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The dietary inclusion of feed additives to improve the carcass characteristics of the final product is of great importance for the pork production chain. The aim of our study was to evaluate the effects of the association of ractopamine (RAC) and conjugated linoleic acid (CLA) on the performance traits of finishing pigs during the last 26 days prior to slaughter. In total, 810 commercial hybrid barrows were used. Animals were distributed among treatments according to a randomised block design in a 3 × 3 factorial arrangement, with three RAC levels (0, 5 or 10 ppm) and three CLA levels (0, 0.3 or 0.6%). Pigs fed the diet with 5 ppm RAC had higher average daily feed intake (ADFI) (2.83 kg; P < 0.05) when compared with those fed 10 ppm RAC and the control diet (2.75 and 2.74 kg, respectively). Lower ADFI values (P < 0.01) were observed with the diets containing CLA compared with the control diet with no CLA (2.73 and 2.75 v. 2.85 kg/day, respectively). The average daily weight gain of pigs fed 5 and 10 ppm RAC was +148 and +173 g/dayhigher (P < 0.001), respectively, than those fed the control diet. Dietary RAC levels influenced (P < 0.001) feed conversion ratio (FCR), which was reduced as RAC levels increased, with the pigs fed 10, 5 and 0 ppm RAC presenting FCR values of 2.57, 2.71 and 3.05, respectively. FCR also improved (P < 0.05) with the inclusion of 0.6% CLA relative to the control diet (2.70 v. 2.84, respectively). There was a significant interaction between CLA × RAC levels (P < 0.01) for final BW, loin eye area (LEA) (P < 0.05) and backfat thickness (BT) (P < 0.05). The treatments containing 10 ppm RAC + 0.6% or 0.3% CLA increased LEA and reduced BT. In conclusion, the level of 10 ppm inclusion of RAC increased the overall performance parameters of pigs and therefore improved production efficiency. The combined use of RAC and CLA promoted a lower feed conversion ratio as well as better quantitative carcass traits, as demonstrated by the higher LEA and lower BT. The dietary inclusion of CLA at 0.3% improved feed efficiency, however, without affecting LEA or BT yields.
Regeneration from seed affects species assembly in plant communities, and temperature is the most important environmental factor controlling the germination process. Thermal dependence of seed germination is thus associated with species occurrence in an ecosystem. Hence, we aimed to investigate the role of temperature on seed germination of ten tree species from the western Brazilian Amazon. Seeds were collected in the state of Rondônia, Brazil, and set to germinate under constant temperatures ranging from 10 to 40°C in germination chambers. We calculated germination capacity (G%), germination rate (GR50, reciprocal of germination time), and thermal parameters, such as cardinal temperatures and thermal time requirements. Most species had a large range of temperatures showing G% ≥80%, with optimal temperature varying from 20 to 40°C. Base temperature ranged from 6 to 12°C and ceiling temperatures were mainly >40°C. Astronium lecointei and Parkia nitida showed high germination capacity under temperatures of 35–40°C, while germination of Theobroma cacao dropped from 100% to zero under temperatures between 37 and 40°C. The climax species Cedrela fissilis had the slowest germination time (10 days) and highest thermal time requirement, while seeds of Enterolobium schomburgkii (a late-successional species) germinated within the first day of the experiment. Rapid recruitment of Amazon species could be favoured with treefall disturbance, which increases temperatures in the understory, but sharp limits might be found in the supra-optimal range of temperatures. Such patterns might indicate different regeneration strategies in the tropical rainforest, providing important information regarding seed germination among Amazon species.
Timneh Parrots Psittacus timneh are a threatened species endemic to the moist forests of West Africa. In 2016, they were categorised as ‘Endangered’ on the IUCN Red List, due to suspected rapid population declines driven by habitat loss and heavy trapping for the pet trade. Systematic assessments of the status of populations are lacking for much of their range and addressing this knowledge shortfall has been identified as a priority action. We combined multiple research approaches to investigate the distribution, trends and threats to Timneh Parrots in Guinea Bissau, where the species is restricted to the islands of the Bijagós archipelago and Pecixe. Direct observational surveys were conducted along line transects on 19 islands. A total of 69 groups were observed on eight of these islands, with the majority (78%) seen on just two islands. Forty-two interviews were conducted with local community members on 24 islands. Interviewees reported the species to occur on 20 islands and that populations are generally perceived to have declined in recent decades. Based on these findings and existing data we conclude that Timneh Parrots occur on 22 of the 32 islands considered and estimate the national population in Guinea-Bissau to be in the order of several hundred individuals, with perhaps half of the parrots occurring on the islands of João Vieira and Meio. Investigations into the factors linked to inter-island variation in parrot densities indicate that densities are highest on the islands which are most remote from permanent human settlements. These findings suggest that human activities including habitat modification and trapping have been important in driving population declines in Guinea-Bissau. We consider the implications of these findings for the conservation of Timneh Parrots.
The use of fast and non-destructive techniques for identifying sugarcane varieties enables the development of automatic sorting systems, contributing towards improving pre-processing steps in the alcohol and sugar industries. In this context, principal component analysis (PCA), factorial discriminant analysis (FDA), stepwise forward discriminant analysis (SFDA) and partial least-squares discriminant analysis (PLS-DA) were used to classify four Brazilian sugarcane varieties based on visible/near infrared (Vis/NIR) spectral reflectance measurements (450–1000 nm range) of stalks. All wavelengths contributed towards discriminating the sugarcane varieties, but the 600–750 nm range was most relevant. When evaluating PCA results considering the four sugarcane varieties, two of them overlapped and it was only possible to use classifiers of three varieties. Factorial discriminant analysis, PLS-DA and SFDA reached correct classifications of 0.81, 0.82 and 0.74, respectively, when considering the external validation data and the four sugarcane varieties evaluated. Results showed that Vis/NIR spectroscopy combined with discriminating methods is a promising tool for non-destructive and fast sugarcane variety classification, which can be used in the agro-food industry or directly in the field.
Exotic species can experience fast expansion in new environments, especially if they left their pathogens behind (Enemy Release hypothesis) or brought novel pathogens to the native competitors (Novel Weapon hypothesis). Common waxbills (Estrilda astrild) are native to sub-Saharan Africa and invaded west Iberia since the 1960s. Past haemosporidian parasite surveys at four locations in Portugal showed that waxbills can be infected with parasites, though with very low prevalence. However, it is not known if this pattern generalizes across their distribution range, or if there are geographic differences in parasite prevalence. It is also not discussed if this is a case of Enemy Release, as opposed to waxbills being also little parasitized in their native range. We screened 617 waxbills in 23 sites in Portugal and detected nine parasite lineages, most of them only known to the Palearctic. Only ten individuals were parasitized, and there was no significant geographical pattern on the prevalence. Overall, this population shows very low prevalence of haemosporidians (1.6% prevalence), which contrasts with significantly higher prevalence in native grounds, as compiled from the literature. These data support Enemy Release as the most likely hypothesis, which may have been important for their success as an exotic species.
Although a national programme for control of visceral leishmaniosis (VL) is being run in Brazil, the disease continues to spread. This programme is essentially based on culling infected dogs from endemic regions. Thus, there is an urgent need to develop other control measures against VL to deter its advance. Here, a subunit vaccine, a recombinant vaccine, an insecticide-impregnated collar and the associations between these measures were evaluated for reducing the incidence of Leishmania infection in dogs. This was through a cohort study conducted in an endemic region of Brazil, considering the incidence and time of total exposure over a period of 1 year. The incidence of VL was estimated by means of serological and molecular diagnostic tests, 180 and 360 days after the application of the control measures. The estimates of the effectiveness (EF) were not significant in any cohort. The EF of the subunit vaccine, the recombinant vaccine and the collar were 26.4%, 32.8% and 57.7% and the upper limit of the 95% confidence interval for EF were 63.7%, 67.9% and 82.5%, respectively. In conclusion, under the conditions of this study, none of the immunogens for VL control was sufficiently effective to protect dogs against infection. On the other hand, use of collars impregnated with insecticide seems to constitute a method with better prognosis, corroborating other studies in this field.
Phosphorus and calcium deficiency in horses represents an important factor responsible for the low equine production in Brazil. The basic mechanisms of P and Ca metabolism differ substantially among species. Regulation of P and Ca metabolism is less well understood in horses than in others species. With the use of the isotopic dilution technique is possible to evaluate the metabolism for this mineral. The aim of the present experiment was to study the effect of different Ca levels in the diet on P and Ca metabolism in horses.
Research in Brazil has been carried out to study mineral metabolism in sheep and cattle, especially phosphorus, by using the isotope dilution technique (Vitti et al., 2000). However there is very little information on calcium metabolism in goats. The proposal of the present study is to measure the intensity of the different processes that occur in goats fed different amounts of calcium, by using radioactive calcium, and to propose a model of Ca metabolism.
The species Phytomonas serpens is known to express some molecules displaying similarity to those described in trypanosomatids pathogenic to humans, such as peptidases from Trypanosoma cruzi (cruzipain) and Leishmania spp. (gp63). In this work, a population of P. serpens resistant to the calpain inhibitor MDL28170 at 70 µm (MDLR population) was selected by culturing promastigotes in increasing concentrations of the drug. The only relevant ultrastructural difference between wild-type (WT) and MDLR promastigotes was the presence of microvesicles within the flagellar pocket of the latter. MDLR population also showed an increased reactivity to anti-cruzipain antibody as well as a higher papain-like proteolytic activity, while the expression of calpain-like molecules cross-reactive to anti-Dm-calpain (from Drosophila melanogaster) antibody and calcium-dependent cysteine peptidase activity were decreased. Gp63-like molecules also presented a diminished expression in MDLR population, which is probably correlated to the reduction in the parasite adhesion to the salivary glands of the insect vector Oncopeltus fasciatus. A lower accumulation of Rhodamine 123 was detected in MDLR cells when compared with the WT population, a phenotype that was reversed when MDLR cells were treated with cyclosporin A and verapamil. Collectively, our results may help in the understanding of the roles of calpain inhibitors in trypanosomatids.
This study assessed the incidence and risk factors for dengue virus (DENV) infection among children in a prospective birth cohort conducted in the city of Recife, a hyperendemic dengue area in Northeast Brazil. Healthy pregnant women (n = 415) residing in Recife who agreed to have their children followed were enrolled. Children were followed during their first 24 months of age (May/2011–June/2014), before the 2015 Zika virus outbreak. DENV infection was detected by reverse-transcriptase polymerase chain reaction and/or serology (anti-DENV IgM/IgG). The incidence rates per 1000 person-years (py) and its association with risk factors by age bands (0–12, >12–30 months) were estimated through Poisson regression models. Forty-nine dengue infections were detected; none progressed to severe forms. The incidence rates were 107·6/1000py (95% CI 76·8–150·6) and 93·3/1000py (95% CI 56·1–154·4) in the first and second years of age, respectively. Male children (risk ratios (RR) = 2·33; 95% CI 1·09–4·98) and those born to DENV-naïve mothers (RR = 2·42; 95% CI 1·01–5·80) were at greater risk of infection in the first year of age. In the second year, children born to Caucasian/Asian descent skin colour mothers had a threefold higher risk of infection (RR = 3·34; 95% CI: 1·08–10·33). These data show the high exposure of children to DENV infection in our setting and highlight the role of biological factors in this population's susceptibility to infection.
Euthanasia of infected dogs is one of the measures adopted in Brazil to control visceral leishmaniasis (VL) in endemic areas. To detect infected dogs, animals are screened with the rapid test DPP® Visceral Canine Leishmaniasis for detection of antibodies against K26/K39 fusion antigens of amastigotes (DPP). DPP-positives are confirmed with an immunoenzymatic assay probing soluble antigens of promastigotes (ELISA), while DPP-negatives are considered free of infection. Here, 975 dogs from an endemic region were surveyed by using DPP, ELISA and real-time PCR (qPCR) for the diagnosis of VL. When DPP-negative dogs were tested by qPCR applied in blood and lymph node aspirates, 174/887 (19·6%) were positive in at least one sample. In a second sampling using 115 cases, the DPP-negative dogs were tested by qPCR in blood, lymph node and conjunctival swab samples, and 36/79 (45·6%) were positive in at least one sample. Low-to-moderate pairwise agreement was observed between all possible pair of tests. In conclusion, the official diagnosis of VL in dogs in Brazilian endemic areas failed to accuse an expressive number of infected animals and the impact of the low accuracy of serological tests in the success of euthanasia-based measure for VL control need to be assessed.
The present study aims to assess the effects of pig’s genotype (lean v. fatty) and dietary protein level (control v. reduced) on intramuscular fat (IMF) content, fatty acid composition and fibre profile of psoas major, a representative red muscle in pig’s carcass scarcely studied relative to white longissimus lumborum. The experiment was conducted on 40 intact male pigs (20 Alentejana purebred and 20 Large White×Landrace×Pietrain crossbred) from 60 to 93 kg of live weight. Pigs were divided and allocated to four dietary groups: control protein diet equilibrated for lysine (17.5% of CP and 0.7% of lysine) and reduced protein diet (RPD) not equilibrated for lysine (13.1% of crude protein and 0.4% of lysine) within a 2×2 factorial arrangement (two genotypes and two diets). Alentejana purebred had higher IMF content (15.7%) and monounsaturated fatty acids (MUFA) (8.9%), whereas crossbred pigs had higher PM weight (46.3%) and polyunsaturated fatty acids (PUFA) (20.1%). The genotype also affected colour with higher lightness (15.1%) and yellowness (33.8%) and lower redness (9.9%) scores in crossbred pigs. In line with this, fatty pigs displayed more oxidative fibres (29.5%), whilst lean pigs had more glycolytic (54.4%). Relative to fatty acids, RPD increased MUFA (5.2%) and SFA (3.2%) but decreased PUFA (14.8%). Ultimately, RPD increased IMF content (15.7%) in the red muscle under study, with no impact on glycolytic to oxidative fibre type transformation.
Hepatitis E virus (HEV) infection is a major cause of acute hepatitis worldwide. This infection causes major water-borne outbreaks in low- and middle-income countries, whilst in industrialised countries this infection is zoonotic. These differences in epidemiology are related to different HEV genotypes. HEV genotype 3 is a zoonotic infection, whilst genotype 2 causes large outbreaks. This study determined the seroprevalence of HEV in blood donors from the Western Cape. Anti-hepatitis A virus (anti-HAV) antibody was detected in 184/300 (61%) donors. Antibody to HEV (anti-HEV) was detected in 78 of 300 donors (26%). It was highest in mixed race donors (62/100), followed by white donors (23/100) and lowest in black donors (19/100) P = 0.019. Since it is thought that genotypes 1 and 2 predominate both viruses would be acquired by the oro-faecal route, it is surprising that HEV seroprevalence does not mirror that of HAV. We postulate that this may reflect differences in socio-economic status and consumption of dietary meat. So the marked divergence between HEV and HAV seroprevalence may be the result of different routes of transmission. Further data are needed to explore the risk factors associated with HEV infection.
The Laboratory for Intense Lasers (L2I) is a research centre in optics and lasers dedicated to experimental research in high intensity laser science and technology and laser plasma interaction. Currently the laboratory is undergoing an upgrade with the goal of increasing the versatility of the laser systems available to the users, as well as increasing the pulse repetition rate. In this paper we review the current status of the laser research and development programme of this facility, namely the upgraded capability and the recent progress towards the installation of an ultrashort, diode-pumped OPCPA laser system.
The production of pork with moderate amounts of intramuscular fat (IMF) without an increase in subcutaneous fat is highly desirable for the meat industry. Several studies indicate that dietary protein reduction during the growing–finishing period of pigs enhances IMF content, but its consequence on carcass fat deposition is still contradictory. In this study, we hypothesized that the effects of reduced protein diets (RPD), corrected or not with the limiting amino acid lysine, on subcutaneous fat deposition from pigs with distinct genotypes are mediated by adipose membranes biophysical properties. In total, 36 crossbred (Large White×Landrace×Pietrain – a lean genotype) and purebred (Alentejana breed – a fatty genotype) male pigs were randomly assigned to the control group, the RPD group or the reduced protein diet equilibrated for lysine (RPDL) group, allowing a 2×3 factorial arrangement (n=6). Backfat thickness and total fatty acid content were higher in Alentejana relative to crossbred pigs. Although dietary treatments did not change backfat thickness, RPD and RPDL increased total fatty acids content of subcutaneous fat. In order to understand this effect, adipose tissue membranes isolated from pig’s subcutaneous fat were assayed for glycerol permeability and fluidity, using 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-(4-(trimethylamino)-phenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH) probes. The glycerol transport across adipose membranes was not mediated by aquaglyceroporins and remained unchanged across dietary groups. Regardless of lysine correction, RPD increased membrane fluidity at the hydrocarbon region (lower DPH fluorescence anisotropy) in both genotypes of pigs. This result was associated with a lower ratio between oleic acid and linoleic acid on membrane’s fatty acid composition. Adipose membrane’s cholesterol content was independent from genotype and diet. Taken together, the present study shows that dietary protein reduction is successful in maintaining backfat thickness, although a negative side effect was observed on total fatty acids in subcutaneous fat, which may be due to changes in the fluidity of adipose membranes.
The traditional beef production in the South of Portugal is based on a discontinuous growth (DG) system that requires lower external inputs and could enhance meat quality and financial returns to cattle producers. This system allows farmers to take advantage of the bull’s compensatory growth when the pasture is abundant and finishes the cattle on concentrates for 2 to 3 months before slaughter. The fast gain rate before slaughter could be a valuable strategy to improve tenderness and to reduce its inconsistency in beef production. Therefore, the aim of this study was to evaluate the effects of production system (continuous growth (CG) v. DG) on longissimus thoracis muscle properties from Alentejana bulls. In total, 40 Alentejana male calves were allocated to two distinct feeding regimes: in the CG system, animals were fed concentrate plus hay and slaughtered at 18 months of age, whereas in the DG system, animals were fed on hay until 15 months of age and then fed the same diet provided to the CG group until 24 months of age. The DG system had a positive impact on meat tenderness (P<0.001) and global acceptability (P<0.001). DG bulls had greater fibre cross-sectional area (CSA) of glycolytic fibres (P<0.05) and relative area of the muscle (RA) occupied by type IIX fibres (P<0.01) and greater levels of α-actinin (P<0.05) and myosin light chain 2 (P<0.01) proteins, and pH24h (P<0.01) than CG bulls. The latter had greater CSA of type I (P<0.05) and type IIA (P<0.01) and greater RA of type IIA (P<0.05) and oxidative (P<0.05) than CG bulls. The compensatory growth production system had a positive impact on meat tenderness and global acceptability, overcoming the negative effects of slaughter of the bulls at a later age. The DG beef system could be a worthwhile strategy of beef production in Mediterranean areas due to the low-quality pasture in summer.
This study aimed to evaluate the systemic and renal renin–angiotensin–aldosterone system (RAAS) at birth in male and female offspring and in mothers fed a high sodium diet (HSD) before and during gestation. Female Wistar rats were fed a HSD (8.0% NaCl) or a normal sodium diet (1.3% NaCl) from 8 weeks of age until delivery of their first litter. Maternal body weight, tail blood pressure, and food and water intake were evaluated. The litter sizes were assessed, and the body and kidney weights of the offspring were measured. Both mothers and offspring were euthanized immediately following the birth of the pups to evaluate plasma renin activity (PRA), renal renin content (RRC), renal angiotensin-converting enzyme (ACE) activity, renal angiotensin (Ang) II content, serum aldosterone (ALDO) levels, and renal cortical and medullary renin messenger RNA expression. In mothers in the HSD group, water intake and kidney mass were higher, whereas renal ACE activity, Ang II, PRA, ALDO and RRC were decreased. In the offspring of HSD-fed dams, the body and kidney mass were lower in both genders, renal ACE activity was lower in females and renal Ang II was lower in males. PRA, RRC, renin gene expression and ALDO levels did not differ between the groups of offspring. The data presented herein showed that a maternal HSD during pregnancy induces low birth weight and a sex-specific response in the RAAS in offspring.
The aim of this study was to determine the seroprevalence of Toxoplasma gondii infection in free-range chickens from Uberlândia, Minas Gerais state, Brazil, and characterize the genotypic and phenotypic features of two isolates of this parasite, considering the importance of these hosts in the epidemiology of toxoplasmosis. Serum samples from 108 free-range chickens were obtained from ten different districts, and submitted to the modified agglutination test (MAT) for the presence of anti-T. gondii antibodies, and brain and heart tissue samples from infected chickens were processed for mouse bioassay. An overall seroprevalence of 71·3% was found and antibody titres ranged from 16 to 4096. After confirmation of seropositivity by mouse bioassay, the determination of the T. gondii genotypes of two isolates was performed by PCR–RFLP, using primers for the following markers: SAG1, SAG2, SAG3, BTUB, GRA6, c22–8, c29–2, L358, PK1, new SAG2, Apico and CS3. These T. gondii isolates, designated TgChBrUD1and TgChBrUD2, were obtained from heart samples of free-range chickens. The TgChBrUD1 isolate belonged to ToxoDB PCR–RFLP genotype 11 and the TgChBrUD2 isolate belonged to ToxoDB PCR–RFLP genotype 6. Both isolates demonstrated high virulence in a rodent model, with the TgChBrUD1 isolate able to induce brain cysts, in accord with its pattern of multiplication rates in human fibroblast culture. Taken together, these results reveal high prevalence of T. gondii infection in free-range chickens throughout Uberlândia, indicating an important degree of oocyst environmental contamination and the existence of considerable risk for T. gondii transmission to humans by consumption of free-range chicken as a food source.