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PubMed2000

Diminished decondensation and DNA synthesis in activated sperm from rats treated with cyclophosphamide.

Standard andrology tests do not predict fertility or assess the genetic quality of spermatozoa. To address these problems, we have analyzed sperm nuclear activation in vitro using cytoplasmic extracts of Xenopus laevis frog eggs. The objective of this study was to determine if rat sperm chemically damaged in vivo by cyclophosphamide treatment would respond abnormally in an in vitro rat sperm activation assay (RSAA). Male Sprague-Dawley rats were treated for 6 weeks with cyclophosphamide (CP) to induce DNA damage in post-meiotic germ cells. After the treatment period, cauda epididymal sperm were isolated, and incubated in cytoplasmic extracts of X. laevis frog eggs to induce chromatin decondensation and DNA synthesis in vitro. Sperm from treated rats displayed significant decreases in both decondensation and DNA synthesis when compared to sperm from control rats, consistent with the presence of CP-induced DNA crosslinks. No differences in body, testes, or epididymal weights were observed between control and treated rats, nor was sperm count diminished in the treatment group. These results demonstrate that the RSAA can be used to detect damaged sperm chromatin in the absence of detrimental effects on sperm count, and testis and epididymal weights.

Animals↗
PubMed2001

Sperm quality in the alternative reproductive tactics of Atlantic salmon: the importance of the loaded raffle mechanism.

The outcome of sperm competition in species with alternative male reproductive strategies may be determined by fair or loaded raffle mechanisms. The sperm production and quality of male Atlantic salmon using alternative reproductive tactics were investigated in order to determine the relative importance of sperm quality for male reproductive success. Sexually mature resident parr males produced greater numbers of spermatozoa per millilitre of ejaculate and invested more in their gonads as a percentage of body mass than their anadromous counterparts. Parr males had greater proportions of motile spermatozoa and a greater sperm ATP content as compared with anadromous males. Parr males invested relatively more in sperm quality and sperm numbers after the effect of body size was accounted for. In fertilization experiments, parr males fertilized greater proportions of eggs than anadromous males. A polynomial model exhibited a trade-off between testes mass and ejaculate expenditure and explained 60% of the variation. These results establish that, in sperm competition with dominant males, parr males may compensate for behavioural subordinance by producing physiologically superior spermatozoa.

Adenosine Triphosphate↗
PubMedDate not supplied

A multivariate analysis of socio-demographic factors, water contact patterns and Schistosoma mansoni infection in an endemic area in Brazil.

Associations between socio-demographic factors, water contact patterns and Schistosoma mansoni infection were investigated in 506 individuals (87% of inhabitants over 1 year of age) in an endemic area in Brazil (Divino), aiming at determining priorities for public health measures to prevent the infection. Those who eliminated S. mansoni eggs (n = 198) were compared to those without eggs in the stools (n = 308). The following explanatory variables were considered: age, sex, color, previous treatment with schistosomicide, place of birth, quality of the houses, water supply for the household, distance from houses to stream, and frequency and reasons for water contact. Factors found to be independently associated with the infection were age (10-19 and > or = 20 yrs old), and water contact for agricultural activities, fishing, and swimming or bathing (Adjusted relative odds = 5.0, 2.4, 3.2, 2.1 and 2.0, respectively). This suggests the need for public health measures to prevent the infection, emphasizing water contact for leisure and agricultural activities in this endemic area.

Adolescent↗
PubMed1999

Staying good while playing god--the ethics of breeding farm animals.

Modern genetics has given us some very efficient tools with which to alter the characteristics of animals. To date, farm animal breeders have mainly used these tools to increase productivity. Thus, each new generation of farm animals matures faster, yields more milk, or produces more meat or eggs, than the previous one. Despite these apparent benefits, modern farm animal breeding has had severe negative consequences, including effects on the quality of the animals' lives and biodiversity. The aim of this paper is to discuss the goals and consequences of farm animal breeding within an ethical context. First, a description of what has happened to broilers and dairy cattle as breeders have pursued the goal of ever more efficient production is given. Second, the ethical values that ought to underlie future breeding schemes are discussed. It is suggested that there are in fact two very different ethical approaches: the 'quality of life-based' approach and the 'preservationist' approach. A view combining elements from both approaches is advanced. Finally, an example is given of how it is possible, in practice, to pursue an ethically defensible breeding goal without compromising production efficiency.

Animal Welfare↗
PubMed2005

Use of circulating cathodic antigen (CCA) dipsticks for detection of intestinal and urinary schistosomiasis.

An evaluation of a commercially available antigen capture dipstick that detects schistosome circulating cathodic antigen (CCA) in urine was conducted in representative endemic areas for intestinal and urinary schistosomiasis in Uganda and Zanzibar, respectively. Under field-based conditions, the sensitivity (SS) and specificity (SP) of the dipstick was 83 and 81% for detection of Schistosoma mansoni infections while positive predictive (PPV) and negative predictive values (NPV) were 84%. Light egg-positive infections were sometimes CCA-negative while CCA-positives included egg-negative children. A positive association between faecal egg output and intensity of CCA test band was observed. Estimating prevalence of intestinal schistosomiasis by school with dipsticks was highly correlated (r=0.95) with Kato-Katz stool examinations, typically within +/-8.5%. In Zanzibar, however, dipsticks totally failed to detect S. haematobium despite examining children with egg-patent schistosomiasis. This was also later corroborated by further surveys in Niger and Burkina Faso. Laboratory testing of dipsticks with aqueous adult worm lysates from several reference species showed correct functioning, however, dipsticks failed to detect CCA in urine from S. haematobium-infected hamsters. While CCA dipsticks are a good alternative, or complement, to stool microscopy for field diagnosis of intestinal schistosomiasis, they have no proven value for field diagnosis of urinary schistosomiasis. At approximately 2.6 US dollars per dipstick, they are presently too expensive to be cost-effective for wide scale use in disease mapping surveys unless Lot Quality Assurance Sampling (LQAS) strategies are developed.

Animals↗
PubMed2002

Impact of local agricultural and industrial practices on organic contamination of little egret (Egretta garzetta) eggs in the Rhone Delta, southern France.

The purpose of this study was to determine the importance of the effects of local agricultural and industrial activities on the contamination of little egret eggs laid in the Camargue area, a protected wetland area in the Mediterranean region. Despite the fact that human activity is widespread in the Camargue, concentrations of lindane (0.01-0.7 microg/g wet wt) and of polycyclic aromatic hydrocarbons (<0.5 microg/g wet wt) do not seem to be deleterious-at least for herons. Residues of dichlorodiethyltrichlorethylene (DDE) were usually below 1 microg/g wet weight. The principal threat comes from high concentrations of polychlorinated biphenyls (PCBs; 0.1-12 microg/g wet wt), which are known to have teratogenic effects in other bird species at similar concentrations and are thought to originate locally (sediments of the delta and industrial complex of Fos/Mer). For this reason, particular interest should be focused on the water/sediment quality of the Rhĵne River (France), on industrial sewage, and on wildlife contamination. A significant but weak link between colony site and lindane concentration was detected in eggs and may be attributed to the fact that our egg collection from each sampled colony was not synchronized with pesticide spread. A stronger site effect was observed for PCBs. Eggs collected near the industrial complex of Fos/Mer (petroleum, power plants) displayed the highest median concentration and the most contaminated eggs. Such results warrant thorough monitoring of this colony.

Agriculture↗
PubMed1984

Relationship between final temperature, thaw rate, and quality of bovine semen.

Relationships between thaw rate, thaw bath time, and initial bath and final seminal temperature with coefficients of determination .99 and .97 were: bath time = -.01 + 220.25(1/thaw rate); initial bath temperature = final seminal temperature - 7.29 + 390.05 (1/bath time). Ejaculates from 10 bulls were split and processed in egg yolk-citrate-glycerol, egg yolk-Tris-glycerol, and whole milk-glycerol. All semen was packaged and frozen in .5-ml French straws at -196 degrees C. Sixteen thaw treatments consisted of factorial combinations of four final seminal temperatures and four thaw rates. Treatments were assessed by post-thaw acrosomal integrity after 3-h 37 degrees C incubation. Seminal quality improved with increasing final seminal temperature up to 31 degrees C and did not differ between 31 and 44 degrees C for any of the extenders. A slow thaw rate (3 degrees C/s) resulted in inferior quality for all extenders, and rates 11, 19, and 27 degrees C/s resulted in similar quality for citrate and milk extended semen. Acrosomal integrity was most for 19 degrees C/s in Tris extended semen. A significant factorial interaction existed for Tris and milk extended semen. Predicted acrosomal response of 57.7% across all extenders was at optimum final seminal temperature and thaw rate 37 degrees C and 18 degrees C/s. Bath temperature and bath time determine optimum thaw rate and final temperature of semen packaged in French straws and thus maximize seminal quality.

Acrosome↗
PubMedDate not supplied

Comparison of interlaboratory variation in amino acid analysis and rat growth assays for evaluating protein quality.

Estimates of inter- and intralaboratory variation of protein efficiency ratio (PER), relative PER (RPER), net protein ratio (NPR), relative NPR (RNPR), and nitrogen utilization (NU) were compared with those of amino acid analysis in the same batches of 7 protein sources (ANRC casein, egg white solids, minced beef, soy assay protein, rapeseed protein concentrate, pea flour, and whole wheat flour). Interlaboratory variation (estimated as between-laboratories coefficients of variation, CV) of NPR and RNPR (up to 6.0%) was lower than that of PER (up to 20.2%) and RPER (up to 18.5%). The interlaboratory determination of NPR and RNPR was also more reproducible than that of most essential amino acids (CV up to 10.0%), especially tryptophan (CV up to 23.7%), cystine (CV up to 17.6%), and methionine (CV up to 16.1%). Intralaboratory variation (estimated as within-laboratories CV) of amino acid analysis (up to 4.7%), however, was comparable to that of protein quality indices in most protein sources (up to 6.0%). The significant (P less than 0.01) positive correlations (r = 0.68-0.74) between amino acid scores and protein quality indices based on rat growth were further improved when amino acid scores were corrected for digestibility of protein (r = 0.73-0.78) or individual amino acids (r = 0.79-0.82).

Amino Acids↗
PubMed2006

Herbimycin A suppresses mitotic activity and egg production of female Schistosoma mansoni.

The eggs of the endoparasite Schistosoma are the causative agent of schistosomiasis, an important disease of humans, which is endemic in (sub-) tropical regions. The absence of a vaccine with sufficient protective qualities and increasing resistance to approved and established drugs like praziquantel, justify the exploration of novel ways to fight schistosomes. Our strategy is based on interference with the sexual maturation of the female. Prerequisites for gonad development in adult females are a continuous pairing contact with the male and significantly increased mitotic activity. In this study we show that the male governs sexual maturation of the female, as the separation of couples causes a clear reduction of female mitotic activity and, consequently, egg production. We demonstrate that treatment of schistosomes with Herbimycin A, an inhibitor of protein tyrosine kinases (PTKs), mimics the separation of couples as the drug blocks mitotic activity and egg production of paired females. However, the synthesis of the eggshell precursor protein p14 is elevated. Furthermore, we show for the first time in invertebrates that Herbimycin A decreases tyrosine phosphorylation and PTK stability in schistosomes. Summarised, our data provide evidence that PTKs have key functions in regulating gonad development, eggshell gene expression and, consequently, egg production. Therefore, we suggest envisaging schistosome PTKs as novel targets for strategies to combat schistosomiasis.

Animals↗
PubMed1998

Toxic effects of cadmium on reproduction, development, and hatching in the freshwater snail Lymnaea stagnalis for water quality monitoring.

The freshwater snail Lymnaea stagnalis was exposed to cadmium concentrations of 0, 25, 50, 100, 200, and 400 microgram liter-1. The influence of this highly toxic metal on various stages of reproduction (number of egg masses, number of eggs, embryo development, and hatching) was studied. Egg production ceased at 400 microgram Cd2+ liter-1 and hatching was reduced to 0.4% with 200 microgram liter-1 at 20 degreesC. The study revealed that embryo development was the most sensitive stage, the main anomalies observed depending on the Cd2+ concentration. At the highest concentration studied (400 microgram liter-1) the eggs were blocked in the first cleavage stage. At 100 and 200 microgram Cd2+ liter-1, development of the eggs was halted at various stages of embryogenesis (cleavage, gastrula, veliger, and prehatching) depending on their position in the egg masses. At concentrations of 25 to 100 microgram Cd2+ liter-1, development was slowed down and hatching occurred 5 to 15 days later than in the controls (controls hatched 12 to 13 days after laying). The results obtained demonstrate the effects of Cd2+ on reproduction and development in L. stagnalis and provide information on the targets affected (neuroendocrine control of laying or cell multiplication and organogenesis of the embryos). It is thus possible to predict the probability of survival of the species in an environment polluted with cadmium and to compare it with the effects of other pollutants in the same or other species.

Animals↗
PubMed2006

Comparing ethylene glycol with glycerol for cryopreservation of canine semen in egg-yolk TRIS extenders.

The objective of this work was to evaluate the possibility of substituting glycerol (G) for ethylene glycol (EG) when cryopreserving dog semen. A total of 15 ejaculates from 13 dogs was pooled into five samples and frozen in egg-yolk Tris extenders with variable ethylene glycol and glycerol concentrations, with or without Equex STM Paste. Two widely used glycerol extenders (Uppsala Equex II and Norwegian) were utilized as controls. Semen quality parameters assessed after thawing were total subjective motility (TSM), computer assisted sperm analysis (CASA), eosin-nigrosin staining, and flow cytometry (FC) after staining with the PI/Fitc-PSA (fluorescein isotiocianate conjugated with the agglutinin of Pisum sativum, PSA) fluorochromes. No advantages were seen in using EG to replace G when freezing dog semen or combining EG and G in the freezing medium. The Uppsala Equex II provided the best overall post-thaw parameters, followed by the egg-yolk Tris experimental extender with 5% EG and Equex STM Paste. The extender with 4% EG produced similar results to the Norwegian extender. High correlations (r>0.98) were obtained between eosin-nigrosin staining and FC, as well as between subjective and computerized motility assessment (r>0.90).

Acrosome↗
PubMed1993

Epidemiological observations on gastro-intestinal nematodes in communal land cattle from the highveld of Zimbabwe.

Monthly individual faecal samples from 12 calves, 12 heifers, 17 steers, 12 lactating and 10 dry cows from the communal lands near Harare in the Mashonaland province of Zimbabwe, were collected over a period of one year. Eggs per gram (epg) were determined and the infective larvae (L3) examined, following culture of pooled samples from each group of animals. The lowest counts were found in steers and the highest in calves. The lactating cows had egg counts as high or higher than the heifers. The general trend of epg was related to the rainfall pattern. The egg counts rose from December to reach a peak during April and May, followed by a decline and low levels during the dry period, from June to December. Cooperia, Haemonchus, Trichostrongylus, Oesophagostomum and Strongyloides (in calves only) were identified on coproculture. About 73-83% of L3 belonged to Cooperia and Haemonchus. The high level of infection by nematodes in the communal land cattle was thought to be due to overstocking, overgrazing and poor pasture quality.

Animals↗
PubMed2005

Crystal quality and differential crystal-growth behaviour of three proteins crystallized in gel at high hydrostatic pressure.

Pressure is a non-invasive physical parameter that can be used to control and influence protein crystallization. It is also found that protein crystals of superior quality can be produced in gel. Here, a novel crystallization strategy combining hydrostatic pressure and agarose gel is described. Comparative experiments were conducted on hen and turkey egg-white lysozymes and the plant protein thaumatin. Crystals could be produced under up to 75-100 MPa (lysozymes) and 250 MPa (thaumatin). Several pressure-dependent parameters were determined, which included solubility and supersaturation of the proteins, number, size and morphology of the crystals, and the crystallization volume. Exploration of three-dimensional phase diagrams in which pH and pressure varied identified growth conditions where crystals had largest size and best morphology. As a general trend, nucleation and crystal-growth kinetics are altered and nucleation is always enhanced under pressure. Further, solubility of the lysozymes increases with pressure while that of thaumatin decreases. Likewise, changes in crystallization volumes at high and atmospheric pressure are opposite, being positive for the lysozymes and negative for thaumatin. Crystal quality was estimated by analysis of Bragg reflection profiles and X-ray topographs. While the quality of lysozyme crystals deteriorates as pressure increases, that of thaumatin crystals improves, with more homogeneous crystal morphology suggesting that pressure selectively dissociates ill-formed nuclei. Analysis of the thaumatin structure reveals a less hydrated solvent shell around the protein when pressure increases, with approximately 20% less ordered water molecules in crystals grown at 150 MPa when compared with those grown at atmospheric pressure (0.1 MPa). Noticeably, the altered water distribution is seen in depressurized crystals, indicating that pressure triggers a stable structural alteration on the protein surface while its polypeptide backbone remains essentially unaltered.

Animals↗
PubMed1995

[Propofol: the ideal long-term sedative?].

Propofol is commercially available as Disoprivan. It is formulated as an aqueous emulsion with 1% 2,6-diisopropylphenol, 10% soya bean oil, 2,5% glycerol and 1.2% egg phosphatide. Since 1986, propofol has been used as a sedative drug in the ICU and is highly valued for its numerous positive qualities. High effectiveness is combined with excellent control, which is demonstrably still present even after 2 weeks of sedation. This control enables short-term neurological surveillance of the patient and rapid weaning from the respirator once drug administration is stopped. Propofol does not disturb cerebral autoregulation. Depression of spontaneous breathing facilitates the ventilation of intubated patients. As the solution contains lipids, it contributes to parenteral nutrition. All in all, ease of control and rapid response make propofol a highly valued product in ICUs. It is easy to understand why many ICU specialists consider propofol an ideal drug for long-term sedation. The present authors, however, are convinced that certain limitations must be taken into account. First, cardiovascular depression, especially if potentiated by drugs such as beta- and Ca-entry blockers, may lead to hypotensive episodes. Potential problems (drug tolerance, hypertriglyceridaemia) may be revealed in long-term studies. As long as no such studies have been presented, the authors believe that it is too early to consider propofol the ideal drug for long-term sedation.

Procedural Sedation↗
PubMed2003

Effects of dietary particulate limestone, vitamin K3 and fluoride and photostimulation on skeletal morphology and osteoporosis in laying hens.

1. Female chicks of a White Leghorn strain were fed three different diets from one day old: control, additional vitamin K3 (10 mg/kg), and a diet containing a combination of additional vitamin K3, sodium fluoride (10 mg/kg) and limestone in particulate rather than powdered form. At 16 weeks photoperiod was increased for half the birds from 8:16 L:D to 16:8 L:D immediately or by one hour per week to the same ultimate photoperiod for the other half. 2. Age at first egg was lower by 4.0 d for birds on the fast lighting regime but there were no overall effects of lighting on bone quality at either 25 or 70 weeks. 3. Additional vitamin K3 resulted in higher proximal tarsometatarsus cancellous bone volumes at 15 weeks and throughout the laying period compared with controls. Plasma osteocalcin concentrations were unaffected by vitamin K3 supplementation during growth. 4. The combination diet resulted in beneficial responses of 12 to 20% in most bone characteristics in hens at 70 weeks. The magnitude of these effects was similar to a previous study involving a particulate calcium source alone (Fleming et al., Poultry Science, 39: 434-440, 1998b). We conclude that the beneficial effects of the combined treatment over the lifetime of the hens were attributable mainly to the presence in the diet of a calcium source in particulate form.

Animal Feed↗
PubMed2003

Modification of standard freezing media to limit capacitation and maximise motility of frozen-thawed equine spermatozoa.

OBJECTIVE: To investigate cryopreservation-induced capacitation-like changes in equine spermatozoa frozen in three different media using chlortetracycline (CTC) fluorescence staining analysis. PROCEDURE: Semen collected from three stallions was diluted in one of three centrifugation media and, after centrifugation and removal of supernatant, extended in corresponding freezing media containing additional egg yolk, glycerol, lactose and Equex paste. The semen was frozen in 5 mL straws and the spermatozoa assessed for motility and membrane quality after thawing. RESULTS: Following centrifugation, spermatozoa diluted with modified Kenney's Centrifugation Medium (MKCM) displayed a higher percentage of (normal) F pattern (94.3%) compared with spermatozoa in Kenney's Centrifugation Medium (KCM) (84.9%) and Glucose-EDTA Centrifugation Medium (GECM) (85.2%). Conversely, the percentage of spermatozoa displaying the (capacitated) B pattern was higher in the KCM (14.1%) and GECM (13.8%) than in the MKCM (5.0%). Following freezing-thawing, there were lower percentages of spermatozoa displaying the AR (acrosome reacted) pattern in modified Kenney's Freezing Medium (MKFM) (45.6%) compared with Kenney's Freezing Medium (KFM) (61.4%) and lactose-EDTA Freezing Medium (LEFM) (61.1%). There was a correspondingly higher percentage of spermatozoa displaying the B pattern in MKFM (52.3%) compared with KFM (37.9%) and LEFM (38.6%). There was no significant difference between the freezing media in the percentage of spermatozoa displaying the F pattern. The percentage of progressively motile spermatozoa was also influenced by the type of freezing medium (P < 0.001). Post-thaw percentages of progressively motile spermatozoa, frozen in MKFM, KFM, and LEFM, were 31.4, 25.8 and 23.3%, respectively. CONCLUSION: MKFM was the preferred medium for cryopreservation of equine spermatozoa due to its superior protection against changes in motility and membrane quality compared with the other freezing media studied.

Animals↗
PubMed2005

Analysis of oocyte quality in recombinant inbred mouse strains developed from KE and CBA strains that differ in fertilization efficiency.

Recombinant inbred (RI) mouse strains were developed from reciprocal crosses between two inbred strains differing in the proportion of fertilized ova (CBA, 100%; KE, 77%), to analyse the underlying factors. A correlation (r = 0.83, P < 0.01) between fertilization efficiency within 22 RI strains and after mating RI females with KE males proved that oocyte quality was involved. The following oocyte parameters were analysed in RI and progenitor strains: time of meiotic maturation, rapidity of enzymatic removal of egg investments, and proportion of fertilized ova with supplementary spermatozoa in the perivitelline space. Among the RI strains, high incidence of supplementary spermatozoa was correlated with lower efficiency of fertilization (r = -0.58, P < 0.05) and with slow meiotic maturation (r = -64, P < 0.01), suggesting that delayed maturation may affect oocyte ability of being fertilized by the first penetrating spermatozoon. However, significant correlations were also found between characters which coexist within the progenitor strains, but are not likely to be physiologically related; this suggests that RI strains have inherited large blocks of progenitor genomes, not disrupted by recombination. The strain distribution pattern (SDP) of the analysed traits revealed CBA-like, KE-like, and intermediate phenotypes, indicating that they are polygenically determined. No linkages were found between the studied traits and 12 enzymatic markers. However, the SDP for fertilization efficiency showed a preponderance of non-matching strains (15/19) in relation to agouti locus; the known instability of this chromosome region makes it possible that a putative linkage was disrupted by recombination when RI strains were created.

Animals↗