Canine visceral leishmaniasis and Rhipicephalus sanguineus: evaluation and comparison of classical techniques

Veterinary Research Communications - The aim of this study was evaluating the association and correlation between the diagnostics tests used for Leishmania spp. detection in dogs and ticks. We...     

Effects of soil flooding on leaf gas exchange and growth of two neotropical pioneer tree species

Schinus terebinthifolius Raddi (Anacardiaceae) and Rapanea ferruginea (Ruiz & Pavon) Mez (Myrsinaceae) are two neotropical pioneer trees with wide geographical distribution in South America, highly degree of adaptation to different soil conditions and intense regeneration in areas with anthropic activities. With the aim to recommend the use Schinus and Rapanea in gallery forest restoration programs, we conducted an experiment with the objective to analyze the capacity of these two pioneer trees to tolerate soil flooding, mainly by accessing the effects of flooding on leaf gas exchange, growth and dry matter partitioning. Seedling survival throughout the 56-day flooding period were 100 and 90% for Schinus and Rapanea, respectively. The mean values of stomatal conductance (g_s) and net photosynthesis (A) observed in the control seedlings were, respectively, 0.4 mol m^–2s^–1 and 14 mmolm^–2s^–1, for Schinus, and 0.5 mol m^–2s^–1 and 14 mmolm^–2s^–1, for Rapanea. On day 20 flooding reduced gs and A by 36 and 29% in Schinus, and 81 and 61% in Rapanea. At the end of the experiment, significant decreases were also observed for root and whole plant biomass, in both species. Based on the results, we concluded that seedlings of Schinus and Rapanea can survive and grow throughout a medium period of soil waterlogging, in spite of the alterations observed in their physiological behavior, such as the decreases in stomatal conductance and in whole plant biomass.     

Evaluation of resistance in different cowpea cultivars to Callosobruchus maculatus infestation

Cowpea [Vigna unguiculata (L.) Walp] seeds are an important source of nutrients for human and animal. However, part of the seed production is lost due to insect attacks, mainly by the weevil Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae), a major pest of stored cowpeas. An efficient method for controlling seed infestation is the use of insect-resistant cultivars. In this work, we studied the resistance of different cowpea Brazilian cultivars (BRS) to infestation and damage by C. maculatus. Our results showed that some cultivars interfered in female oviposition. The time necessary for the larvae to perforate the seed coat of some cultivars increased up to 40 %. No relationship between seed coat thickness, textures, or pigmentation and the larval ability of crossing seed coats was observed. Larval survival was also affected by cowpea cultivars. In BRS Xiquexique, only 30 % of the larvae survived at 20 days after oviposition. The weight of larvae developed into BRS Pajeu, and BRS Xiquexique cultivars decreased about 50 %. Cysteine protease, α-glucosidase, and α-amylase activities decreased in larvae developed in some cultivars, mainly in Pajeu, Guariba, Tucumaque, and Xiquexique. Adult emergence also decreased in Xiquexique, Pajeu, Tucumaque, and Paraguaçu BRS cultivars. A direct relationship between higher infestation and lower seed germination and seedling growth potential was observed. From these data, we would recommend the use of Pajeu, Guariba, Tucumaque, and Xiquexique BRS cultivars as a way to reduce cowpea infestation, and suggest that their resistance mechanism is related to the diminishment of larval digestive abilities.     

Renal failure in a pregnant mare

Although chronic renal disease is uncommon in horses, guidelines for management of the broodmare with kidney disease are needed to ensure successful foaling. Herein, we present a case report of a broodmare with chronic renal disease that produced a live foal, and parturition was predicted by monitoring pH and electrolytes in the milk. A 15-year-old pregnant mare presented with a history of poor body condition and weight loss despite an excellent appetite. At presentation, the mare was bright, alert and responsive, with severe pitting ventral oedema and vital parameters within normal limits. Plasma biochemistry revealed azotaemia, hypercalcaemia and hypophosphataemia. Based on clinical ultrasonographic and biochemical parameters, the mare was diagnosed with renal failure. Pregnancy was assessed by transabdominal ultrasound, and the fetal parameters were within normal limits; however, an increased combined thickness of the uterus and placenta and oedematous fetal membranes were found. Monitoring of mammary secretions accurately predicted the onset of foaling at 326 days of gestation. A healthy filly was delivered, and the fetal membranes were passed in a timely manner without complications. Physical examination and haematological parameters were within the normal limits for a neonate foal, except for a mild elevation in blood urea nitrogen. Two weeks later, the mare was subjected to euthanasia due to worsening of her condition. At necropsy and on histopathological examination, the findings were consistent with chronic renal disease. This case demonstrates that a pregnant horse with chronic renal disease can be managed with supportive care and produce a viable foal. Fetal well-being and mare’s prefoaling milk electrolytes were similar to parameters measured in healthy pregnant mares, suggesting that the feto-placental unit may be spared of the dam’s systemic disease. Prepartum physiological changes in the milk may be unaltered with concurrent maternal renal disease and still be useful for foaling prediction.     

Gonadal Development of the Piau Leporinus copelandii (Characiformes,Anostomidae) in a Tropical River in South‐eastern Brazil

Histological analysis of the gonadal development of Leporinus copelandii Steindachner, 1875, a rheophilic Characiformes species in the Paraiba do Sul River, South‐eastern Brazil, was described. We expect that this species adapt gonadal development to succeed in this river basin that has its longitudinal profile blocked by several impoundments. Fishes were examined by routine macroscopic and histological techniques. Stages of oocyte and spermatocyte development were described, and gonadal maturation was proposed. Mean oocyte diameter obtained from histological observations increased from the pre‐spawning (4.2–175.5 μm) to spawning (148.5–262.0 μm) phases, followed by a sharp decrease in the post‐spawning (27.0–56.7 μm) phase. Based on occurrence of different oocytes phases and oocyte size distribution, this species has group‐synchronic development of oocytes. Further studies are necessary to clarify the spawning grounds for L. copelandii in the Paraíba do Sul River basin, especially considering that several impoundments obliterate the natural river course and this could limit spawning grounds.     

Fatty acids as trophic biomarkers in vitellogenic females in an impounded tropical river

Fatty acids have been used in marine biogeochemistry as food chain biomarkers, but in freshwater these studies are rare. In order to evaluate the fatty acid potential as biomarkers in freshwater, their profile was analyzed during vitellogenesis in two fish species, in both waterfall and reservoir environments of the Paraíba do Sul River Basin. Detrivorous Hypostomus affinis and omnivorous Geophagus brasiliensis seem to elongate and desaturate polyunsaturated fatty acids (PUFA) and transfer them to the ovaries’ phospholipids. Waterfall Geophagus brasiliensis have more highly unsaturated fatty acids in the liver, but in the reservoir, accumulation mainly occurs in muscle and ovary triglycerides, suggesting trophic opportunism and a plasticity during vitellogenesis. In Hypostomus affinis, PUFA alteration occurs only in the reservoir, suggesting a high phytoplankton occurrence. Eutrophication and water speed is reflected in Hypostomus affinis ovaries by higher PUFAn3 and bacterial fatty acids. As in marine environments, analysis of mono- and polyunsaturated fatty acids during vitellogenesis can be used as a tool in food chain studies in freshwater.     

Salt Tolerance is Associated with Differences in Ion Accumulation,Biomass Allocation and Photosynthesis in Cowpea Cultivars

Cowpea is widely cultivated in arid and semi‐arid regions of the world where salinity is a major environmental stress that limits crop productivity. The effects of moderate salinity on growth and photosynthesis were examined during the vegetative phase of two cowpea cultivars previously classified as salt‐tolerant (Pitiúba) and salt‐sensitive (TVu). Two salt treatments (0 and 75 mm NaCl) were applied to 10‐day‐old plants grown in nutrient solution for 24 days. Salt stress caused decreases (59 % in Pitiúba and 72 % in TVu) in biomass accumulation at the end of the experiment. Photosynthetic rates per unit leaf mass, but not per unit leaf area, were remarkably impaired, particularly in TVu. This response was unlikely to have resulted from stomatal or photochemical constraints. Differences in salt tolerance between cultivars were unrelated to (i) variant patterns of Cl^? and K⁺ tissue concentration, (ii) contrasting leaf water relations, or (iii) changes in relative growth rate and net assimilation rate. The relative advantage of Pitiúba over TVu under salt stress was primarily associated with (i) restricted Na⁺ accumulation in leaves paralleling an absolute increase in Na⁺ concentration in roots at early stages of salt treatment and (ii) improved leaf area (resulting from a larger leaf area ratio coupled with a larger leaf mass fraction and larger specific leaf area) and photosynthetic rates per unit leaf mass. Overall, these responses would allow greater whole‐plant carbon gain, thus contributing to a better agronomic performance of salt‐tolerant cowpea cultivars in salinity‐prone regions.