Leptospirosis as the most frequent infectious disease impairing productivity in small ruminants in Rio de Janeiro,Brazil

Despite the importance of small ruminants breeding in developing countries, milk/meat productivity remains unsatisfactory. Infectious diseases, such as leptospirosis, brucellosis, and small ruminant lentiviruses (SRLVs), contribute to this scenario. The objective of the present study was to determine the role of each of these diseases in the productivity of small ruminants breeding in Rio de Janeiro, Brazil. In goats, 343 samples were tested for leptospirosis, 560 for Brucella abortus, and 506 for caprine arthritis-encephalitis (CAE), whereas in sheep, 308 samples were tested for leptospirosis, 319 for B. abortus, 374 for Brucella ovis, and 278 for Maedi-Visna (MV). Regarding leptospirosis, 25.9% of goats and 47.4% sheep were seroreactive, with serovar Hardjo the most prevalent in both species. Anti-B. abortus agglutinins were found in 0.7% of all samples, exclusively in goats. In relation to SRLVs, 8.6% of goats and 3.2% of sheep samples were positive for CAE and MV, respectively. Leptospirosis was the major infectious problem in the small ruminants sampled and may contribute to impaired productivity of these animals.     

Interleukin-8 as a prognostic serum marker in canine mammary gland neoplasias

Mammary gland tumors in female dogs are an excellent model for the clinic-pathological, diagnostic and prognostic investigation of mammary neoplasias. Prognostic and predictive markers are effective in research and routine diagnosis. Interleukins play a fundamental role in cancer, with a particular function in tumor growth, invasion and metastatic potential. Interleukin-8 (IL-8) is known to possess tumorigenic and pro-angiogenic properties, and its overexpression is seen in a number of human tumors. IL-8 serum levels were determined and correlated with the clinic-pathological features and clinical evolution of mammary gland neoplasias in female dogs. IL-8 was measured by an immunoenzymatic assay in 30 female dogs with mammary neoplasias within a 12 month follow-up and in 50 control animals. The correlation between IL-8 concentration and clinical parameters was investigated. A statistically significant difference in the IL-8 serum levels was found in tumor-bearing dogs compared to the controls. In addition, when the individual parameters were evaluated, IL-8 content showed a positive correlation with the tumor progression, lymph node involvement, recurrence and death. Single and multivariate analyses showed associations between tumor recurrence, metastasis, high clinical staging and high IL-8, and also with the death risk. This was also consistent with the high IL-8 content in dogs showing tumor recurrence and metastasis. IL-8 superexpression has been detected in a number of human tumors, usually associated with a poor prognostic. Besides promoting angiogenesis, IL-8 is strongly related with the metastatic phenotype of mammary tumor cells. High IL-8 concentration was found in mammary gland cancer patients with advanced disease stages. Our results show that IL-8 can be used as a non-invasive prognostic marker for mammary gland cancer, and can be useful for the prediction of disease progression and recurrence in dogs with mammary neoplasias. The increased level of this cytokine acts as an independent prognostic marker of survival and the identification of animals with the poor prognostic.     

Update on the role of innate immune receptors during Brucella abortus infection

The innate immune system constitutes an efficient defense mechanism against invading microbial pathogens. Recent studies have revealed the intracellular signaling cascades involved in the TLR-initiated immune response to Brucella spp. infection. However, there is a piece of the puzzle missing that is the role of non-TLR receptors in innate immunity. The involvement of TLR receptors in brucellosis has been investigated by different research groups. It was demonstrated that TLR2 clearly does not play any role in controlling Brucella abortus infection in vivo, whereas TLR9 has been shown to be required for clearance of this bacterium in infected mice. The participation of adaptor molecules, such as MyD88 and TRIF has also been discussed. Recently, we and others have reported the critical role of MyD88- and not TRIF-mediated signaling in dendritic cell maturation and in vivo resistance during B. abortus infection. However, the relationship between specific Brucella molecules and non-TLR receptors and signal transduction pathways needs to be better understood. It is now clear that the interaction between TLRs and recently identified cytosolic innate immune sensors is crucial for mounting effective immune responses. Finally, this review discusses the mechanisms used by Brucella to escape detection by the host innate immune system.     

Risk factors for avian influenza and Newcastle disease in smallholder farming systems, Madagascar highlands

Newcastle disease (ND) and avian influenza (AI) are issues of interest to avian producers in Madagascar. Newcastle disease virus (NDV) is the major constraint for village aviculture, and avian influenza viruses type A (AIAV) are known to circulate in bird flocks. This study aims at classifying smallholder poultry farms, according to the combination of risk factors potentially associated with NDV and AIAV transmission and to assess the level of infection for each farm class. Two study sites, Lake Alaotra and Grand Antananarivo, were chosen with respect to their differences in terms of agro-ecological features and poultry productions. A typology survey involving 526 farms was performed to identify possible risk factors for (i) within-village, and (ii) between-village virus transmission. A cross-sectional serological study was also carried out in 270 farms to assess sero-prevalences of NDV and AIAV for each farm class and the link between them and risk factor patterns. For within-village transmission, four classes of farms were identified in Grand Antananarivo and five in Lake Alaotra. For between-village virus transmission, four classes of farms were identified for each site. In both sites, NDV sero-prevalence was higher than for AIAV. There was no evidence of the presence of H5 or H7 subtypes of AIAV. Sero-prevalences were significantly higher in Lake Alaotra than in Grand Antananarivo for both viruses (OR=2.4, p=0.02 for NDV, and OR=9.6, p<0.0001 for AIAV). For within-village NDV transmission in Grand Antananarivo, backyard chicken farms (OR=3.6, p<0.001), and chicken farms with biosecurity awareness (OR=3.4, p<0.01) had greater odds of having antibodies against NDV than the others. For between-village virus transmission, farms with multiple external contacts, and farms using many small markets had greater odds of having antibodies against NDV than the others (OR=5.4, p<0.01). For AIAV, there were no differences in sero-prevalences among farm classes. In Lake Alaotra, the observed high density of palmipeds and widespread rice paddies were associated with high sero-prevalences for both viruses, and a homogeneous risk of virus transmission between the different farm classes. In Grand Antananarivo, farm visits by collectors or animal health workers, and farm contacts with several markets were identified as potential risk factors for NDV transmission. Further studies are needed to identify the circulating virus genotypes, model their transmission risk, and provide adapted control measures.     

Gene expression and immunolocalization of fibroblast growth factor 2 in the ovary and its effect on the in vitro culture of caprine preantral ovarian follicles

This study quantified Fibroblast growth factor 2 (FGF-2) mRNA and localized FGF-2 protein in different categories of follicles isolated from goat ovaries. In addition, we verified the effects of this factor on the in vitro culture of preantral follicles isolated from goats. For mRNA quantification, we performed real-time PCR using primordial, primary and secondary follicles, as well as cumulus-oocyte complexes (COCs) and mural granulosa and theca cells of small and large antral follicles. For FGF-2 protein localization, the ovaries were subjected to conventional immunohistochemical procedures. Preantral follicles were isolated and cultured in vitro for 12 days in either control (basic) or supplemented with FGF-2 medium. The expression of FGF-2 mRNA was detected in all categories of follicles and there was no difference in preantral follicles and COCs or granulosa/theca cells from small and large antral follicles. However, in large antral follicles, COCs showed expression levels significantly lower than in granulosa/theca cells (p < 0.05). We observed moderate expression of FGF-2 protein in preantral follicles but not in granulosa cells of primordial follicles and theca cells of secondary follicles. In both small and large antral follicles, strong, moderate and weak staining was observed in oocytes, granulosa and theca cells, respectively. The addition of FGF-2 caused a significant increase in the daily follicular growth rate compared to the control group. We conclude that FGF-2 mRNA is expressed throughout follicular development and that its protein can be found in different patterns in preantral and antral follicles. Furthermore, FGF-2 increases the follicular growth rate in vitro.     

The effect of LIF in the absence or presence of FSH on the in vitro development of isolated caprine preantral follicles

We investigated the effect of the leukaemia inhibitory factor (LIF) alone or in association with FSH on the in vitro culture (IVC) of caprine preantral follicles. Preantral follicles >200 μm in size were isolated and cultured for 18 days in basic medium either alone (control) or supplemented with LIF (10 or 50 ng/ml) in the absence or presence of FSH. Every 6 days, follicular survival, growth and antrum formation were evaluated. At the end of the culture period, the oocytes underwent in vitro maturation (IVM), and their viability and chromatin configuration were assessed. Follicles of the control group and those cultured in 10 ng/ml LIF maintained the structural integrity (particularly the preservation of the basement membrane) when compared to the oocytes cultured in 50 ng/ml LIF, regardless the presence of FSH. In the absence of FSH, the percentage of antrum formation after 18 days of culture in the 50 ng/ml LIF group was significantly lower than in either the control group or the 10 ng/ml LIF group. However, this effect was not observed in the presence of FSH. The rate of resumption of meiosis was significantly higher in the 50 ng/ml LIF group in the absence of FSH in comparison with the control and 10 ng/ml LIF groups. Metaphase II was observed only when follicles were cultured in a combination of FSH and 50 ng/ml LIF. In conclusion, LIF alone does not interfere with antral formation and oocyte growth, but at concentration of 50 ng/ml and combined with FSH, it promotes oocyte maturation.     

Effect of Adding Different Dietary Fiber Sources on Farinographic Parameters of Wheat Flour

Breadmaking is a complex process that involves a series of parameters that must be controlled. Rheological measurements are often used to predict the behavior of wheat dough during processing and the quality of the final product. There are many different dietary fiber sources that can be used to enhance the nutritional quality of bread. However, they will affect processing and final product quality. Response surface methodology (RSM) was employed to study the effects of adding different dietary fiber sources (wheat bran, resistant starch, and locust bean gum) on farinographic parameters of wheat flour. The experiments were conducted according to a 2³ central composite rotational design (CCRD). With the experimental results or responses (farinographic parameters), the effect of each variable was calculated and the interactions between them were determined. Models that explain the effects of the different fiber sources on water absorption, arrival time, dough development time, and mixing tolerance index of wheat flour were established. The fiber sources interacted for some of the parameters analyzed, demonstrating that if two or more sources of dietary fiber are present in the mix, they might act different to what would be expected of the sum of them. It was also noticed that for most parameters, wheat bran and locust bean gum had a greater influence on farinographic parameters than resistant starch. The simultaneous presence of the three fibers, within the ranges studied, contributed to an increase in water absorption, arrival time, and mixing tolerance index, and to a reduction in departure time and dough stability.     

Studies about the mechanism of internalization by mammary epithelial cells of Escherichia coli isolated from persistent bovine mastitis

The purpose of this study was to investigate the interaction between Escherichia coli and primary mammary epithelial cell cultures derived from cows with persistent intramammary infection (IMI). Two strains of E. coli, isolated from the milk of two different cows suffering from persistent E. coli IMI were tested for adhesion to and invasion of three primary mammary epithelial cell cultures derived from mammary biopsies of the two infected cows. Intracellular E. coli were detected during five days post infection in vitro. Both strains of E. coli adhered to and invaded monolayers of all three primary mammary epithelial cell cultures. One strain adhered less but invaded more than the other. Comparison with other mammary pathogens indicated that E. coli invaded the cells less efficiently than Staphylococcus aureus, about as efficiently as Streptococcus dysgalactiae and more efficiently than Streptococcus uberis. The mechanism of E. coli invasion was studied using the cytoskeleton disrupting agents colchicine and cytochalasin D. These compounds inhibited the invasion of E. coli. Invasion of E. coli could also be inhibited by the phosphokinase inhibitors genistein and staurosporin in a dose-dependent fashion. Phorbol-myristyl-acetate (PMA) had no effect on the invasion of E. coli. Histology of mammary tissue revealed chronic inflammatory changes in quarters that were persistently infected by E. coli. Intracellular bacteria were not detected in mammary tissue sections. Polymerase chain reaction (PCR) analysis suggested that the two strains of E. coli lacked genes encoding for bundle-forming pili (bfpA), intimin (eae) and translocated intimin receptor (tir), which are characteristic for enteropathogenic E. coli (EPEC).     

Identification of resistance to rust (Uromyces appendiculatus) and powdery mildew (Erysiphe diffusa) in Portuguese common bean germplasm

Portugal has a diverse common bean germplasm, which is still grown in farmers' fields. In this work, we searched for resistance to rust (Uromyces appendiculatus) and powdery mildew (Erysiphe diffusa) in a representative collection of the Portuguese common bean germplasm. Despite many accessions depicting intermediate levels of resistance when compared to the susceptible check, 24 and 13 accessions showed low levels of infection, in spite of a compatible interaction (disease severity (DS) values lower than 5% and infection type (IT) of 4), to rust and powdery mildew, respectively, indicative of partial resistance. Moreover, a resistant reaction was observed in 11 accessions when inoculated with powdery mildew (IT = 0–1) and in additional 11 accessions (one in common) when inoculated with rust (IT = 0–2). The levels of resistance found in this report anticipate great potential of the Portuguese national germplasm, recently reported as genetically closer to the Andean common bean gene pool, for disease resistance breeding of this important crop.     

Stem Volume Equations for Valuable Timber Species in Mozambique

Development of stem volume for umbrella-shaped crown trees remains a big challenge for efficient use of forest resources in Mozambique. In this study, species-specific stem volume equations were developed for the first time for three of the most important timber species in Mozambique: Afzelia quanzensis Welw. (Chanfuta), Millettia stuhlmannii Taub. (Jambire), and Pterocarpus angolensis D.C. (Umbila). The study was carried out at three locations in Mozambique: Inhaminga, Mavume, and Tome covering 58 trees from which, 24 of Chanfuta, 15 of Jambire, and 19 of Umbila. The volume of the sampled stem sections (logs) was calculated using Smalian’s formula, where stem volume total was obtained through the sum of the respective defined sections. Using a nonlinear procedure, different volume models were tested for each tree species independently. The coefficient of the determination of the tested equations in the tree species ranged from .90 to .95, making the equations potential candidate models for the stem volume equations object of the study. Based on statistical parameters analysis, the best fit nonliner power equation was Equation 2 with the lowest AICc and lowest average absolute bias. The stem volume for the studied species is better explained by models including both diameter and height as explanatory variables.