Inferring source attribution from a multiyear multisource data set of Salmonella in Minnesota

Salmonella enterica is a global health concern because of its widespread association with foodborne illness. Bayesian models have been developed to attribute the burden of human salmonellosis to specific sources with the ultimate objective of prioritizing intervention strategies. Important considerations of source attribution models include the evaluation of the quality of input data, assessment of whether attribution results logically reflect the data trends and identification of patterns within the data that might explain the detailed contribution of different sources to the disease burden. Here, more than 12,000 non‐typhoidal Salmonella isolates from human, bovine, porcine, chicken and turkey sources that originated in Minnesota were analysed. A modified Bayesian source attribution model (available in a dedicated R package), accounting for non‐sampled sources of infection, attributed 4,672 human cases to sources assessed here. Most (60%) cases were attributed to chicken, although there was a spike in cases attributed to a non‐sampled source in the second half of the study period. Molecular epidemiological analysis methods were used to supplement risk modelling, and a visual attribution application was developed to facilitate data exploration and comprehension of the large multiyear data set assessed here. A large amount of within‐source diversity and low similarity between sources was observed, and visual exploration of data provided clues into variations driving the attribution modelling results. Results from this pillared approach provided first attribution estimates for Salmonella in Minnesota and offer an understanding of current data gaps as well as key pathogen population features, such as serotype frequency, similarity and diversity across the sources. Results here will be used to inform policy and management strategies ultimately intended to prevent and control Salmonella infection in the state.     

Selection and realized heritability for growth in the scallop,Euvola ziczac (L.)

Specimens taken from natural populations of the scallop, Euvola ziczac (L.), were mass spawned in order to produce an initial stock of parents for a selection experiment. The purpose of the present study was to improve scallop shell growth and to calculate the degree of heritability of this characteristic. At one year of age, the top 10‰ of the stock (i.e. the larger scallops) were segregated to create the selected line. An equal number of mean-sized scallops was used to create the control line. In the second generation, after 294 days in culture, the heritability values of the scallops were calculated. Heritability estimates fluctuated between 0.47 and 0.54 depending on the character investigated, i.e. shell length or shell height. The selected line was 5.5‰ longer and 4.5‰ higher than the control line, and 7.3‰ longer and 9.4‰ higher than the parental line.     

Effect of Steeping Corn with Lactic Acid on Starch Properties

Pasting and thermal properties of starch from corn steeped in the presence of lactic acid and at different steeping times (8, 16, 24, 32, and 40 hr) were investigated. Corn kernels were steeped at 52°C with 0.2% (w/v) SO₂ and with and without 0.5% (v/v) lactic acid. The isolated starch obtained by corn wet‐milling was characterized by determining starch recoveries, retrogradation, and melting transition properties of the lipid‐amylose complex by differential scanning calorimetry (DSC), and pasting properties by the Rapid Visco Analyser (RVA). Damaged granules and the starch granule size were determined by using microscopic techniques. Starches from corn steeped in the presence of lactic acid (LAS) were compared with control starch (CS) steeped without lactic acid. Greater starch recoveries were obtained for LAS samples than for CS samples, and practically no damaged starch was present in the former preparations. The presence of lactic acid affected the RVA profiles and steeping time affected the viscosities of the starch suspensions. In general, the RVA parameters of LAS suspensions were lower than those of CS suspensions. No great modification of the thermal properties was observed; only a slight decrease in amylopectin retrogradation and in the melting enthalpy of the amylose‐lipid complex was observed. Hydrolysis of the starch during steeping seems the most probable explanation to the starch modifications produced by lactic acid addition.     

Stress response and lipid composition in shrimp Litopenaeus vannamei fed diets enriched with squid or scallop viscera meal

We substituted 10% of fishmeal with scallop (Argopecten ventricosus) or squid (Dosidiscus gigas) by‐product meal in a feed for shrimp (Litopenaeus vannamei) growth assay that lasted 60 days and then shrimps were submitted to handling stress. Shrimp fed the control diet had smaller weight gain and lower recovery after stress. Prostaglandins in gills were affected by diet and stress, with significant differences in shrimp fed the control diet before and after the stress. Hydroperoxides were increased after stress, while isoprostanoids were higher in shrimp fed the control diet. The gene expression of Glutathione peroxidase and Catalase was increased on the stressed shrimp fed the scallop diet, with no differences among diets for Superoxide dismutase or Cyclooxygenase. Arachidonic acid in the phospholipid fraction of muscle was the only fatty acid affected by stress and diet. Cholesterol oxidation products were significantly higher in shrimp fed the scallop diet compared to shrimp fed the control diet before applying the stress. A PCA analysis grouped in one‐factor growth variables, as well as Superoxide dismutase, esterified astaxanthin and isoprostane, while another factor was determined by stress, prostaglandin and hydroperoxide levels in gills. The partial substitution of fishmeal with scallop of squid by‐product meals affected growth and stress differently, indicating shrimp that grew up more were not necessarily more tolerant to handling stress, which can have a strong repercussion in aquaculture, particularly during density control, recording of growth and harvest.     

Fish meal replaced by hydrolysed soybean meal in diets increases growth and improves the antioxidant defense system of silver catfish (Rhamdia quelen)

One of the current challenges of global fish farming is developing plant‐based proteins as a feasible substitute for fishmeal in the formulation of aquafeeds. Substitution levels of fishmeal with hydrolyzed soybean meal (HSM) in diets for silver catfish (Rhamdia quelen) were evaluated for growth, protein metabolism and antioxidant activity. The experiment was carried out in a recirculation system of 20 tanks of 250 L. A total of 300 silver catfish juveniles were used to compose five treatments and four replicates per treatment. Levels of soybean hydrolysate (0%, 5%, 10%, 15% and 20%) were tested in diets (39% protein and 3,500 Kcal) for 60 days. Silver catfish growth was higher at all inclusion levels of HSM when compared to the control diet. No change was shown for body protein deposition. The production of nitrogenous compounds in the liver and muscle was also unaffected by any of the diets. The diet containing 20% HSM promoted an increase in the amounts of non‐protein thiols in the gills and brain. The HSM substitution levels of up to 20% of fishmeal in the diet increases growth and contributes to silver catfish antioxidant activity.     

DNA fragmentation in blue mussel (Mytilus edulis) sperm: aquaculture and fisheries implications

The objective of this study was to assess sperm DNA longevity in blue mussels (Mytilus edulis) using a dynamic assessment of sperm DNA fragmentation (SDF) after sperm activation. Mature blue mussels (n = 57) in Vigo (Galicia, Spain) were obtained, specifically rope farmed blue mussels (n = 38) and wild blue mussels (n = 19). After the sperm collection, a subsample was assessed for SDF (0 h), while the rest of the sample was incubated for 6, 9, 12, 24 and 48 h at 15°C, assessing each time point using the Sperm‐Halomax kit (Halotech DNA, Madrid, Spain). The Kaplan–Meier estimator, log‐rank (Mantel–Cox) test and Mann–Whitney U‐test were used for statistical analyses (spss v. 16.0), α = 0.05. The rate of SDF (r‐SDF) between rope farmed and wild blue mussels over 0–6 h incubation was not significantly different (P = 0.278), but was for 6–24 h (P = 0.004). Differences in r‐SDF were observed when comparing the means between the two groups (P < 0.0001). Individual differences in r‐SDF existed among the rope farmed (P < 0.0001) and wild blue mussels (P < 0.0001). Wild blue mussels presented a higher DNA longevity than the farmed blue mussels. Selection of blue mussel males with a low level of sperm DNA damage and greater sperm DNA longevity may result in better fertilization and seed production.     

Landscape changes as visible indicators in the social,economic and political process of soil erosion: A case study of the municipality of puebla de valles (Guadalajara Province), Spain

This paper proposes a methodological approach to data gathering as a sound basis for understanding land degradation processes, breaking down barriers of distrust between Government officials and land users, and promoting participation in planning for soil and water conservation. It examines how landscape changes, of value as indicators of erosion, are perceived by land users and can be used in planning. It is proposed that the participation of land users in the construction of questionnaires, data gathering, analysis and writing up of the findings are examples of the participatory initial stages in planning.