The effect of Vibrio parahaemolyticus IPNGS16 on the bacterial profile of the gut of Penaeus vannamei was assessed by 16S metagenomic analysis. The V3 hypervariable region of the bacterial 16S rDNA was amplified by PCR. Sequencing reads were generated using the 2×150 (300 cycles) for the base-read length chemistry of the Illumina MiniSeq platform. The web-based Shaman and MicrobiomeAnalyst platforms were used to analyze the sequences. The phyla Proteobacteria, Bacteroidetes, and the genera Vibrio, Ruegeria, Nautella, and Pseudoalteromonas were found among the most abundant taxonomic ranks in control, diseased, and healthy shrimp. Alpha and beta indices showed significant differences between shrimp survival in the control condition and dying shrimp (lower diversity). Metabolism (carbohydrate and amino acid metabolism-related genes and, to a lesser extent, energy, lipid, and cofactors and vitamin metabolism-related genes) of dying and surviving shrimp was affected by Vibrio infection. The top metabolic functions (cell cycle, glycine, serine, threonine, cysteine, methionine, purine, pyrimidine, pyruvate, and quorum sensing) in dying and surviving shrimp were affected by Vibrio, especially quorum sensing. The interaction network analysis showed fewer interactions in dying shrimp than control and surviving shrimp. Proteobacteria, Bacteroidetes, Vibrio, and Ruegeria predominated in all samples, and Vibrio changed bacterial diversity and metabolism in the intestine of P. vannamei. Ruegeria and Pseudoalteromonas showed negative interactions with Vibrio, suggesting their use as probiotics. This study sheds light on the Vibrio infection in the gut microbiota of shrimp.

Shrimp is one of the most important aquaculture industries. Therefore, we determined the effect of nitrifying-probiotic bacteria on water quality, growth, survival, immune response, and intestinal microbiota of Litopenaeus vannamei cultured without water exchange. In vitro, only Bacillus licheniformis used total ammonia nitrogen (TAN), nitrites, and nitrates since nitrogen bubbles were produced. TAN decreased significantly in the treatments with B. licheniformis and Pediococcus pentosaceus and Leuconostoc mesenteroides, but no differences were observed in nitrites. Nitrates were significantly higher in the treatments with bacteria. The final weight was higher only with bacilli and bacilli and LAB treatments. The survival of shrimp in the bacterial treatments increased significantly, and superoxide anion increased significantly only in lactic acid bacteria (LAB) treatment. The activity of phenoloxidase decreased significantly in the treatments with bacteria compared to the control. Shrimp treated with bacilli in the water showed lower species richness. The gut bacterial community after treatments was significantly different from that of the control. Linoleic acid metabolism was positively correlated with final weight and superoxide anion, whereas quorum sensing was correlated with survival. Thus, bacilli and LAB in the water of hyperintensive culture systems act as heterotrophic nitrifers, modulate the intestinal microbiota and immune response, and improve the growth and survival of shrimp. This is the first report on P. pentosaceus and L. mesenteroides identified as nitrifying bacteria.

Currently, studying the environment is important because of the phenomena that take place on the earth every day. That is why it is a priority to carry out studies that relate environmental changes to the biology of organisms. This allows us to know the interactions with the environment, and in this way solve, reduce or prevent ecological and economic problems, if they are organisms with a commercial value. The objective of this investigation is to determine ecological parameters of the gastropod community from the intertidal zone on five islands from the Gulf of California, México, to model the diversity, distribution and abundance of malacological fauna. We considered to evaluate the Shannon-Wiener diversity (H′), Pielou’s of evenness (J) and the Margalef species richness indexes, in order to evaluate through an analysis from biotic and abiotic factors, the species status that was collected from the exposed and non-exposed zone tidal. The generated data were contemplated from a year-based biodiversity project (2016–2017) on the following islands: Patos, Bledos, Bleditos, Tunosa, and Mazocahui which belong to the Ohuira lagoon in Ahome, Sinaloa, southeast of the Gulf of California, México. Likewise a status about the importance of gastropods is mentioned for the study area.

Macrobrachium americanum has a high commercial value with good fishing and cultivation possibilities in Mexico. Currently there is little information on reproductive aspects so the present work analyzed the sex ratio, fecundity and morphometry of the eggs of M. americanum in the Petatlán River, Sinaloa, Mexico. A total of 31 ovigerous females were captured. The sex ratio was 0.39 F: 1 M. The partial fecundity (Pf) varied from 34, 554 to 342, 372 eggs (128, 246 ± 12, 306 eggs, average Pf). The relationships between body and length-fecundity (R ² = 0.5546), cephalothorax and length-fecundity (R ² = 0.4995) were adjusted to a linear model, and the total weight-fecundity to a potential model (R ² = 0.5013). The average relative fecundity was 37, 132 ± 5, 162 eggs/g. A total of 7 stages of embryonic development were observed. In the first stages, the egg presents a spherical form and in the latter an ovoid shape. Maximum egg diameter values are presented in stages VII, VI and VIII. Stage II provided the largest number of eggs (1, 013, 073 eggs). It is essential to optimize the exploitation of the population of M. americanum present in the Petatlán River through the creation of scientific bases for the sustainability of the fishery.

Invertebrates' immune defense mechanisms play a critical role in pathogen recognition and elimination. De novo assembly and annotation of the Argopecten ventricosus transcriptome were performed for the immune-related gene identification. Scallops (height: 4.4 cm) were challenged with inactivated Vibrio parahaemolyticus IPNGS16. The RNA from different tissues was pooled for a single cDNA library construction sequenced by NextSeq 500 platform 2×75 paired‐end chemistry. Before de novo assembling with Trinity, reads were analyzed with FastQC, Trimmomatic, and Prinseq. Assembled sequences were analyzed by CD-HIT-EST and TransDecoder. The corresponding annotation was performed against NCBI-nr, RefSeq protein, and KAAS (KEGG) databases. The Trinity assembly yielded 107,516 contigs. TransDecoder yielded 25,285 sequences as CDSs of which, 16,123 were annotated against the NCBI-nr protein, most of them scored with Crassostrea gigas data. Gene ontology mapped sequences (15,262) were classified in molecular functions (~13,000), cellular components (~11,000), and biological processes (~13,000). The KAAS analysis showed biological categories for metabolism (13%), cellular processes (12%), genetic information processing (10%), organismal systems (19%), environmental information (13%), and human diseases (33 %). Within the organismal systems, 467 immune-related genes (KO) were identified. Sixty-four immune-related genes were annotated/blasted against the NCBI-nr and RefSeq protein databases. An RT-qPCR was performed to analyze the expression level of immune-related genes obtained in the transcriptome analysis in scallops (height 4.5 cm) treated with probiotic bacilli added to culture water. Bacilli significantly increased the expression of the HSP70 and PGRP genes. The gene transcripts analysis of A. ventricosus will better understand its immune response against pathogens in culture systems.