Microbial protein production determined by urinary allantoin and renal urea sparing in normal and low protein fed Corriedale sheep

The aim of the present study was to compare the amount of microbial N entering the duodenum and the efficiency of N utilisation for microbial protein synthesis in normal (NP, 17.4 g N/d) and low protein (LP, 7.5 g N/d) fed Corriedale sheep. Renal functional tests for urea handling studies, and determination of urinary allantoin as an indirect method to estimate the microbial protein production were used. Although the N intake was 57% lower in LP sheep, the microbial N production was not very different between both diets (NP: 3.99 +/- 0.01 vs. LP: 3.79 +/- 0.02 g/d, P < 0.05). The efficiency of the microbial protein synthesis in the rumen, expressed as grams of microbial N per kg of digestible organic matter apparently digested in the rumen, was not statistically different for both diets. The urinary elimination of urea was reduced by 84% in LP sheep, essentially due to an important decrease in both renal plasma flow (-63%) and glomerular filtration rate (-71%). These haemodynamic changes would also reduce the filtered load and the urinary elimination of allantoin, thereby leading to an underestimation of the amount of microbial protein entering in the duodenum. Since the renal urea spared by the kidneys remains in the blood, it limits the drop ofthe available urea for ruminal recycling consecutive to a low nitrogen diet.     

Iatrogenic brainstem injury during cerebellomedullary cistern puncture

Cerebrospinal fluid collection is fundamental to the investigation of central nervous system disorders although it carries potential risks. Herein we report the clinical signs and magnetic resonance (MR) imaging findings associated with needle injury to the brainstem during cerebellomedullary cistern puncture in four dogs. Three dogs were nonambulatory tetraparetic with cranial nerve deficits and one dog had unexplained left thoracic limb paresis. In MR images, there were conspicuous T2 hyperintensities in the myelencephalon in all dogs. In T2* gradient echo images, the lesions were hypointense in two dogs with multiple cranial nerve deficits, and hyperintense in another dog. One dog was euthanized due to sudden neurologic deterioration 12 days later, one died shortly after MR imaging, and a third was euthanized due to concurrent cervical spondylomyelopathy. The fourth dog recovered gradually. Diagnosis was confirmed histopathologically in one dog and was presumptive based on clinical signs and MR findings in three dogs. None of the dogs with cranial nerve deficits recovered, only the one dog with left thoracic limb paresis and concurrent syringomyelia.     

Long‐term anesthetic protocol in rats: feasibility in electrophysiology studies in visual prosthesis

Electrical stimulation of excitable cells provides therapeutic benefits for a variety of medical conditions, including restoration of partial vision to those blinded via some types of retinal degeneration. To improve visual percepts elicited by the current technology, researchers are conducting acute electrophysiology experiments, mainly in cats. However, the rat can provide a model of a range of retinal diseases and possesses a sufficiently large eye to be used in this field. This article presents a long‐term anesthetic protocol to enable electrophysiology experiments to further the development of visual prostheses. Six Long‐Evans rats (aged between 14 and 16 weeks) were included in this study. Surgical anesthesia was maintained for more than 15 h by combining constant intravenous infusion of ketamine (24.0–34.5 mg/kg/h), xylazine (0.9–1.2 mg/kg/h), and inhaled isoflurane in oxygen (<0.5%). Overall heart rate, respiratory rate, and body temperature remained between 187–233 beats/min, 45–58 breaths/min, and 36–38 °C, respectively. Neural responses to 200‐ms light pulses were recorded from the superior colliculus using a 32‐channel neural probe at the beginning and before termination of the experiment. Robust responses were recorded from distinct functional types of retinal pathways. In addition, a platinum electrode was implanted in the retrobulbar space. The retina was electrically stimulated, and the activation threshold was determined to be 5.24 ± 0.24 μC/cm². This protocol may be used not only in the field of visual prosthesis research, but in other research areas requiring longer term acute experiments.     

Dermatophytosis caused by Trichophyton mentagrophytes in the southern chamois (Rupicapra pyrenaica) in the Eastern Pyrenees

Two free-ranging southern chamois (Rupicapra pyrenaica) - one 4-year-old male and one 3-year-old male - were diagnosed with clinical dermatophytosis in the French and Spanish Eastern Pyrenees respectively. Skin samples were collected for microbiological studies, Trichophyton mentagrophytes being isolated and identified in both animals. The first chamois was found dead at the base of a cliff, and presented with alopecia and scaling on the dorsum and left forelimb. The second chamois showed grey-yellow, rough to raised scaling and crusting skin lesions at the base of the horns, around the eyes, dorsum of the nose, sternum, tail and limbs. Histological examination was carried out only on the second animal. The main lesions were orthokeratotic hyperkeratosis with focal parakeratosis, irregular to papillary epidermal hyperplasia, intracorneal neutrophilic pustules, perivascular to diffuse dermatitis with neutrophilic folliculitis and furunculosis. In those follicles with folliculitis and/or furunculosis, fungal hyphae and arthrospores associated with the follicular keratin and hair shafts were seen.     

Evaluation of embedding strength on Uruguayan wood to apply the European yield theory for double shear bolted joint

The main objective of this study was to evaluate embedding strength on Uruguayan wood to apply the European yield theory (EYT) for double shear bolted joints’ on Eucalyptus grandis H.(EGH). To introduce the dowel-type connection performance, double shear tests were conducted. The embedding tests were conducted to calculate the yield strength of bolted joint by EYT and the compression test, to estimate the embedding strength. The yield strength obtained from the experiments showed a good agreement with the yield strength calculated by EYT method. The yield strength of double shear bolted joint evaluated from compressive strengths is a very close to the yield strength calculated by EYT. The average value and variability of the yield strength of double shear bolted joint calculated by EYT applying the embedding strengths of experimental results were very close to the yield strength or 5 % offset method of experimental results. The results from this study showed a good behavior to structural design with EGH in accordance to the Japanese standard code.     

Intestinal microbiota variation in Senegalese sole (Solea senegalensis) under different feeding regimes

The aim of this study was to determine the influence of the feeding regimes in Senegalese sole (Solea senegalensis) cultured under extensive, semi‐extensive and intensive production systems. A total of 254 bacterial isolates from guts of fish cultured under different production systems and feeding regimes were tested. Biochemical tests and genetic analyses based on the 16S rDNA sequence analysis were conduced to identify bacterial strains. Vibrio species were the most represented taxonomic group in the culturable microbiota of S. senegalensis guts tested. Particularly, Vibrio ichthyoenteri was the most frequently isolated Vibrio species. Comparison among diets showed a significant reduction (P<0.05) in vibrio percentages and a higher occurrence of Shewanella species in Senegalese soles fed polychaeta. In addition, a major influence of environmental temperature on microbiota composition was detected. Cold temperatures brought about a change in the percentages of Vibrio species and a higher representation of α‐Proteobacteria in both outdoor systems (extensive and semi‐extensive). The significant differences between intestinal bacterial composition in Senegalese soles fed commercial diets and natural preys (polychaeta) reveal the necessity to develop specific optimized diets for the intensive rearing of this fish species.     

Río de la Plata voyagers: Deciphering the migration ecology of a vulnerable marine catfish (Genidens barbus) in a large subtropical river (lower Uruguay River)

1. Genidens barbus is a vulnerable marine migrant catfish with low fecundity, a complex life cycle (i.e. mouth breeding), and is the target of industrial and artisanal fisheries of several countries. This species regularly migrates from marine to freshwater environments of the south-western Atlantic.
2. The aim of this work was to delve deeper into the migration ecology of G. barbus, characterizing both its timing and potential environmental drivers. Furthermore, aspects of the population structure and reproduction of migrants in the lower Uruguay River were studied and the presence of juveniles in the adjacent estuarine recruitment area was evaluated.
3. Data from 11 years (2008–2018) of records of adult G. barbus captured by artisanal fisheries were used alongside relevant environmental variables that were recorded monthly. Reproductive biology (i.e. sex ratio, gonadosomatic index, fecundity, and oocyte size) was analysed for a period of 3 years (2016–2018). The juvenile abundance in the Río de la Plata estuary was evaluated seasonally.
4. A total of 935 adult individuals of G. barbus were captured, representing a total biomass of 3,123 kg. The migration timing was from early spring to early summer. The abundance of migrants strongly increased with river discharge, suggesting that this variable regulates the upriver migration. Furthermore, pre- and post-spawn females and males displaying mouth breeding were recorded during the study period, confirming G. barbus reproduction in the lower Uruguay River.
5. The results obtained suggest that G. barbus ascend to spawn in the freshwater environments upstream from the mouth of the Uruguay River. Then, adult males incubate and carry the embryos downstream, releasing juveniles in the Río de la Plata estuary.
6. This relevant information will help with the implementation of effective management polices (e.g. fishing restrictions during the reproductive period) for the presently unregulated fishery of this vulnerable species in the lower Uruguay River.

     

Short communication: Estrus synchronization using progestogens or cloprostenol in tropical hair sheep

The objective of the experiment was to compare the use of a PGF2α analogue (Cloprostenol) IM, with an intravaginal progestagen sponge, flurogestone acetate (FGA), and equine chorionic gonadotropin (eCG) IM application protocol. A total of 30 cyclical hair ewes (54.07?±?0.5 kg live weight, body condition score 3.5?±?0.5, and age 3?±?1 years) were used. For the control group ewes (n?=?15), intravaginal sponges (IS) impregnated with 20 mg of FGA were inserted for 12 days with 500 IU of eCG IM at sponges withdrawal. For the PG group ewes (Treatment group n?=?15), two injections of Cloprostenol (75 mcg) were given 12 days apart. The presence of estrus was detected using two rams with 8 h interval beginning at the end of the treatment. Progesterone concentrations in blood were measured by solid phase radioimmunoassay. A student’s t test was performed to analyze the duration of estrus and the interval between the ends of the treatment and the onset of estrus (ET-OE) presentation. Progesterone levels were compared with two-way ANOVA, with treatment, and day of menstrual cycle as fixed factors. Treatment costs ratio was calculated by dividing the total costs of FGA IS application between total costs of Cloprostenol application. Significant differences (P?P?相似文献   

Morphological variation and domestication of Escontria chiotilla (Cactaceae) under silvicultural management in the Tehuacán Valley, Central Mexico

People of the Tehuacán Valley, Central Mexico utilise the columnar cactus Escontria chiotilla for their edible fruits, gathering them in the wild and in silviculturally managed populations. Silvicultural management consists in sparing and enhancing selectively, in disturbed areas, individual trees producing fruits of the better quality for consumption and commercialisation. Fruits of trees in silviculturally managed populations are generally larger (27.23 ± 0.39 cm) and heavier (11.10 ± 0.44 g), with a higher amount of pulp (4.84 ± 0.27 g), and more (532.72 ± 15.60) and heavier (0.78 ± 0.013 mg) seeds than in wild non-manipulated populations (22.62 ± 0.31 cm, 6.44 ± 0.22 g, 2.33 ± 0.11 g, 407.63 ± 20.67, and 0.62 ± 0.015 mg, respectively). Phenotypes of trees producing better fruits were significantly more abundant in manipulated populations than in the non-manipulated ones. Artificial selection appears to be the cause of such differences among populations and, therefore, domestication process of this plant species is seemingly occurring under silvicultural management.