Showing papers by "Jaime Romero published in 2020"

Quantification and Distribution of Omega-3 Fatty Acids in South Pacific Fish and Shellfish Species.

Abstract: Fatty acid composition and distribution in edible species of fish and shellfish captured in the South Pacific were studied, with a focus on n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA). Fatty acids were quantified using gas-chromatography coupled with flame ionization detection (GC-FID), and the distribution of different fatty acids within lipid classes (neutral and polar lipids) was achieved after oil extraction using the Folch method and separation of lipid classes via solid-phase extraction for further GC-FID analysis. Red cusk-eel was the fish species with the lowest content of both EPA and DHA (40.8 and 74.4 mg/100 g, respectively) whereas mackerel contained the highest amount (414.7 and 956.0 mg/100 g for EPA and DHA, respectively). Sea squirt was the shellfish species with the highest content of EPA and DHA (375.0 and 165.7 mg/100 g, respectively) whereas the lowest amount of EPA + DHA was found in Chilean abalone (63.6 mg/100 g). PUFA were mostly found in neutral or polar lipids depending on the studied species. Indexes used to discuss the nutritional quality of lipids (PUFA/SFA, n-6/n-3 ratio and the hypocholesterolemic/hypercholesterolemic fatty acid index) were calculated and reported in the manuscript. This information provides a novel nutritional insight which may be useful to help nutritionists and other health professionals give more accurate counseling for the population to reach the recommended daily intakes of EPA and DHA.

Effect of mannan oligosaccharides on the microbiota and productivity parameters of Litopenaeus vannamei shrimp under intensive cultivation in Ecuador

Abstract: The white leg Litopenaeus vannamei shrimp is of importance to the eastern Pacific fisheries and aquaculture industry but suffer from diseases such as the recently emerged early mortality syndrome. Many bacterial pathogens have been identified but the L. vannamei microbiota is still poorly known. Using a next-generation sequencing (NGS) approach, this work evaluated the impact of the inclusion in the diet of mannan oligosaccharide, (MOS, 0.5% w/w), over the L. vannamei microbiota and production behavior of L. vannamei under intensive cultivation in Ecuador. The MOS supplementation lasted for 60 days, after which the shrimp in the ponds were harvested, and the production data were collected. MOS improved productivity outcomes by increasing shrimp survival by 30%. NGS revealed quantitative differences in the shrimp microbiota between MOS and control conditions. In the treatment with inclusion of dietary MOS, the predominant phylum was Actinobacteria (28%); while the control group was dominated by the phylum Proteobacteria (30%). MOS has also been linked to an increased prevalence of Lactococcus- and Verrucomicrobiaceae-like bacteria. Furthermore, under the treatment of MOS, the prevalence of potential opportunistic pathogens, like Vibrio, Aeromonas, Bergeyella and Shewanella, was negligible. This may be attributable to MOS blocking the adhesion of pathogens to the surfaces of the host tissues. Together, these findings point to the fact that the performance (survival) improvements of the dietary MOS may be linked to the impact on the microbiota, since bacterial lines with pathogenic potential towards shrimps were excluded in the gut.

Potential biomarkers of DNA quality in cryopreserved fish sperm: impact on gene expression and embryonic development

Abstract: Fund for the Promotion of Scientific and Technological Development of CONICYT Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1171129 1180387 Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 3180765

Microbiota of the Digestive Gland of Red Abalone ( Haliotis rufescens) Is Affected by Withering Syndrome

Abstract: Withering syndrome (WS), an infectious disease caused by intracellular bacteria Candidatus Xenohaliotis californiensis, has provoked significant economic losses in abalone aquaculture. The pathogen infects gastroenteric epithelia, including digestive gland, disrupting the digestive system and causing a progressive wilting in abalone. Nonetheless, our knowledge about WS implications in digestive gland microbiota, and its role in diseases progress remains largely unknown. This study aims to determine whether digestive gland-associated microbiota differs between healthy red abalone (Haliotis rufescens) and red abalone affected with WS. Using high-throughput sequencing of the V4 region of the 16S rRNA gene, our results revealed differences in microbiota between groups. Bacterial genera, including Mycoplasma, Lactobacillus, Cocleimonas and Tateyamaria were significantly more abundant in healthy abalones, whilst Candidatus Xenohaliotis californiensis and Marinomonas were more abundant in WS-affected abalones. Whilst Mycoplasma was the dominant genus in the healthy group, Candidatus Xenohaliotis californiensis was dominant in the WS group. However, Candidatus Xenohaliotis californiensis was present in two healthy specimens, and thus the Mycoplasma/Candidatus Xenohaliotis californiensis ratio appears to be more determinant in specimens affected with WS. Further research to elucidate the role of digestive gland microbiota ecology in WS pathogenesis is required.

Partial Evaluation of Autochthonous Probiotic Potential of the Gut Microbiota of Seriola lalandi

Abstract: Seriola lalandi is an economically important species that is globally distributed in temperate and subtropical marine waters. Aquaculture production of this species has had problems associated with intensive fish farming, such as disease outbreaks or nutritional deficiencies causing high mortality. Intestinal microbiota are involved in many processes that benefit a host, such as disease control, stimulation of the immune response, and the promotion of nutrient metabolism. The aim of this study is to evaluate the in vitro probiotic properties of bacteria isolated from the intestinal content of wild Seriola lalandi. The probiotic potential was evaluated in terms of (i) the antimicrobial activity against vibrios causing outbreaks in farmed fish; (ii) the ability to stimulate genes related to an innate immune response in fish; and (iii) antibiotic resistance. Nineteen isolates identified as Pseudomonas, Shewanella, Psychrobacter, and Acinetobacter showed antimicrobial activity and significant relative expression of cytokines, serum amyloid A protein (SAA), hepcidin, and lysozyme. A positive correlation was observed between the levels of expression and the bacterial load after 24 h of exposure. Pseudomonas isolates showed a level of antibiotic resistance. In conclusion, isolates of the genera Shewanella, Psychrobacter, and Acinetobacter could serve as potential probiotics in S. lalandi culture.

Effects of dietary polyunsaturated fatty acid sources on expression of lipid-related genes in bovine milk somatic cells.

Abstract: The objective of this study was to compare the effect of contrasting sources of dietary n-6 and n-3 PUFA on expression of genes related to lipid metabolism in dairy cows. During 63 days, fifteen lactating cows were assigned to a control or basal diet containing no added lipid (n = 5 cows); and treatment diets supplemented with SO (n = 5 cows; unrefined soybean oil; 2.9% of DM) or FO (n = 5 cows; fish oil manufactured from salmon oil; 2.9% of DM). Plasma for fatty acid (FA) analysis and milk somatic cells (MSC) were obtained from all cows at the beginning of the study (day 0) and on days 21, 42 and 63. Plasma was used to determine FA transport dynamics. Compared with control and FO, plasma from SO had increased contents of C18:1 cis-9, C18:1 trans-11, C18:2 cis-9, trans-11 and total monounsaturated FA. On the other hand, compared with control and SO, FO increased plasma contents of C20:3 n-3, C20:3 n-6, C20:4 n-6, C20:5 n-3, C22:6 n-3 and total polyunsaturated FA. Moreover, plasma C18:3 n-3 and C20:5 n-3 increased over time for all diets. Compared with control, SO downregulated ACACA, INSIG1, and DGAT1, whereas FO downregulated ACACA, PPARGC1, LPIN1 and FABP3 on day 63, in MSC. At different time-points, SO and FO downregulated genes related to synthesis and intracellular transport of FA, synthesis of triglycerides, and transcription factors.

Live Feeds Used in the Larval Culture of Red Cusk Eel, Genypterus chilensis, Carry High Levels of Antimicrobial-Resistant Bacteria and Antibiotic-Resistance Genes (ARGs)

Abstract: The culture of red cusk eel Genypterus chilensis is currently considered a priority for Chilean aquaculture but low larval survival rates have prompted the need for the continuous use of antibacterials. The main aim of this study was to evaluate the role of live feed as a source of antibacterial-resistant bacteria in a commercial culture of G. chilensis. Samples of rotifer and Artemia cultures used as live feed were collected during the larval growth period and culturable bacterial counts were performed using a spread plate method. Rotifer and Artemia cultures exhibited high levels of resistant bacteria (8.03 × 104 to 1.79 × 107 CFU/g and 1.47 × 106 to 3.50 × 108 CFU/g, respectively). Sixty-five florfenicol-resistant isolates were identified as Vibrio (81.5%) and Pseudoalteromonas (15.4%) using 16S rRNA gene sequence analysis. A high incidence of resistance to streptomycin (93.8%), oxytetracycline (89.2%), co-trimoxazole (84.6%), and kanamycin (73.8%) was exhibited by resistant isolates. A high proportion of isolates (76.9%) carried the florfenicol-resistance encoding genes floR and fexA, as well as plasmid DNA (75.0%). The high prevalence of multiresistant bacteria in live feed increases the incidence of the resistant microbiota in reared fish larvae, thus proper monitoring and management strategies for live feed cultures appear to be a priority for preventing future therapy failures in fish larval cultures.