The European sardine (Sardina pilchardus) faces several challenges, such as the need to regulate fishing pressure to ensure the long-term sustainability of the resource. Its decline highlights the need to consider alternative blue fish, which can help diversify consumer choices. In an effort to identify alternative fish species, the current study examined the physiologic conditions, reproductive states and fat contents of sardines and three other blue fish species throughout the complete annual cycle. These species include the Atlantic horse mackerel (Trachurus trachurus), the Atlantic mackerel (Scomber scombrus), and the round sardinella (Sardinella aurita). The extensive sampling effort, which was conducted at nearly monthly intervals, yielded a total of 5358 individuals across the four species. Atlantic horse mackerel exhibited high reproductive success, rapid postspawning recovery, and favourable muscle fat content and has emerged as a strong candidate for complementing or replacing sardines in the market during closures or fishing bans. Although the Atlantic mackerel is a promising candidate, the poor physiological condition of captured specimens indicates that its populations may be under considerable stress. As such, we cannot currently recommend this species as a sustainable resource but emphasise the need for continued monitoring. The low fatty acid levels in the round sardinella limit its potential as a direct replacement for sardines. However, given its favourable characteristics, such as low parasite counts and low mercury levels, it could be considered an alternative to sardines. Our results highlight the importance of constantly reviewing the knowledge and status of commercially exploited fish populations.

While effective subunit vaccines against African swine fever (ASF) are still under development, live attenuated vaccines (LAVs) remain the only approach capable of inducing robust protective immunity, though biosafety concerns limit their field use. Thus, further research is required to improve LAV safety while maintaining its immunogenicity. Because both the ASF virus (ASFV) and derived LAVs suppress macrophage innate responses, we hypothesized that adjuvants could restore functionality of LAV-infected cells, allowing dose reduction and consequently minimizing the risk of adverse events. To test this, we intranasally vaccinated pigs with a suboptimal dose of the LAV BA71ΔCD2, either alone or combined with two immunostimulatory adjuvants derived from Rothia nasimurium. Both immunostimulants enhanced the in vitro responsiveness of BA71ΔCD2-infected macrophages, which acquired antigen-presenting features. However, in vivo, both adjuvants lowered humoral and cellular responses induced by BA71ΔCD2, consequently decreasing protection against lethal challenge. Further in vitro analyses demonstrated that adjuvant-activated macrophages acquired an antiviral state, limiting LAV replication. These results suggest the hypothesis that reduced vaccine efficacy might result from insufficient antigen production. Overall, the study indicates that combining adjuvants with ASFV-based LAVs would require a fine-tune macrophage activation to enhance functionality without excessively inhibiting viral replication.

The European sardine is experiencing a decline in somatic condition and body size, raising concerns about the long-term viability of its populations. Despite its ecological and economic importance, population structure and adaptive variability in this species remain insufficiently understood. We used a genomic approach to investigate population structure and examine associations between genetic markers and somatic condition across six locations in the Atlantic Ocean and Mediterranean Sea. Based on 5,506 SNPs, we identified strong genetic differentiation between the Atlantic–Alboran group and the remaining Mediterranean populations. We also detected weaker but significant structure within the Mediterranean. The Almeria–Oran Front was confirmed as a major biogeographical barrier, while the Adriatic population showed evidence of genetic admixture, consistent with a transitional role between the western and eastern Mediterranean. Although population differentiation was detected using both neutral and selected loci, outlier SNPs (2.3% of all loci) contributed disproportionately to divergence (FST = 0.242), highlighting the role of local adaptation. Estimates of effective population size (Ne) are affected by chromosomal inversions, as linked loci within these regions bias Ne downward, with a pronounced reduction in Ne in Mediterranean populations. Using two complementary approaches, we identified four SNPs (potentially up to 30) significantly associated with somatic condition (Kn). Together, these results provide new insights into the genetic structure and adaptive potential of European sardines and represent the first genomic evidence linking specific loci to somatic condition. Our findings highlight the value of integrating genomic and phenotypic data to inform conservation and management strategies.

Limited understanding of African swine fever (ASF) immunity remains a major barrier to the rational development of safe and effective vaccines. While antibody-mediated protection is still poorly defined, growing evidence highlights a central role for cellular immunity, particularly cytotoxic cells, as components associated with ASF virus (ASFV) infection control. However, the contribution of individual cytotoxic subsets across different virological and immunological contexts is not well characterized. Here, we investigated cytotoxic responses during BA71ΔCD2 live attenuated vaccine-induced protection and during late-stage lethal ASFV infection. Protective immunity was characterized by antigen-specific cytotoxic T-cell responses, whereas acute ASF was associated with broad cytotoxic activation. Early increases in perforin-positive CD4-CD8αβ+ T cells coincided with the onset of protection, and elevated recall responses correlated with survival following lethal challenge, supporting their association with protective immunity. Additional correlates of protection included CD4+CD8αβ+ cytotoxic T cells, IFNγ-producing cells, and specific antibodies, illustrating the multifactorial nature of protective immunity. In contrast, pigs with acute ASF showed broad cytotoxic expansion, perforin-positive natural killer and γδ T cells showing the strongest association with viremia. Together, these findings advance our understanding of cytotoxic responses to ASFV and identify perforin-positive T cells, alongside complementary immune components, as potential correlates of protection for future vaccine development.

Globalization has increased the incidence of infectious diseases in livestock, further aggravated by the reduction of antibiotic usage. To minimize the resulting economic consequences to the meat production industry, as well as the risk of zoonotic events, the use of immunostimulants has emerged as a potential strategy to enhance animal resilience to diseases. In particular, the capability of bacterial-based immunostimulants to modulate innate immune cells functionality makes them cost-effective candidates as vaccine adjuvants, antimicrobials, or preventive immunostimulators inducing long-term innate immune memory in livestock. However, further research is required to identify novel bacterial strains with immunostimulatory properties. Here we characterized in vitro the immunostimulatory properties of Rothia nasimurium isolated from warthog fecal microbiota. Stimulation with heat-inactivated Rothia induced cytokine production by porcine immune cells, and a robust innate immune transcriptomic signature in porcine alveolar macrophages. Interestingly, the bacteria induced inflammasome activation and IL-1β production, thus confirming its pro-inflammatory properties, and suggesting its potential as vaccine adjuvant. Importantly, this immunostimulatory status functionally resulted in an antimicrobial state, enhancing the phagocytic capability of alveolar macrophages, and hampering the replication levels of two major porcine viral pathogens: the porcine reproductive and respiratory syndrome virus (PRRSV) and the African swine fever virus (ASFV). Moreover, macrophages showed an enhanced cytokine response upon ASFV infection several days after heat-inactivated Rothia stimulation, suggesting the induction of an innate immune memory phenotype. This nonspecific response resulted in a significant reduction of ASFV replication kinetics, demonstrating the capacity of the bacteria to induce a more resistant state in macrophages against a virus infection. Altogether, these results demonstrate the immunostimulatory capability of heat-inactivated R. nasimurium in porcine macrophages, showing potential to enhance animal resilience to diseases through the modulation of innate immune cells responsiveness to infections.

Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) has a profound impact on the swine industry due to its ability to persist in infected animals. The PRRSV family exhibits considerable genetic variability, with PRRSV-1 and PRRSV-2 now classified as two distinct species (Betaarterivirus suid 1 and 2). Interestingly, both species - and their corresponding attenuated vaccine strains - can persist for months, in part by delaying the appearance of neutralizing antibodies. Leveraging recently developed tools for in-depth analysis of the previously poorly characterized porcine inverted lymph node (LN), we investigated early events in LN B cell maturation during PRRSV-1 infection and compared them to those induced by acute swine influenza A virus infection. We highlighted PRRSV-specific mechanisms, including PD-L1 upregulation in efferent macrophages, the presence of extrafollicular centrocytes, and the influx of inflammatory monocytes/macrophages. These findings are consistent with previous observations in PRRSV-2 infections and may therefore reflect conserved immune evasion mechanisms across PRRSV strains.

The European sardine exhibits drastic changes in body condition, growth, and reproduction outputs with fluctuating environments, leading to trade-offs in life history traits. This study aimed to compare the health status of sardines collected in four areas of the western Mediterranean facing different environmental and anthropogenic pressures (the Gulf of Lion, the northern Catalan coast, the southern Catalan coast, and the Alboran Sea). A decreasing gradient was observed in the somatic condition of sardines from south to north in the western Mediterranean. Sardines from the Gulf of Lion exhibited poor body condition throughout their reproductive cycle and reached relatively small adult sizes. These sardines did not waste energy for growth but favored energy investment in reproduction, which in turn could lead to increased mortality after the spawning season. Moreover, sardines from the Alboran Sea tended to exhibit satisfactory conditions throughout their reproductive cycle, using mesenteric fat almost as a unique energy resource for reproduction investment. These sardines probably invested energy in both reproduction and growth, as energetic resources were abundant. Moreover, they fed intensively during the winter spawning season and maintained high body condition throughout their reproductive cycle, which suggests an income breeding strategy. Along the Catalan coast, sardines followed a capital breeding strategy, as they developed gonads using the energy stored during the primary production blooms of spring. Although they depleted a considerable part of their tissue fat and mesenteric fat contents during the spawning season, they could invest energy in growth. Finally, under the highest levels of relative batch fecundity in December, sardines produced the best egg quality, which could likely ensure greater larval survival and good recruitment.

BACKGROUND Helicobacter pylori (H. pylori ) is a widespread microorganism related to gastric adenocarcinoma (AC). In contrast, it has been reported that an inverse association exists between H. pylori infection and esophageal carcinoma. The mechanisms underlying this supposedly protective effect remain controversial. AIM To determine the prevalence of H. pylori infection in esophageal carcinoma patients, we performed a retrospective observational study of esophageal tumors diagnosed in our hospital. METHODS We retrospectively reviewed the prevalence of H. pylori infection in a cohort of patients diagnosed with esophageal carcinoma. Concomitant or previous proton pump inhibitor (PPI) usage was also recorded. RESULTS A total of 89 patients with esophageal carcinoma (69 males, 77.5%), with a mean age of 66 years (range, 26-93 years) were included. AC was the most frequent pathological variant (n = 47, 52.8%), followed by squamous cell carcinoma (n = 37, 41.6%). Fourteen ACs (29.8%) originated in the gastroesophageal junction and 33 (70.2%) in the esophageal body. Overall, 54 patients (60.7%) presented at stages III and IV. Previous H. pylori infection occurred only in 4 patients (4.5%), 3 with AC (6.3% of all ACs) and 1 with squamous cell carcinoma (2.7% of all squamous cell tumors). All patients with previous H. pylori infection had stage III-IV. Only one patient had received prior H. pylori eradication therapy, whereas 86 (96.6%) had received previous or concomitant PPI treatment. CONCLUSION In our cohort of patients, and after histologic evaluation of paraffin-embedded primary tumors, we found a very low prevalence of previous H. pylori infection. We also reviewed the medical history of the patients, concluding that the majority had received or were on PPI treatment. The minimal prevalence of H. pylori infection found in this cohort of patients with esophageal carcinoma suggests a protective role.

African swine fever (ASF) is a deadly disease of swine currently causing a worldwide pandemic, leading to severe economic consequences for the porcine industry. The control of disease spread is hampered by the limitation of available effective vaccines. Live attenuated vaccines (LAVs) are currently the most advanced vaccine prototypes, providing strong protection against ASF. However, the significant advances achieved using LAVs must be complemented with further studies to analyze vaccine-induced immunity. Here, we characterized the onset of cross-protective immunity triggered by the LAV candidate BA71ΔCD2. Intranasally vaccinated pigs were challenged with the virulent Georgia 2007/1 strain at days 3, 7 and 12 postvaccination. Only the animals vaccinated 12 days before the challenge had effectively controlled infection progression, showing low virus loads, minor clinical signs and a lack of the unbalanced inflammatory response characteristic of severe disease. Contrarily, the animals vaccinated 3 or 7 days before the challenge just showed a minor delay in disease progression. An analysis of the humoral response and whole blood transcriptome signatures demonstrated that the control of infection was associated with the presence of virus-specific IgG and a cytotoxic response before the challenge. These results contribute to our understanding of protective immunity induced by LAV-based vaccines, encouraging their use in emergency responses in ASF-affected areas.

Over the past few decades, the fishing industry and species conservationists have grown increasingly concerned about the decrease in catches and poor health of European sardines (Sardina pilchardus), particularly in the northwestern Mediterranean region. The species is threatened by a number of factors, including parasite illnesses, rising seawater temperatures, and overfishing. Increasing seawater temperatures due to climate change might lead to the proliferation of protistan parasites, such as Ichthyodinium chabelardi. This parasite has been documented in the literature to cause 100% larval mortality in sardines, which may have detrimental effects on fish populations and the fishing industry. We confirmed the existence of I. chabelardi in pelagic eggs and the ovaries of European sardines from the Catalan coast (northwestern Mediterranean) by means of stereomicroscopic analysis and a genetic methodology for parasite identification. The incidence of this infection was 22.5% in ovarian tissue and 11.5% in eggs. In this study, we present new data on the vertical transmission of I. chabelardi from one generation to another in sardines captured in the Mediterranean region. Interpreting outbreaks of I. chabelardi, especially in sardine populations, requires further research into the transmission of infection and improving our understanding of protozoan parasites.

In recent years, a drop in the condition of the European sardine has been observed. Although several causes have been attributed to this issue, as overfishing and climate change, little is known about the link between ascaridoid nematode parasitisation and fish status. In this study, sardines were obtained from four fishing grounds along the Mediterranean (Alboran, Northern Spain, Northern Adriatic, and Aegean), and one location in the Atlantic Ocean (Southern Portugal). After analysing individual fish body condition (by direct tissue fat content measurements and condition indices), and reproductive status (by a detailed gonadal examination) throughout the entire annual cycle, ascaridoids were recognised by combining naked eye and UV-press method along flesh, viscera, and gonads. Afterwards, sequence analysis of the rDNA internal transcribed spacers region (ITS) and the mtDNA cox2 gene were used to identify and characterise the different species of ascaridoids from the fish host in the localities throughout the seasons. The main species found along different areas was Hysterothylacium aduncum, present in the Northern Adriatic (prevalence of 7.6%, mean intensity 1.700), the Atlantic (7.5%, 3.889), and the Northern Spain (3.9%, 1.600). Moreover, few individuals of Anisakis simplex (s.s.) and A. pegreffii were observed in the Atlantic (1.7% and 0.8%, respectively), and the latter species was also found in the Adriatic stock (0.8%). All ascaridoid specimens were found in viscera. Obtained results seem to indicate that in stocks with medium sizes, small variations in length are related to parasite intensity. This study highlights the importance of seasonal parasitological analyses at stock level and, especially, in capital breeders, as relationships between condition and reproduction parameters and parasitism are conditioned by seasonality.

Small pelagic fish are key elements of marine trophic networks and are of great importance to the total landing of marine species. Over the last decades, a decrease in biomass and catches of European sardine has been described, especially in the Mediterranean Sea, as an indication of a drop in stock condition. Multiple causes, including direct and indirect anthropogenic factors, seem to affect this ecologically and economically important species. To address this issue, it is important to identify the current variability in sardine status and understand the strategies for energy allocation, which are intimately related to reproductive potential and recruitment. We analyzed the somatic condition through tissue and mesenteric lipid measurements, relative condition ( Kn ) and hepatosomatic ( HSI ) indices, and reproductive condition with the gonadosomatic index ( GSI ) in four subareas of the Mediterranean (Northern Alboran, Northern Spain, the Northern Adriatic, and the Aegean Sea) and an outgroup from the Atlantic. The analyses were performed within the gonadal development cycle since translocation to reproduction may mask the state of actual energy reserves for comparison. The results revealed marked differences in health status among subareas, highlighting the low condition of Northern Spain sardines throughout the annual cycle. The uniform condition throughout gonadal development in the Northern Adriatic suggests that resource availability modulates the reproductive strategy since in this locality, sardines would have high dependence on immediate reserves, not behaving as strict capital breeders. Moreover, similarities between Alboran and Atlantic stocks are discussed, highlighting the marked energy replenishment of the latter after reproduction compared to the Mediterranean stocks. The Aegean stock was the fastest to reach its maximum after spawning, presenting low condition values from the developing to actively spawning period, but with the greatest recovery at the regressing phase, coinciding with a peak in productivity. Finally, the role of the liver in sardine energy storage is analyzed considering stock heterogeneity, potentially indicating that HSI is intimately related to feeding activity. Given the divergences among stocks, we propose concrete measures for managing this resource (i.e., the need for adapting the close seasons), which could be applied to other species in similar contexts.

The European sardine, Sardina pilchardus (Walbaum, 1792), is a cold-temperate water species from the Clupeid family. This small pelagic has a key functional role in the marine ecosystem along its distributional range in the northeast of the Atlantic Ocean, the Sea of Marmara, the Black Sea and the Mediterranean Sea. Furthermore, sardine is one of the most important commercial fishery resources caught by the purse seine fleet in the Mediterranean Sea. There is reported a decline in annual sardine catches in the Northwestern Mediterranean Sea, as well as smaller mean total length and sexual maturation size of the individuals, mainly attributed to increased water temperature and overfishing, which have a negative impact on energetic body condition, growth and reproduction. However, little is known about the impact of parasitism on sardine health status. In this work we analyzed the incidence of parasites in sardines from the Catalan Coast of the Northwestern Iberian Peninsula, using two approaches: visual inspection by stereo microscope and the UV-press method, based on the autofluorescence of certain parasites, along a complete reproductive cycle. The main parasite found was the nematode Hysterothylacium sp., although other species were identified by visual inspection (i.e., Contracaecum sp., digenea trematodes). No Anisakis spp. were observed under either of the methodologies. Using the former method, we detected 35.3 % of individuals infected by, at least, one nematode parasite with a mean intensity of 1.68 %. With the UV-press technique, we quantified a prevalence of 16.5 %. In both cases, the Southern Catalan Coast presented a larger number of parasitized sardines, which was remarkably higher in spring. Combined methodologies are suggested to more precisely detect parasites, since visual inspection allows a more detailed study of the viscera, but UV-press also allows the study of parasites that may be present in the musculature. Furthermore, genetic validation should be performed in order to accurately determine the parasite species found.

The small pelagic European sardine presents high commercial and ecological values. Due to its cold-temperate water affinity, stocks are affected by global warming. Water temperature rise may change primary productivity patterns, negatively affecting fish condition and increasing parasite incidence. In this context, sardine health status was evaluated through the annual cycle on the Catalan Coast using thermal regimes comparison. Morphogravimetric parameters, sex and gonadal stages were assessed; infection by nematodes was characterised, and body condition was estimated by the Le Cren Factor and lipid content measured using a fish fat meter. Significant statistical differences were observed in spawning dynamics, body condition, and parasite infection between thermal regimes. Sardines from the colder north area had better condition and an earlier spawning, with lower parasite incidence (in terms of total prevalence, mean intensity and abundance) than those from the southern coast. Hysterothylacium spp. was the most abundant nematode, while Anisakis spp. prevalence was null in the two locations. Seasonal differences in nematode load were observed along the Catalan Coast, with lower prevalence during the summer and higher in winter-spring. Although previous studies have underestimated parasite influence on sardine health status, parasite abundance and sardine condition were negatively correlated. Seawater temperature and primary productivity are the proposed factors promoting differentiation in nematode infection and fish condition throughout the annual cycle and between locations.

To achieve sustainable fisheries implies that resources' management is carried out in accordance with biologically and ecologically relevant processes. In this context, to infer the boundaries of the genetic stocks along their distribution is crucial to avoid the depletion of genetic diversity induced by fishing pressure. Despite its remarkable ecological role and commercial interest, there are still many uncertainties about the genetic population structure and local adaptation processes of the European sardine (Sardina pilchardus) along its distributional range. Our analysis revealed that in addition to the uneven genetic study effort throughout its distribution, there are discrepancies when it comes to delimiting populations, especially in the waters surrounding the Iberian Peninsula. Also, powers of the genetic markers applied in the studies were examined, showing that allozymes detected a larger number of significant pairwise values of genetic differentiation, while mtDNA-RFLP detected a greater degree of differentiation among genetic stocks. Moreover, large values of genetic diversity in all the locations were identified regardless of marker type. Thereby, we provide a discussion of updated knowledge, contributing to shape long-term and genetically sustainable harvest strategies for this pelagic fish, since our findings indicate a mismatch between the genetic stocks and the managed stocks currently defined.

African swine fever virus (ASFV) is causing a worldwide pandemic affecting the porcine industry and leading to important global economic consequences. The virus causes a highly lethal hemorrhagic disease in wild boars and domestic pigs. Lack of effective vaccines hampers the control of virus spread, thus increasing the pressure on the scientific community for urgent solutions. However, knowledge on the immune components associated with protection is very limited. Here we characterized the in vitro recall response induced by immune cells from pigs intranasally vaccinated with the BA71ΔCD2 deletion mutant virus. Vaccination conferred dose-dependent cross-protection associated with both ASFV-specific antibodies and IFNγ-secreting cells. Importantly, bulk and single-cell transcriptomics of blood and lymph node cells from vaccinated pigs revealed a positive feedback from adaptive to innate immunity. Indeed, activation of Th1 and cytotoxic T cells was concomitant with a rapid IFNγ-dependent triggering of an inflammatory response characterized by TNF-producing macrophages, as well as CXCL10-expressing lymphocytes and cross-presenting dendritic cells. Altogether, this study provides a detailed phenotypic characterization of the immune cell subsets involved in cross-protection against ASFV, and highlights key functional immune mechanisms to be considered for the development of an effective ASF vaccine.

Cold- and deep-water species such as Molva species show low resilience to anthropogenic pressures, and they become particularly vulnerable at the warm edges of their distribution. In this study, the poorly documented Mediterranean ling (Molva macrophthalma) population from the northwestern Mediterranean Sea was analysed. This area is considered a cul-de-sac in a sea-warming hotspot, where M. macrophthalma shows a low population health status and is experiencing a climate-related reduction in abundance. Several life-history traits (length at maturity, reproductive cycle, fecundity style, oocyte recruitment pattern, and breeding strategy) are here described for the first time to evaluate the reproductive performance (oocyte diameter and production) in relation to the fish condition status (the HSI and relative condition index). Additionally, the results are compared with those of a population of a similar species, the blue ling (Molva dypterygia), inhabiting the cool edge of its distribution, hypothesised to have a higher condition status. Our results indicate that M. macrophthalma is a capital breeder with restricted secondary growth recruitment and group-synchronous oocyte development. In relative terms, the stressed southern M. macrophthalma exhibited a worse condition, a lower investment in reproduction, a smaller size at maturity, larger but fewer primary growth oocytes, and a smaller size-standardized production of secondary growth oocytes than the northern M. dypterygia. Significant differences in the secondary growth oocyte recruitment were also found. These findings reinforce the environment’s role in shaping the reproductive potential and condition status. Altogether, this study suggests high sensitivity to anthropogenic pressures for both species, and, especially for Mediterranean ling, it shows the importance of introducing monitoring and conservation measures to ensure the sustainability of its populations.