Effects of vitrification techniques on the formation of skin cryobank of the ocelot (Leopardus pardalis).

BACKGROUND: Skin cryobanks represent important tools for the conservation of the maximum genetic representation of a population, especially those with a certain degree of threat to extinction, such as the ocelot. A relevant step towards the proper establishment of these banks is the definition of adequate cryopreservation techniques for the conservation of the skin. OBJECTIVE: We evaluated the effects of two different techniques [direct vitrification in cryovials (DVC) and solid-surface vitrification (SSV)] for the preservation of ear skin derived from ocelot. MATERIALS & METHODS: For both techniques, we vitrified the ear skin using Dulbeccos modified Eagles medium with 3.0 M dimethyl sulfoxide, 0.25 M sucrose, and 10% fetal bovine serum. Non-cryopreserved tissues were used as control (control group). All tissues were analyzed for their morphometric characteristics by conventional histology and morphological / functional analysis by cell ability during the culture. RESULTS: While tissues cryopreserved by DVC showed similar values for dermis thickness and number of perinuclear halos to the control, tissues cryopreserved by SSV showed similarities to the control regarding the number of melanocytes, percentage of collagen fibers, and numbers of viable cells by apoptosis analysis. Additionally, none of the vitrification techniques affected stratum corneum thickness, number of keratinocytes, tissue proliferative activity, cell viability, or metabolism. CONCLUSION: Both vitrification techniques (DVC and SSV) can be used for the conservation of ocelot skin; however, SSV guarantees a higher cellular quality after in vitro tissue culture in most of the parameters evaluated, such as viability, metabolism, and apoptosis analysis. doi.org/10.54680/fr23110110412.

The accessory heads of the muscles flexor pollicis longus and flexor digitorum profundus (Gantzer muscle) - An anatomical study in Brazilian cadavers.

An important accessory anatomical variation, exclusively human, and related to the muscular ventres of the flexor pollicis longus and flexor digitorum profundus is frequently denominated Gantzer. These variations have close relations with the anterior interosseous nerve (AIN), which provides, for many authors, by direct compression, one of the rare neuropathic syndromes. In this work, thirty-four forearms were dissected from the collections of the Medical School of the Federal University of Minas Gerais and the Department of Basic Sciences of the Federal University of Juiz de Fora, with a prevalence of 50% of the 34 forearms studied for the Gantzer muscle. The muscle relationship was mainly with the flexor pollicis longus muscle and only one occurrence related to the flexor digitorum profundus muscle, described as a rare occurrence of unilateral double formation of Gantzer muscle. Bilaterality was observed in 88.23% of the findings and the dominant innervation for this muscle variation occurred in 82.35% by the anterior interosseous nerve (AIN). The type morphological in all forms found was the fusiform, with 10.5cm of total length and an average of 0.3cm in diameter and all related, as origin, in the medial aspect of the coronoid process of the ulna, next to the origin of the flexor digitorum superficialis muscle. Our work largely reflected the findings of most publications and, considering the controversy of the occurrence of a compressive neuropathy, the data were not sufficient, from a strictly anatomical point of view, to confirm or refute the hypothesis.

Steroidogenesis during prenatal testicular development in Spix's cavy Galea spixii.

Spix's cavy is a potentially good experimental model for research on reproductive biology and sexual development. The aim of the present study was to evaluate the ontogeny of the steroidogenic enzymes involved in testicular androgen synthesis during prenatal development. Testes were investigated on Days 25, 30, 40 and >50 of gestation. Immunohistochemistry and immunoblotting were used to establish the site and relative amount of androgenic enzymes, including 5α-reductase, cytosolic 17ß-hydroxysteroid dehydrogenase (17ß-HSDI) and mitochondrial microsomal 3ß-hydroxysteroid dehydrogenase (3ß-HSDII), throughout prenatal development. The testicular parenchyma began to organise on Day 25 of gestation, with the development of recognisable testicular cords. The mesonephros was established after Day 25 of gestation and the ducts differentiated to form the epididymis, as testicular cords were beginning to proliferate and the interstitium to organise by Day 30 of gestation, continuing thereafter. The androgen-synthesising enzymes 5α-reductase, 17ß-HSDI and 3ß-HSDII were evident in Leydig cells as they differentiated at all subsequent gestational ages studied. In addition, immunoblotting showed an increase in immunoreactivity for the enzymes at Days 30 and 40 of gestation (P<0.05) and a decrease at Day 50 of gestation (P<0.05). It is concluded that the increase in androgenic enzymes in Leydig cells coincides with the functional differentiation of the testes, and with the stabilisation and differentiation of mesonephric ducts forming the epididymis.

Evaluation of different cryoprotectant solutions for the cryopreservation of somatic tissues of Dasyprocta leporina (Linnaeus, 1758).

BACKGROUND: Somatic tissue banks represent important tools for the conservation of wild mammals, aiming at the immediate maintenance and safeguarding of biological samples. For agouti, Dasyprocta leporina, studies on the formation of these banks are still scarce, especially regarding protocols of the best cryoprotectant solution employed. OBJECTIVE: To optimize the cryoprotectant solution [ethylene glycol (EG), dimethyl sulfoxide (DMSO), sucrose (SUC)] used for the cryopreservation of agouti somatic tissues. MATERIALS AND METHODS: We treated ear tissues with various cryoprotectant solutions: 3.0 M EG (EG group), 3.0 M EG and 0.25 M SUC (EG-SUC group), 3.0 M DMSO (DMSO group), 3.0 M DMSO and 0.25 M SUC (DMSO-SUC group), 1.5 M EG and 1.5 M DMSO (EG-DMSO group) and 1.5 M EG, 1.5 M DMSO and 0.25 M SUC (EG-DMSO-SUC group). Non-cryopreserved tissues were used as controls. All tissues were analyzed for their ultrastructural and morphometric characteristics by scanning electron microscopy and conventional histology. RESULTS: EG-DMSO-SUC was found to be the optimal cryoprotectant solution in terms of the evaluated parameters, such as thickness of the dermis and skin, number of perinuclear halos, proliferative potential, number of empty lacunas and degenerated chondrocytes. CONCLUSION: Agouti somatic tissue cryopreservation may serve for its conservation and as an experimental model for the development of preservation methods for species of the same genus that are either vulnerable or critically endangered.

Performance and Meat Quality of Broiler Chickens Reared on two Different Litter Materials and at two Stocking Densities.

1. This study evaluated the performance and meat quality of broiler chickens reared on two litter materials and at two stocking densities.2. The chicks were allotted in a completely randomised design in a 2 × 2 factorial arrangement with two litter materials (wood shavings or rice straw) and two stocking densities (24 or 30 kg/m2), with six replicates per treatment. Broiler performance, carcase yield, prime cuts, blood plasma proteins, the enzymes alanine aminotransferase and aspartate aminotransferase, edible viscera, immune organs, intestine weight and length, abdominal fat, breast meat colour, pH, weight loss by defrosting, weight loss by cooking and shear force were evaluated.3. The density of 24 kg/m2 positively influenced feed consumption and weight gain. The type of litter had a positive influence on feed conversion, with a lower value for birds raised on wood shavings.4. Breast production was improved in birds reared at a density of 24 kg/m2 when compared to birds reared at a density of 30 kg/m2. The rice straw bedding negatively affected abdominal fat (resulting in higher percentages) when compared to birds reared on wood shavings.5. The types of litter affected the enzyme aspartate aminotransferase in birds raised on wood shavings, although these values were not increased to the point of influence on the physiological functions of broilers.6. The colour of the breast meat, pH, temperature, weight loss after thawing or cooking, shear force, cholesterol, triglycerides, albumin, total proteins, glucose or alanine aminotransferase content were not influenced by the stocking densities or bedding.7. The use of wood shavings as poultry bedding at a stocking density of 24 kg/m2resulted in the best performance for broiler chickens at 42 days of age.

Composition of semen and foreskin mucosa aerobic microbiota and its impact on sperm parameters of captive collared peccaries (Pecari tajacu).

AIM: To evaluate the bacterial composition of collared peccary semen and foreskin mucosa, and to verify the sensitivity of isolates to antimicrobials used in semen conservation and to Aloe vera gel, which is an alternative external cryoprotectant. METHODS AND RESULTS: Nine foreskin mucosa and ejaculate samples from adult animals were used. Sperm characteristics and bacterial load were evaluated in fresh semen. The preputial mucosa and semen bacterial isolates were identified and tested against five concentrations of each antimicrobial (streptomycin-penicillin and gentamicin) and A. vera gel. Corynebacterium sp. and Staphylococcus sp. were isolated in greater numbers than others in both semen (64·10 and 20·51%, respectively) and the foreskin mucosa (60·60 and 24·25%, respectively), and ranged from 0·4 to 21 × 105 colony-forming units (CFU) per ml. The average load of Corynebacterium sp. was negatively correlated (P < 0·05) with the sperm membrane integrity (r = -0·73055) and curvilinear velocity (r = -0·69048). Streptomycin-penicillin and gentamicin inhibited most micro-organisms, and A. vera showed lower antimicrobial activity. CONCLUSION: Several Gram-positive bacteria are present in semen and foreskin mucosa of collared peccary, and the benefits of using primarily penicillin-streptomycin and gentamicin antimicrobials in the bacterial control of diluted semen of these animals are strongly indicated. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides insight into the reproductive microbiota of captive male-collared peccary. This work provides a theoretical basis to assist reproductive biotechnologies for ex situ conservation of the species.

Dual-task effects on postural sway during sit-to-stand movement in children with Down syndrome.

BACKGROUND: Cognitive and postural tasks require common cognitive mechanisms, resulting in conflicts when both tasks are simultaneously performed. The presence of neuromotor dysfunctions, such as Down syndrome, may impair coordination processes required to perform dual-tasks. The objective of this study was to investigate the dual-task effects on postural sway during sit-to-stand movements in typical children and children with Down syndrome in a cross-sectional study. METHODS: Twenty six typical children (10.2 ± 2.4 years) and 21 with Down syndrome (10.3 ± 2.3 years) performed sit-to-stand in the following conditions: (1) simple task; (2) dual-task bimanual activity (DT-Bim): sit-to-stand while carrying a tray using both hands; (3) dual-task unimanual dominant activity (DT-Uni-Dom): sit-to-stand while holding a plastic cup simulating water using the dominant hand; (4) dual-task unimanual non-dominant activity (DT-Uni-Nondom): sit-to-stand movement while holding a plastic cup simulating water. For data analysis, sit-to-stand was divided into three phases: preparation (phase 1), rising (phase 2), and stabilisation (phase 3). The following variables were calculated for each phase: anterior-posterior and medial-lateral amplitude of centre-of-pressure displacement, anterior-posterior and medial-lateral velocity of centre-of-pressure sway and area of centre-of-pressure sway. RESULTS: Children with Down syndrome showed greater sway than typical children in all sit-to-stand phases. Typical children showed greater anterior-posterior amplitude in phase 2 of sit-to-stand during DT-Uni Nondom compared with DT-Uni Dom. Children with Down syndrome during simple task condition showed greater and faster values sway in phases 2 and 3 of sit-to-stand movement than in DT-Bim activity, DT-Uni Dom activity and DT-Uni Nondom activity. During the condition of DT-Bim activity, these children showed lower anterior-posterior velocity of sway in phase 2 than during DT-Uni Dom activity. CONCLUSIONS: Children with Down syndrome showed greater postural sway during sit-to-stand than typical children. The addition of a concurrent motor task to sit-to-stand impacted postural sway in different intensities and in different ways across groups. Dual-tasks increased body sway in typical children in the DT-Uni Nondom condition compared with dominant one. In children with Down syndrome, dual-tasks decreased body sway, apparently resulting in a postural strategy of stiffness.

Steroidogenesis during postnatal testicular development of Galea spixii.

The androgen/estrogen balance is essential for normal sexual development and reproduction in mammals. Studies performed herein investigated the potential for estrogen synthesis in cells of the testes of a hystricomorph rodent, Galea spixii The study characterized the expression of the key enzymes responsible for estrogen and androgen synthesis, cytochromes P450 aromatase (P450arom), 17α-hydroxylase/17,20-lyase (P450c17) respectively, as well as the redox partner NADPH cytochrome P450 oxido-reductase (CPR) required to support electron transfer and catalysis of these P450s, by immunohistochemistry (IHC) and quantitative polymerase chain reaction (qPCR) analysis, throughout postnatal sexual development. Testes (immature, pre-pubertal, pubertal and post-pubertal) were collected, fixed for IHC (CYP19, CYP17 and CPR) and stored frozen for qPCR for the relevant gene transcripts (Cyp19a1 and Cyp17a1). Expression of P450c17 was significantly elevated at the pre-pubertal and pubertal stages. Based on IHC, P450c17 was expressed only in Leydig cell clusters. The expression of P450arom was detectable at all stages of sexual development of Galea spixii IHC data suggest that estrogen synthesis was not restricted to somatic cells (Leydig cells/Sertoli cells), but that germ cells may also be capable of converting androgens into estrogens, important for testicular function and spermatogenesis.

Crystalline phases found in rapidly quenched Ni-Nb-Zr alloys.

The properties of metallic alloys can be significantly improved by developing non-equilibrium phases in the microstructures through rapid solidification techniques, thus the characterisation of these unusual structures is extremely important. In this research, the microstructures of three rapidly quenched alloys, namely Ni65.2 Nb33.8 Zr1.0 , Ni54.8 Nb31.1 Zr14.1 and Ni54.8 Nb21.6 Zr23.6 (at. %) were investigated in greater detail in order to determine the structures and compositions of their crystalline phases. These crystalline phases were characterised using a combination of scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction and transmission electron microscopy techniques. The phases were compared to the crystalline structures reported in the literature. Our results indicate some agreement with the Ni-Nb phase diagram and an isothermal section of the Ni-Nb-Zr phase diagram; however, it is detected zirconium solubility in the Ni3 Nb phase, as well as, the absence of expected crystalline phases.

Ultrastructure of spermatogenesis and spermatozoa in agoutis during sexual development.

The aim was to study the ultrastructure of testicular parenchyma and define the morphological ultrastructure of spermatozoa of agoutis kept in captivity. Segments of testes from eight agouti males at prepubescence, prepuberty, pubescence and sexual maturity were fixed in glutaraldehyde. Laboratory procedures were performed for transmission electron microscopy. Spermatogonial cells of Type A - pale, Type A - dark, intermediate and Type B were found. Spermatocytes in the pachytene phase were abundant among primary spermatocytes. From the prepubertal phase, Sertoli cells exhibited invaginations in the nuclear membrane and lipid inclusions in the cytoplasm due to their phagocytic function. Leydig cells displayed higher metabolic activity during puberty as evidenced by the presence of lipid droplets. Spermatozoa were fully formed morphologically at prepuberty. The centriolar complex had partially degenerated and featured a centriolar space as in rodents. Sperm heads were tapered, without prominence of the acrosome or evidence of the perforatorium, differing from cavies, rats and mice. This is the first study to describe the ultrastructure of agouti spermatozoa. This research may assist as a basis for future work related to fertility and other biotechnologies applied to reproductive biology in agoutis.

Short-term low-intensity blood flow restricted interval training improves both aerobic fitness and muscle strength.

The present study aimed to analyze and compare the effects of four different interval-training protocols on aerobic fitness and muscle strength. Thirty-seven subjects (23.8 ± 4 years; 171.7 ± 9.5 cm; 70 ± 11 kg) were assigned to one of four groups: low-intensity interval training with (BFR, n = 10) or without (LOW, n = 7) blood flow restriction, high-intensity interval training (HIT, n = 10), and combined HIT and BFR (BFR + HIT, n = 10, every session performed 50% as BFR and 50% as HIT). Before and after 4 weeks training (3 days a week), the maximal oxygen uptake (VO2max ), maximal power output (Pmax ), onset blood lactate accumulation (OBLA), and muscle strength were measured for all subjects. All training groups were able to improve OBLA (BFR, 16%; HIT, 25%; HIT + BFR, 22%; LOW, 6%), with no difference between groups. However, VO2max and Pmax improved only for BFR (6%, 12%), HIT (9%, 15%) and HIT + BFR (6%, 11%), with no difference between groups. Muscle strength gains were only observed after BFR training (11%). This study demonstrates the advantage of short-term low-intensity interval BFR training as the single mode of training able to simultaneously improve aerobic fitness and muscular strength.

Osteopontin, CCL5 and CXCL9 are independently associated with psoriasis, regardless of the presence of obesity.

Psoriasis is an autoimmune disease associated with the production of pro-inflammatory cytokines. The identification of these molecules in the pathogenesis of psoriasis facilitated the use of monoclonal antibodies to block their actions as a treatment for severe psoriasis. An increased inflammatory response has been documented in patients with obesity, a condition that is associated with the occurrence and severity of psoriasis. Osteopontin (OPN), TNF and CXCL9 levels are enhanced in patients with psoriasis, although OPN has been documented in the adipose tissue of obese patients without psoriasis. The prevalence of obesity is much higher in psoriasis patients compared with the general population. Thus, we aimed to evaluate the relationship between cytokine levels and psoriasis in the context of obesity. We compared OPN and CXCL9 plasma levels among 117 psoriasis patients and 27 healthy body mass index-matched subjects using ELISA. We also analyzed the TNF, CCL2 and CCL5 levels in a smaller subgroup of patients and matched controls. Median OPN, CCL5 and CXCL9 levels were significantly higher in psoriasis patients compared with the controls, independent of obesity. There was no difference between the median CCL2 levels in the psoriasis patients and the controls (P<0.05), although the CCL2 levels were elevated in obese patients compared with non-obese psoriasis patients (P<0.001). Facial involvement and the psoriasis area severity index (PASI) score were not associated (P<0.05) with OPN levels or elevated levels of chemokines. There was no significant correlation between the OPN and CXCL9 levels or the OPN and TNF levels in psoriasis patients. This work confirms that OPN, CCL5 and CXCL9 plasma levels are higher in psoriasis patients and provides evidence that their higher levels are not a consequence of obesity. Furthermore, the results demonstrate that OPN production is independent of TNF-α and CXCL9.

Interactions Among Different Devices and Electrical Stimulus on the Electroejaculation of Captive Agoutis (Dasyprocta leporina).

The interactions among different electroejaculation devices associated with serial or continuous stimuli were investigated to improve the efficiency of the electroejaculation for semen collection in agoutis. Ten sexually matured male Dasyprocta leporina were restrained by the intramuscular administration of xylazine-ketamine association. Each individual was randomly subjected to four electroejaculation protocols, by combining two devices (one presenting longitudinal electrodes emitting square waves and other presenting ring electrodes emitting sine waves) and two electrical stimuli protocols (serial or continuous). A total of 40 attempts for electroejaculation were conducted in agoutis, being 10 per treatment. The most efficient treatment in providing ejaculates containing sperm (p < 0.05) was that using and electroejaculator connected to a probe with ring electrodes and associated with serial stimuli (4/7; 57%). In spite of semen parameters obtained by sine waves were adequate for using the samples for assisted reproduction, higher values for sperm motility and functional membrane integrity were obtained in the use of the square wave, independently of the electric stimulation protocol used (p < 0.05). In conclusion, we verified that the use of a device presenting a probe with ring electrodes and emitting sine waves, associated with a serial stimuli protocol, improves the efficiency for semen obtaining by electroejaculation in adults D. leporina.

Morphometry, Morphology and Ultrastructure of Ring-tailed Coati Sperm (Nasua nasua Linnaeus, 1766).

The ring-tailed coati (Nasua nasua) is a procyonid whose population is in sharp decline. Therefore, studies are needed to better understand the reproduction of this animal. For this reason, this study aimed to evaluate the morphology, morphometry and sperm ultrastructure of ring-tailed coati sperm. Four captive adult males were used for this study. Slides stained with Bengal Rose were used for the morphometric and morphologic analyses. The length and width of the head were measured, as well as the length of the midpiece and tail and the total length of the sperm. Scanning electron microscopy and transmission electron microscopy were used for the ultrastructural analyses. The most obvious morphological abnormalities observed were coiled tails (6.1 ± 8.7%) and the lack of acrosomes (5.4 ± 4.4%). Regarding the morphometry, the measurements of the head (length × width), midpiece (length) and tail (length) were (mean ± SD) 6.2 ± 0.4 × 8.1 ± 0.6 µm, 14.1 ± 0.5 and 63.9 ± 4.1 µm, respectively, and the total length of the sperm was 86.1 ± 4.3 µm. Through electron microscopy, the presence of electron-lucent points in the nucleus and the presence of approximately 55 mitochondrial spirals in the midpiece were identified. The data obtained in this study provide detailed information on the sperm characteristics of coatis and may inform future research on germplasm conservation, both for this species and other threatened procyonids.

Ultrastructure of spermatogenesis in Spix's yellow-toothed cavy (Galea spixii).

This was a pioneer study of the spermatogenic process from the onset of puberty in Spix's yellow-toothed cavies (SYC, Galea spixii) bred in captivity. The study aimed to characterize fine structure of spermatogenesis. Twelve testes from pubertal and post-pubertal SYC males were studied using transmission electron microscopy. Spermatogenesis can be divided into three phases: proliferation, meiosis, and spermiogenesis. In proliferation phase, three types of spermatogonia were identified and characterized as A(dark), A(pale), and B. In the second phase, spermatocytes (2n) undergo meiotic divisions that generate spermatids (n); the process begins in spermatocytes in the preleptotene stage when they increase their nuclear size, differentiating into spermatocytes in the leptotene stage when cell division is initiated. In addition, we found chromatin condensation, and formation of a structure composed of proteins that formed a central shaft and two lateral bars associated with pairing of homologous chromosomes. During spermiogenesis, the following main events occurred: condensation of nuclear chromatin, formation of acrosome with perfuratorium, elimination of residual cytoplasm, and development of the flagellum. The sperm head is different from that of other rodents. The endoplasmic reticulum and the Golgi complex are the two main organelles demonstrated during this process. These organelles collaborate through synthesis of proteins and hormones for the development of germ cells during spermatogenesis in SYC.

Protein profile of the seminal plasma of collared peccaries (Pecari tajacu Linnaeus, 1758).

This study was conducted to characterize the major proteins of the peccary seminal plasma, based on the semen samples collected from nine adult and reproductively sound animals. Our approach included the use of two-dimensional electrophoresis followed by Coomassie blue staining and analysis of polypeptide maps with PDQuest Software (Bio-Rad). Proteins were identified by tandem mass spectrometry (LC-MS/MS). We detected 179 protein spots per gel and 98 spots were identified by mass spectrometry, corresponding to 23 different proteins. The combined intensity of those spots accounted for 56.2±6% of the intensities of all spots and 60.9% of the intensities of spots presented in every protein map. Protein spots identified as clusterin represented 19.7±8.3% of the integrated optical densities of all spots detected in the seminal plasma maps. There was a negative association (r=-0.87; P<0.05) between the intensity of a clusterin spot and the percentage of sperm with functional membrane. Spermadhesin porcine seminal plasma protein 1 and bodhesin 2 comprised 5.4±1.9 and 8.8±3.9% of the total intensity of all spots respectively. Many proteins appeared in a polymorphic pattern, such as clusterin (27 spots), epididymal secretory glutathione peroxidase (ten spots), inter-α-trypsin inhibitor (12 spots), and IgG-binding protein (ten spots), among others. In conclusion, we presently describe the major seminal plasma proteome of the peccary, which exhibits a distinct high expression of clusterin isoforms. Knowledge of wild species reproductive biology is crucial for an understanding of their survival strategies and adaptation in a changing environment.

Reproductive biology of Donax striatus (Linnaeus, 1758) (Mollusca: Bivalvia) on Gado Bravo Beach, municipality of Tibau do Norte, state of Rio Grande do Norte, Brazil.

Aspects of the reproductive biology of Donax striatus were studied from individuals collected from Gado Bravo Beach in the municipality of Tibau do Norte, state of Rio Grande do Norte, Brazil. Donax striatus is a dioic species without external (on the shell) or internal (gonads) macroscopic dimorphism. Thus, a microscopic examination of the reproductive cells is necessary. For the characterization of the gonadal development stages and determination of the size at first sexual maturity (L50), 30 specimens were selected monthly between February 2021 and January 2022 and submitted to histological processing. The condition index (CI) of each individual was estimated and monthly variations were statistically assessed. The size at first maturity (L50) was estimated to be 14.2 mm in shell length. To foster conservation of the species, catches of individuals larger than 14.2 mm is recommended. The lowest condition indices were found in the dry season, with a greater occurrence of organisms in the elimination stage and exhibiting gonad tissue reorganization. Higher indices were found in the rainy season, with the presence of mature individuals. The continuous nature of gametogenesis in Donax stritatus reflects the influence of rainfall in the region. Males and females have peak gamete elimination with pauses during the year, but with the presence of maturing and eliminating individuals throughout the year. As shellfish gathering targeting Donax striatus is excessive on Gado Bravo Beach in the state of Rio Grande do Norte, it is hoped that the results of the present study can contribute to the establishment of management measures for the activity and conservation strategies for the species.

Cryopreservation of collared peccary (Pecari tajacu) semen using different freezing curves, straw sizes, and thawing rates.

The objective of this study was to verify the effect of different freezing curves, straw sizes, and thawing rates on the cryopreservation of collared peccary semen. Twelve ejaculates were obtained from captive adult males by electroejaculation, and evaluated for sperm motility, kinetic rating, viability, morphology, and functional membrane integrity. The ejaculates were diluted in a coconut water extender (ACP-116c) with egg yolk and glycerol, packaged into 0.25 mL or 0.50 mL plastic straws and cryopreserved in liquid nitrogen following a slow (-10 °C/min) or a fast (-40 °C/min) freezing curve. After one week, samples were thawed at 37 °C/1 min or 70 °C/8s and evaluated as reported for fresh semen, and also for kinematic parameters (computerized analysis). A significant decrease in sperm motility and kinetic rating was observed after glycerol addition at 5 °C and also after thawing for all the treatments (P<0.05). Regarding post-thaw semen variables, no differences were verified between freezing curves when the same straw size and thawing rate were taken as reference (P>0.05). In general, values for sperm characteristics found after thawing at 37 °C were better preserved than at 70 °C (P<0.05), both in the use of 0.25 mL or 0.50 mL straws, which were similar for semen packaging (P>0.05). The evaluation of the kinematic parameters of sperm motility confirmed these results at values varying from 20% to 30% motile sperm for the samples tha wed at 37 °C, and values fewer than 12% motile sperm for samples thawed at 70 °C (P<0.05). In conclusion, we recommend the use of a fast freezing curve that reduces the time spent on the cryopreservation of collared peccary semen, which could be packaged both in 0.25 mL or 0.50 mL straws, but the thawing should be conducted at 37 °C/1 min.

Development of spermatogenesis in captive-bred Spix's yellow-toothed cavy (Galea spixii).

The aim of this study was to evaluate the phases of sexual development and spermatogenesis of Spix's yellow-toothed cavy (Galea spixii) based on analyses of the structural components of the testes. The testes of animals from 0 to 150 days of age were collected by orchiectomy, weighed, and processed for analysis by light microscopy. At 45 days of age, spermatozoa were seen in the tubular lumen. Spermatogenesis was not established in animals from 45 to 150 days of age. The stages of sexual development may be classified into the following phases: from birth to the age of 15 days (immature); 30 days of age (prepubertal); 45-105 days of age (pubertal); and 120 and 150 days of age (postpubertal). This is the first study to address the male reproductive biology of Spix's yellow-toothed cavy.

Stroking parameters during continuous and intermittent exercise in regional-level competitive swimmers.

This study aimed to determine whether maximal lactate steady state (MLSS) represents a boundary above which not only physiological but also technical changes occur. On different days, 13 male swimmers (23 ± 9 years) performed the following tests: 1) a 400-m all-out swim, to determine maximal aerobic speed (S-400); 2) a series of 30-min sub-maximal swims, to determine continuous MLSS (MLSSc), and; 3) a series of 12×150 s sub-maximal swims, to determine intermittent MLSS (MLSSi). Stroke rate (SR), distance per stroke cycle (DS) and stroke index (SI) were analyzed at and above (102.5%) MLSSc and MLSSi. MLSSi (1.17 ± 0.09 m.s (- 1)) was significantly higher than MLSSc (1.13 ± 0.08 m.s (- 1)) while blood lactate concentration (mmol.L (- 1)) was similar between the 2 conditions (4.3 ± 1.1 and 4.4 ± 1.5, respectively). The increase in SR and decreases in DS and SI were significant during MLSSi, 102.5% MLSSc and 102.5% MLSSi. During MLSSc, DS also decreased significantly (- 3.6%) but with no change in SR or SI. Thus, stroking technique of regional-level competitive swimmers changes over time when they swim at or above MLSS. This is the case during both continuous and intermittent swimming, despite steady state blood lactate concentrations.