Serological status of mares in parturition and the levels of antibodies (IgG) against protozoan family Sarcocystidae from their pre colostral foals

Protozoa from the family Sarcocystidae are agents of reproductive and neurological disorders in horses. The transmission of these protozoa may occur via horizontal or vertical means, and the frequency and potential of the later is not fully elucidated in horses. Thus, the aim of study was to correlation levels of antibodies in mares with pre colostral foals seropositive and assess the level and distribuition of antibodies against Neospora spp., Sarcocystis neurona and Toxoplasma gondii, in mares and pre colostral foals at the parturition. The blood samples were collected from mares immediately after parturition and from newborns before the ingestion of colostrum, and sera were analyzed for the presence of IgG by ELISA. It was found that 21.5%, 33.7% and 27.6% of mares were seropositive for Neospora spp., S. neurona and T. gondii, respectively; foals had antibodies at a rate of 8.3%, 6.6% and 6.6% for Neospora spp., S. neurona and T. gondii, respectively. Additionally, paired samples from mares and pre-colostral foals revealed an overall negative correlation between the serum reactivity against these three parasites and suggested that seronegative mares, or those with low to intermediate antibody levels, have a higher risk of giving birth to seropositive foals.     

Detection of Toxoplasma gondii DNA in Fresh and Frozen Semen from Rams in Brazil

The aim of this study was to estimate the prevalence of genomic DNA of Toxoplasma gondii in semen samples from commercial rams in artificial insemination centres in Brazil, as well as in fresh semen from rams in the northeast of Brazil. In total, 108 semen samples were obtained from artificial insemination centres, and genomic DNA of T. gondii was detected in 24 of 108 (22.2%). The prevalence of antibodies anti‐Toxoplasma gondii among sheep on rural properties was 9.2% (10/109), and 100% of the semen samples of these animals were positive in the PCR for T. gondii DNA. The molecular identity was confirmed through sequencing, which indicated 99.9% similarity with the T. gondii DNA sequences stored in the GenBank. This study reports the first occurrence of T. gondii DNA in the semen of rams, which came from artificial insemination centres in Brazil, as well as the occurrence of T. gondii DNA in the fresh semen of naturally infected rams in the northeast of Brazil.     

Experimental infection with a low virulence isolate of Neospora caninum at 70 days gestation in cattle did not result in foetopathy

The Nc-Spain 1H isolate of Neospora caninum, which was newly obtained from the brain of a congenitally asymptomatic infected calf, demonstrated a reduced in vitro tachyzoite yield and viability rate, as well as low virulence in mouse models. The objective of the present study was to determine the ability of this isolate to induce foetal death in a pregnant bovine model. For this purpose, 13 naïve pregnant heifers were divided into three groups and were experimentally challenged with either 10⁷ tachyzoites of Nc-1 (group 1, n = 5), Nc-Spain 1H (group 2, n = 5) isolates or phosphate-buffered saline (group 3, n = 3) intravenously at 70 days of gestation. After inoculation, pregnancy was monitored and dams were sacrificed when foetal death was detected. The remaining animals were slaughtered at 45 days post-infection. Maternal and foetal samples were collected for examination by histology and parasite DNA detection. Parasitaemia, specific anti-N. caninum IgG and interferon γ responses were also studied. At 3–4 weeks after infection, foetal death was detected in 3 out of 5 Nc-1-infected dams. However, no evidence of foetal death was observed in either Nc-Spain 1H-infected or control groups during the period studied. The most severe histopathological lesions were observed in the placenta and foetal organs from Nc-1-infected cattle that exhibited foetal death. It was in these animals that N. caninum DNA was more frequently detected. Parasitaemia was observed in all Nc-1-infected dams and in only 3 out of 5 Nc-Spain 1H-infected animals. The magnitude of the immune response was significantly higher in the Nc-1-inoculated group than in the group inoculated with the Nc-Spain 1H isolate. These data reveal the reduced virulence of the Nc-Spain 1H isolate in cattle.     

The Effect of Season on Semen Characteristics and Freezability in Bos indicus and Bos taurus Bulls in the Southeastern Region of Brazil

The objectives of this study were to evaluate the effects of season in southeast of Brazil comparing genotypes on semen characteristics, freezability and peripheral plasma concentrations of testosterone. Ejaculates of five Bos indicus bulls and six Bos taurus bulls were evaluated over a period of 27 months, which was divided into winter (July, August, September), spring (October, November, December), summer (January, February, March) and autumn (April, May, June). Semen was evaluated according to standard procedures for ejaculate volume, sperm concentration, gross-motility, progressive motility and sperm morphology. After preparing and freezing the ejaculates according to commercial procedures, the straws were stored in liquid N₂ until post-thaw evaluation. Ejaculate volume, sperm concentration, gross-motility, progressive sperm motility, vigor and morphological sperm defects were significantly influenced by season and genotype (p < 0.05). Heat tolerance was better in B. indicus bulls than in B. taurus bulls characterized by lower values of sperm abnormalities throughout the observation period. The highest values were recorded for abnormal heads followed by cytoplasmatic droplets in B. taurus bulls. The proportion of ejaculates which were eliminated before freezing for reasons of bad quality was lower in the B. indicus bulls. Temporal changes in peripheral plasma testosterone concentrations were higher in B. indicus bulls than in B. taurus bulls not revealing seasonal influences. The results of this study show clear genotype differences regarding semen quality. Freezability of B. taurus semen varies considerably throughout the year, leading to a high proportion of eliminated ejaculates. Collecting semen from B. taurus bulls during the summer in an artificial insemination centre may not be profitable.     

Basal levels of enzymatic biomarkers and energy reserves in Porcellionides pruinosus

In the last decades biomarkers have been widely used for the assessment of effects and/or exposure to environmental contaminants, but to our knowledge few data has been published for isopod species. Along with biomarkers the quantification of energy reserves has also been used to evaluate organisms’ energetic budget. Enzymatic biomarkers can also be useful to understand chemicals/stress modes of action. The aim of this study was to obtain information on biomarker basal level activities and energy contents of the isopod Porcellionides pruinosus as little information is available. Results can then be used as foundations for other ecotoxicological or biomonitorization studies and also as control values for evaluating isopod status in laboratory cultures.The cholinesterase (ChE) type of the isopod P. pruinosus was characterized using three substrates (acetylthiocholine iodide, propionylthiocholine iodide, and S-butyrylthiocholine iodide) and three ChE inhibitors (eserine hemisulfate, tetraisopropyl pyrophosphoramide (iso-OMPA) and 1,5-bis(4-allyldimethyl-ammonimphenyl) pentan-3-one dibromide (BW284C51)]. The results showed that this organism has only one cholinesterase form, the acetylcholinesterase with a mean basal level of 113.6 ± 4.7 U/mg protein.Other biomarkers related to oxidative stress or metabolism were assessed, showing activity ranges of 3.0 ± 1.1 U/mg protein for lactate dehydrogenase (LDH), 6.1 ± 1.1 U/mg protein for catalase (CAT), 2.7 ± 1.1 U/mg protein for glutathione peroxidase (GPx), 34.6 ± 4.7 nmol/mg ww for lipid peroxidation (LPO) and 137.8 ± 7.1 U/mg protein for glutathione S-transferases (GST) (mean ± st. error). The carbohydrates and protein contents were 12290.8 ± 56.4 J/mg organism (org) and 22905 ± 57.5 J/mg org, respectively (mean ± st. error). The mean lipid content was 503.1 ± 12.7 J/mg org.Our results were compared to other previous works with isopod species but also with other species, showing high levels of inter and intraspecific variability. Even tough this study can contribute as foundations for other studies as ChE characterization, optimization of homogenization procedures and basal levels for biomarker activity and energy reserves were described.     

Comparison of in vitro solubilization activity of diverse phosphate-solubilizing bacteria native to acid soil and their ability to promote Phaseolus vulgaris growth

To identify plant growth promotion ability of phosphorus-solubilizing native bacteria, we have examined a collection of isolates representing the diversity of culturable phosphate-solubilizing bacteria from acid soils of the northeast of Argentina. Assays in growth medium supplemented with tricalcium phosphate revealed different phosphorus solubilization activity and temporal patterns of solubilization. Acidification of the broth medium coincided with phosphorus solubilization. The isolates were grouped according to their Rep fingerprinting profiles and phylogenetically classified by 16S rDNA and biochemical analyses. These isolates were assigned to the genera Enterobacter, Pantoea, Pseudomonas, Acinetobacter, Burkholderia, and Exiguobacterium. Four isolates showing high phosphorus solubilizing activity in in vitro assays were inoculated on common beans (Phaseolus vulgaris); some of them promoted plant growth and increased photosynthesis and the P and N content of leaves. The results indicated that the ability to in vitro solubilize P is not necessarily associated to the promotion of plant growth.     

Soil fungal isolates produce different organic acid patterns involved in phosphate salts solubilization

Phosphorus availability is a major limiting factor for yield of most crop species. The objective of this study was to compare the solubilization of three sources of phosphorus (P) by different fungal isolates and to determine the possible mechanisms involved in the process. Talaromyces flavus (S73), T. flavus var flavus (TM), Talaromyces helicus (L7b) and T. helicus (N24), Penicillium janthinellum (PJ), and Penicillium purpurogenum (POP), fungal strains isolated from the rhizosphere of crops, are known to be biocontrol agents against pathogenic fungi. The P solubilization efficiency of these fungal strains in liquid media supplemented either with tricalcium phosphate (Ca₃(PO₄)₂; PC), aluminum phosphate (AlPO₄; AP), or phosphorite (PP) depended on the source of P and the fungal species. The type and concentration of organic acids produced by each species varied according to the source of available P. In the medium supplemented with PC, the highest proportion was that of gluconic acid, whereas in the media supplemented with the other P sources, the highest proportion was that of citric and valeric acids. This suggests that the release of these organic compounds in the rhizosphere by these microorganisms may be important in the solubilization of various inorganic P compounds. Results also support the hypothesis that the simultaneous production of different organic acids by fungi may enhance their potential for solubilizing insoluble phosphate.     

Effect of eprinomectin pour-on treatment around calving on reproduction parameters in adult dairy cows with limited outdoor exposure

The objective of this study was to investigate if treatment of cows with eprinomectin around calving had any beneficial effects on the calving to first artificial insemination interval, calving to conception interval, and number of services per conception in totally- and semi-confined dairy herds. In totally-confined herds lactating- and dry-cows were housed throughout the summer and had no access to pasture. In semi-confined herds lactating- and dry-cows had limited outdoor exposure to a small pasture or paddock but were still fed a ration that met all their nutritional requirements. The study was carried out between February 2002 and February 2003 in 35 herds (2381 cows) located in Quebec, Ontario and Minnesota (USA) participating in a larger clinical trial. The herds kept electronic reproduction records. Cows were randomly allocated to receive eprinomectin or a placebo, with treatment being administered on or close to the day of calving. Monthly bulk tank milk samples from each farm were tested with an indirect ELISA using a crude Ostertagia ostertagi antigen and these data were averaged over the study year. The optical density ratio (ODR) values were then dichotomized into high and low using a cut-point of 0.50. Treatment effects were analyzed using Cox proportional hazards survival models with herd frailty effects for calving to conception and calving to first service intervals. Aalen's linear hazards model was used to investigate time-varying effects in the Cox models. A random effects poisson regression model was used to model the number of services per conception. Other predictor variables tested in the models were lactation number, calving season, study site, peak milk production, ODR and the lactating- and dry-cow housing variables. Overall, there was no significant effect of treatment on the three indices of reproductive performance. The effect of season of calving depended on how much time had passed since calving. Presumably this effect reflected a seasonal effect at the time of breeding. Hazard of conception in younger cows was higher than in older cows. Early bred cows tended to have a higher number of inseminations per conception than those bred late. The results of the study suggested that eprinomectin treatment at calving was not beneficial to reproduction.     

Effect of dietary conjugated linoleic acid and monounsaturated fatty acid content on pig muscle and adipose tissue lipase and esterase activity

Three levels (0%, 1%, and 2%) of conjugated linoleic acid (CLA) were combined with two levels (low and high) of monounsaturated fatty acids (MUFA) for pig feeding. The activity of neutral lipase (NL), acid lipase (AL), phospholipase (PL), neutral esterase (NE), and acid esterase (AE) was measured in extracts from muscle and subcutaneous adipose tissues. The addition of CLA in the diet only affected the lipolytic activity in muscle, whereas differences in MUFA content of pig diets were mainly responsible for the lipolytic enzyme modifications observed in adipose tissue. Nevertheless, a significant effect of the interaction CLA x MUFA on the activity of several lipolytic enzymes was observed in both tissues. The effect of either linoleic acid (LA) or CLA on the activity of muscle and adipose lipolytic enzymes was determined by in vitro assays. Remarkable inhibitory or activation effects were detected depending on the enzyme and kind of tissue.