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PubMed1993

Topographic patterns of brain activity in response to swim stress: assessment by 2-deoxyglucose uptake and expression of Fos-like immunoreactivity.

Alterations in brain activity patterns were assessed in response to swim stress by immunocytochemical detection of Fos-like immunoreactivity (Fos-LI) and high-resolution autoradiographic imaging of 14C-2-deoxyglucose (2-DG) uptake. The stress paradigm investigated was a classic behavioral screen for antidepressant drug activity, the forced swim test. One of the most pronounced effects produced by swim stress was an increase in 2-DG uptake and induction of Fos-LI in a restricted region of the lateral septal nucleus. Specific "limbic" cortical regions, including the medial prefrontal, ventrolateral orbital, and cingulate cortices, also exhibited both increased 2-DG uptake and expression of Fos-LI in response to swim stress. In the hypothalamic paraventricular nucleus of swim-stressed rats, Fos-LI was induced but no change in 2-DG uptake was apparent. Since the specific swim stress protocol used is a behavioral screen for antidepressant drugs, the effects of imipramine on stress-induced alterations in 2-DG uptake and induction of Fos-LI were examined. The stress-induced increase in 2-DG uptake in the lateral septum was blocked by treatment with imipramine, but treatment with imipramine had no effect on induction of Fos-LI in the same region. Neither 2-DG uptake nor Fos-LI expression was altered by imipramine treatment in the cortical regions influenced by swim stress. Administration of imipramine alone under basal conditions produced a robust induction of Fos-LI in the central nucleus of the amygdala and in the dorsal lateral subdivision of the bed nucleus of the stria terminalis. No effect of imipramine treatment on 2-DG uptake was apparent in these latter regions. The results provide insights into topographic patterns of brain activity associated with swim stress and neuroanatomically selective actions of imipramine. The different and complementary information obtained by assessment of Fos-LI and 2-DG uptake illustrates the utility of applying both functional mapping approaches to examine neuroanatomical correlates of behavioral states and drug treatment.

Amygdala↗
PubMedDate not supplied

Quantification of bovine sperm separation by a swim-up method. Relationship to sperm motility, integrity of acrosomes, sperm migration in polyacrylamide gel and fertility.

The number of bovine spermatozoa separated in a swim-up procedure was quantified using an electronic cell counter. In an initial test of the swim-up procedure, non-frozen sperm samples with different ratios of live to dead cells were prepared and tested for the number of spermatozoa counted by the swim-up procedure. In ejaculates from six bulls, the number of spermatozoa swimming up was related to the number of live cells present (R2 = 0.97). Next, sperm quality of frozen-thawed semen immediately after thawing was measured at 37 C by swim-up sperm count, sperm motility, spermatozoa with an intact acrosome and migration in polyacrylamide gel and then compared with the fertility of the semen used for artificial insemination. Twenty-nine ejaculates of frozen-thawed semen from 11 bulls were evaluated. Correlations with fertility were highest on an ejaculate basis for motility (r = 0.41, P = 0.05) and for swim-up sperm count (r = 0.35, P = 0.06). On a bull basis, swim-up sperm count had the highest correlation with fertility (r = 0.59, P = 0.06). In a multiple regression model to predict male fertility that included all described measures of semen quality, a R2 value of 0.69 was obtained. This is the first report showing that the ability of spermatozoa to swim out of a more dense medium (whole milk-glycerol extender) into culture media is quantitatively related to in vivo fertility.

Acrosome↗
PubMed1998

Antidepressant behavioral effects by dual inhibition of monoamine reuptake in the rat forced swimming test.

Because of clinical interest in the effects of antidepressant drugs that exert their effects on multiple neurotransmitter systems, the behavioral effects produced by combined treatment with an SSRI (fluoxetine) with a selective norepinephrine (NE; desipramine) or dopamine (DA) reuptake inhibitor (buproprion) were examined in the forced swimming test (FST), a behavioral test in rodents that predicts the clinical activity of antidepressants. Three additional compounds with mixed activity as NE-5-HT reuptake inhibitors, milnacipran, duloxetine and venlafaxine, were also examined. Desipramine and fluoxetine both reduced immobility in the FST, but desipramine increased only climbing behavior, whereas fluoxetine increased only swimming behavior. The combination of fluoxetine with desipramine or bupropion increased both climbing and swimming behaviors at certain doses, but higher doses of desipramine when combined with fluoxetine replaced swimming behavior with climbing behavior. The mixed NE-5-HT reuptake inhibitors milnacipran and duloxetine reduced immobility and increased climbing behavior, but did not alter swimming. Venlafaxine reduced immobility and increased swimming behavior, except at the highest dose tested (80 mg/kg), which increased both swimming and climbing behaviors. Thus, combining certain doses of pharmacologically selective monoamine reuptake inhibitors, or the mixed reuptake inhibitor venlafaxine, produced a pattern of mixed active behaviors in the FST (climbing and swimming) that may reflect the activity of multiple neurotransmitters, especially the combination of enhanced 5-HT and DA activity. The combination of higher doses of desipramine with fluoxetine, or compounds with mixed activity at inhibiting NE and 5-HT reuptake, demonstrated effects similar to those of desipramine alone and may reflect inhibition of the expression of serotonergic antidepressant behavioral effects by selective NE reuptake inhibitors.

Animals↗
PubMed2003

Nitric oxide is not involved in the control of vasopressin release during acute forced swimming in rats.

Neurons of the hypothalamo-neurohypophyseal system (HNS) are known to contain high amounts of neuronal nitric oxide (NO) synthase (nNOS). NO produced by those neurons is commonly supposed to be involved as modulator in the release of the two nonapeptides vasopressin (AVP) and oxytocin into the blood stream. Previous studies showed that forced swimming fails to increase the release of AVP into the blood stream while its secretion into the hypothalamus is triggered. We investigated here whether hypothalamically acting NO contributes to the control of the AVP release into blood under forced swimming conditions. Intracerebral microdialysis and in situ hybridization were employed to analyze the activity of the nitrergic system within the supraoptic nucleus (SON), the hypothalamic origin of the HNS. A 10-min forced swimming session failed to significantly alter the local NO release as indicated both by nitrite and, the main by-product of NO synthesis, citrulline levels in microdialysis samples collected from the SON. Microdialysis administration of NO directly into the SON increased the concentration of AVP in plasma samples collected during simultaneous forced swimming. In an additional experiment the effect of the defined stressor exposure on the concentration of mRNA coding for nNOS within the SON was investigated by in situ hybridization. Forced swimming increased the expression of nNOS mRNA at two and four hours after onset of the stressor compared to untreated controls. Taken together, our results imply that NO within the SON does not contribute to the regulation of the secretory activity of HNS neurons during acute forced swimming. Increased nNOS mRNA in the SON after forced swimming and the increase in AVP release in the presence of exogenous NO under forced swimming points to a possible role of NO in the regulation of the HNS under repeated stressor exposure.

Animals↗
PubMed1982

Evidence for a correlation between swimming velocity and membrane fluidity of Tetrahymena cells.

The influence of the physical state of the membrane on the swimming behaviour of Tetrahymena pyriformis was studied in cells with lipid-modified membranes. When the growth temperature of Tetrahymena cells was increased from 15 degrees C to 34 degrees C or decreased from 39 degrees C to 15 degrees C, their swimming velocity changed gradually in a similar to the adaptive change in membrane lipid composition. Therefore, such adaptive changes in swimming velocity were not observed during short exposures to a different environment. Tetrahymena cells adapted to 34 degrees C swam at 570 microns/s. On incubation at 15 degrees C these cells swam at 100 microns/s. When the temperature was increased to 34 degrees C after a 90-min incubation at 15 degrees C, the initial velocity was immediately recovered. On replacement of tetrahymanol with ergosterol, the swimming velocity of 34 degrees C-grown cells decreased to 210 microns/s, and the cells ceased to move when the temperature was decreased to 15 degrees C. To investigate the influence of the physical state of the membrane on the swimming velocity, total phospholipids were prepared from Tetrahymena cells grown under these different conditions. The fluidities of liposomes of these phospholipid were measured using stearate spin probe. The membrane fluidity of the cells cooled to 15 degrees C increased gradually during incubation at 15 degrees C. On the other hand, the fluidity of the heated cell decreased during incubation at 34 degrees C. Replacement of tetrahymanol with ergosterol decreased the membrane fluidity markedly. Consequently, a good correlation was observed between swimming velocity and membrane fluidity; as the membrane fluidity increased, the swimming velocity increased linearly up to 600 microns/s. These results provide evidence for the regulation of the swimming behaviour by physical properties of the membrane.

Animals↗
PubMed1989

Development of early swimming in Xenopus laevis embryos: myotomal musculature, its innervation and activation.

The development of the axial musculature, its innervation and early locomotion in Xenopus laevis embryos are described. Between stages 17 and 40 some 45 myotomes are formed on each side of the body. During this period the animals develop from non-motile to free swimming embryos. Using fluorescein-conjugated bungarotoxin the acquisition of acetylcholine receptor-sites was studied. At stage 25 (early flexure stage) bound bungarotoxin was confined to the first seven intermyotomal clefts, in free swimming embryos (stage 33) to the first 20 clefts. Application of horseradish peroxidase to the intermyotomal clefts in embryos ranging from stages 25 to 37/38 revealed that primary motoneurons were usually situated 100-400 microns, i.e. 0.5-1.5 myotomes, rostral to the cleft they innervated. The motor axons left the spinal cord at the caudal side of each spinal segment where neural crest was present between the cord and the myotomes. At stage 25 ventral root activity could be recorded extracellularly from only the first three intermyotomal clefts, at stage 32/33 from the first 16 clefts. The first spontaneous rhythmic swimming-like activity could be recorded around stage 28. Between stages 27 and 32/33 the initial swimming frequency and the swimming episode duration increased at least three-fold. Comparable results were obtained with high-speed cinematography and measurements with a photoelectric transducer. Between stages 17 and 40 the number of myotomes increased by 0.9 myotome h, approximately 11.4 h later followed by the innervation of the myotomes at 0.7 cleft/h. About 3.6 h after this, ventral root activity appeared at the rate of 0.6 cleft h. This study shows that the early swimming pattern generating neuronal network, located within the rostral spinal cord, reaches a state of "critical mass" around stage 27, at which the first rhythmic swimming activity occurs. At least 6-10 functional spinal segments and adjacent myotomes are required for early swimming.

Animals↗
PubMed1995

Comparison of the behavioural and endocrine response to forced swimming stress in five inbred strains of rats.

Some inbred strains of rats showed behavioural differences in the forced swimming test, which is considered a putative animal model of depression. In the present work, the behavioural and physiological responses to forced swimming were studied in male and female rats of five inbred strains of rats: Brown-Norway (BN), Fischer 344 (FIS), Lewis (LEW), Spontaneously Hypertensive (SHR) and Wistar-Kyoto (WKY). Physiological measures were aimed at characterizing emotional reactivity, a very important issue which has usually been approached by studying a single endocrine system, and its relationship to the forced swimming behaviour. The four indices of reactivity to stress used were serum glucose, ACTH, corticosterone and prolactin. No behavioural differences between sexes were observed in the forced swimming test. In addition, BN and WKY rats showed passive behaviour compared with the other three strains, the FIS strain being the most active. Whereas only minor differences were found in the resting levels of the variables studied with regard to either sex or strain, pituitary-adrenal (PA) and glucose responses to 15 min forced swimming differed among sexes and strains. Stress-induced hyperglycaemia was lowest in WKY and highest in SHR, being lower in females than in males. The lowest ACTH and corticosterone responses to forced swimming were observed in LEW and the highest in FIS. Female rats showed a clearly higher PA response to stress in all strains. Prolactin response to stress was very similar between sexes and strains. It might thus be concluded that: (i) there are important inter-strain differences in the forced swimming behaviour, with no differences between sexes; (ii) the various physiological indices of emotional reactivity follow a different trend and no warranted conclusion on differences in emotional reactivity should be based upon a single endocrine system or even only upon physiological measures; (iii) we cannot be sure, therefore, whether or not there are differences in emotionality between the strains studied in spite of well-established inter-strains differences in the forced swimming behaviour.

Adrenocorticotropic Hormone↗
PubMed2006

Influence of swim-up time on the ratio of X- and Y-bearing spermatozoa.

OBJECTIVE: The objective was to examine the separation of X- and Y-bearing spermatozoa in a modified swim-up procedure using fluorescent in situ hybridization (FISH), and to find out the influence of swim-up time on the ratio of X- and Y-bearing spermatozoa. STUDY DESIGN: Prospective study. SETTING: Reproductive testing laboratory in a university hospital. PATIENTS: Normal spermatozoa samples were obtained from 10 volunteers by masturbation after sexual abstinence for 3-5 days. INTERVENTIONS: Spermatozoa were put into 18 tubes with 0.25 ml in each, then mixed with HTF medium and centrifuged for 5 min (400 x g). The supernatant was removed and discarded and 0.5 ml HTF was added slowly along the tube wall. Motile spermatozoa were collected after swimming up in different times (from 5 up to 150 min, with a total of 17 intervals). The X- and Y-bearing spermatozoa were determined using the FISH technique. The X/Y dual-color CEP probes that were marked by fluorescein isothiocyanate (FITC) and Texas red were applied to analyze the ratio of X- and Y-bearing spermatozoa. The FISH staining slides were analyzed under an immunofluorescence microscope. About 1000-1500 spermatozoa were counted per slide. MAIN OUTCOME MEASURES: The percentages of X- and Y-bearing spermatozoa were calculated. RESULTS: The study results suggested that the total ratio of hybridization was 98.33%. The ratio of X-bearing spermatozoa after swimming up for different amounts of time is 50.03 +/- 0.91% at 0 min, 50.45 +/- 2.06% after 15 min, 50.61 +/- 2.47% after 30 min, 50.16 +/- 2.67% after 60 min, 50.72 +/- 2.64% after 90 min, and 50.56 +/- 2.20% after 150 min. The statistical analysis showed that there were no significant differences among different swim-up times in the ratio of X-bearing spermatozoa. CONCLUSIONS: There was no significant effect of swim-up time on the ratios of X- and Y-bearing spermatozoa using a modified swim-up procedure. No direct evidence was found that the swim-up procedure for separating motile spermatozoa to use for either intrauterine insemination (IUI) or in vitro fertilization (IVF) would lead to an imbalance of boys and girls.

Cell Separation↗
PubMed1995

Simultaneous measurement of bacterial flagellar rotation rate and swimming speed.

Swimming speeds and flagellar rotation rates of individual free-swimming Vibrio alginolyticus cells were measured simultaneously by laser dark-field microscopy at 25, 30, and 35 degrees C. A roughly linear relation between swimming speed and flagellar rotation rate was observed. The ratio of swimming speed to flagellar rotation rate was 0.113 microns, which indicated that a cell progressed by 7% of pitch of flagellar helix during one flagellar rotation. At each temperature, however, swimming speed had a tendency to saturate at high flagellar rotation rate. That is, the cell with a faster-rotating flagellum did not always swim faster. To analyze the bacterial motion, we proposed a model in which the torque characteristics of the flagellar motor were considered. The model could be analytically solved, and it qualitatively explained the experimental results. The discrepancy between the experimental and the calculated ratios of swimming speed to flagellar rotation rate was about 20%. The apparent saturation in swimming speed was considered to be caused by shorter flagella that rotated faster but produced less propelling force.

Biophysical Phenomena↗
PubMed1998

Role of corticotropin-releasing factor in forced swimming test.

Several aspects of the role of corticotropin-releasing factor (CRF) in the forced swimming test were investigated in this study by using two different administration schedules. I.c.v. microinjection of CRF produced a dose-dependent increase in swimming activity when the administration schedule originally reported for this test to screen antidepressant drugs was followed. The most effective doses were 1 and 3 microg of CRF. A lower dose of CRF (0.5 microg) was also effective when repetitive experimental stress was present. CRF receptor antagonist, alpha-helical CRF-(9-41) (alpha-helical CRF-(9-41)), was able to block CRF-induced increases in swimming in all sessions of the forced swimming test. However, the effects of CRF and CRF receptor antagonist depended on the administration schedule. A decrease in swimming in the forced swimming test was observed when CRF and CRF receptor antagonist were given together, using a different administration schedule. I.c.v. CRF was ineffective and CRF receptor antagonist alone produced an increase in swimming when administered according to this schedule. These behavioural responses were maintained after twelve days without any treatment. The results of the current study suggest that endogenous CRF seems to play a determinant role in behavioural responses in the forced swimming test. The involvement of the level of activation and memory processes in these behavioural responses is discussed.

Animals↗
PubMed1992

Preparation of human frozen-thawed seminal specimens using the SpermPrep filtration method: improvements over the conventional swim-up method.

OBJECTIVE: To examine the qualitative and quantitative characteristics of frozen-thawed spermatozoa recovered through the SpermPrep (ZBL, Inc., Lexington, KY) filtration method or the swim-up technique for the purpose of intrauterine insemination (IUI) or other techniques for assisted reproduction. DESIGN, SETTING, PATIENTS: Thirty pairs of frozen specimens purchased from three commercial semen suppliers were used in this study. Each pair consisted of two aliquots from the same semen specimen. MAIN OUTCOME MEASURES: Spermatozoa recovered via the SpermPrep filtration and swim-up processes were evaluated for sperm numbers recovered, sperm motility, grade of sperm motility, percentage of morphologically normal spermatozoa, the response of spermatozoa to a hypo-osmotic environment (hypo-osmotic swelling test), and the amount of debris present. RESULTS: Application of the SpermPrep filtration method resulted in recovery of significantly greater numbers of spermatozoa (P less than 0.01) than were recovered with the swim-up method (31.1 +/- 3.2 x 10(6) versus 10.2 +/- 1.8 x 10(6) spermatozoa, respectively). This represents a mean recovery of approximately one half (49%) of all spermatozoa applied to the filter, whereas for the swim-up method, it was only 15%. The overall quality of recovered spermatozoa was virtually identical between the two methods (P greater than 0.05). The percent motile sperm improved by a mean of 18% to 20%, the grade of motility improved by a mean of 0.4 points (scale 0 to 4), the percent of morphologically normal spermatozoa increased by a mean of approximately 10%, the percent of spermatozoa reactive to a hypo-osmotic medium test increased by a mean of approximately 9%, and the debris score decreased by a mean of 0.2 to 0.3 points (scale 0 to 4). Most importantly, the mean total number of motile, morphologically normal spermatozoa after filtration through the SpermPrep column was 20.2 +/- 1.1 x 10(6), representing a mean recovery of 73% of the normal spermatozoa originally applied to the column. This was 316% greater than the yield obtained with the swim-up method (6.4 +/- 0.8 x 10(6)), which was significantly greater (P less than 0.01) than that recovered via the swim-up method. Also, the time required to harvest sperm through SpermPrep filtration was 20 to 25 minutes versus 80 minutes required for the swim-up method (P less than 0.05). CONCLUSION: Considering that the effectiveness of frozen-thawed semen is already limited when compared with fresh semen, SpermPrep filtration is the method of choice over the swim-up technique of sperm selection because the former provides significantly greater numbers of high quality sperm. It should be considered as an adjunct in semen preparation for IUI or other forms of assisted reproduction.

Evaluation Studies as Topic↗
PubMed1993

Detection of X- and Y-bearing human spermatozoa after motile sperm isolation by swim-up.

OBJECTIVE: To assess the ratio of X- to Y-bearing human spermatozoa in motile fractions isolated by the swim-up technique. DESIGN: The proportions of X- and Y-bearing sperm were determined in neat semen samples (control) and in motile fractions isolated from the same samples by swim-up. X- and Y-bearing sperm were simultaneously identified using chromosome-specific DNA probes and double fluorescence in situ hybridization. SETTING: Hospital-based university department. PARTICIPANTS: Ten healthy donors with normal semen characteristics. MAIN OUTCOME MEASURES: The distribution of haploid cells (X or Y), normal size cells with two sex chromosome (XX, YY, or XY), and large cells containing two (XX, YY, or XY) or four (XXYY) sex chromosomes were measured in neat semen samples and in motile fractions prepared by swim-up. RESULTS: Overall, 95% of sperm in the neat semen and swim-up fractions were labeled with the probes. The ratios of X- to Y-bearing sperm were 47.3:46.9 (neat semen) and 48.4:47.1 (swim-up fractions), which were not significantly different from a 1:1 ratio. The frequencies of sperm with normal size nuclei and two sex chromosomes (XX, YY, or XY) in the swim-up fractions were not significantly different from the controls, but there was a significant reduction in the proportion of cells with large nuclei and two (XX, YY, or XY) or four (XXYY) sex chromosomes in the swim-up fractions. CONCLUSIONS: The swim-up technique does not selectively enrich either X- or Y-bearing sperm. Because the isolation of motile spermatozoa is an important procedure for routine IUI, IVF-ET, and GIFT, the results of this study are important reassurance that the sex ratio is not altered by this method of sperm preparation.

Cell Nucleus↗
PubMed1992

Comparison of Percoll, mini-Percoll and swim-up methods for sperm preparation from abnormal semen samples.

Two methods of density gradient centrifugation, Percoll (P) and mini-Percoll (MP), were compared with the swim-up technique for preparing spermatozoa from each of 40 abnormal semen samples. P and MP produced similar results with a mean recovery of spermatozoa with progressive motility which was significantly higher (18-19%) than that achieved with swim-up (5%). However, the swim-up method resulted in the recovery of spermatozoa with a higher mean motility (89 versus 58%), velocity (69 versus 56 microns/s), percentage with normal morphology (22 versus 16%) and intact acrosomes (61 versus 36%) than P and MP. The mean amplitude of lateral head displacement was the only characteristic of spermatozoa in semen which correlated with the recoveries of motile spermatozoa. Combining MP and swim-up methods for 10 samples produced a higher recovery (11 versus 6.9%) of spermatozoa with significantly better mean motility (94 versus 87%) than did swim-up alone. Although P and MP resulted in greater yields of motile spermatozoa than the swim-up preparation, the latter procedure selected higher proportions of spermatozoa with improved characteristics (velocity, intact acrosomes and normal morphology) which correlate with fertilization rates in vitro. It is concluded that P and MP are not superior to swim-up. However, sequential MP and swim-up preparation improves yields of high quality spermatozoa from some abnormal semen samples and therefore has potential for improving fertilization rates.

Cell Separation↗
PubMed1995

Speed effects on midline kinematics during steady undulatory swimming of largemouth bass, Micropterus salmoides

We used frame-by-frame analysis of high-speed videotapes to quantify midline kinematics during steady swimming in largemouth bass at five standardized speeds (0.7, 1.2, 1.6, 2.0 and 2.4 L s-1, where L is total length). By combining morphological data from X-ray photographs with mathematical reconstructions of the midline of each fish, we determined the amplitude and timing of lateral displacement (zmax), lateral flexion (ssmax) and the angle between the midline and the axis of forward travel (thetamax) for each vertebral joint, the hypural bones and four equally spaced segments of the caudal fin rays. Analysis of variance revealed pervasive significant effects of both swimming speed and longitudinal location on variables describing amplitude, phase and wavelength. The amplitudes of zmax, ssmax and thetamax generally increased in a non-linear fashion from approximately 25 %L to the tip of the caudal fin, and the greatest speed-related increases occurred between 0.7 and 1.6 L s-1. For the snout, the first caudal vertebra and the trailing edge of the caudal fin, mean values of zmax increased with speed from 0.004 to 0.012 L, from 0.005 to 0.012 L and from 0.053 to 0.066 L, respectively. For joints between the skull and the first vertebra, between the trunk and the tail vertebrae, and among the most posterior caudal vertebrae, mean values of ssmax increased with speed from 1.2 to 1.7 degrees, from 0.6 to 0.9 degrees and from 1.4 to 2.2 degrees, respectively. Within each swimming speed, values of ssmax of the distal caudal fin commonly exceeded twice those of the proximal caudal fin. Surprisingly, at a given longitudinal location, the times of maximum lateral displacement and bending did not occur simultaneously. Instead, the phase of zmax relative to ssmax was commonly shifted by more than one-sixth of a cycle. Furthermore, the phase shift between zmax and ssmax changed significantly with increased swimming speed. Angles of attack of the tail structures changed periodically from negative to positive values. Maximum angles of attack of the distal caudal fin ranged from 5 to 17 degrees, changed significantly with swimming speed and were less than those of the hypural bones of the tail. Mean tail-beat frequency increased significantly from 2.0 to 4.2 Hz with increased swimming speed. Estimated speeds of wave propagation showed considerable longitudinal variation, and the ratio of swimming speed to posterior wave speed increased from 0.59 to 0.83 with increased swimming speed.

Journal Article↗
PubMed1997

The interactive effects of feeding and exercise on oxygen consumption, swimming performance and protein usage in juvenile rainbow trout (Oncorhynchus mykiss)

The impacts of feeding on the rate of O2 consumption (O2), aerobic swimming performance, nitrogenous waste excretion (ammonia-N and urea-N) and protein utilization as an aerobic fuel were investigated in juvenile rainbow trout. Feeding trout to satiation (in groups of 120) resulted in rapid growth and elevated routine O2 by 68% relative to fasted fish and by 30% relative to trout fed a maintenance ration of 1% of body mass daily. This in-tank O2 of satiation-fed trout was approximately 70% of the O2max observed at the critical swimming speed (UCrit) when trials were performed on individual trout in swimming respirometers. Feeding increased O2 at all swimming speeds; the absolute elevation (specific dynamic action or SDA effect) was dependent on ration but independent of swimming velocity. There was no difference in O2max at UCrit amongst different ration treatments, but UCrit was significantly reduced by 15% in satiation-fed fish relative to fasted fish. These results suggest that the irreducible SDA load reduces swimming performance and that O2max is limited by the capacity to take up O2 at the gills and/or to deliver O2 through the circulatory system rather than by the capacity to consume O2 at the tissues. Ammonia-N and urea-N excretion increased with protein intake, resulting in a 6.5-fold elevation in absolute protein use and a fourfold elevation in percentage use of protein as an aerobic fuel for routine metabolism in satiation-fed trout (50-70%) relative to fasted fish (15%). Urea-N excretion increased greatly with swimming speed in all treatments, but remained a minor component of overall nitrogen excretion. However, even in satiation-fed fish, ammonia-N excretion remained constant as swimming speed increased, and protein did not become more important as a fuel source during exercise. These results suggest that the reliance on protein as a fuel is greatly dependent on feeding quantity (protein intake) and that protein is not a primary fuel for exercise as suggested by some previous studies.

Journal Article↗
PubMed1997

Quantitative and qualitative characteristics of frozen-thawed bovine spermatozoa recovered via a conventional and a standardized swim-up technique.

The objective of this study was to use the bovine as a model to evaluate the recovery of frozen-thawed spermatozoa via a conventional and a standardized swim-up technique. Frozen-thawed semen specimens (3 bulls) were washed and reconstituted with 2.9% (w/v) sodium citrate extender containing 20% (v/v) chicken egg yolk (SC-EY). Reconstituted sperm specimens were used for selection via conventional swim-up and the standardized ZSC method. The swim-up method consisted of overlayering the sperm specimen with 0.7 to 1.0 ml of isolation media (Ham's F-10), followed by 1 hr of incubation. The ZSC consisted of a conical cavity on the bottom of a glass column. The sperm specimen was placed into the conical cavity until the surface of the specimen was at the same level as the upper boundaries of the conical cavity. The surrounding periconical and epiconical areas were filled with 0.7 to 1.0 ml of isolation media followed by 1 hr of incubation. The isolation media was removed (harvesting) from swim-up (80% volume) and ZSC specimens (100% volume) at the end of incubation. Recovered specimens were assessed for volume (ml), sperm concentration (x10(6) spermatozoa/ml), the percentage and grade of motility (0 to 4), the occurrence of osmotic shock and the percentage of spermatozoa reactive to the hypoosmotic swelling (HOS) test. Swim-up and ZSC selected specimens were qualitatively similar to each other. However, higher numbers of spermatozoa were recovered when sperm specimens were processed via the ZSC method (1.6 fold increase) than with the conventional swim-up technique. Because the ZSC method enabled the recovery of up to 100% of the overlayered media, it also enabled the recovery of most of the spermatozoa that migrated from the sperm specimen into the isolation media with no possibility of mixing the two, which was the case with the swim-up method, and which could also contaminate the recovered specimen with dead and immotile spermatozoa. Thus, the ZSC technique enabled the harvesting of the medium closest to the underlayered sperm specimen, which contributed to maximize the number of sperm recovered. When all assessed parameters were noted and all clinical improvements and efficiency of the method were compared to the swim-up technique, the sperm manipulation procedure of choice was clearly the ZSC method.

Animals↗
PubMedDate not supplied

Swim-down: a rapid and easy method to select motile spermatozoa.

A method is developed to improve the quality and the number of sperm recovered after laboratory processing, consisting of a swim-down technique. This study was designed to compare quality sperm after selection with a swim-up and a swim-down method. Fifty-nine men, 23-52 years of age, with a period of infertility of 1 to 14 years were included in the study. The efficacy of the swim-down technique as compared to the swim-up technique was assessed by measuring percentage of sperm recovery, sperm motility, the hypoosmotic swelling test, acrosome reaction, and the sperm penetration to zona-free hamster oocyte assay. The swim-down procedure using pure serum as culture medium showed a higher percentage (p < .02) of spermatozoa with forward progression and a higher number of recovered (p < .05) spermatozoa than the swim-up technique. The fertilizability was similar with both methods. The swim-down procedure using pure serum could be useful for intrauterine insemination where a higher number of spermatozoa is required.

Adult↗
PubMedDate not supplied

Effect of swim-up sperm washing and subsequent capacitation on acrosome status and functional membrane integrity of normal sperm.

OBJECTIVE: Sperm preparation techniques select sperm population with improved sperm motion characteristics. We sought to determine whether the swim-up technique selects spermatozoa with the ability to undergo hypoosmotic swelling, and how swim-up and subsequent capacitation affect the acrosome reaction rate. METHODS: Semen specimens from 15 normal donors were divided into unprocessed, swim-up, and capacitated groups, and sperm motion characteristics, ability to undergo hypoosmotic swelling, and acrosome reaction rate were measured. RESULTS: Sperm motility, viability, and all motion characteristics (except linearity) were significantly increased in both swim-up and capacitated specimens. The ability to respond to hypoosmotic swelling was significantly higher in the spermatozoa isolated by swim-up. The percentage of acrosome-reacted spermatozoa remained unchanged in both unprocessed and swim-up groups, but was significantly higher in the capacitated group. CONCLUSIONS: Swim-up isolates sperm with greater ability to undergo hypoosmotic swelling, but does not change the acrosome reaction rate. In vitro capacitation of spermatozoa selected by swim-up enhances the acrosome reaction rate.

Acrosome↗