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PubMed2000

Genetics of growth and reproduction in the turkey. 14. Changes in genetic parameters over thirty generations of selection for increased body weight.

A line (F) of turkeys was selected over 30 generations for increased 16-wk BW. The base population for the F line was a randombred control population (RBC2) that was maintained without conscious selection and used to remove yearly environmental variation in the F line. Selection was effective in increasing 16-wk BW in the F line. Selection differentials based on the mean of selected parents minus mean of entire population (intended) and intended selection differentials weighted for number of offspring produced (actual) did not consistently differ, indicating that natural selection was not significantly opposing artificial selection. The realized heritability (h2) of 16-wk BW in the F line, based on the linear regression of the selection response on accumulated actual selection differentials, declined with selection; the decline appeared to be slightly different for males than females. For both sexes combined, the realized h2 was 0.309+/-0.022 (SE), 0.268+/-0.033, 0.242+/-0.026, and 0.254+/-0.007, respectively, for Generations 1 to 10, 11 to 20, 21 to 30, and 1 to 30. Genetic increases in 16-wk BW in the F line were positively associated with BW at other ages (8, 20, and 24 wk of age and at 50% production), days from stimulatory lighting to production of the first egg, and egg weight. Genetic increases were negatively associated with egg production, intensity of lay (maximum and average clutch length and rate of lay), and hatch of fertile eggs. There was no significant relationship between 16-wk BW and total days lost from broodiness or fertility. The genetic changes in some correlated traits were not consistent in all generation intervals studied, indicating that the genetic correlation between the selected trait (16 wk BW) and the correlated trait changed with selection.

Animals↗

PubMed2005

Evaluation of immuno- and reproductive toxicities and association between immunotoxicological and genotoxicological parameters in waste incineration workers.

In this study, we investigated immunotoxicity levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin in 31 waste incineration workers and in 84 control subjects, and evaluated the association between immunological and genotoxicological parameters. DNA damage in mononuclear and polynuclear lymphocytes, and the level of the urinary metabolites, 1-OHP and 2-naphthol, were evaluated in both waste incineration workers and control subjects. Significant differences were detected in these values between exposed and control groups. Number of sperms was lower in the waste incineration workers than in the control subjects, as was the percentage of motile sperms, but a significant difference existed only in the number of sperms (p=0.05). DNA damage in the spermatozoa of waste incineration workers and control subjects measured 1.40+/-0.08 and 1.26+/-0.03, respectively (p=0.001). Specific surface antigens of peripheral lymphocytes, namely, CD3, CD4, CD8, CD19, and CD69 were used to measure immune status in waste incineration workers and control subjects. There was no significant difference in T- and B-cell profiles showed between waste incineration workers and control subjects (p=0.684 and 0.157). In addition, the ratio of T helper cells to T cytotoxic cells was also not remarkably different between groups (p=0.174). However, T-cell activation was found to be significantly higher in the waste incineration workers than in the control subjects (p=0.001), although B-cell activation did not exhibit this trend. The levels of two cytokines (IL-4 an INF-gamma) and four immunoglobulins (IgA, IgE, IgG, and IgM) were also measured in the experimental population. All immunoglobulin types were found in lower amounts in the waste incineration workers, but this diaparity was not significant one. In addition, the levels of two cytokines, IL-4 and INF-gamma, were also found to be lower in the waste incineration workers than in the control subjects, and only in IL-4 was a significant difference determined to exist.

Adult↗

PubMed2000

Reproductive characteristics of Ethiopian highland sheep. II. Genetic parameters of semen characteristics and their relationships with testicular measurements in ram lambs.

A study was conducted to investigate the effect of season on, and to estimate heritabilities of, and genetic correlations among, semen and spermatozoa characteristics and the relationship of these characteristics with measures of testicular or scrotal size in 6-, 9- and 12-month old ram lambs of Menz and Horro sheep breeds indigenous to Ethiopian highlands. A total of 278 ram lambs with substantial pedigree information were involved in the study. There was improvement in all semen and spermatozoa traits with age, the means at 12 months being consistently superior to values at 6 and 9 months of age. There were no significant breed differences in any of the traits studied, except semen volume at 9 months (0.67, S.E. 0.07 for Horro versus 0.39, S.E. 0.05ml for Menz) and proportion of dead spermatozoa at 12 months (0.18, S.E. 0.03 versus 0.23, S.E. 0.02, respectively). Season was significant (p<0.05) for most of the traits studied, and differences were attributed primarily to nutrition. Semen collected in the wet season had higher spermatozoa concentration while samples collected in the dry season had higher proportion of abnormalities. After correcting for differences in total spermatozoa abnormalities, the wet season (of collection) had the highest spermatozoa output (volumexconcentration) in 12-month old ram lambs. Heritability estimates varied substantially in magnitude, ranging from zero to over 0.4. Traits with non-trivial heritability estimates were mass motility at 9 months (0.32, S.E. 0.11), individual motility at 9 months (0.32, S.E. 0.12) and at 12 months (0.16, S.E. 0.12) and proportion of abnormal spermatozoa at 9 months (0.35, S.E. 0.13). Genetic correlations among semen and spermatozoa characteristics, as well as correlations with testicular measurements, were medium to high and generally favourable, but were associated with large standard errors. The genetic correlations of scrotal circumference with semen volume (0.55, S.E. 0.11), mass motility (0.62, S.E. 0.20), individual motility (0.54, S.E. 0.12), concentration (0.25, S.E. 0.04) and proportion of abnormal spermatozoa (-0.75, S.E. 0.24) in 12-month old rams indicated that selection based on this trait, which is highly heritable and easy to measure and can be measured early in life, should have appreciable favourable correlated response in semen quality and spermatozoa production.

Journal Article↗

PubMed1996

[Immunologic parameters in breast cancer patients (depending on age, reproductive function, clinical and pathologic pattern and growth rate of the tumor)].

The immunological indices were studied by spontaneous rosette-formation and immunocytochemical procedure in 226 patients with breast cancer. The levels, ratio and phenotypic patterns of peripheral blood T-cells were assessed in patients with primary tumors vis-a-vis biological pattern of tumor, stage, rate of growth, locally-regional extension, pathogenetical type of tumor and such breast cancer-related physiological characteristics as age and menstrual function. It was found that immunodepression in breast cancer patients can be detected by laboratory examination at stage IIb. It may manifest itself in a changed ratio of main subpopulations of T-lymphocytes, decrease in the total level of T-cells and increase in dysfunctional ones. The worst immunological indices were identified in patients younger than 35 and those with rapidly growing tumors.

Adult↗

PubMed1990

Overall efficacy of chronically administered recombinant bovine somatotropin to lactating dairy cows.

Recombinant bST at daily dosages of 0, 10.3, 20.6, and 41.2 mg/d were injected for 266 d into 8, 10, 9, and 9 Holstein cows, respectively. Treatment effects of recombinant bST were assessed for milk production traits, BW, blood components, and health and reproductive variables. Data reported compare controls to all bST-treated cows. There was an average increase of 18% in 3.5% FCM for bST versus control cows. This increase resulted in enhanced feed efficiency for bST cows, as their DM intakes were not elevated above those of the control cows. Recovery of BW was similar between control and bST groups. Milk composition was unaffected except for a slight decrease in protein percentage during the first 9 wk of treatment, and an elevated SCC between wk 19 and 28. Blood parameters were not different between control and bST cows, except for hematocrit, which decreased with bST treatment. The only health and reproductive parameters affected by bST were mastitis and days open, which were increased in the highest dosage groups.

Animals↗

PubMed1997

Population Dynamics of Evolutionary Change: Demographic Parameters as Indicators of Fitness

I evaluated demographic parameters as indicators of fitness by calculating the net reproductive rate (R0), exponential rate of change (r), lifetime reproductive success (LRS), and Malthusian parameter (m) for nine genotypes and four phenotypes (two alleles at each of two independent loci) of an age-structured population. The given starting conditions included age-specific survival rates of males and females and age-specific fecundity of females for each genotype (to simplify the problem I presumed no differences in survivorship or fecundity of genotypes with the same phenotype) and the same age structure for each genotype. The prevailing genotype had the greatest m, but it did not have the greatest r, R0 , or LRS, or even the greatest survivorship of either juveniles or adults, or the greatest fecundity. This result indicates that m is the only correct measure of fitness (i.e., as a predictor of which genotype should prevail from among a group of genotypes) and that comparisons of r, R0 , LRS, juvenile or adult survival rates, or fecundity may be misleading indicators of which genotype should prevail (i.e., be most "fit") over time (i.e., be selected for).

Journal Article↗

PubMed2003

Male smokers have a decreased success rate for in vitro fertilization and intracytoplasmic sperm injection.

OBJECTIVE: Smoking by one or both partners can adversely affect IVF outcome. We investigated whether smoking may also play a role in the success rate of intracytoplasmic sperm injection (ICSI), in which initial steps of fertilization are bypassed. DESIGN: Three hundred one couples (ICSI: 153, IVF: 148) participated in 415 treatment cycles (ICSI: 202, IVF: 213). One hundred thirty-nine men were habitual smokers (ICSI: 71, IVF: 68). Seventy-seven women were smokers (ICSI: 41, IVF: 36). Multiple nominal regression analyses of various steps of assisted reproduction included smoking status, age, semen parameters, and number of embryos transferred. SETTINGS: Reproductive and andrology unit of the university. PATIENT(S): Three hundred one couples seeking fertility treatment. INTERVENTION(S): Assisted reproduction by in vitro fertilization (IVF) or ICSI. MAIN OUTCOME MEASURE(S): Clinical pregnancy. RESULT(S): Intracytoplasmic sperm injection success (clinical pregnancy) in women with smoking male partners was 22% and was 38% with nonsmoking partners. Similar results were seen for IVF, with 18% vs. 32%. Multinominal logistic regression analysis revealed smoking in men to be a significant predictor of ICSI outcome, along with female age and the number of embryos transferred, whereas clinical pregnancies after IVF were dependent on smoking in men, number of embryos transferred, sperm motility, and female age. Female smoking influenced the number of oocytes retrieved and the fertilization rate of oocytes in IVF but not in ICSI. The odds ratio for failure of ICSI for male smokers in comparison to male nonsmokers was 2.95 (IVF: 2.65). CONCLUSION(S): Smoking by males decreases the success rates of assisted reproduction procedures, not only in IVF, but also in ICSI. Apart from putative adverse effects during fertilization, altered DNA in spermatozoa might hamper development of the embryo.

Female↗

PubMed2006

On the population dynamics of the malaria vector.

A deterministic differential equation model for the population dynamics of the human malaria vector is derived and studied. Conditions for the existence and stability of a non-zero steady state vector population density are derived. These reveal that a threshold parameter, the vectorial basic reproduction number, exist and the vector can established itself in the community if and only if this parameter exceeds unity. When a non-zero steady state population density exists, it can be stable but it can also be driven to instability via a Hopf Bifurcation to periodic solutions, as a parameter is varied in parameter space. By considering a special case, an asymptotic perturbation analysis is used to derive the amplitude of the oscillating solutions for the full non-linear system. The present modelling exercise and results show that it is possible to study the population dynamics of disease vectors, and hence oscillatory behaviour as it is often observed in most indirectly transmitted infectious diseases of humans, without recourse to external seasonal forcing.

Animals↗

PubMed2005

Decreased fertility in mice exposed to environmental air pollution in the city of Sao Paulo.

It has largely been shown that air pollution can affect human health. Effects on human fertility have been shown mainly in males by a decrease in semen quality. Few studies have focused on the environmental effects on female fertility. The aim of the present study was to analyze the effects of air pollution in the city of Sao Paulo on mouse female fertility. Four groups of female Balb/c mice were placed in two chambers 10 days (newborn) or 10 weeks (adults) after birth. Mice were maintained in the chambers 24 h a day, 7 days a week, for 4 months. The first chamber received air that had passed through an air filter (clean chamber) and the second received ambient air (polluted chamber). We measured PM10 and NO2 inside both chambers. Mice belonging to the adult groups were bred to male mice after living for 3 months inside the chambers. The newborn groups mated after reaching reproductive age (12 weeks). After 19 days of pregnancy the numbers of live-born pups, reabsorptions, fetal deaths, corpora lutea, and implantation failures were determined. PM10 and NO2 concentrations in the clean chamber were 50% and 77.5% lower than in the polluted chamber, respectively. Differences in fertility parameters between groups were observed only in animals exposed to air pollution at an early age (10 days after birth). We observed a higher number of live-born pups per animal in the clean chamber than per animal from the polluted chamber (median=6.0 and 4.0, respectively; P=0.037). There was a higher incidence of implantation failures in the polluted group than in the clean group (median=3.5 and 2.0, respectively; P=0.048). There were no significant differences in the other reproductive parameters between groups. These results support the concept that female reproductive health represents a target of air pollutants.

Air↗

PubMed1999

Constraints to milk production in grazing dairy cows in Brazil and management strategies for improving their productivity.

Productivity in most Brazilian dairy herds is low and depends exclusively on pasture. To study the productive potential of pastures and to devise strategies to further improve pasture and animal productivity in this production system, studies were carried out to obtain basic on-farm information. The constraints which affect productivity and reproductive performance of dairy cows, the effects of restrictions in suckling time of calves, and strategic supplementation during the dry season upon animal production were the evaluated parameters. From March 1992 through February 1997, studies were carried out on four private farms in the northern region of the State of São Paulo. Between March 1992 and February 1994 (Study 1--survey phase), 142 cows (parity = 1-6) grazed pasture which consisted of signal grass (Brachiaria decumbens and Brachiaria brizanta). Once-a-month data were collected on body weight, body condition, and milk production. Reproduction parameters were assessed by milk progesterone profiles. From March 1996 to February 1997 (Study 2--intervention phase), 45 lactating dairy cows from two farms were hand-milked once a day and the calf suckling was restricted to two hours after milking. Data were collected on milk production and cow body weight. In Study 1, cows were grouped by calving date for the analysis of the reproductive and production data. Concentrations of blood metabolites, hemoglobin, and hematocrit were compared among randomly selected cows (n = 69) from all farms. Estimated pasture available per hectare (ha) at any time, crude protein (CP), and dry matter digestibility (DMD) of pasture available for grazing differed (p < 0.05) between seasons [pasture available = 1.2, 1.4, 1.8 and 2.2 t/ha (SE = 0.70); CP = 42, 60, 48 and 57 g/kg (DM) (SE = 10.1); DMD = 399, 468, 401 and 457 g/kg (DM) (SE = 21), respectively, for dry season 1992 (D92), wet season 1992 (W92), dry season 1993 (D93), and wet season 1993 (W93)]. The proportion of animals showing ovarian activity at 90 days postpartum (DPP) was higher for cows which calved in the wet season than cows which calved in the dry season. In Study 2, milk production tended to the higher (7.3 and 6.5 kg/day, respectively, for the intervention and survey studies; p = 0.08). The data suggest that milk production is being limited by pasture availability, the quality of pasture, and the lack of supplementation. We suggest that, although supplementing cows in the dry period may have an economic advantage, better pasture management needs to be introduced. Stocking rate must be adapted to pasture productivity and pasture quality throughout the year.

Animal Feed↗

PubMed2005

Sublethal effects of imidacloprid and pymetrozine on the life table parameters of Aphis gossypii Glover (Homoptera: Aphididae).

In this study we report the sublethal effects of recommended concentrations of imidacloprid and pymetrozine on cotton aphid's reproduction. Fecundity life table parameters for AG were studied on cucumber under conditions of 25+/-1 degrees C, 70+/-5% RH and photoperiod of 16:8 (L:D). Leaf discs of cucumber immersed in the recommended concentrations of the above mentioned insecticides and controls and the new born female was released on the lower surface of leaf discs. Values of parameters such as adult longevity and daily fecundity rate were recorded. Standard error of population growth parameter was calculated using the Jacknife method. The results show that these two insecticides significantly reduce life table parameters compared with control.

Animals↗

PubMedDate not supplied

[Complex perception of stimuli during conditioning].

The review concerns the effects of a variety of stimuli on the reproduction of conditioned reflexes. By the literature data, during conditioning of any type, besides the single stimulus intentionally applied by an experimenter as a conditioned one, an animal perceives the whole complex of stimuli (acoustic, visual, olfactory, algesic, and other exteroceptive, proprioceptive, and interoceptive stimuli), including those of the environment and time of the day during training. Many of these stimuli are essential for the reproduction of the acquired habit. The complex of stimuli that act on an animal during the reproduction should in all parameters correspond to that perceived by the animal during training. If the complexes differ at least in one stimulus, the reproduction of the reflex may fail.

Animals↗

PubMedDate not supplied

[Evolutionary stability in the dynamics of populations having short reproduction periods].

A special class of models of competition (D-systems) were constructed in which the coefficients of population growth are periodic delta-functions. Effective methods for the analysis of the global dynamics of D-systems were proposed. In the framework of this model system, the problem of the existence of evolutionarily stable parameters, the periods of reproduction of populations in a variable medium, was studied. Using analytical methods and the data of computer-assisted experiments, open sets of evolutionarily stable parameters were found.

Animals↗

PubMed1978

Effects of an essential fatty acid deficiency, pair-feeding and level of dietary corn oil on the hypothalamic-pituitary-gonadal axis and other physiological parameters in the male chicken.

Two studies were conducted to observe the effects of an essential fatty acid (EFA) deficiency, added dietary corn oil and pair-feeding on growth, reproduction and other physiological parameters in the mature cockerel. A purified, linoleic acid (LA)-deficient diet (0.01% LA), or additions of 5% (3.01% LA) or 15% (9.04% LA) corn oil, were fed ad libitum from hatching through 24 weeks of age. Reductions in growth, feed consumption, and comb, and testes size, incomplete spermatogenesis, increased tissue eicosatrienoic acid (20: 3 omega 9) and changes in weights of selected internal organs were observed in deficient cockerels. Total pituitary gonadotropic activity was measured by two bioassay procedures and blood luteinizing hormone was measured by radioimmunoassay. By maturity both of these parameters were significantly reduced in deficient chickens. When these chickens were fed diets with 5% or 15% corn oil under pair-feeding or ad libitum conditions from 20 to 24 weeks, the reduced growth, comb and testes size and gonadotropin metabolism appeared to be caused by depressions in appetite and energy intake rather than EFA per se. The degenerate testicular histology of the 20-week old deficient cockerels, while responding fully to the ad libitum intake of the diets containing corn oil, showed only partial rehabilitation of spermatogenesis when diets with either 5% or 15% corn oil were pair-fed. In general, increasing the level of dietary fat from 5% to 15% did not cause many physiological changes.

Animals↗

PubMed1993

Sexual maturation and seasonal changes in plasma levels of sex steroids and fecundity of wild Norway rats selected for reduced aggressiveness toward humans.

Parameters of sexual maturation and reproductive function were compared in two groups of Norway rats, one selected for reduced aggressiveness towards man and the other for aggressiveness. It was found that selection for reduced aggressiveness produced an acceleration of sexual maturation as judged by earlier vaginal opening in the female and presence of mature spermatozoa in the testes of the male as well by earlier prepubertal increase in plasma testosterone in the male. In domesticated adults, seasonal variations in the parameters of the reproductive function narrowed; they showed neither the winter decrease in sexual activity nor the marked fall in plasma testosterone and estradiol exhibited by their aggressive counterparts.

Aggression↗

PubMed1984

Kinetics of in vitro ageing of mouse embryo fibroblasts.

The kinetics of ageing of normal mouse embryo fibroblast cells in culture have been determined. The growth pattern during every passage was established. It was observed that the growth pattern was not exponential, but that the growth rate declined progressively both within and with every passage. We also estimated the cell cycle parameters using the Fraction of Labelled Mitoses method at every passage. We found that the cell cycle duration was constant throughout the lifespan of this cell strain; the median value of the cell cycle duration was found to be 15.5 +/- 0.5 h (S.D., n = 8). From these two sets of observations we infer that the fraction of dividing cells declines smoothly from the beginning of the culture. Our data exclude quite positively any description of ageing of the fibroblast population in terms of a catastrophe or any abrupt change in the population. Our data are also inconsistent with a linear decline in growth fraction. On the contrary, we observed that there was a gradual and smooth decline in the growth rate of the strain, due to a smoothly declining growth fraction. This smooth change in the growth behaviour of this cell strain is accurately described by the mortalization theory of Shall & Stein in which the single parameter gamma (gamma), describes the change in reproductive potential over the entire lifespan. The parameter gamma describes the rate at which the doubling time of the culture increases. It is the number of generations at which half of the newborn cells are themselves reproductively sterile. Our present data provided an estimate of gamma for this cell strain, which was consistent during the entire lifespan of the strain; the best estimate of gamma for this cell strain was 20.3 +/- 0.6 generations (S.D., n = 19).

Animals↗

PubMed2007

Impact of cryopreservation and reactive oxygen species on DNA integrity, lipid peroxidation, and functional parameters in ram sperm.

Assisted reproduction using frozen-thawed semen has practical advantages, although cryopreservation is detrimental to sperm fertility in most mammals. We examined the influence of cryopreservation and reactive oxygen species (ROS) on ram sperm DNA stability (using SCSA), lipid peroxidation (LPO), chlortetracycline fluorescence (CTC) patterns, motility and viability. In Experiment 1, DNA integrity, LPO, CTC, motility and viability tests were performed on fresh and cryopreserved sperm after 0, 6, and 24 hr in synthetic oviductal fluid (SOF). In Experiment 2, fresh sperm were incubated in serum-free SOF (SOF-S; 1, 4, and 24 hr) with 0, 50, 150, or 300 microM H2O2 then assayed. Cryopreservation increased the percentage of sperm with a high DNA fragmentation index (%DFI), decreased the percentages of motile and viable sperm at thawing (0 hr), but did not affect LPO. H2O2 (150 or 300 microM) increased %DFI after 24 hr. LPO or sperm viability were not affected by H2O2, although most motility parameters decreased. H2O2 decreased the percentage of chlortetracycline pattern F sperm at 4 hr and increased the percentage of acrosome-reacted sperm (pattern AR) after 1 hr. Pooled data of Experiment 2 showed LPO was positively correlated with SCSA (r = 0.29 to r = 0.59; P < 0.05 to P < 0.01), while most motility parameters and the percentage of viable sperm were negatively correlated with LPO (r = -0.30 to r = -0.38; P < 0.05 to P < 0.01). LPO was positively correlated with the percentage of pattern AR sperm (r = 0.33; P < 0.01). Cryopreservation and H2O2 promote DNA instability in ram sperm, though motility is a more sensitive indicator of oxidative stress than the other parameters investigated.

Animals↗

PubMed2006

Studies on the reproductive, cytological and biochemical toxicity of Ginkgo Biloba in Swiss albino mice.

Ginkgo biloba (an herbal product), used as a folkloric medicine in the treatment of dementia, was evaluated for its effects on reproductive, cytological and biochemical toxicity in male Swiss albino mice. The mice were treated with different doses (25, 50 and 100mg/kg/day) of the aqueous suspension of Ginkgo biloba for 90 days by oral gavage. The following parameters were evaluated: (1) reproductive organ weight; (2) motility and content of sperms; (3) spermatozoa morphology; (4) cytology of the testes chromosomes; (5) study on reproduction; (6) biochemical study on proteins, nucleic acids, malondialdehyde (MDA) and nonprotein sulfhydryl (NP-SH). The treatment caused significant changes in the weight of caudae epididymis, prostate, chromosomal aberrations, rate of pregnancy and pre-implantation loss. However, the percent motility, sperm count and morphology of spermatozoa were not affected. Our study on biochemical parameters showed depletion of nucleic acids, NP-SH and increase of MDA, which elucidated the role of free radical species in the induced changes in testis chromosomes and the reproductive function. The exact mechanism is not known, however, the activation of GABA, glycine and glutamate under the influence of Ginkgo biloba and its constituents might have generated free radicals and depleted cellular glutathione by calcium influx and membrane depolarization. The observed toxicity is attributed to the toxic constituents (ginkgolic acids, biflavones, cardanols, cardols, bilobalides and quercetin) of Ginkgo biloba. Our results warrant careful use of Ginkgo biloba as a remedy for impotence and/or erectile dysfunction.

Animals↗