Microalgae Ankistrodesmus gracilis as feed ingredient for ornamental fish Xiphophorus maculatus

International Aquatic Research - A trial evaluated the effectiveness of macrophytes, Azolla caroliniana (AAC) and Lemna minor (ALM) as a culture media for microalgae Ankistrodesmus gracilis, and...     

Schizochytrium as a replacement for fish oil in a fishmeal free diet for jade perch,Scortum barcoo (McCulloch & Waite)

A 10‐week trial was conducted to determine the response of juvenile jade perch Scortum barcoo on the replacement of dietary fish oil (FO) in a fishmeal free diet. Three iso‐nitrogenous, isocaloric and isolipidic diets were formulated, each containing a different primary fat source: FO, linseed oil (LO), and a mixture of Schizochytrium and LO. The substitution of FO with the mixture of Schizochytrium and LO did not cause a difference in growth. However, there was an 8% reduction in weight gain in fish fed dietary LO, indicating that juvenile jade perch do require a minimal concentration of dietary n‐3 highly unsaturated fatty acids (HUFA). Fish fed the Schizochytrium diet stored more efficient n‐3 HUFA and in particular DHA in their flesh, and retained a higher fillet recovery compared to fish fed FO. In addition, we demonstrated that jade perch are able to produce both n‐3 HUFA and n‐6 HUFA when dietary PUFA are present. Fish fed the LO diet for 10 weeks contained the lowest amount of n‐3 HUFA in fillets among dietary treatment groups. However, feeding these fish the Schizochytrium diet for an additional 4 weeks increased the n‐3 HUFA content towards the same concentration of n‐3 HUFA found in the flesh of fish fed FO, without affecting the sensory properties of the fillets. In contrary, feeding the Schizochytrium diet for a continuous period of 14 weeks lowered overall sensory property scores.     

Cerebellum shapes hippocampal spatial code

Spatial representation is an active process that requires complex multimodal integration from a large interacting network of cortical and subcortical structures. We sought to determine the role of cerebellar protein kinase C (PKC)-dependent plasticity in spatial navigation by recording the activity of hippocampal place cells in transgenic L7PKCI mice with selective disruption of PKC-dependent plasticity at parallel fiber-Purkinje cell synapses. Place cell properties were exclusively impaired when L7PKCI mice had to rely on self-motion cues. The behavioral consequence of such a deficit is evidenced here by selectively impaired navigation capabilities during a path integration task. Together, these results suggest that cerebellar PKC-dependent mechanisms are involved in processing self-motion signals essential to the shaping of hippocampal spatial representation.     

Detection of Echinococcus multilocularis infection in a colony of cynomolgus monkeys (Macaca fascicularis) using serology and ultrasonography.

Five animals in a colony of cynomolgus monkeys (Macaca fascicularis) died or were euthanatized because of alveolar echinococcosis, during a period of 5 years. The remainder of the colony was screened for possible infection with Echinococcus multilocularis, using serology and ultrasonography. A total of 46 animals out of a group of 55 were examined. The presence of anti-Em2 antibodies analyzed with enzyme-linked immunosorbent assay was demonstrated in 3 monkeys. In 2 of these 3 monkeys, multilocular structures compatible with metacestodal cysts in the liver were identified, using ultrasonography. The presence of alveolar echinococcosis was subsequently confirmed at postmortem examination in 1 animal. The other animals are still alive. Two other monkeys were negative in the serological examination but had cystic structures in the liver, which were identified as bile duct cysts at postmortem examination in 1 animal. The other monkey is still alive. These findings suggest that serology for antibodies against the Em2 antigen may represent a useful method in identifying animals that might be infected with E. multilocularis and are therefore at risk of developing fatal alveolar echinococcosis.     

Free-range system and supplementation of 25-hydroxicholecalciferol increases the performance and serum vitamin levels in mixed-parity sows

Improvements in sow productivity have raised questions regarding dietary vitamin D recommendations. The present study aimed to evaluate the effects of the housing system with access to sunlight exposure and supplementation of 25-hydroxicholecalciferol on performance and serum levels of 25(OH)D₃ in sows during gestation and lactation. Sows were distributed in an experimental design with two housing systems: gestation crates or gestation free-range system with external area for sunlight exposure; and two diets: 0 or 50 μg of 25-hydroxicholecalciferol kg⁻¹. The use of 25-hydroxicholecalciferol tended (P = 0.052) to improve total born and influenced (P = 0.046) on number of born alive. Litter weight at birth was also increased (P = 0.01) by 25-hydroxicholecalciferol supplementation; 25-hydroxicholecalciferol supplementation and housing system (free-range with sunlight exposure) tended to increase weaning weight (P = 0.07) and litter daily gain (P = 0.051) during lactation. Exposure to sunlight and 25-hydroxicholecalciferol supplementation increased 25(OH)D₃ serum levels when compared with control treatment during gestation (136.95 vs. 113.92 ng mL⁻¹; P = 0.035) and lactation (120.29 vs. 88.93 ng mL⁻¹; P = 0.026). In conclusion, the association of 25-hydroxicholecalciferol supplementation with exposure to sunlight during gestation improved significantly 25(OH)D₃ serum levels and consequently performance traits in gestation and lactation.     

Quantifying and simulating carbon and nitrogen mineralization from diverse exogenous organic matters

The potential contributions of exogenous organic matters (EOMs) to soil organic C and mineral N supply depend on their C and N mineralization, which can be assessed in laboratory incubations. Such incubations are essential to calibrate decomposition models, because not all EOMs can be tested in the field. However, EOM incubations are resource-intensive. Therefore, easily measurable EOM characteristics that can be useful to predict EOM behaviour are needed. We quantified C and N mineralization during the incubation of 663 EOMs from five groups (animal manures, composts, sewage sludges, digestates and others). This represents one of the largest and diversified set of EOM incubations. The C and N mineralization varied widely between and within EOM subgroups. We simulated C and N mineralization with a simple generic decomposition model. Three calibration methods were compared. Individual EOM calibration of the model yielded good model performances, while the use of a unique parameter set per EOM subgroup decreased the model performance, and the use of two EOM characteristics to estimate model parameters gave an intermediate model performance (average RMSE-C values of 32, 99 and 65 mg C g⁻¹ added C and average RMSE-N values of 50, 126 and 110 mg N g⁻¹ added N, respectively). Because of the EOM variability, individual EOM calibration based on incubation remains the recommended method for predicting most accurately the C and N mineralization of EOMs. However, the two alternative calibration methods are sufficient for the simulation of EOMs without incubation data to obtain reasonable model performances.     

Soil erosion modelling of burned and mulched soils following a Mediterranean forest wildfire

Soil erosion modelling applied to burned forests in different global regions can be unreliable because of a lack of verification data. Here, we evaluated the following three erosion models: (1) Water Erosion Prediction Project (WEPP), (2) Morgan-Morgan-Finney (MMF) and (3) Universal Soil Loss Equation-Modified (USLE-M). Using field plots that were either untreated or mulched with straw, this study involved observations of soil loss at the event scale at a burned pine forest in Central Eastern Spain. The erosion predictions of the three models were analysed for goodness-of-fit. Optimization of the MMF model with a new procedure to estimate the C-factor resulted in a satisfactory erosion prediction capacity in burned plots with or without the mulching treatment. The WEPP model underestimated erosion in the unburned areas and largely overestimated the soil loss in burned areas. The accuracy of soil loss estimation by the USLE-M model was also poor. Calibration of the curve numbers and C-factors did not improve the USLE-M model estimation. Therefore, we conclude that an optimized MMF model was the most accurate way to estimate soil loss and recommend this approach for in Mediterranean burned forests with or without postfire mulching. This study gives land managers insight about the choice of the most suitable model for erosion predictions in burned forests.     

Predominance of the papGII allele with high sequence homology to that of human isolates among avian pathogenic Escherichia coli (APEC)

Avian pathogenic Escherichia coli (APEC) are often found in poultry and are responsible for a set of diseases, commonly referred to as avian colibacillosis. One of the important virulence factors is adhesion to different epithelial surfaces, which is mediated by pili. P pili are thought to play a role by means of their PapG adhesin, which occurs in three molecular variants: PapGI, PapGII and PapGIII. This study is the first to determine and analyse the distribution of the different papG alleles in APEC. Our results show a significant predominance of the papGII allele above all other alleles or allele combinations. No statistically significant associations could be found between papG allele distribution and the type of bird, organ of isolation and O serogroup. Finally, the papGII and papGIII sequences showed high homology with mammalian (including human) source papG sequences.     

Neospora caninum: Serological follow-up in dairy cows during pregnancy

We conducted a longitudinal study to follow-up the anti-Neospora caninum serologic status in 30 initially seropositive and 83 initially seronegative cows during their pregnancy. Study cows were blood-sampled every other month during pregnancy until parturition. Blood serum samples were screened for anti-N. caninum antibodies by ELISA. Cows that seroconverted were re-tested by immunoblot as a confirmation test. Among 30 seropositive cows, 28 cows remained seropositive during the whole pregnancy, whereas 2 cows transiently tested negative at least once during pregnancy. Among 83 seronegative cows, 82 cows remained seronegative and 1 cow tested positive three times during the sixth, eighth and last month of pregnancy. As only 2 out of 30 seropositive animals and 1 out of 83 animals changed their serologic status during pregnancy, the study results indicate that there is only a minor temporal instability of anti-N. caninum antibody reactivity in adult cattle.