Effects of cortisol on pregnancy rate and corpus luteum function in heifers: an in vivo study

To determine whether glucocorticoids affect the function of the bovine corpus luteum (CL) during the estrous cycle and early pregnancy, we examined the effects of exogenous cortisol or reduced endogenous cortisol on the secretion of progesterone (P4) and on pregnancy rate. In preliminary experiments, doses of cortisol and metyrapone (an inhibitor of cortisol synthesis) were established (n=33). Cortisol in effective doses of 10 mg blocked tumor necrosis factor-induced prostaglandin F(2α) secretion as measured by its metabolite (PGFM) concentrations in the blood. Metyrapone in effective doses of 500 mg increased the P4 concentration. Thus, both reagents were then intravaginally applied in the chosen doses daily from Day 15 to 18 after estrus (Day 0) in noninseminated heifers (n=18) or after artificial insemination (n=36). Pregnancy was confirmed by transrectal ultrasonography between Days 28-30 after insemination. Plasma concentrations of P4 were lower in cortisol-treated heifers than in control heifers on Days 17 and 18 of the estrous cycle (P<0.05). However, the interestrus intervals were not different between control and cortisol-treated animals (P>0.05). Moreover, metyrapone increased P4 and prolonged the CL lifespan in comparison to control animals (P<0.05). Interestingly, in inseminated heifers, cortisol increased the pregnancy rate (75%) compared with control animals (58%), whereas metyrapone reduced the pregnancy rate to 16.7% (P<0.05). The overall results suggest that cortisol, depending on the physiological status of heifers (pregnant vs. nonpregnant), modulates CL function by influencing P4 secretion. Cortisol may have a positive influence on CL function during early pregnancy, leading to support of embryo implantation and resulting in higher rates of pregnancy in heifers.     

Gel-Bead Delivery of Eimeria oocysts protects chickens against coccidiosis

Vaccines composed of either virulent or attenuated Eimeria spp. oocysts have been developed as an alternative to medication of feed with ionophore drugs or synthetic chemicals. The purpose of this study was to evaluate the use of gel-beads containing a mixture of Eimeria acervulina, Eimeria maxima, and Eimeria tenella oocysts as a vaccine against coccidiosis. Newly hatched chicks (Gallus gallus domesticus) were either sprayed with an aqueous suspension of Eimeria oocysts or were allowed to ingest feed containing Eimeria oocysts-incorporated gel-beads. Control day-old chicks were given an equivalent number of Eimeria oocysts (10(4) total) by oral gavage. After 3 days, chicks were randomly assigned to individual cages, and feces were collected between days 5 and 8 postinfection. All samples were processed for total Eimeria oocysts. At 4 wk of age, all chickens and a control nonimmunized group received a high-dose E acervulina, E maxima, and E. tenella challenge infection. Oocyst excretion by chicks fed gel-beads or inoculated by oral gavage was 10- to 100-fold greater than that of chicks spray-vaccinated with the Eimeria oocysts mixture (log 6.3-6.6 vs. log 4.8). Subsequent protection against challenge as measured by weight gain and feed conversion efficiency was significantly greater (P < 0.05) in gel-bead and oral gavage groups compared with spray-vaccinated or nonimmunized groups. Also, gel-bead and oral gavage groups showed no significant difference (P > 0.05) in weight gain and feed conversion efficiency compared with nonchallenged controls. These findings indicate that incorporation of Eimeria spp. oocysts in gel-beads may represent an effective way to deliver live oocyst vaccines to day-old chicks for preventing subsequent outbreaks of coccidiosis in the field.     

The effect of copper nanoparticles and copper (II) salt on redox reactions and epigenetic changes in a rat model

The aim of the study was to evaluate the effects of a diet containing different levels of Cu in two different chemical forms (carbonate and nanoparticles) on redox reactions and epigenetic changes in a rat model. For 4 weeks, five experimental groups (eight rats in each) were fed diets with two dosages of added Cu (standard—6.5 mg/kg or half of the standard dosage—3.25 mg/kg, and as a negative control no additional Cu in the mineral mixture) in two forms (standard—CuCO₃ and copper nanoparticles). Addition of Cu nanoparticles resulted in higher Cp (ceruloplasmin) activity and LOOH (lipid peroxides) and MDA (malondialdehyde) content, as well as decrease the CAT (catalase) activity and level of PC (protein carbonyl), 3‐NT (3‐nitrotyrosine), 8‐OHdG (8‐hydroxydeoxyguanosine), GSH + GSSG (total glutathione) and DNA methylation. Reducing the dose of copper resulted in a decrease in the level of LOOH and GSH + GSSG as well as CAT activity, but increased the level of PC and methylated DNA. Based on these evidence, we concluded that addition of copper nanoparticles in the diet reduces protein oxidation and nitration as well as DNA oxidation and methylation. Lowering the level of Cu in the diet increases the oxidation of proteins and DNA methylation.     

Leptin and ghrelin levels in colostrum,milk and blood plasma of sows and pig neonates during the first week of lactation

Radioimmunology was used to determine leptin and ghrelin levels in sow colostrum and milk in relation to those in sow and neonatal pig blood plasma and to the body weight of piglets during the first week of lactation. The highest concentration of leptin was found in colostrum on the second day of lactation (69.3 ± 6.3 ng/mL). Leptin concentrations in sow plasma were significantly lower than in colostrum/milk (2.19 ± 0.9 ng/mL, P = 0.7692) and were stable in the first 7 days of lactation. Total and active ghrelin concentrations in colostrum/milk were stable in the measured time points (6734 ± 261 pg/mL, P = 0.3397; 831 ± 242 pg/mL, P = 0.3988, respectively). Total ghrelin concentrations in sow plasma were lower than in colostrum/milk. These results indicate that pigs follow a unique species‐specific pattern of leptin and ghrelin synthesis, release and existence, and that the mammary gland is an important source of leptin and ghrelin contained in colostrum/milk.     

Occurrence of reproductive disorders in pig herds with and without Chlamydia suis infection – statistical analysis of breeding parameters

Chlamydiae are frequently encountered Gram‐negative intracellular eubacteria that can cause clear manifestations or clinically asymptomatic disorders. C. suis and other chlamydia are primarily isolated in cases of reproductive disorders. This study was performed to estimate the impact of Chlamydia suis infection on reproduction in sows by analyzing reproduction rates and breeding parameters. The test was conducted on first generation (F1) pigs from Polish Landrace (PL) × Polish Large White (PLW). Sixty‐four herds were investigated and 500 vaginal swabs were collected. Isolation of DNA was carried out directly from the swabs. All samples were analyzed for Chlamydia suis by real‐time PCR with a locked nucleic acid (LNA)‐containing probe. To analyze the impact of chlamydia infection on reproductive parameters, evaluation questionnaires were used. Reproductive problems were found in 77.3% of the farms tested. The receiver operating characteristic curve indicated that in the farms with 10 up to 120 sows, there were higher reproductive problems with chlamydia infection than in smaller and bigger pig farms. The most common problems were estrus repetition, which was reported by 57.81% of the surveyed farms, and the birth of dead piglets, which was reported by 31.25% of the investigated pig farms. Abortions, which were reported by 28.12% of the surveyed farms, were the least common reproductive disorders.     

Androgenic capability among genotypes of winter and spring barley

Variable efficiency of androgenesis remains a serious problem in many species of cereals. It is still unclear what makes certain genotypes more amenable to androgenesis than others. This study was undertaken to quantify the previously suspected advantage of winter barley genotypes over spring ones with regard to regeneration efficiency in anther culture. The material consisted of 40 barley hybrids originating from Polish breeding companies. The number of androgenic structures per 100 anthers did not differ significantly between analysed groups (119 vs. 152 non‐significant), but the average regeneration of green plants per 100 anthers was five times higher in winter genotypes (6.4 vs. 1.3). The incidence of albinism was lower for the winter than for the spring materials (70% vs. 90%), while the rate of spontaneous chromosome doubling was similar in both groups (58% vs. 56%). The results strongly support the notion that winter genotypes are more amenable to androgenesis and this may be a consequence of their better adaptation to stress conditions.     

Profiles of seroconversion to porcine circovirus type 2 in herds affected and not affected by postweaning multisystemic wasting syndrome

The aim of the present study was to explore the usefulness of serological methods in the diagnosis of postweaning multisystemic wasting syndrome (PMWS). The study was carried out in 4 PMWS-affected and 6 control farms. Based on the serological profiles, infection with porcine circovirus type 2 (PCV2) was determined to take place at 3-7 weeks of age in the PMWS-affected and at 3-11 weeks of age in the control farms. To compare the dynamics of seroconversion to PCV2 among farms, cross-sectional serological profiles were normalised in relation to the inferred age of infection. The results indicated that the proportion of seropositive pigs increased significantly slower in the affected herds. The most pronounced difference was observed about 4 weeks after infection, when the proportion of seropositive pigs ranged from 0 to 53.3% and from 70 to 100% in PMWS-affected and control herds, respectively. Mean antibody titres at that age were also significantly lower in the affected farms. These observations suggest a delay in the production of PCV2-specific antibodies and indicate that serological methods may be helpful in identifying herds with a high risk of PMWS.     

Ecophysiological aspects of in vitro biotechnological studies using somatic embryogenesis of callus tissue toward protecting forest ecosystems

This review on current biotechnological methods in forestry for in vitro tissue cultures to define the effect of stress conditions on trees,concentrates on somatic embryogenesis.Callus tissue,the key product of somatic embryogenesis,grows over a tree wound under ex vitro conditions.Callus tissue can be used in research in areas such as pathogenic susceptibility at the embryonic level,effect of heavy metals,influence of low temperatures(cryopreservation),production of secondary metabolites and transformation of plants.Callus of arborescent plants can be induced in vitro by fungal elicitors to produce secondary metabolites for pharmaceutical and cosmetic industries and are strongly repellant to herbivores and can thus act to protect forests.Analyses of dual cultures demonstrated that callus tissue exposed to a pathogenic fungus responds by synthesizing low-molecular-mass proteins belonging to an immune protein class.Cryopreservation of embryonic callus tissue also has broad applications,e.g.,for valuable plant genotypes in gene banks.Without strategies to protect forests against stressfactors,forest ecosystems will degrade to the detriment of all life,including humans.In vitro biotechnological research using callus tissue contributes to progress in forestry and the disciplines of ecology,physiology,phytopathology,culture and selection of plants.     

Managing small remnants of native forest to increase biodiversity within plantation landscapes in the south west of Western Australia

Recent expansion of industrial-scale plantations into agricultural areas in Australia has the potential to assist biodiversity conservation by rehabilitating ecosystems at the landscape scale and reducing edge effects, isolation and disturbance within remnants of native vegetation. However, the efficient management of remnants for biodiversity within a plantation estate requires knowledge of both the causes and the consequences of remnant degradation. With this in mind, we examined key ecosystem features and processes relating to soil chemistry, decomposition, native tree health and regeneration and vertebrate abundance, within small forest remnants (1-4 ha) embedded within Eucalyptus globulus plantations in south west Western Australia. Soil nutrient enrichment was significantly associated with a scale of vegetation modification in order from: (1) intact forest, (2) remnants with native understorey (UDN), (3) remnants with exotic understorey (UDE), (4) plantation and (5) pasture. We propose that, in this region, UDE remnants will often remain in a degraded state even after plantation establishment and the cessation of stock grazing. This is due, in part, to more rapid rates of nutrient turnover sustaining higher nutrient availability in the soil following the replacement of ligneous understorey plants with annual ones. Cotton strips placed in surface soils were often disintegrated in UDE remnants and largely intact in UDN remnants, indicating that decomposition was accelerated in the former. Continued tree decline and regeneration failure within UDE remnants will also reinforce the UDE condition. There was less canopy seed set and little or no seedling establishment in UDE remnants compared to UDN remnants. Therefore, management interventions to assist native tree regeneration in UDE remnants are needed. Fauna trapping highlighted the desirability of retaining, and preferably restoring, small remnants in plantations. Small native mammals were found exclusively in remnants and fewer introduced Mus musculus were present in UDN remnants. Higher numbers of native lizards were found in UDN remnants, but this result was not significant (marginally).     

Effects of the commercial extract of aronia on oxidative stress in blood platelets isolated from breast cancer patients after the surgery and various phases of the chemotherapy

Since the extract from berries of Aronia melanocarpa presents antioxidative properties in plasma and in blood platelets, not only from healthy group, but also from patients with benign breast diseases and in patients with invasive breast cancer before surgery, the aim of our present study was to evaluate the oxidative stress by measuring the level of various biomarkers of this process such as the generation of superoxide anion radicals (O(2)(-·)), the amount of carbonyl groups and 3-nitrotyrosine in proteins or the amount of glutathione in blood platelets isolated from breast cancer patients after the surgery and after various phases of the chemotherapy in the presence of A. melanocarpa extract (Aronox) in vitro. We demonstrated in platelet proteins from patients with invasive breast cancer (after the surgery and after various phases of the chemotherapy) higher level of carbonyl groups than in control healthy group. The level of 3-nitrotyrosine in platelet proteins from patients with invasive breast cancer was also significantly higher than in healthy subject group. We observed an increase of other biomarkers of oxidative stress such as O(2)(-·) and a decrease of GSH in platelets from patients with breast cancer (after the surgery and after various phases of the chemotherapy) compared to the healthy group. In model system in vitro our results showed that the commercial extract from berries of A. melanocarpa due to antioxidant action, significantly reduced the oxidative/nitrative stress in platelets from patients with invasive breast cancer caused by the surgery and various phases of the chemotherapy.