Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The effect of diets with varying crude protein-to-precooked cornstarch (P:S) ratios on growth performance, feed efficiency, carbohydrase activity, and blood chemistry of juvenile Lutjanus guttatus was evaluated. Four isoenergetic (19.0 kJ g-1) diets containing different P:S ratios (46:18, 38:30, 34:35, and 31:40) were formulated to feed fish for ten weeks in triplicate. Each diet was tested in triplicate in groups of 35 fish per tank (average body weight 19.4 ± 0.3 g) to apparent satiation three times a day. The weight gain, specific growth rate, and feed conversion ratio obtained with P38S30 and P34S35 were not significantly different vs. P46S18. Survival does not present significant differences among treatments. Biological indices (condition factor, hepatosomatic index, viscerosomatic index, and intraperitoneal fat rate) showed no significant differences among treatments. Body protein content decreased significantly with increasing precooked cornstarch concentration, while body lipid levels increased. Blood chemistry values were within those of healthy juveniles, except for glucose values. An increase in pancreatic α-amylase and intestinal α-glucosidase blood chemistry values were within those of healthy juveniles, except for glucose values. An increase in pancreatic α-amylase and intestinal α-glucosidase levels concomitant with increasing precooked cornstarch concentration showed the capacity of juvenile L. gutattus to digest high precooked cornstarch levels. Growth performance, biological indices, and hematological parameters showed that L. guttatus could digest and metabolize up to 35% of precooked cornstarch through increased plasma glucose levels and the α-amylase and α-glucosidase activities. Without negative effect on growth performance.

This study evaluates the application of highly-diluted bioactive compounds (HDBC) as an alternative to improve the white shrimp Penaeus vannamei performance reared during a semi-intensive commercial-scale production cycle (130 days) in arid environmental conditions. The effects of HDBC were analyzed on productive performance, enzyme activity, and energy reserves associated with the nutritional condition. Six 10-ha earthen ponds were used. Two experimental HDBC treatments and one control treatment were evaluated: [T1 = PhA+SiT (phosphoric acid 7C and Silicea terra 7C); T2 = PaV+ViT (Passival® 7C and Vidatox® 31C); T3 = Control (No HDBC)], using 2 ponds × 3 treatments = 6 ponds. Three shrimp samples were taken (S1, S2, S3) at 7, 52, and 130 days. The results indicated that organisms from T2 significantly increased in several productive indicators, such as weight gain, daily weight gain, specific growth rate, total length, feed efficiency, and productive performance. T2's bioactive compounds ingested with the pelleted feed and present in the gut -even at highly diluted concentration- improved energetic reserves, such as lipids in the hepatopancreas and digestive enzyme activity, enhancing the physiological status of shrimp farmed under semi-intensive rearing conditions, suggest that HDBC used in this study could have a beneficial and eco-friendly impact on commercial-scale shrimp production.

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.

Otolith analysis allows studying multiple aspects of fish biology, including age estimation; however, otoliths collected from avian stomach content have not been used to estimate the age of ingested fish. We evaluated the potential ability to estimate the age of Pacific sardine (Sardinops sagax) from otoliths collected from blue-footed booby (Sula nebouxii) stomach contents sampled in the Galapagos Islands. Blue-footed boobies were selected because they mostly forage close to their colony (<100 m) and were, therefore, more likely to have almost intact otoliths. To estimate age, we employed three previously developed methods for otoliths. We then related these estimates to the fish's standard length and compared these relations statistically using the Akaike Information Criterion (AIC) to determine which method was most parsimonious. We collected 32 otoliths in relatively good condition, of which we aged 31 with the surface-reading method, 26 with the otolith weight method, and 29 with the posterior otolith length method. Average ages obtained with the otolith methods were 5.6 ± 1.7 yr (± standard deviation), 5.7 ± 2.0 yr, and 3.9 ± 1.5 yr, respectively. Estimates obtained with the otolith weight method had the highest correlation with standard length and the lowest AIC values of the three suggesting it was the best method for aging. Our results indicate that aging otoliths extracted from bird stomachs are possible; however, their use depends on the availability of previously developed methods and how digested the fish are when the birds return to the colony.

Artificial cultivation increases clams' availability and is an alternative to the extraction from natural banks. The culture of clams requires species-specific research in the different growth stages, and studies on the effects and interactions of culture parameters are essential to obtain and control the proper development of larvae. This paper aims to compare methods to induce spawning, describe the embryonic development, and compare the effect of different culture densities on the yield of "D" larvae of the "taca" clam Ameghinomya antiqua. Breeders were collected on the southwest coast of Quinchao Island, Chiloé, Chile. Spawning induction assays were performed comparing different combinations of biological and physical factors. Experiments on the effect of embryonic density in the obtention of "D" larvae were performed, and the embryonic development was described at 11 ± 1°C. The spawning inductions were successfully achieved with the addition of food combined with temperature changes, resulting in the liberation of oocytes with a jelly coat with a diameter of 140 μm. Trochophore larvae were observed at 40 h post-fertilization. The percentage of embryos developed showed significant differences when testing cultures with densities of 20, 40, and 60 embryos mL-1. Experiments with 20 embryos mL-1 density were the ones that obtained a greater number of developed embryos (50%). These results suggest spawning induction with the addition of food and temperature changes with a density of 20 embryos mL-1. This paper describes the embryonic development and technology development for spawning induction for the first time.

Inconsistencies in the nutritional values of live food such as Artemia and Moina are well-known issues. The enrichment of live food is necessary to obtain the optimum nutrients needed for the growth, survival, and immune competence of fish and crustaceans' larvae. The enhanced growth and survival of fish and crustaceans' larvae are vital to continuous aquaculture production. However, enriched live food could be species-specific as various aquatic larval species may respond differently to the enrichment diets. The enrichment of Artemia and Moina as the "bags of nutrients" has been widely studied and involved various enrichment diets such as commercial diets containing essential fatty acids, highly unsaturated fatty acids, and vitamin C. The use of natural enrichment diets such as yeast, microalgae, and herbal extract, including the common name Chinese chaste tree leaf (Vitex negundo), is becoming popular in aquaculture nutritional development. These natural enrichment diets are more economical and environmentally friendly than commercial diets. The compositions of Artemia and Moina are both affected by the enrichment diets that they consumed, hence directly affecting the growth of the larvae that fed on them. Hence, this review highlights the development of enriched Artemia and Moina and their effects on the growth performance and the immune competence of fish and crustaceans' larvae.

The populations of Acropora palmata have decreased over the last four decades, and although there are several studies on their genetic diversity in the Caribbean, no studies have been published about the reefs from the southern Gulf of Mexico. This research aimed to determine, using five microsatellite markers, the genetic variation of three A. palmata populations in the Mexican Atlantic located in the southwest Gulf of Mexico, in the Campeche Bank, and in the Caribbean. The mean of genetic richness (Ng/N) in the studied reefs was 0.583; the lowest estimated value corresponded to the Campeche Bank reef. A low genetic diversity was registered in the studied reefs (reef mean He = 0.315 ± 0.052). The significant genetic structure observed among studied populations could be related to ocean currents from the region and specific biological characteristics, mainly, short larvae phase, high mortality, and high rate of self-recruitment. These results may be particularly useful for designing management strategies, considering the lack of studies of this type in the region.

This note analyzes for the first time the geomorphology and sedimentary features of the Simpson Submarine Canyon (SSC), located between Chiloé Island and the Taitao Peninsula. For that purpose, multibeam bathymetric data were obtained in 2018. The SSC has a unique orientation compared to most canyons on the Chilean margin. Slope escarpments, topographic irregularities, and sinuosity of the canyon could be associated with regional tectonics. Sediment transport and deposition along the axis define the transversal morphology. On the canyon walls, erosion and transport processes dominate, evidenced by gullies, channels, and mass removals, which leave debris on the axis. We report a large landslide from a canyon wall, which could be due to a high-energy event such as an earthquake; and the generation of a large sediment wave field outside the canyon mouth, indicating a great activity by sedimentary processes. All the above could indicate that the canyon is continuously evolving.

The objective of this study was to identify morphological characteristics of different populations of Penaeus schmitti Burkenroad, 1936 to contribute to its biology and conservation. In order to compare geographically isolated populations, between 2014 and 2016, selected biological variables were analyzed in six populations dispersed along the Brazilian coast and one from the Cuban coast. Specimens with eight upper rostral teeth predominated. The ordination of shrimp measurements by non-metric multidimensional scaling showed the greatest dispersion on data from Cuba, Rio Grande do Norte, and Espirito Santo, which are also the localities that presented the highest coefficient of variation. On the other hand, the values corresponding to Sergipe, Rio de Janeiro, Paraná, and Santa Catarina showed a greater similarity or clustering of the data of each location. Tail weight was estimated using length and depth of the sixth abdominal segment. The populations of Santa Catarina, Brazil (28°S), had the longest and heavier abdomens proportionally among all the compared populations, while the organisms of Manzanillo, Cuba (20°N), had proportionally shorter abdomens and the narrowest cephalothorax. The regression equation indicated a positive allometric growth for P. schmitti, and the largest total length reported for genus Penaeus in the natural environment corresponded to a P. schmitti specimen. This information could be useful in future taxonomic studies to correctly identify the species and its morphological variability. Color differences were also observed, with white ventral spots in the sternite XIV of some females from Brazilian populations, which was not previously reported in the literature. Extending these studies is recommended to contribute to the conservation and culture of P. schmitti.

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.