Evaluation of Soybean Meal-Red Blood Cell Coextruded Feed Ingredient in Diets Fed to Rainbow Trout Oncorhynchus mykiss

Abstract.— Fish meal is one of the predominant sources of crude protein used in practical feeds for most cultured species. However, with overfishing and increasing demand for protein feedstuffs, new competitively priced sources of dietary protein are needed. A coextruded soybean meal-red blood cell (SBM-RBC) ingredient was evaluated as a source of crude protein for rainbow trout Oncorhynchus mykiss . The SBM-RBC ingredient was incorporated at either 0, 21, 42 or 63% of the dietary protein, replacing an isoni-trogenous amount of fish meal. All diets were fed for 8 wk to triplicate groups of juvenile rainbow trout (average initial weight 49.5 g) stocked into a recirculating system consisting of 48, 114-L aquaria. There were no significant differences in weight gain, feed conversion ratio, protein efficiency ratio, apparent crude protein digestibility, apparent gross energy digestibility, dress-out percentage, or fillet protein and fat concentrations in fish fed any of the experimental diets. Based on these data, extruded SBM-RBC appears to be a suitable ingredient in diets fed to rainbow trout.     

Ankyrin repeat proteins comprise a diverse family of bacterial type IV effectors

Specialized secretion systems are used by many bacteria to deliver effector proteins into host cells that can either mimic or disrupt the function of eukaryotic factors. We found that the intracellular pathogens Legionella pneumophila and Coxiella burnetii use a type IV secretion system to deliver into eukaryotic cells a large number of different bacterial proteins containing ankyrin repeat homology domains called Anks. The L. pneumophila AnkX protein prevented microtubule-dependent vesicular transport to interfere with fusion of the L. pneumophila-containing vacuole with late endosomes after infection of macrophages, which demonstrates that Ank proteins have effector functions important for bacterial infection of eukaryotic host cells.     

Blood neutrophil-to-lymphocyte ratio (NLR) as a diagnostic marker in dogs with chronic enteropathy

Few routinely available biomarkers are clinically useful in assessing dogs with chronic enteropathy (CE) and aid in CE subclassification. The diagnostic potential of the blood neutrophil-to-lymphocyte ratio (NLR) has not been evaluated in canine CE. We evaluated the NLR in 93 dogs with CE (no steroid treatment for ≥2 wk prior) and tested for an association with clinical, clinicopathologic, and histologic characteristics and also with CE subclassification. NLR was significantly higher in CE dogs with severe clinical disease than dogs with mild clinical disease (p = 0.047). Hypoalbuminemia (p < 0.001), but not hypocobalaminemia, was associated with higher NLRs. NLR was correlated with fecal alpha₁-proteinase inhibitor concentrations (ρ = 0.47) and the serum-to-fecal alpha₁-proteinase inhibitor ratio (ρ = –0.48; both p < 0.001) but not with serum or fecal inflammatory markers nor with the overall histologic score (all p > 0.05). Dogs with steroid- or other immunosuppressant-responsive (IRE) or nonresponsive enteropathy (NRE) had significantly higher NLRs (median: 7.3) than dogs with food-responsive enteropathy (FRE; median: 3.0; p = 0.003), and a NLR ≥5.5 best distinguished both groups of dogs. No difference in NLR was detected between dogs with IRE and dogs diagnosed with NRE. These findings suggest that leukogram changes (i.e., NLR) could be clinically useful in canine CE, and that neutrophils might play a role in the systemic inflammatory response associated with canine CE. The NLR can be easily assessed on routine hematology and can potentially aid in the subclassification of dogs with CE based on the response to treatment.     

The alarmin interleukin-33 drives protective antiviral CD8⁺ T cell responses

Pathogen-associated molecular patterns decisively influence antiviral immune responses, whereas the contribution of endogenous signals of tissue damage, also known as damage-associated molecular patterns or alarmins, remains ill defined. We show that interleukin-33 (IL-33), an alarmin released from necrotic cells, is necessary for potent CD8(+) T cell (CTL) responses to replicating, prototypic RNA and DNA viruses in mice. IL-33 signaled through its receptor on activated CTLs, enhanced clonal expansion in a CTL-intrinsic fashion, determined plurifunctional effector cell differentiation, and was necessary for virus control. Moreover, recombinant IL-33 augmented vaccine-induced CTL responses. Radio-resistant cells of the splenic T cell zone produced IL-33, and efficient CTL responses required IL-33 from radio-resistant cells but not from hematopoietic cells. Thus, alarmin release by radio-resistant cells orchestrates protective antiviral CTL responses.     

Optimizing the size of the area surveyed for monitoring a Eurasian lynx (Lynx lynx) population in the Swiss Alps by means of photographic capture–recapture

We studied the influence of surveyed area size on density estimates by means of camera‐trapping in a low‐density felid population (1–2 individuals/100 km²). We applied non‐spatial capture–recapture (CR) and spatial CR (SCR) models for Eurasian lynx during winter 2005/2006 in the northwestern Swiss Alps by sampling an area divided into 5 nested plots ranging from 65 to 760 km². CR model density estimates (95% CI) for models M₀ and M_h decreased from 2.61 (1.55–3.68) and 3.6 (1.62–5.57) independent lynx/100 km², respectively, in the smallest to 1.20 (1.04–1.35) and 1.26 (0.89–1.63) independent lynx/100 km², respectively, in the largest area surveyed. SCR model density estimates also decreased with increasing sampling area but not significantly. High individual range overlaps in relatively small areas (the edge effect) is the most plausible reason for this positive bias in the CR models. Our results confirm that SCR models are much more robust to changes in trap array size than CR models, thus avoiding overestimation of density in smaller areas. However, when a study is concerned with monitoring population changes, large spatial efforts (area surveyed ≥760 km²) are required to obtain reliable and precise density estimates with these population densities and recapture rates.     

(Highly pathogenic) avian influenza as a zoonotic agent

Zoonotic agents challenging the world every year afresh are influenza A viruses. In the past, human pandemics caused by influenza A viruses had been occurring periodically. Wild aquatic birds are carriers of the full variety of influenza virus A subtypes, and thus, most probably constitute the natural reservoir of all influenza A viruses. Whereas avian influenza viruses in their natural avian reservoir are generally of low pathogenicity (LPAIV), some have gained virulence by mutation after transmission and adaptation to susceptible gallinaceous poultry. Those so-called highly pathogenic avian influenza viruses (HPAIV) then cause mass die-offs in susceptible birds and lead to tremendous economical losses when poultry is affected. Besides a number of avian influenza virus subtypes that have sporadically infected mammals, the HPAIV H5N1 Asia shows strong zoonotic characteristics and it was transmitted from birds to different mammalian species including humans. Theoretically, pandemic viruses might derive directly from avian influenza viruses or arise after genetic reassortment between viruses of avian and mammalian origin. So far, HPAIV H5N1 already meets two conditions for a pandemic virus: as a new subtype it has been hitherto unseen in the human population and it has infected at least 438 people, and caused severe illness and high lethality in 262 humans to date (August 2009). The acquisition of efficient human-to-human transmission would complete the emergence of a new pandemic virus. Therefore, fighting H5N1 at its source is the prerequisite to reduce pandemic risks posed by this virus. Other influenza viruses regarded as pandemic candidates derive from subtypes H2, H7, and H9 all of which have infected humans in the past. Here, we will give a comprehensive overview on avian influenza viruses in concern to their zoonotic potential.     

Variability in Macro- and Micronutrients of 15 Commercially Available Microalgae Powders

The nutrient composition of 15 commercially available microalgae powders of Arthrospira platensis, Chlorella pyrenoidosa and vulgaris, Dunaliella salina, Haematococcus pluvialis, Tetraselmis chuii, and Aphanizomenon flos-aquae was analyzed. The Dunaliella salina powders were characterized by a high content of carbohydrates, saturated fatty acids (SFAs), omega-6-polyunsaturated fatty acids (n6-PUFAs), heavy metals, and α-tocopherol, whereas the protein amounts, essential amino acids (EAAs), omega-3-PUFAs (n3-PUFAs), vitamins, and minerals were low. In the powder of Haematococcus pluvialis, ten times higher amounts of carotenoids compared to all other analyzed powders were determined, yet it was low in vitamins D and E, protein, and EAAs, and the n6/n3-PUFAs ratio was comparably high. Vitamin B₁₂, quantified as cobalamin, was below 0.02 mg/100 g dry weight (d.w.) in all studied powders. Based on our analysis, microalgae such as Aphanizomenon and Chlorella may contribute to an adequate intake of critical nutrients such as protein with a high content of EAAs, dietary fibers, n3-PUFAs, Ca, Fe, Mg, and Zn, as well as vitamin D and E. Yet, the nutritional value of Aphanizomenon flos-aquae was slightly decreased by high contents of SFAs. The present data show that microalgae are rich in valuable nutrients, but the macro- and micronutrient profiles differ strongly between and within species.     

Immunopathogenesis and immunotherapy of Culicoides hypersensitivity in horses: an update

Culicoides hypersensitivity (CH) is a strongly pruritic dermatitis of horses, characterised histologically by mixed perivascular to diffuse cellular infiltrates of mononuclear cells and eosinophils, and caused by helper T cell (Th)2, immunoglobulin (Ig)E-mediated reactions to antigens present in the saliva of biting Culicoides midges. As treatment of CH is still not satisfactory, a better knowledge of the pathogenesis of CH is needed for the development of new therapeutic modalities. Accordingly, availability of pure Culicoides allergens instead of crude whole body extracts is essential for the improvement of in vitro diagnosis of CH and development of a more effective allergen immunotherapy (AIT). Beside the Th2 cytokines interleukin (IL)-4 and IL-13, recent studies have shown the involvement of thymic stromal lymphopoietin, IL-5 and IL-31 in the pathogenesis of CH. The importance of IL-5 and IL-31 has been confirmed through targeting these cytokines by active immunisation of CH patients, resulting in a significant decrease of CH lesion scores. Thirty Culicoides salivary allergens have been described over the last 10 years and produced as pure recombinant (r-) proteins. Use of a protein microarray has allowed the identification of the most relevant Culicoides r-allergens for CH in central and northern Europe. An immunisation protocol has been developed for preventive AIT against CH. Small amounts of r-Culicoides allergens injected into the submandibular lymph nodes with Alum/MPLA as adjuvants seem to induce a suitable immune response for both preventive and therapeutic AIT. The next years will reveal whether these recent advancements will translate into an improved diagnosis, treatment and prevention of CH.     

Use of a Single-Layer Density Centrifugation Method Enhances Sperm Quality in Cryopreserved–Thawed Equine Spermatozoa

The objective of this study was to improve the quality of cryopreserved–thawed equine sperm using single-layer density centrifugation (SLC). Sperm quality was assessed by DNA integrity, motility, morphology, mitochondrial membrane potential, viability, and plasma membrane alteration. The percentage of DNA-damaged sperm (expressed in % COMP) was lower (P = .001) after SLC (1.6 ± 0.5% vs. 6.8 ± 0.5%). Total sperm motility (80 ± 2.4% vs. 41.7 ± 2.4%) and progressive sperm motility (69.5 ± 2.9% vs. 31.5 ± 2.9%) (P < .001), as well as the percentage of morphologically normal sperm (45 ± 3.9% vs. 27.7 ± 3.9%), increased after SLC compared with control sample. In addition, the proportion of sperm with high mitochondrial membrane potential increased (81.6 ± 1.8% vs. 42.1 ± 1.8%), as did the viability of sperm (71.1 ± 2.4% vs. 39.5 ± 2.4%), after SLC compared with the control sperm. The proportion of sperm with alteration in plasma membrane structure was lower after SLC compared with control sample (6.4 ± 1.1% vs. 18.9 ± 1.1%). Overall, sperm recovery was 72.7 ± 3.6% in the control sample compared with 14.8 ± 3.6% after SLC (P < .001). We conclude that based on the sperm parameters evaluated, SLC improves the quality of cryopreserved–thawed equine spermatozoa.