Use of a Piezo Drill for Intracytoplasmic Sperm Injection into Cattle Oocytes Activated with Ionomycin Associated with Roscovitine

Intracytoplasmic sperm injection (ICSI) consists of the introduction, by micromanipulation, of a single sperm into the cytoplasm of a mature egg. This technique is particularly advantageous when only a few sperm are available for fertilization, representing an important tool in preserving genetic material, especially from poorly fertile males. The results from ICSI in cattle are very often unsatisfactory and difficult to reproduce. Thus, the goal of this study was to evaluate the effect of the use of a Piezo drill (PD) and oocyte activation with ionomycin + roscovitine (I + R) during ICSI in cattle oocytes. After in vitro maturation (24 h), cumulus complex oocytes were divided into four groups: G1 – the ICSI was performed without the use of a PD and the oocyte was activated with I + R; G2 – the ICSI was performed with the use of the PD and activation with I + R; G3 – the ICSI was performed with the use of the PD, but without activation and G4 – parthenogenetic control, treated with I + R, but without sperm injection. The presumptive zygotes were cultured for 7 days and evaluated on day 3 for cleavage rate and on day 7 for blastocyst formation. Embryo production by standard in vitro fertilization in the laboratory was 78% for cleavage (117/150) and 35% for blastocyst formation (41/150). The cleavage rates obtained in G1, G2 and G4 were similar (66.7%, 71.6% and 66.3%, respectively), demonstrating the beneficial effect of oocyte activation. However, in G3, despite the presence of the sperm and the electric stimulation of a PD, the cleavage rates were significantly lower (17.5%) compared with the groups that used chemical activation, even in the absence of sperm (G4). Despite the beneficial effects of activation, this stimulus alone, or in the absence of the PD, was not sufficient for adequate morulae formation (13.4%, 37.9%, 0.0% and 13.5% for G1, G2, G3 and G4, respectively). Only in G2, when the PD was used followed by artificial activation, blastocysts were obtained (14.7%). These results indicate that cattle oocytes must be activated after ICSI to produce viable embryos.     

High-temperature mechanical properties and thermal recovery of balsa wood

This article presents an experimental study into thermal softening and thermal recovery of the compression strength properties of structural balsa wood (Ochroma pyramidale). Balsa is a core material used in sandwich composite structures for applications where fire is an ever-present risk, such as ships and buildings. This article investigates the thermal softening response of balsa with increasing temperature, and the thermal recovery behavior when softened balsa is cooled following heating. Exposure to elevated temperatures was limited to a short time (15 min), representative of a fire or postfire scenario. The compression strength of balsa decreased progressively with increasing temperature from 20° to 250°C. The degradation rates in the strength properties over this temperature range were similar in the axial and radial directions of the balsa grains. Thermogravimetric analysis revealed only small mass losses (<2%) in this temperature range. Environmental scanning electron microscopy showed minor physical changes to the wood grain structure from 190° to 250°C, with holes beginning to form in the cell wall at 250°C. The reduction in compression properties is attributed mostly to thermal viscous softening of the hemicellulose and lignin in the cell walls. Post-heating tests revealed that thermal softening up to 250°C is fully reversible when balsa is cooled to room temperature. When balsa is heated to 250°C or higher, the post-heating strength properties are reduced significantly by decomposition processes of all wood constituents, which irreversibly degrade the wood microstructure. This study revealed that the balsa core in sandwich composite structures must remain below 200°–250°C when exposed to fire to avoid permanent heat damage.     

Conditional cooperation and costly monitoring explain success in forest commons management

Recent evidence suggests that prosocial behaviors like conditional cooperation and costly norm enforcement can stabilize large-scale cooperation for commons management. However, field evidence on the extent to which variation in these behaviors among actual commons users accounts for natural commons outcomes is altogether missing. Here, we combine experimental measures of conditional cooperation and survey measures on costly monitoring among 49 forest user groups in Ethiopia with measures of natural forest commons outcomes to show that (i) groups vary in conditional cooperator share, (ii) groups with larger conditional cooperator share are more successful in forest commons management, and (iii) costly monitoring is a key instrument with which conditional cooperators enforce cooperation. Our findings are consistent with models of gene-culture coevolution on human cooperation and provide external validity to laboratory experiments on social dilemmas.     

Codigested dairy slurry as a phosphorus and nitrogen source for Zea mays L. and Amaranthus cruentus L.

Residues from biogas production contain essential plant nutrients such as nitrogen (N), phosphorus (P), and potassium (K) but also organic matter, and should be recycled in crop production. For efficient re‐use as fertilizers, the availability of nutrients for crops and the effect of the residues on soil fertility need to be evaluated. Focusing on the element P, we compared effects of codigested slurry with dairy slurry, highly soluble mineral NPK fertilizer, and a control without any P supply (NK). Codigested slurry used in this experiment was based on anaerobic digestion of dairy slurry, maize silage, and wheat grain. The fertilizing effects were tested in an 8‐week pot experiment on a sandy and a loamy soil using two crop species (Zea mays L., Amaranthus cruentus L.). The plant P uptake was up to 64% greater in the slurry treatments than in the treatment without P. The effect of codigested slurry on P uptake was comparable to that of dairy slurry and mineral P. Plant N uptake from codigested slurry was lower than that from mineral N (NK, NPK), but tended to be higher than from dairy slurry. The water‐soluble and double lactate–soluble P content of the soil was lower in the slurry treatments than in the mineral‐P treatments and accompanied by higher contents of microbial‐bound P. Differences between both organic fertilizers were detected for dehydrogenase activity which was up to 32% lower in soils fertilized with codigested slurry than it was in soils fertilized with dairy slurry. Our results indicate that codigestion of slurries in biogas plants does not substantially alter their fertilizer value as P and N sources for crops.     

Implications of the population effect in the selection of soybean progeny

The goal of this study was to verify the influence of the population effect in the estimates of genetic and phenotypic components and to identify the best soybean progeny or lines in a commercial soybean breeding programme. We evaluated 292 populations for grain yield and absolute maturity during three agricultural years. To quantify the efficiency of the inclusion of the population's effect in the model, we estimated genetic gain with the selection, the Spearman's correlation, the coincidence index, the realized gain and correlated response of selected genotypes with and without the effect of the population. It was found that the variance components, heritability and coefficient of experimental variation were better estimated when the effect of the population was included, providing greater gain with selection for grain yield and absolute maturity. Coincidence and ranking among the selected progeny with and without the effect of the population are of greater magnitude in more advanced inbreeding generations and at higher percentage of selected progeny. The use of the population effect has greater importance in earlier generations of inbreeding.     

Estimation of intestinal permeability in healthy dogs using the contrast medium iohexol

Background: Iohexol is a nonradioactive marker that has been used successfully to test intestinal permeability in humans with inflammatory bowel disease. There is evidence in dogs that iohexol shares a similar permeability pathway as ⁵¹chromium‐EDTA, the gold standard marker. Objective: The objective of this study was to determine an optimal oral iohexol dosage for an intestinal permeability serum test (IPST) and to use the test to estimate intestinal permeability in healthy dogs. Methods: Eight clinically healthy dogs free of gastrointestinal, liver, and pancreatic disease were used in the study. Dosages of 0.25, 0.5, 1.0, 2.0, and 4.0 mL/kg of Omnipaque‐350 (iohexol) were administered to 2 dogs at weekly intervals. Iohexol concentration was determined in serum samples obtained hourly for 6 hours after administration by high‐performance liquid chromatography. Using the optimal dosage, iohexol was administered to 8 dogs twice, 6–36 days (mean 10 days) apart, and coefficients of variation (CVs) for iohexol concentration were calculated. Results: A dosage of 2.0 mL/kg was chosen as optimal for the IPST, based on ease of iohexol detection in serum, intestinal contrast, and clinical effects of iohexol. Following administration of this dose to healthy dogs, mean (±SD) serum iohexol concentrations were 8.74±4.38, 11.89±5.67, 12.40±5.47, 9.23±5.54, 7.61±5.13, and 5.27±2.67 μg/mL at 1, 2, 3, 4, 5, and 6 hours after iohexol administration, respectively. CVs between the 2 test days were 28–45%. Conclusions: Using the iohexol dosage established in this study, the iohexol IPST was easy to perform as a marker for intestinal permeability in dogs. Further studies to establish reference intervals and evaluate the diagnostic value of the iohexol IPST in dogs with gastrointestinal disease are warranted.     

Are dietary genistein and equol potent enhancers of eicosapentaenoic acid and docosahexaenoic acid levels in rainbow trout (Oncorhynchus mykiss)?

Phytoestrogens are putatively able to enhance the biosynthesis of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), but have also been shown to affect fish growth dose dependently. The aim of the present study was to identify a concentration for the phytoestrogen genistein and the phytoestrogen metabolite equol that further increases the endogenous biosynthesis of EPA and DHA without impairing fish growth. Juvenile rainbow trout (87.2 ± 0.3 g) were fed seven diets on a fixed ratio for 8 weeks. A vegetable oil‐based diet served as a control diet and was supplemented with equol (EQ) and genistein (G), respectively, at 0.1%, 0.2% and 0.3% of feed dry matter (1, 2 and 3). Growth and nutrient composition of whole body homogenates were not affected by dietary treatments. EPA and DHA levels in liver, fillet and whole body samples were not significantly increased by EQ and G diets. Fish fed EQ diets showed dose dependently increased liver weights and C18:0 liver levels, indicating estrogen‐like effects at increased dietary dosages. In conclusion, the utilization of equol and genistein in plant oil‐based diets in order to enhance the biosynthesis of EPA and DHA seems not reasonable in rainbow trout.