Influence of diet and feeding strategy on the performance of nitrifying trickling filter,oxygen consumption and ammonia excretion of gilthead sea bream (Sparus aurata) raised in recirculating aquaculture systems

Gilthead sea bream (Sparus aurata) was raised in six individual recirculating aquaculture systems (RAS) whose biofilters’ performance was analyzed. Fish were fed with three different diets (a control diet, a fishmeal-based diet (FM), and a plant meal-based diet (VM)) and with three different feeding strategies (manual feeding to apparent satiation, automatic feeding with restricted ration, and auto-demand feeding). For every combination of diet and feeding strategy, the mean oxygen consumption, ammonia excretion, and ammonia removal rate were determined. Fish fed with the VM diet consumed the most oxygen (20.06?±?1.80 gO₂ consumed kg^?1 day^?1). There were significant differences in ammonia excretion depending on the protein content and protein efficiency of the diet, as well as depending on feeding strategy, which in turn affected ammonia removal rates. Fish fed by auto-demand feeders led to the highest mean ammonia removal rate (0.10 gN-TAN removed m^?2 biofiltration area day^?1), while not leading to peaks of high ammonia concentration in water, which preserve fish welfare and growth.

     

Updated Trends on the Biodiscovery of New Marine Natural Products from Invertebrates

From 1990–2019, a total of 15,442 New Marine Natural Products from Invertebrates (NMNPIs) were reported. The 2010s saw the most prolific decade of biodiscovery, with 5630 NMNPIs recorded. The phyla that contributed most biomolecules were the Porifera (sponges) (47.2%, 2659 NMNPIs) and the Cnidaria (35.3%, 1989 NMNPIs). The prevalence of these two phyla as the main sources of NMNPIs became more pronounced in the 2010s. The tropical areas of the Pacific Ocean yielded more NMNPIs, most likely due to the remarkable biodiversity of coral reefs. The Indo-Burma biodiversity hotspot (BH) was the most relevant area for the biodiscovery of NMNPIs in the 2010s, accounting for nearly one-third (1819 NMNPIs) of the total and surpassing the top BH from the 1990s and the 2000s (the Sea of Japan and the Caribbean Islands, respectively). The Chinese exclusive economic zone (EEZ) alone contributed nearly one-quarter (24.7%) of all NMNPIs recorded during the 2010s, displacing Japan’s leading role from the 1990s and the 2000s. With the biodiscovery of these biomolecules steadily decreasing since 2012, it is uncertain whether this decline has been caused by lower bioprospecting efforts or the potential exhaustion of chemodiversity from traditional marine invertebrate sources.     

Soil quality assessments in integrated crop–livestock–forest systems: A review

Integrated crop–livestock–forest is a promising strategy to improve soil quality. It comprises four different integrated farming systems: crop–livestock, crop–forest, forest–livestock and crop–livestock–forest. This work systematically reviewed studies about integrated crop–livestock–forest systems and soil quality. A total of 92 papers were retrieved from the Web of Science—Clarivate Analytics platform, and the following information was analysed: publication year, institution, region of the studied site, type of integrated system, soil type, tillage system, maximum soil depth and the soil quality indicators assessed. Most studies were published in the second half of the 2010s. Brazil is a prominent focus of research about soil quality and integrated crop–livestock–forest systems, with significant contribution from its central and southern regions. The Embrapa was the main publishing institution, present in over one‐third of the studies. Crop–livestock was the most common integrated system, Ferralsols was the most common soil group, and most of the studied soils were clayey. No tillage was the main tillage system. Most studies focused on the topsoil, assessing physical and/or chemical soil quality indicators. More emphasis on biological indicators of soil quality is required, as well as assessments integrating biological, physical and chemical indicators of soil quality. Future works should compare different integrated systems, including assessments deeper in the soil profile, especially in systems with the forest component, and also in sandy and silty soils. Soil quality indicators that have been rarely used should be further tested. Novel indicators should be added to better understand the promotion of soil quality by integrated crop–livestock–forest systems.     

The coefficient of dominance is not (always) estimable with biallelic markers

The genetic relationship among individuals at one locus is characterized by nine coefficients of identity. The coefficients of inbreeding, coancestry and dominance (or fraternity) are just linear functions of them. Here, it is shown how they can be estimated using biallelic and triallelic markers using the method of moments, and comparisons are made with other methods based on molecular coancestry or molecular covariance. It is concluded that in the general case of dominance and inbreeding with biallelic markers, only the coefficients of inbreeding and coancestry can be estimated, but neither the single coefficients of identity nor the coefficient of dominance can be estimated. More than two alleles are required for a full estimation as illustrated with the triallelic situation.     

Results from an indirect fluorescent antibody test using three different strains of Ehrlichia canis

An indirect fluorescent antibody (IFA) test is usually performed to detect antibodies in dogs naturally infected by Ehrlichia canis. In this work, results obtained using three different E. canis strains as antigen (a commercial antigen, the E. canis Oklahoma strain and the E. canis Madrid strain) were compared. One hundred and forty-nine serum samples obtained from dogs living in the centre of Spain were analysed. When qualitative results were evaluated, identical results were detected in 87.2% of samples for the three antigens tested. When comparing antibody titre results, differences between the Madrid strain and the commercial antigen, and between the Madrid and Oklahoma strains were statistically significant (P < 0.0001). No differences were found when comparing the Oklahoma strain with the commercial antigen (P = 0.562). Subtle intra-laboratory variations shown in this study suggest a higher sensitivity of the IFA test when an autochthonous strain is used as antigen.     

Optimization of the extraction of antioxidants from Dunaliella salina microalga by pressurized liquids

In this work, extraction of antioxidant compounds from Dunaliella salina microalga is optimized by combining pressurized liquid extraction (PLE) and experimental design (three-level factorial design) with three different solvents (hexane, ethanol, and water). Two main factors were considered, the extraction temperature (40, 100, and 160 degrees C) and the extraction time (5, 17.5, and 30 min). As response variables, the extraction yield (percent dry weight/initial weight) and the antioxidant activity of the extracts (determined using the TEAC method) were used. The parameters of the model were estimated by multiple linear regression. Results showed that the extraction temperature was the factor having the strongest influence (positive) on the two response variables. The best yields were obtained with ethanol at the higher extraction temperature and time tested. Besides, although hexane extracts provided the best antioxidant activity, ethanol extracts were also very active. The chemical characterization of ethanol extracts was carried out using HPLC-DAD, and attempts have been made to correlate their chemical composition with the antioxidant activity measured. Results pointed out that the extracts contained, besides all-trans-beta-carotene and isomers, several different minor carotenoids that seemed to make a contribution to the antioxidant activity of the extracts.     

Molecular Characterization of the USDA White Clover (Trifolium repens L.) Core Collection by RAPD Markers

White clover is one of the most important forage legume species worldwide, playing an important role in Southern Brazil temperate cultivated pastures. This work was aimed to characterize the genetic variability of the USDA white clover core collection formed by 78 accessions representing 50 countries, together with two very well known cultivars (Huia and Ladino Regal), using RAPD (Random Amplified Polymorphic DNA) markers to produce genetic fingerprints. There were used DNA bulks formed by the extraction and mixture of 20 random individuals from each accession. Twenty four primers were used, which revealed from 3 to 29 bands, forming a total of 371 polymorphic bans and only one monomorphic, ranging from 50 to 3098 bp. The results showed a genetic similarity among the accessions, ranging from 0.18 to 0.58 (Jaccard’s index), with an average of 0.24, allowing the identification of each individual accession using just three primers. The results also showed a large genetic variability within the white clover core collection, probably due to its reproduction mode and ploidy level, which could be used in plant breeding program.     

Influence of age and purpose for testing on the cut-off selection of serological methods in bovine neosporosis

The aim of this study was to investigate the need for different cut-off points, according to animal age and the purpose of testing, for two of the most widely used serological techniques in bovine neosporosis, IFAT and a crude antigen ELISA (Civtest, HIPRA). Therefore, the population reference sera used were defined using a combination of multiple criteria such as epidemiological/clinical and histopathological parameters and an immunoblot test. Firstly, foetuses and breeding cattle (heifers and cows) were considered as separate subpopulations for serological evaluation. Secondly, cut-off points for each serological technique (IFAT and ELISA) according to age group (foetuses and breeding cattle) and the different practical applications (detection of infection and abortion) were calculated following the receiver operating characteristics (ROC) analysis. Cut-off points were defined, for IFAT and ELISA for aborted breeding cattle and for IFAT alone in the case of the foetuses, assuming an equivalent cost of false positive and negative results. In infected breeding cattle, for IFAT and ELISA and in foetuses for ELISA, two possible cut-off values were obtained, one for a maximum sensitivity and one for a maximum specificity and the intervals of unclear results were defined. In this case, a cut-off value for equal sensitivity and specificity was also estimated. When cut-off points for infected breeding cattle, 1:100-1:250 for IFAT and 0.306-0.451 for ELISA were applied to a target population, optimal and similar negative and positive predictive values together with similar apparent and true prevalence results were observed suggesting the possibility of using both tests interchangeably.     

Retrospective analysis of exploratory laparotomies in 192 Andalusian horses and 276 horses of other breeds

The medical records of 468 horses that underwent 490 exploratory laparotomies for the correction of gastrointestinal diseases were reviewed to search for differences between Andalusian horses and other breeds. The seasonal distribution of surgical colics and their outcome and complications were also investigated. Bivariant analysis was used to compare the horses' age, gender and breed with the type of surgery, the bowel affected and the type of colic, and all these variables were compared in relation to euthanasia during surgery, complications, short-term survival and seasonal distribution. A total of 405 horses survived the surgery and 329 were discharged from the hospital. Horses less than one year old had better short-term survival than older horses. Andalusian horses suffered more inguinal hernias than the other breeds and were more prone to suffer laminitis as a complication. Colic surgery and inguinal hernias were also more common in the summer.