Persistent Contamination of Octopuses and Mussels with Lipophilic Shellfish Toxins during Spring Dinophysis Blooms in a Subtropical Estuary

This study investigates the occurrence of diarrhetic shellfish toxins (DSTs) and their producing phytoplankton species in southern Brazil, as well as the potential for toxin accumulation in co-occurring mussels (Perna perna) and octopuses (Octopus vulgaris). During the spring in 2012 and 2013, cells of Dinophysis acuminata complex were always present, sometimes at relatively high abundances (max. 1143 cells L⁻¹), likely the main source of okadaic acid (OA) in the plankton (max. 34 ng L⁻¹). Dinophysis caudata occurred at lower cell densities in 2013 when the lipophilic toxins pectenotoxin-2 (PTX-2) and PTX-2 seco acid were detected in plankton and mussel samples. Here, we report for the first time the accumulation of DSTs in octopuses, probably linked to the consumption of contaminated bivalves. Perna perna mussels were consistently contaminated with different DSTs (max. 42 µg kg⁻¹), and all octopuses analyzed (n = 5) accumulated OA in different organs/tissues: digestive glands (DGs) > arms > gills > kidneys > stomach + intestine. Additionally, similar concentrations of 7-O-palmytoyl OA and 7-O-palmytoly dinophysistoxin-1 (DTX-1) were frequently detected in the hepatopancreas of P. perna and DGs of O. vulgaris. Therefore, octopuses can be considered a potential vector of DSTs to both humans and top predators such as marine mammals.     

Survival times in dogs with right atrial hemangiosarcoma treated by means of surgical resection with or without adjuvant chemotherapy: 23 cases (1986-2000)

OBJECTIVE: To determine survival times in dogs with right atrial hemangiosarcoma treated by means of pericardectomy and tumor resection, with or without adjuvant chemotherapy, and identify complications associated with treatment. DESIGN: Retrospective study. ANIMALS: 23 dogs. PROCEDURE: Dogs were included only if the diagnosis was confirmed histologically. RESULTS: The most common initial complaints included acute collapse (8 [35%] dogs), anorexia or inappetence (8 [35%]), and lethargy (8 [35%]). The most common physical examination abnormalities included muffled heart sounds (12 [52%] dogs), tachycardia (7 [30%]), and weak pulses (7 [30%]). Postoperative complications developed in 12 (52%) dogs; however, most complications were minor. Twenty (87%) dogs were discharged from the hospital. Survival time was significantly longer in the 8 dogs that received adjuvant chemotherapy (mean, 164 days; median, 175 days) than in the 15 dogs that did not receive chemotherapy (mean, 46 days; median, 42 days). Dogs that received chemotherapy were significantly younger and had significantly lower WBC counts than did dogs that did not receive chemotherapy. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that in dogs with right atrial hemangiosarcoma, surgical resection of the tumor was associated with a low complication rate and complications that did arise typically were minor. In addition, use of adjuvant chemotherapy following resection was associated with significantly longer survival times, compared with resection alone.     

Effects of oral potassium supplementation on acid-base status and plasma ion concentrations of horses during endurance exercise

OBJECTIVE: To compare effects of oral supplementation with an experimental potassium-free sodium-abundant electrolyte mixture (EM-K) with that of oral supplementation with commercial potassium-rich mixtures (EM+K) on acid-base status and plasma ion concentrations in horses during an 80-km endurance ride. ANIMALS: 46 healthy horses. PROCEDURE: Blood samples were collected before the ride; at 21-, 37-, 56-, and 80-km inspection points; and during recovery (ie, 30-minute period after the ride). Consumed electrolytes were recorded. Blood was analyzed for pH, PvCO2, and Hct, and plasma was analyzed for Na+, K+, Cl-, Ca2+, Mg2+, lactate, albumin, phosphate, and total protein concentrations. Plasma concentrations of H+ and HCO3-, the strong ion difference (SID), and osmolarity were calculated. RESULTS: 34 (17 EM-K and 17 EM+K treated) horses finished the ride. Potassium intake was 33 g less and Na+ intake was 36 g greater for EM-K-treated horses, compared with EM+K-treated horses. With increasing distance, plasma osmolarity; H+, Na+, K+, Mg2+, phosphate, lactate, total protein, and albumin concentrations; and PvCO2 and Hct were increased in all horses. Plasma HCO3-, Ca2+, and Cl- concentrations were decreased. Plasma H+ concentration was significantly lower in EM-K-treated horses, compared with EM+K-treated horses. Plasma K+ concentrations at the 80-km inspection point and during recovery were significantly less in EM-K-treated horses, compared with EM+K-treated horses. CONCLUSIONS AND CLINICAL RELEVANCE: Increases in plasma H+ and K+ concentrations in this endurance ride were moderate and unlikely to contribute to signs of muscle fatigue and hyperexcitability in horses.     

Carbon dioxide emissions after application of tillage systems for a dark red latosol in southern Brazil

Soil tillage may influence CO₂ emissions in agricultural systems. Agricultural soils are managed in several ways in Brazil, ranging from no tillage to intensive land preparation. The objective of this study was to determine the effect of common soil tillage treatments (disk harrow, reversible disk plow, rotary tiller and chisel plow tillage systems) on the intermediate CO₂ emissions of a dark red latosol, located in southern Brazil. Different tillage systems produced significant differences in the CO₂ emissions, and the results indicate that the chisel plow produced the highest soil carbon loss during the 15 days period after tillage treatments were performed. Emissions to the atmosphere increased as much as 74 g CO₂ m⁻², at the end of a 2-week period, in the plot where the chisel plow treatment was applied, in comparison to the non-disturbed plot. The results indicate that the total increase on the intermediate term soil CO₂ emissions due to tillage treatments in southern Brazil is comparable to that reported for the more humid and cooler regions.     

Secreted phosphatase activities in trypanosomatid parasites of plants modulated by platelet-activating factor

ABSTRACT The secreted phosphatase activities of two trypanosomatid parasites were characterized and compared with supernatants of living cells. The plant parasite Phytomonas fran?ai and the phytophagous hemipteran parasite Herpetomonas sp. hydrolyzed p-nitrophenylphosphate at a rate of 15.54 and 6.51 nmol Pi/mg of protein per min, respectively. Sodium orthovanadate (N(a)VO(3)) and sodium fluoride (NaF) decreased the phosphatase activities. The phosphatase activity of P. fran?ai was drastically diminished (73% inhibition) in the presence of sodium tartrate, whereas the phosphatase activity of Herpetomonas sp. was inhibited by 23%. Cytochemical analysis showed the localization of these enzymes on the external surface and in the flagellar pocket of the two trypanosomatids. Sodium tartrate inhibited this reaction, confirming the biochemical data. Platelet-activating factor modulated the phosphatase activities, inhibiting P. fran?ai activity and stimulating Herpetomonas sp. phosphatase activity.     

Factors affecting width of the canine femorotibial joint space in nonweight-bearing radiographs.

Caudocranial stifle radiographs with variations in positioning were made in two greyhound cadavers. Radiographs were repeated after each of three interventions: cranial cruciate desmotomy; release of the caudal horn of the medial meniscus; complete medial meniscectomy. The joint space on medial and lateral aspects of the joint was measured by a observer who was unaware of positioning or intervention. One dog had significantly wider joint space than the other (1.0 vs. 1.5mm). The lateral aspect of the joint space was wider than the medial aspect (1.7 vs. 0.7 mm). Medial rotation of the stifle resulted in an increase of 0.4 mm in width of the lateral joint space, whereas lateral rotation of the stifle reduced the lateral joint space by an average of 0.4 mm. Decentering the X-ray beam had no significant effect on joint space width. Tension increased the width of the medial joint space by an average of 1.2 mm and the lateral aspect by an average of 1.3 mm. Cranial cruciate desmotomy resulted in an average 0.3 mm increase in width of the joint space, and medial meniscectomy with an average 0.2 mm reduction of the joint space. Although the femorotibial joint space was affected by iatrogenic stifle injuries and by medial or lateral rotation, these changes were less than the differences between the two dogs. Hence it seems unlikely that the small changes in joint space width associated with cruciate ligament desmotomy and medial meniscectomy will be detectable in clinical practice.     

Effects of protein-energetic supplementation frequency on growth performance and nutritional characteristics of grazing beef cattle

Two experiments were conducted to evaluate reduced supplementation frequencies for grazing beef cattle in rainy season. In experiment 1, evaluating the nutritional parameters, four rumen-cannulated Nellore bulls (BW = 410 kg) were used. In experiment 2, evaluating animal performance, 48 Nellore bulls (BW = 358 kg) were used. The treatments were as follows: mineral supplement (MS) alone and MS plus protein-energy supplement provided 3×, 5× and 7×/week. Supplementation frequency did not affect (P > 0.05) intake and digestibility. Average daily gain was greater (P < 0.001) to supplementation compared with MS. The supplementation 5×/week resulted in greater weight gain per hectare (9.24) and higher economic returns during the study period (1.64%) compared to other supplementations. Supplementation 5×/week increased animal performance and positively influenced economic returns.     

Growth, stress response and free amino acid levels in Senegalese sole (Solea senegalensis Kaup 1858) chronically exposed to exogenous ammonia

Stressful husbandry conditions are likely to affect growth and amino acid metabolism in fish. In this study, chronic ammonia exposure was used to test the effects of a stressor on growth and amino acid metabolism of Senegalese sole juveniles. The fish were exposed for 52 days to 11.6 mg L⁻¹ [low‐TAN (L‐TAN)] or 23.2 mg L⁻¹ [high‐TAN (H‐TAN)] of total ammonia nitrogen (TAN), or to 0 mg L⁻¹ (Control). Growth in L‐TAN groups was slightly but significantly different from the Control groups [relative growth rate (RGR=0.35±0.13 and 0.52±0.23% day⁻¹ respectively)]. In H‐TAN groups, growth was severely affected (RGR=0.01±0.13% day⁻¹). Stress parameters (plasma cortisol and glucose) showed slight or no significant differences between treatments. Plasma free amino acid (FAA) concentrations were affected after H‐TAN treatment. Increases in glutamine and aspartate concentrations in H‐TAN fish suggest alterations in amino acid metabolism related to nitrogen excretion processes. Some of the changes in FAA concentrations also suggest mobilization to energy supply and synthesis of metabolites related to stress response. Therefore, Senegalese sole seem to adapt to the L‐TAN concentration tested, but the H‐TAN concentration reduced growth and affected amino acid metabolism.     

Feeding responses of juvenile shrimp Litopenaeus vannamei (Boone) fed at different frequencies under laboratory conditions

In shrimp farms, food partitioning during the course of the day is contradictory, ethology studies may help in determining the proper frequency. Litopenaeus vannamei juveniles were placed in 30 L aquariums (41 m⁻²), exposed to a 12:12 h light–dark cycle. Feeding was provided at 10% of biomass three, four and seven times per day, with observations made in 15 min h⁻¹ windows, initiated after the ration was offered. Latency to access the feeding tray and to start eating was recorded using instantaneous focal sampling and digestive tract filling (DTF) by the continuous focal method. Weight gain was recorded at the end of the experiment. We performed seven repetitions, with 28 individuals observed for 33 days for each treatment (490 h of observation). The three-times offering induced less latency for accessing the tray and for ingesting the feed as well as a higher DTF when compared with the other frequencies. Animals fed three and four times had similar weight gains, and were greater than those fed seven times. Our results indicate that a more spaced food offering stimulates the search for and ingestion of feed. As compared with other frequencies, the three-times-per-day option assumes lower labour costs and a more efficient use of the feed.     

Aeration strategy for controlling grain storage based on simulation and on real data acquisition

In this work a new control strategy for grain aeration systems was proposed. This strategy was implemented in a software package called AERO and relates four conditions which depend on real time data acquisition and on the process simulation. The main advantage of AERO controller is that it can be used in different geographic regions, during different seasons and with different aeration systems, automatically adjusting its set points. The objectives of AERO controller are to equalize the temperatures inside the bin, to cool the grain mass whenever is possible and to maintain the moisture content under safe conditions. The results showed that the proposed strategy is efficient to achieve these objectives. Moreover, significant energy saving has been achieved with the AERO controller.