Differentiation between canine cutaneous and visceral leishmaniasis by the detection of immunoglobulin G specific for Leishmania (Viannia) braziliensis and Leishmania (Leishmania) chagasi antigens using flow cytometry

Flow cytometry employing Leishmania (L.) chagasi (Lc) and L. (Viannia) braziliensis (Lb) antigen was used to establish the differential diagnosis between visceral (VL) and cutaneous leishmaniasis (CL) in dogs. Flow cytometry permitted the detection of Leishmania-specific immunoglobulin G in sera from 19 dogs: nine with CL and 10 with VL. A significant difference in the percentage of positive staining was observed in sera from dogs with CL between the homologous antigen (69% for Lb) and the heterologous antigen (42% for Lc). However, this difference was not significant in sera from dogs with VL (61% for Lb and 73% for Lc). No significant staining was observed in control sera (0.6% for Lb and 0.4% for Lc) consisting of samples from healthy dogs, or in the group with sporotrichosis (1.8% for Lb and 1.5% for Lc), a differential diagnosis of CL. The results suggest that flow cytometry might be useful for the differentiation between CL and VL in dogs, with practical applications in areas where the two infections overlap.     

Epidural injection of ketamine for caudal analgesia in the cow

The objective of the study was to determine the analgesic and sedative effects of epidural ketamine in the cow. Eight healthy cows weighing 350–450 kg were used. One of 3 doses of ketamine (0.5, 1 and 2.0 mg/kg) or a saline control were injected into the epidural space at the first intercoccygeal interspace in random sequence at one-week intervals. Ketamine was diluted in saline (0.9%) before the experiment, and the volume adjusted according to animal size. Analgesia was tested by applying a standard stimulus (needle insertion into the skin and deep muscle) and scored using a 3-point scale. A second voltage-based stimulus was also applied and the responses scored. Another scale was used for scoring the degree of sedation. The response and the degree of sedation were assessed before drug administration and at 2, 5, 10, 15 min, and every 15 min until 120 min after ketamine or saline administration. Ketamine produced dose-related analgesia of the tail, anus, perineum and vulva but not of the hindlimb area. The effect was dose-dependent in terms of intensity and duration. None of the doses produced analgesia when 70 or 80 volts were applied. Minimal side effects were observed. Epidural ketamine produces caudal analgesia in the cow. Further studies are required to determine whether this is sufficient for surgery.     

Cage aquaculture in Neotropical waters promotes attraction and aggregation of fish

The influence of cage aquaculture on the attraction and aggregation of wild fish was evaluated with an experimental tilapia farming structure. The structure was installed in the Corvo River, Rosana Reservoir, Paranapanema River basin, for 140 days. Samples were taken before and after farming began. Gillnets on the surface and near the bottom at different distances from the cages (0, 100 and 400 m) were used for fish sampling. The effects of the food supply at two protein levels were also analysed: Phase 1 = 32% PB and Phase 2 = 28% PB. Changes in species richness and abundance were observed, with the number of individuals and the fish biomass increasing significantly just after the farming began. Some species, such as Iheringichthys labrosus, presented increased abundance near the cages, while others, such as Plagioscion squamosissimus, were more abundant far from the cages. Auchenipterus osteomystax was the most abundant species during the experiment, especially when the protein content of the pellets was higher. It was demonstrated that farming tilapia in cages profoundly altered the abundance and composition of the wild ichthyofauna, suggesting the need to propose effective regulations for such activities, including fisheries restrictions in farmed areas or even the prohibition of cage farming.     

Aurantiochytrium sp. meal can replace fish oil in practical diets for the juvenile Pacific white shrimp

This study evaluated the use of microalgae (Aurantiochytrium sp.) meal as a substitute for fish oil in the diet of juvenile Pacific white shrimp (Litopenaeus vannamei) reared in a clear‐water system. Dietary treatments at five replacement levels (0%, 25%, 50%, 75%, 100%) were performed in triplicate. After 46 days, only a slight difference in shrimp final weight was observed among treatments (0.61 g). An increase in final weight was observed with replacement of up to 50% fish oil for microalgae meal, while the optimal percentage of replacement estimated was 44.7%. Feed conversion rate (FCR) of animals fed a diet of Aurantiochytrium sp.meal to replace up to 50% fish oil decreased, and the optimal percentage of replacement estimated was 49.3%. The fatty acids profile in shrimp muscle tissue demonstrated an increase in docosahexaenoic acid (DHA) from 10.03% to 14.28% with increased replacement of fish oil by microalgae meal in the diet. Therefore, the partial replacement of fish oil by microalgae meal resulted in improved shrimp growth and FCR, and total replacement of dietary fish oil had no negative effects on these parameters. In addition, inclusion of microalgae meal raises the level of DHA in shrimp muscle.     

Response of juvenile pacu (Piaractus mesopotamicus Holmberg, 1887) to balanced digestible protein

This 45‐day work aimed to determine the response of juvenile pacu (Piaractus mesopotamicus) to balanced digestible protein (BDP) and to use these responses to determine whether the optimum economic levels of BDP would differ depending on the form in which the fish is sold. Six isoenergetic diets containing 163, 201, 238, 272, 315 and 348 g/kg BDP (dry‐matter basis) were prepared through the serial dilutions of a high‐protein diet with the low‐protein diet. Fish (initial average body weight, 10.82 ± 0.14 g) were fed with respective experimental diets three times a day until apparent satiation. The optimum biological level of BDP was calculated as 326 g/kg (dry‐matter basis) by the quadratic regression model for maximum body weight gain of juvenile pacu. To maximize economic returns (US$/kg) for different end products, the optimum economic levels of BDP were calculated as 311, 317 and 319 g/kg (dry‐matter basis) by an economic model for whole‐body, eviscerated and sliced juvenile pacu respectively. This finding revealed that obtaining maximum biological performance of fish in the case of high feed costs or low prices of the end product in consumer market would substantially reduce the economic returns.     

Digestible protein requirements and muscle growth in juvenile tambaqui (Colossoma macropomum)

Several investigations have been carried out to improve the productivity of tambaqui, an economically important fish species in Brazil and other Latin American countries. This study determined the digestible protein (DP) requirements in juvenile tambaqui by assessing their productive performance and nutritional efficiency. It also evaluated the effects of different dietary DP levels on the morphology and cellularity of skeletal fast muscle fibres. The 1750 tambaqui tested (6.53 ± 0.43 g body weight, 7.58 ± 0.18 cm length) were randomly distributed into 35 tanks. Fish were fed one of the seven isocaloric diets, which contained 140, 170, 200, 230, 260, 290 or 320 g/kg DP. The DP requirement, calculated by segmented (broken line) regression of weight gain data, was 290 g/kg. An increase in diet DP to 290 g/kg significantly improved final weight, weight gain, feed intake, specific growth rate and crude protein gain, and changed fibre diameter in deep muscle. Muscle fibres were randomly distributed into a mosaic pattern, characterized by fibres with different diameters. Treatments with 290 and 320 g/kg DP increased the frequency of large‐diameter fibres (>50 µm), indicating hypertrophic growth of skeletal muscle during the juvenile phase, which occurred in conjunction with hyperplasia.     

Marine-Derived Penicillium purpurogenum Reduces Tumor Size and Ameliorates Inflammation in an Erlich Mice Model

Background: This study addresses the antitumoral properties of Penicillium purpurogenum isolated from a polluted lagoon in Northeastern Brazil. Methods: Ethyl Acetate Extracellular Extract (EAE) was used. The metabolites were studied using direct infusion mass spectrometry. The solid Ehrlich tumor model was used for antitumor activity. Female Swiss mice were divided into groups (n = 10/group) as follows: The negative control (CTL−), treated with a phosphate buffered solution; the positive control (CTL+), treated with cyclophosphamide (25 mg/kg); extract treatments at doses of 4, 20, and 100 mg/kg; animals without tumors or treatments (Sham); and animals without tumors treated with an intermediate dose (EAE20). All treatments were performed intraperitoneally, daily, for 15 days. Subsequently, the animals were euthanized, and the tumor, lymphoid organs, and serum were used for immunological, histological, and biochemical parameter evaluations. Results: The extract was rich in meroterpenoids. All doses significantly reduced tumor size, and the 20 and 100 mg/kg doses reduced tumor-associated inflammation and tumor necrosis. The extract also reduced the cellular infiltration of lymphoid organs and circulating TNF-α levels. The extract did not induce weight loss or renal and hepatic toxic changes. Conclusions: These results indicate that P. purpurogenum exhibits immunomodulatory and antitumor properties in vivo. Thus, fungal fermentation is a valid biotechnological approach to the production of antitumor agents.