was calculated by the dilution coordinates method. The shrimp postlarvae treated with tilapia GH were 42.4% heavier and 5.2% longer than the control group (P <0.05). On the other hand, the water content was lower in the postlarvae treated with GH (75.9%) than in the control group (77.3%) (P <0.05). Content of soluble proteins per mg of weight was 1.33 times higher in the GH-treated animals than control animals. No significant differences in survival rates were detected between the experimental groups. Tilapia GH was able to bind to a GH receptor-like protein on BBMV with an affinity constant of 1.30⁎108 M−1. In conclusion, a GH receptor-like protein was detected on vesicles from hepatopancreas of the shrimp L. vannamei. Also, it was established that the TiGH was able to enhance the growth of shrimp postlarvae. To our knowledge, this is the first report to demonstrate an interaction between a vertebrate growth hormone and a GH receptor-like protein of a crustacean. [Copyright &y& Elsevier]

Knowledge of the genetic diversity and composition of stocks enable decisions on improving the genotypes of the populations, and their family structure, as well as the potential use of genetic selection. The present study sought to assess the genetic diversity of stocks of Penaeus vannamei used by the shrimp industry in Cuba by means of single nucleotide polymorphisms (SNP) and growth-related traits. We evaluated a total of 310 individuals from six stocks using a panel of 192 SNPs. We analyzed the diversity and genetic structure of six commercial stocks. We also compared the stocks using growth-related traits (harvest weight (g), specific growth rate (g), survival (%), yield (kg/ha/harvest), feed conversion efficiency, and culture duration (days). The pair-wise F st value estimation indicates a moderate level of genetic differentiation among the stocks. The factorial correspondence analysis plots indicated that the six stocks show genetic distinctness. A comparison of some growth-related traits from different stocks showing genetic diversity was performed and, in this study, showed that stock 24 has the highest survival 80.9 ± 1.3% and yield at 1505 ± 50 kg/ha/harvest. From our data, survival negatively correlates with growth (r = −0.55) and feed conversion efficiency (−0.45). The genetic diversity measures indicate that the six stock populations contain moderate to moderately-high levels of genetic diversity. After ten years without new shrimp broodstock introductions into Cuba, there appeared to be little or no inbreeding depression of the growth-related traits. • A panel of 159 SNP for detection of genetic diversity of commercial shrimp stocks. • Two subpopulations justify the genetic variation among the six commercial shrimp stocks. • Ten years without introducing shrimp stock show no impact on growth-related traits. [ABSTRACT FROM AUTHOR]