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Aleutian disease (AD) is a devastating infectious disease in American mink ( Neogale vison ) industry caused by Aleutian mink disease virus (AMDV). Two crucial steps toward controlling infectious diseases in farm animals are: (i) assessment of the infection risk factors to minimize the likelihood of infection and (ii) selection of animals with superior immune responses against pathogens to build tolerant farms. This study aimed to investigate AD risk factors and evaluate a novel “ImmunAD” approach for genetic improvement of AD tolerance. Phenotypic records and pedigree information of 1,366 and 24,633 animals were included in this study. The risk of animal’s age, sex, color type, and year of sampling on AMDV infection was assessed using a logistic regression model and counter immune-electrophoresis (CIEP) test results. ImmunAD phenotype was calculated based on AMDVG enzyme-linked immunosorbent assay (ELISA) and CIEP test results, and breeding values for ImmunAD were estimated using an animal model. Animals were classified into high-coordinated (HCIR), average-coordinated (ACIR), and low-coordinated immune responders (LCIR) using ImmunAD’s breeding values, and the impact of selection of HCIR on live grade of pelt quality (PQ), harvest weight (HW), and harvest length (HL) breeding values were evaluated. Age of > 1 year, male sex, and year of sampling were identified as significant risk factors of AD (p < 0.05). A moderate-to-high heritability (0.55±0.07) was estimated for ImmunAD, while a higher heritability was observed among the CIEP-positive animals (0.76±0.06). Significantly higher breeding values were observed for PQ and HL among HCIR than those for LCIR and ACIR (p < 0.05). Our findings indicate the critical role of male breeders in AD distribution within mink farms. Regular screening of AD in male breeders before pairing them with females during breeding seasons can help disease control. ImmunAD strategy can be applied to genetic improvement of AD tolerance, with favorable impacts on some growth and production traits. Higher genetic gains can be achieved in populations with higher AD seroprevalences.

Analyzing juvenile American lobster populations using fishery-independent data enhances understanding of population dynamics and supports fishery sustainability. This repeated cross-sectional study investigated trends in juvenile lobster populations by analyzing size distributions from nine Lobster Fishing Areas (LFAs) in Nova Scotia, Canada. Data were collected in season from lobsters sampled using ventless research traps between 2003 and 2023. Mixed effect linear and logistic regression models assessed spatial and temporal influences on mean carapace length (CL) and proportions of juvenile lobster. This study provides a 20-year overview of mean CL and juvenile probability, accounting for factors including water depth, sampling month, and lobster sex. Results showed significant variation in temporal effects on mean CL and proportion of juvenile lobster between LFAs. Decreasing trends in sampling juvenile lobsters were observed along the Northeastern coast of Cape Breton and in a highly productive area on the South Shore of Nova Scotia. In contrast, other LFAs showed more resilience, with the southwestern area displaying a relatively stable trend. The findings highlight variability in juvenile lobster trends across LFAs, which reflect the relative effectiveness of local management measures and provide insights to inform management decisions in Nova Scotia.

Aleutian disease (AD) is a multi-systemic infectious disease in American mink ( Neogale vison ) caused by Aleutian mink disease virus (AMDV). This study aimed to identify candidate regions and genes underlying selection for response against AMDV using whole-genome sequence (WGS) data. Three case–control selection signatures studies were conducted between animals (N = 85) producing high versus low antibody levels against AMDV, grouped by counter immunoelectrophoresis (CIEP) test and two enzyme-linked immunosorbent assays (ELISA). Within each study, selection signals were detected using fixation index (FST) and nucleotide diversity (θπ ratios), and validated by cross-population extended haplotype homozygosity (XP-EHH) test. Within- and between-studies overlapping results were then evaluated. Within-studies overlapping results indicated novel candidate genes related to immune and cellular responses (e.g., TAP2 , RAB32 ), respiratory system function (e.g., SPEF2 , R3HCC1L ), and reproduction system function (e.g., HSF2 , CFAP206 ) in other species. Between-studies overlapping results identified three large segments under strong selection pressure, including two on chromosome 1 (chr1:88,770–98,281 kb and chr1:114,133–120,473) and one on chromosome 6 (chr6:37,953–44,279 kb). Within regions with strong signals, we found novel candidate genes involved in immune and cellular responses (e.g., homologous MHC class II genes, ITPR3 , VPS52 ) in other species. Our study brings new insights into candidate regions and genes controlling AD response.

This study evaluated the effect of the delivery of a commercial essential oil blend containing the phytonutrients star anise, cinnamon, rosemary, and thyme oil (via different routes) on broiler chickens’ ileal and ceca microbiota and liver transcriptome compared to an antibiotic growth promoter. Eggs were incubated and allocated into three groups: non-injected, in ovo saline, and in ovo essential oil. On day 18 of incubation, 0.2 mL of essential oil in saline (dilution ratio of 2:1) or saline alone was injected into the amnion. At hatch, chicks were assigned to post-hatch treatment combinations: (A) a negative control (corn-wheat-soybean diet), (B) in-feed antibiotics, (C) in-water essential oil (250 mL/1000 L of drinking water), (D) in ovo saline, (E) in ovo essential oil, and (F) in ovo essential oil plus in-water essential oil in eight replicate cages (six birds/cage) and raised for 28 days. On days 21 and 28, one and two birds per cage were slaughtered, respectively, to collect gut content and liver tissues for further analysis. Alpha and beta diversity differed significantly between ileal and ceca samples but not between treatment groups. In-feed antibiotic treatment significantly increased the proportion of specific bacteria in the family Lachnospiraceae while reducing the proportion of bacteria in the genus Christensenellaceae in the ceca, compared to other treatments. Sex-controlled differential expression of genes related to cell signaling and tight junctions were recorded. This study provides data that could guide the use of these feed additives and a foundation for further research.

The native Atlantic rock crab (Cancer irrotatus) and the invasive European green crab (Carcinus maenas) are commercially and ecologically important crustacean species in Atlantic Canada. The importance of microbiomes for host health and ecology has been recognized in many species, although very few studies have focused on crustaceans or their external shell microbiome. This is the first-ever study to characterize and analyze the microbial communities associated with the external carapace of C. irrotatus and C. maenas. Microbiome samples were collected from three locations in Atlantic Canada, processed using standard 16S Illumina MiSeq PE250 sequencing and analyzed with the openaccess QIIME2 software. Taxonomic classification of the microbial compositions, as well as alphaand beta diversities, reveal that the shell microbiome differs by host species between C. irrotatus and C. maenas sampled from the same location and between C. irrotatus sampled from different locations. Interestingly, the differences are greater between species at the same location than between locations for the same species. These are the first-ever results showing that the crustacean shell microbiome not only depends on environmental geographical factors but also on intrinsic factors specific to the host species. This implies that crustaceans exert some impact on their shell microbiome, potentially selecting beneficial taxa. These are important findings that could elucidate contributing factors of crustacean shell diseases that are important for commercial species, yet still poorly understood.

Anthropogenic carbon emissions released into the atmosphere is driving rapid, concurrent increases in temperature and acidity across the world's oceans. Disentangling the interactive effects of warming and acidification on vulnerable life stages is important to our understanding of responses of marine species to climate change. This study evaluates the interactive effects of these stressors on the acute response of gene expression of postlarval American lobster (Homarus americanus), a species whose geographic range is warming and acidifying faster than most of the world's oceans. In the context of our experiment, we found two especially noteworthy results: First, although physiological end points have consistently been shown to be more responsive to warming in similar experimental designs, our study found gene regulation to be considerably more responsive to elevated pCO2. Furthermore, the combined effect of both stressors on gene regulation was significantly greater than either stressor alone. Using a full factorial experimental design, lobsters were raised in control and elevated pCO2 concentrations (400 ppm and 1,200 ppm) and temperatures (16°C and 19°C). A transcriptome was assembled from an identified 414,517 unique transcripts. Overall, 1,108 transcripts were differentially expressed across treatments, several of which were related to stress response and shell formation. When temperature alone was elevated (19°C), larvae downregulated genes related to cuticle development; when pCO2 alone was elevated (1,200 ppm), larvae upregulated chitinase as well as genes related to stress response and immune function. The joint effects of end‐century stressors (19°C, 1,200 ppm) resulted in the upregulation of those same genes, as well as cellulase, the downregulation of calcified cuticle proteins, and a greater upregulation of genes related to immune response and function. These results indicate that changes in gene expression in larval lobster provide a mechanism to respond to stressors resulting from a rapidly changing environment. Using nextgen transcriptomic sequencing methodologies, our study evaluates the single and joint effects of elevated temperature and CO2 on gene regulation in the postlarval stage of the American lobster. Our study shows gene regulatory response to be considerably more affected by elevated pCO2 levels than elevated temperature, contrasting what has been shown in studies of physiological end points of larval crustaceans, as well as a strong joint effect of simultaneous stressors.

Shore-based live holding is a required step for post-harvest economic success in the American lobster (Homarus americanus H. Milne Edwards, 1837) fishery. This study evaluated and quantified nutritional condition and gene expression of hepatopancreas during live storage of American lobsters harvested from inshore and offshore locations in Nova Scotia, Canada in early winter. Crude-fat percentage of lobster hepatopancreas and plasma biochemical indicators in haemolymph were used to evaluate the nutritional status of lobsters during live storage. Hepatopancreas crude-fat levels were significantly higher in lobsters from inshore in contrast to offshore locations. Similarly, inshore lobsters were easily distinguished from offshore lobsters because of higher haemolymph Brix and plasma triglyceride, cholesterol, and total protein concentrations. Elevated plasma aspartate aminotransferase activity in inshore lobsters when compared to offshore lobsters suggests that handling practices in the inshore fishery have more impact on harvested lobsters than offshore fishing practices. Inshore lobsters were nevertheless able to recover by four weeks in storage with no obvious mid- and long-term effects. Microarray analysis of hepatopancreas tissue resulted in gene expression profiles that routinely separated inshore from offshore lobsters at all storage time points. The biochemistry of haemolymph and the crude-fat and molecular gene expression analysis of hepatopancreas proved to be useful tools for differentiating lobster harvesting locations. Lobsters harvested inshore in January and stored at the wharf for one month in contrast to lobsters harvested fresh in February had similar gene expression and biochemical profiles; indicating that there is no disadvantage to the livestorage of lobsters caught early in the winter, compared to fresh caught lobsters a month later.