Effects of modifying olfactory and pineal gland function on the seasonality of semen production and plasma luteinizing hormone,testosterone and prolactin levels in rams

In an experiment designed to evaluate neuroendocrine mechanisms which could mediate seasonality of reproduction in Romney rams, the effects on semen production and plasma hormone levels of olfactory bulbectomy, cranial cervical ganglionectomy, or both operations, were studied over a period of 16 months.Concentrations and total numbers of spermatozoa in ejaculates from surgically treated rams were higher than in those from unoperated controls. Although mean fructose concentrations were lower in semen from treated animals, the pattern of seasonal changes in seminal fructose was similar in all groups of rams. Olfactory bulbectomy disrupted the regular seasonal changes in plasma luteinizing hormone (LH) levels, while cranial cervical ganglionectomy abolished the seasonality of secretion of both LH and prolactin. The annual pattern of testosterone secretion was not affected by any surgical treatment. Ganglionectomy reduced hydroxyindole-O-methyl transferase activity and cell volumes in pineal glands, so it was concluded that this treatment produced its effects by reducing the capacity of the pineal gland to respond to seasonal variations in daily photoperiod. No conclusions could be drawn about the role of olfactory function in regulating seasonality of reproduction in rams.     

The influence of breed,season and photoperiod on semen characteristics,testicular size,libido and plasma hormone concentrations in rams

Twenty-seven adult rams (9 Suffolk, 9 Texel and 9 Dorset Horn) were raised under natural photoperiod and were trained to serve into an artificial vagina. On 1 April they were abruptly exposed to 3 different photoperiods as follows: (i) 8 hours light and 16 hours darkness (8L : 16D); (ii) 16 hours light and 8 hours darkness (16L : 8D); (iii) natural photoperiod. All rams were kept at pasture daily between 09.30 h and 16.00 h except when required indoors for experimental work. Rams on artificial photoperiod had appropriate supplemental lighting in an environmental chamber. Semen collection was attempted from each ram on alternate weeks during the experiment which lasted for 6 months. Semen was evaluated for volume, density, motility and abnormalities. Testicular length and circumference were recorded at 2-week intervals and libido was recorded at 4-week intervals. Three blood samples were collected from each ram at 30-min intervals on a weekly basis and the plasma was stored at ?20°C until assayed for testosterone and prolactin.Photoperiod had no significant effect on semen volume, motility and percentage dead or abnormal cells. Breed of ram had a significant effect on semen motility (P < 0.05) with Dorset Horn rams producing semen with the highest motility. Volume and motility scores both increased as the breeding season approached (P < 0.05), while the percentage of abnormal cells decreased (P < 0.01). Breed or photoperiod did not significantly affect scrotal measurements although animals exposed to 8L : 16D had the highest measurements. Month affected testicular measurements which generally increased from April to September. Suffolk rams had higher testosterone concentrations, and this breed also completed the highest number of mounts within an allocated test time (P < 0.05). Dorset Horn rams reached a peak in testosterone concentrations in June/ July whereas Suffolks and Texels reached a similar peak in August. Prolactin concentrations decreased from a maximum at the start and rams on natural photoperiod tended to have highest levels. These results show that month can have a bigger influence on semen characteristics than imposed artificial photoperiods in rams which have been exposed to increasing natural daylength for some months.     

Seasonality of semen production and plasma luteinizing hormone,testosterone and prolactin levels in Romney,Merino and polled dorset rams

An attempt was made to define the seasonality of reproduction in rams in the southern hemisphere by repeated measurement of semen characteristics and of plasma luteinizing hormone (LH), testosterone and prolactin concentrations. These parameters were studied for 16 months in Romney rams on pasture, with Merino and Polled Dorset rams included for comparison.Semen from all three breeds showed regular seasonal changes in ejaculate volumes, with peak values being recorded during March. A similar autumnal peak of seminal fructose levels was noted for ejaculates from Romney and Merino rams, but not for those from Polled Dorsets. Most of the other semen parameters measured showed little tendency for seasonal variations. However, a change in semen collection technique, from predominantly artificial vagina to entirely electroejaculation, may have masked some seasonal changes.Plasma hormone levels also varied in a regular manner, with peak levels occurring in summer and autumn: highest levels for prolactin were recorded in November–March, for LH in December–February and for testosterone in January–March. An exception to this pattern was recorded from the Merino rams, for which there was no definite peak of LH secretion.It is suggested that these seasonal changes resulted primarily from changes in daily photoperiod.     

Sperm output and hormone concentrations in Finn and Dorset rams exposed to long- and short-day lighting

Seasonal changes in photoperiod have a substantial effect on sexual behavior and reproduction in rams. Little information is available on sperm output from high libido versus average libido rams subjected to intensive semen collection while being exposed to controlled short versus long photoperiods. Six Finn and six Dorset rams were compared in a reversal design, which allowed rams of both breeds to be exposed to 8 h versus 16 h of light. During each of two 84-d periods rams were subjected twice to an initial depletion of epididymal sperm reserves by collecting up to 26 ejaculates of semen in 3 d, followed by up to 10 ejaculates per day, 1, 3, 5, and 7 d after the initial depletion. A total of 2673 semen samples were collected. Nearly twice as many ejaculates (63.6% of the total) were obtained from Finn rams as from Dorset rams during both the initial and subsequent 3-d sperm depletion periods. This difference in libido was associated with obtaining 33.6 +/- 3.1 x 10(9) sperm from Finn rams versus 10.0 +/- 2.2 x 10(9) sperm from Dorset rams during the initial depletion period (P<0.05). Changes in photoperiod did not affect sperm output (P>0.05) in Finn rams, but may have affected Dorset rams. With 16 h of light, prolactin was significantly (P<0.05) increased in both breeds, particularly in Finn rams. Testosterone in both breeds followed an endogenous rhythm, not affected by the change in controlled photoperiods.     

Concentration of prostaglandins E and F,fructose and glycerylphosphorylcholine in ram semen obtained by electro-ejaculation or artificial vagina and in vesicular fluid

The concentration of spermatozoa in electrically ejaculated ram semen was lower than in semen obtained by an artificial vagina. Glycerylphosphorylcholine concentrations were also lower in the electrically ejaculated semen and there was a high correlation between sperm and glycerylphosphorylcholine concentrations.Seminal fructose, prostaglandin E (PGE) and prostaglandin F (PGF) levels did not differ significantly between the two methods of collection but there was greater variability between rams when they were electrically ejaculated.The concentration of fructose in the vesicular secretion of rams was less variable and higher than in seminal plasma whereas PGE or PGF concentrations were not significantly different in the two fluids.     

Effects of exposing boars to different artificial light regimens on semen plasma markers and "in vivo" fertilizing capacity

This study was designed to assess the effects of exposing boars to an artificial photoperiod on semen quality in terms of sperm concentration, sperm vitality, sperm motility and acrosome integrity. We also determined biochemical semen plasma variables, such as total protein concentration, phosphorylated tyrosine residues and fructose, glucose and sorbitol contents, along with their effects on the fertility, prolificacy and libido of the boars. Three groups of 10 males were kept for 3 months under experimental conditions of 24, 12 and 0 h of artificial light, and a constant temperature of 21 +/- 1 degrees C and 60-75% humidity. The animals were fed a nutritious diet and subjected to semen collection twice per week. Semen samples were analyzed throughout the entire experimental period. Our results indicate that, while the extreme photoperiods (0 and 24 h of light) affected semen quality in terms of sperm concentration, acrosome integrity and semen volume, its fertilizing capacity was only significantly reduced under conditions of absolute darkness. Sperm motility was found to be a poor indicator of fertilizing ability, while other sperm factors, such as acrosome integrity or other functional variables seemed to behave better. The photoperiod was found to affect the production of accessory sex gland secretions more than their composition. In addition, light effects on fertility, prolificacy and libido seemed to be achieved through independent mechanisms.     

Testosterone secretion and semen plasma enzyme activity in rams with genital pathology stimulated with GnRH

Testosterone secretion in response to GnRH stimulation and enzymatic activity of semen plasma was evaluated comparatively in rams with or without genital abnormality. Scrota, testes and epididymides of 128 rams between 1.5 and 6 years old from various breeds were examined clinically and ultrasonographically. Bilaterally cryptorchid rams (n = 2), and rams with focal testicular degeneration (n = 3) or unilateral sperm granuloma localized in the caput (n = 3) epididymis or the cauda epididymis (n = 3), diagnosed by either clinical or ultrasonographic examination, were selected for the further investigation of spermatologic parameters, testosterone secretion in response to GnRH stimulation, and enzymatic activity of semen plasma before histopathologic confirmation of lesions. Except for the cryptorchid rams, sperm parameters determined in ejaculates were similar to intact controls (n = 3). GnRH administration increased plasma testosterone levels significantly irrespective of the type of genital pathology (P < 0.01). The testosterone response calculated based on area under the curve following GnRH administration in rams having genital abnormality was not significantly different from the controls. Aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) activity in the semen plasma varied between rams, with the lowest mean values in the bilaterally cryptorchid group (P < 0.05). Spermatic granuloma localized either in the caput or cauda of the epididymis was associated with a significant reduction in the semen plasma AST activity compared to controls (P < 0.01). In conclusion, our results indicated that the ability of testicular tissue to secrete testosterone in response to GnRH stimulation in rams with bilateral cryptorchidism, focal testicular degeneration and unilateral sperm granuloma was similar to that of intact controls, and that reduced semen plasma AST activity may have a diagnostic value in the diagnosis of the epididymal obstruction in rams. Focal testicular degeneration did not influence AST, alkaline phosphatase (ALP) and LDH activity in semen plasma.     

Genetic and environmental effects on semen traits in Lacaune and Manech tête rousse AI rams (Open Access publication)

Data from 51 107 and 11 839 ejaculates collected on rams of the "Lacaune" and "Manech tête rousse" breeds, respectively, were analysed to determine environmental and genetic factors affecting semen production traits (ejaculate volume, semen concentration, number of spermatozoa and motility) in young (≤1 year) and adult (≥2 years) rams. Fixed effects and variance components were estimated using multiple trait animal models within each breed. For all traits, the main environmental effects identified were year, season, number of ejaculations, daily variation, interval from previous to current collection and age. Heritability estimates were moderate for volume, concentration and number of spermatozoa (0.12 to 0.33) and lower for motility (0.02 to 0.14). Genetic correlations between ages differed from 1 for all traits (0.14 to 0.90), indicating that semen characteristics corresponded to different traits in young and adult rams. Genetic and phenotypic correlations among traits within age category were globally similar for the different breeds and categories of animals.     

Semen characteristics, scrotal circumference and bacterial isolates of fine wool range rams

During 1983, 887 fine wool rams were subjected to breeding soundness evaluation to determine effects of age and scrotal circumference on semen characteristics. Of rams evaluated, 94.4, 84.8, and 81.9% of young (6 yr), respectively, were rated as satis-factory. Old rams had fewer (P < 0.05) motile cells and more (P < 0.05) abnormal cells than young rams. Among older rams there was a higher percentage (P < 0.05) with testicular lesions than among young or mature rams. Scrotal circumference was positively correlated (P < 0.01) with semen volume and percentage of motile normal cells. Motility was negatively correlated (P < 0.01) with percentage of abnormal cells. Mature and old rams with large (>/=36.7 cm) testis had more (P < 0.10) abnormal cells than those in the same age groups with smaller testis. Scrotal circumference was positively correlated (P < 0.10) to volume and motility in mature and old rams, while motility was negatively correlated (P < 0.01) to percentage of abnormal cells in all age groups. Previous semen testing reduced (P < 0.05) the percentage of mature rams with leucocytes. Vaccination against epididymitis reduced (P < 0.05) the incidence of mature rams with leucocytes and testicular lesions. Brucella ovis was recovered from 54 (67.5%) of 80 ejaculates cultured. Among rams infected with B . ovis , only three (5.6%) were vaccinated against B . ovis and had their semen tested previously.     

Acrosome reaction and concentration of prostaglandin E2 in semen of rams treated with flunixin meglumine (Banamine)

The objectives of this study were to determine 1) the effect of Banamine on the seminal concentration of PGE2 and 2) the ability of sperm cells from treated rams to undergo acrosome reaction in vitro as an indirect measure of their fertilizing capacity. Seven rams, approximately 55 kg bodyweight and 2 to 5 yr of age, were divided into two groups: Group 1, treated (n = 4) and Group 2, controls (n = 3). Treatment consisted of administration of 75 mg i.m. Banamine twice daily, 6 to 8 h apart, for 45 d. On Day 0 (first day of treatment) and on Days 2, 9, 11, 16, 23, 25, 28, 30, 36, 39, 43 and 46 semen samples were collected from both groups using an electroejaculator. Blood samples were obtained for determination of serum levels of Banamine using high-performance liquid chromatography. Semen samples were examined for motility and morphology. Highly motile (>/=85%), normal-appearing semen samples were pooled on each day of collection and 25 ul of the pooled sample (1x10(6)/ml) of each group were induced to undergo acrosome reaction in vitro using ionophore A23187. Acrosome reaction was demonstrated using a staining technique designed for demonstrating the process in bull sperm cells. The percentage of acrosome-reacted and non-acrosome-reacted sperm was determined by random microscopic examination of 100 sperm cells using a double-blind approach. The supernatants of the remainder of the semen samples were assayed for levels of PGE2 using RIA. Values for acrosome-reacted sperm cells and PGE2 levels on the first day of treatment from both groups were compared with corresponding values from each day of sampling using Wilcoxon Rank Sums test (P<0.05). In Group 1, the mean serum level of Banamine was 3.02+/-0.58ug/ml. There was a significant increase in the ability of sperm cells from rams in Group 1 to undergo acrosome reaction as treatment progressed compared with the sperm cells from rams in Group 2. However, there was a significant decrease in concentration of PGE2 in semen from rams in Group 1 compared with those from Group 2. The results of this study suggest an inverse relationship between the capacity of sperm cells to undergo acrosome reaction and concentration of PGE2 in semen of rams treated with a nonsteroidal anti-inflammatory drug.     

Semen quality of postpubertal boars during increasing and decreasing natural photoperiods

The present study analyses the effects of increasing and decreasing photoperiods on the semen quality of 20 selected postpubertal Landrace boars. The boars were exposed, throughout 75 days, to increasing and decreasing photoperiods of natural light, a constant temperature of 21 +/- 1 degrees C and 60-70% of humidity, fed with a nutritious diet and, submitted to a rhythm of semen collection of twice a week. During the last 2 weeks of each treatment, semen samples were analysed and the parameters measured were: ejaculate volume and pH, sperm concentration, sperm production and the number of semen doses per ejaculate, sperm vitality, sperm motility, osmotic resistance of spermatozoa and sperm morphology. The comparative analysis between increasing and decreasing photoperiods indicated that the semen quality of boars exposed to a decreasing photoperiod was reduced as a consequence of decreases in sperm concentration, sperm production and the number of semen doses. There was no difference between increasing and decreasing photoperiods in terms of sperm vitality and sperm motility, nor in the osmotic resistance of spermatozoa to isotonic and hypotonic media. The analysis of sperm morphology showed significantly lower frequencies of mature and immature spermatozoa with a distal cytoplasmic droplet, and significantly higher frequencies of immature spermatozoa with a proximal droplet in boars exposed to the decreasing photoperiod. These results indicate that the sperm quality of the selected boars decreased during decreasing photoperiods, in comparison with increasing photoperiods, mainly due to impaired testicular function.     

Photoperiod entrainment of testosterone, luteinizing hormone, follicle-stimulating hormone, and prolactin cycles in rams in relation to testis size and semen quality

Adult rams were exposed to photoperiod treatments over 2 years to study the influence of light regimes on pituitary-testicular activity and semen quality. Initially, all rams (12 per group) were exposed to 3 months of long days (16L:8D). Group 1 was then exposed to a regime of continuous short days (8L:16D) and Groups 2, 3, and 4 were exposed to 4 months of short days alternated with 1, 2, or 4 months, respectively, of long days. Every 2 weeks, serum hormone levels and scrotal circumference were determined and semen quality was evaluated. Regular cycles in pituitary and testicular activities corresponding to the period of the lighting regime resulted in Groups 2, 3, and 4, but not in Group 1. In general, the change from long days to short days induced increases in follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone levels, scrotal size and sperm numbers and a decrease in prolactin. The reverse occurred after subsequent exposure to long days. After 4 months of long days, testicular regression was complete, but when long-day exposure was reduced, less regression occurred. With continuous exposure to short days, FSH and testosterone remained above basal levels, prolactin levels were depressed, scrotal size remained near the maximum, and elevated numbers of motile sperm were sustained.     

Effects of levamisole on hyaluronidase activity and sperm characteristics in rams

The aim of this study was to determine the effects of levamisole on sperm characteristics and hyaluronidase activity of blood serum and semen. For this purpose, 12 Akkaraman rams (2-3 years old) were used. Levamisole hydrochloride was administered orally at a dose of 7.5mg/kg body weights once daily for 2 days. Serum and semen samples were collected from the rams at post-treatment 1, 2, 4, 24, 48, 72, 96, 120, 144, 216, 288 and 384 h and examined for sperm characteristics and hyaluronidase activity. The results showed that the use of levamisole caused significant (P < 0.01) increase in serum hyaluronidase activity at all times except the 72 h, and in semen hyaluronidase activity at 1, 2, 4, 24, 72, 96 and 120 h compared to the control group. In addition, the levamisole caused significant (P < 0.05) decreases in semen volume, sperm motility, concentration and total sperm number at all times. There was no correlation between semen hyaluronidase activity and the sperm characteristics. In conclusion, levamisole did not have any deleterious effect on hyaluronidase enzyme. However, the use of this drug in rams during the breeding season is harmful due to the decrease of sperm characteristics.     

In vitro fertilization as a predictor of fertility from cervical insemination of sheep

The objective of this study was to determine if the quality of frozen-thawed ram semen could be effectively evaluated through in vitro fertilization (IVF) procedures prior to insemination as a means of improving pregnancy rate. In experiment 1, frozen semen from four Belclare rams was assessed using IVF and was used for cervical insemination of ewes (n = 181) in 13 pedigree Belclare flocks. There was a significant association between IVF score (proportion of oocytes cleaved at 48 h post insemination) and non-return rate (P < 0.001). For experiment 2, semen from nine Belclare rams was evaluated by IVF and semen from rams with the highest (n = 3) and lowest (n = 2) IVF scores was used for cervical insemination of ewes (n = 111) under experimental conditions. Differences in pregnancy rates between individual rams did not reach significance. Experiment 3 was designed to determine if differences detected between rams at field level could be accurately identified via IVF evaluation and involved frozen semen from eight Norwegian rams of known field fertility (non-return rates ranged from 45.7 to 73.8%). IVF score did not reflect the differences in field fertility. In the final experiment six of the eight Norwegian rams involved in experiment 3 were selected based on IVF score (three highest and three lowest) and their semen was used for cervical insemination (n = 90 ewes). While significant differences in pregnancy rate were found between individual rams (P < 0.02, range: 12.9-65.8%) they were not associated with IVF score. Ewe breed had a significant effect (P < 0.003) on pregnancy rate in both experiments 2 and 4. In conclusion, there was no evidence from this study that the evaluation of semen quality through IVF provided a useful predictor of pregnancy rate under field conditions. It may be that the IVF procedures as used routinely, which are essentially designed to maximize blastocyst yields rather than for detecting differences in fertilizing ability between batches of sperm, need to be modified.     

The effects of filiform appendage removal on semen collection in the ram

The effects of removal of the filiform appendage and the type of collection cone used (polyethylene, rubber, Teflon) on the quantity and quality of semen collected from rams were examined. A total of 182 semen collections from six rams (three appendage-intact and three appendage-amputated rams) were utilized in the study. Observations of ejaculated semen distribution and drainage patterns indicated differences between appendage-intact and appendage-amputated rams. A larger volume of semen and a higher number of spermatozoa were collected from amputated than from intact rams (P<0.05). Amputation of the filiform appendage had no effect (P>0.05) on initial motility, thermal stress resistance, or morphology of spermatozoa, regardless of the type of collection cone used. Spermatozoa retained on collection cone surfaces were more sensitive to thermal stress (P<0.05). The morphology of spermatozoa was not affected by type of collection cone (P>0.05). Thus, filiform appendage removal increases ram semen collection efficiency while maintaining semen quality.     

Androgenic activity in 15-day-old male rats: role of the maternal pineal gland.

Female Sprague-Dawley rats, exposed to a long (18L:6D) or a short (6L:18D) photoperiod from 21 days of age, were mated when they reached 55 days of age. On Day 2 of gestation, dams were pinealectomized or sham-operated. Pre- and postnatal photoperiods were identical, and offspring were killed at 15 days of age. Maternal pinealectomy had no effect when rats were kept on 18L:6D. Rats born to sham-operated mothers and kept on 6L:18D had higher testicular testosterone and androstenedione content than offspring raised on the long photoperiod. This stimulatory effect of the short photoperiod was blocked by maternal pinealectomy and was not dependent on the offspring's own pineal since it was observed in both sham-operated and neonatally (on Day 5 after birth) pinealectomized rats. When sham-operated mothers housed on 18L:6D were treated daily during pregnancy and lactation by s.c. melatonin injection, there was an increase in the testicular testosterone content of offspring. It was concluded that when rats are maintained on a 6L:18D cycle the maternal pineal gland enhances the testicular testosterone and androstenedione content in 15-day-old offspring. This effect is probably mediated by maternally derived melatonin. At 15 days of age, the pineal of the offspring had no influence on testicular function.     

Melatonin modifies scrotal circumference but not plasma testosterone concentrations and semen quality of rams during the seasonal anestrus at 43°S

The effect of melatonin implants on semen quality on semen samples at 43°S has been studied. Scrotal circumference and plasma testosterone levels have also been determined. Sixteen (experiment 1) and twelve rams (experiment 2) were used from September to December 2011 and 2012, respectively. Half of the rams were treated with melatonin (M groups), the remaining rams being the control group (C groups). M rams presented a higher scrotal circumference than C animals (p < 0.01) from 30 days after melatonin implantations up to the end of experiment 1 and from day 45 to day 75 in experiment 2. No differences between groups were detected for any of the seminal parameters under study and plasma testosterone levels. In conclusion, the use of melatonin implants during the seasonal anoestrus at 43°S produces a significant increment of the scrotal circumference of rams without changing seminal quality parameters of fresh and frozen/thawed semen.     

Prevalence of chlamydiae in semen and genital tracts of bulls, rams and bucks

Chlamydiae infect male genital organs of ruminants. However, little is known about their prevalence. Hence, we investigated fresh and cryopreserved semen (bulls: n=304; rams: n=78; bucks: n=44) by polymerase chain reaction (PCR), as well as genital organs (bulls: n=13; rams: n=10; bucks: n=6) by immunohistochemistry (IHC) and PCR. Sera from bulls (n=104) and small ruminants (n=61) were tested by LPS and rMOMP (recombinant major outer membrane protein) ELISA and competitive ELISA (cELISA), respectively. Three PCR assays were compared in this study for detection of chlamydial DNA in semen: 16S rRNA, IGS-S (intergenic spacer 16S/23S-short), and IGS-L (intergenic spacer 16S/23S-long) PCRs. PCR sensitivity and inhibitory effects were determined by spiking semen with Chlamydophila (Cp.) abortus DNA. In bull semen, detection limits of the 16S, IGS-S and IGS-L PCRs were 10, 10, 100 templates, respectively. However, PCR sensitivity was reduced in ram and buck semen suggesting the presence of potential PCR inhibitors. Of 304 bull semen samples, the 16S PCR revealed DNA of chlamydiae in 20 samples (6.6%), including Cp. abortus (n=2), Cp. psittaci (n=1), Chlamydia suis (n=2), and Chlamydia-like organisms (n=15). In rams, one semen sample was positive for Chlamydia-like organism. All investigated male genital organs were negative for Chlamydia. Serology revealed 47.1% (49/104) positive bulls by LPS ELISA. Of these, 30 samples were positive by rMOMP ELISA, predominantly for Cp. pecorum. In small ruminants, cELISA displayed 34.8% (16/46) and 60% (9/15) positivity for Cp. abortus in rams and bucks, respectively. There was no correlation between serology and PCR of semen. The presence of chlamydiae in semen suggests the possibility of venereal transmission, although risk may be low in Switzerland.     

Semen characteristics of Ile-de-France rams of different age and physical condition

A breeding soundness examination (BSE) involving animal physical examination, scrotal circumference (SC) and semen evaluation was undertaken on 80 Ile-de-France rams at a government breeding farm, 32 km south-west of Casablanca (Morocco) from March to May 1988. A large percentage of rams (21.4%) was found to be unfit for breeding due to physical and genital abnormalities; 11 and 5% had disorders of the feet and respiratory system; upon genital palpation, 17.5, 13.8 and 7.5% of animals had orchitis, epididymitis and posthitis, respectively. The SC increased with age from 28.8+/-3.2 cm at 相似文献   

Semen sialic acid surge and modulation of alpha-L-fucosidase activity: possible link to loss in reproductive capacity during trypanosomiasis

The profiles of semen sialic acid and the enzyme alpha-L-fucosidase were studied in rams undergoing chronic infection by Trypanosoma congolense. Our data showed a significant surge in the level of sialic acid with parasitaemia. The pattern followed a polynomial function we had reported for erythrocyte sialic acid in mice undergoing acute infection by T. congolense. The activity of the enzyme alpha-fucosidase decreased progressively with approximately 60% decrease at the end of the 14 weeks of infection. Representative semen samples from the control and infected rams were subjected to kinetic characterization. While the uninfected semen sample showed two active pH peaks at 4.5-5.5 and at 6.8-7.2, respectively, there was an apparent shift to only a single pH optimum at 4.5-5.5 for the pathological semen. The fucosidases from both sources were optimally active at 35 degrees C albeit with contrasting activation energies (E(a)) with values 20.58 and 35 kJ/mol for the control and infected semen, respectively. Kinetic studies using methylumbelliferyl-beta-fucoside (4MU-Fuc) as substrate gave K(M) and V(max) values of 3.25 microM and 14.6 micromol. min(-1) mg(-1), respectively for the control semen. The values for the infected semen were 18.25 microM and 10.5 micromol. min(-1) mg(-1), respectively. The significance of these results is discussed as they relate to loss in reproductive capacity in trypanosomoses.