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PubMed2003

Regulation of the resistance to nematode parasites of single- and twin-bearing Merino ewes through nutrition and genetic selection.

Periparturient Merino ewes obtained from lines of sheep that had been selected either for increased resistance to Haemonchus contortus (R) or at random (C) were supplemented, while grazing at pasture, with either nil or 250 g/day cottonseed meal (CSM) for the 6 weeks prior to or the 6 weeks after the start of parturition. Ewes from both supplement groups had lower (mean 66% reduction) faecal egg counts (FECs) during the postpartum period and this coincided with a period of maternal body weight loss. Factors which increased the rate of maternal body weight loss, such as pregnancy and lactation status, also increased FEC. Evidence is presented that the magnitude of the periparturient rise (PPR) in FEC in grazing ewes will be greatest during periods of maternal weight loss and at these times supplementation to increase metabolisable protein (MP) supply will be most effective in increasing resistance to nematode parasites. The resistance of R ewes to nematode parasites was greater than that of C ewes throughout the experiment and was sufficiently low such that anthelmintic treatment in a commercial environment may not have been required. Irrespective of actual FEC, ewes from all treatment combinations exhibited a PPR in FEC. Reduced FEC of R ewes resulted in reduced apparent pasture larval contamination after 18 weeks of continuous grazing but supplementation was ineffective in this regard. It is suggested that integrated parasite management (IPM) programs for periparturient ewes should make use of both protein supplementation and genetic selection to increase worm resistance and reduce dependency on anthelmintics for worm control.

Animal Nutritional Physiological Phenomena↗
PubMed2001

The role of basal ganglia in reinforcement learning and imprinting in domestic chicks.

Effects of bilateral kainate lesions of telencephalic basal ganglia (lobus parolfactorius, LPO) were examined in domestic chicks. In the imprinting paradigm, where chicks learned to selectively approach a moving object without any explicitly associated reward, both the pre- and post-training lesions were without effects. On the other hand, in the water-reinforced pecking task, pre-training lesions of LPO severely impaired immediate reinforcement as well as formation of the association memory. However, post-training LPO lesions did not cause amnesia, and chicks selectively pecked at the reinforced color. The LPO could thus be involved specifically in the evaluation of present rewards and the instantaneous reinforcement of pecking, but not in the execution of selective behavior based on a memorized color cue.

Animals↗
PubMed2005

Male song quality affects circulating but not yolk steroid concentrations in female canaries (Serinus canaria).

Male song complexity is a sexually selected trait found in many songbirds, including strains of the domestic canary. Studies on several species have shown that male song can affect the hormonal state of females and may also influence concentrations of maternal hormones in the yolk of their eggs. In this study, we show that the level of circulating androgens and oestrogens of female canaries, as measured in faeces, varies with the quality of male song to which they are exposed. The female-perceived quality of male canary song depends on the production of special 'sexy syllables' to which females respond with more sexual displays. Using playback of synthetic song we show that females hearing songs with sexy syllables have higher levels of faecal testosterone than control females hearing songs without them. However, unlike previous studies on the canary, we found no evidence that such females laid eggs with more testosterone (or other steroids) in their egg yolks. We discuss these results in relation to the evolution of male signalling and maternal investment strategies.

Animals↗
PubMedDate not supplied

Mercury resistance among clinical isolates of Escherichia coli.

The use of organomercurials in liquid detergents and disinfectants promoted resistance to mercury among bacteria. Dental amalgam and industries using mercury are the main source of human exposure to mercury vapor. Release of mercury from dental amalgam contributes to the enrichment of the intestinal flora with mercury resistance plasmids which may be associated with antibiotic resistance. The aim of our study was to evaluate the frequency of E. coli strains resistant to mercury and other antimicrobial agents currently used in therapy. The bacterial mercury and ampicillin, cephalexin, cefotaxime, gentamicin, tetracycline and chloramphenicol resistance was tested against 363 E. coli strains obtained from faeces and urine between 1999-2000. According to the guidelines suggested by NCCLS (1998), minimum inhibitory concentrations (MICs) were determined on Mueller-Hinton agar, using the dilution technique with an inoculum of about 10(5) CFU. The MICs were read after 18 h incubation at 37 degrees C as the lowest concentration that inhibited the development of visible growth. Plasmids in enterobacteria may carry genes encoding resistance to both mercury and antibiotics. Among the tested E. coli strains, mercury resistance rose to 29.2%. Mercury resistance in E. coli is significantly linked to multiresistance to antimicrobial agents. Between 91.5-23.6 of mercury chloride resistant isolates were also resistant to the tested antibiotics. The increased use of non antibiotic antimicrobial agents is a possible selection factor for antibiotic-resistant strains in clinical and domestic environments.

Anti-Bacterial Agents↗
PubMed2002

[The canine genome: alternative model for the functional analysis of mammalian genes].

The pace of genome sequencing has been tremendously accelerated during the last few years leading to the determination of dozens of entire bacterial genome sequences in addition to several eukaryotic genome sequences and to the publication in 2000 of a draft of the human one. Nowadays scientists have to face a new challenge that corresponds to the elucidation of the function(s) of the thousands of genes uncovered by sequencing. Obviously this task will necessitate a large panel of methodologies. Since its domestication, dog has been the subject of intense breeding and selection practices that result in the creation of many breeds that differ one from the others by a huge variation in shape, size, coat colour, aptitude. Unfortunately these breeding practices along the selection of specific alleles governing those characters have co-selected various deleterious or morbid alleles and nowadays most of the canine breeds suffers from many different diseases of genetic origin. In addition many breeds have developed susceptibility toward many diseases very often similar to those affecting humans such as cancers, heart diseases, allergies.... In this paper we present arguments in favour of the utilisation of the canine model to sort out through linkage disequilibrium studies the phenotype/genotype relationship as an aid to understand the function(s) of the thousands of genes uncovered by sequencing.

Animals↗
PubMed1986

[Endangered domestic animal species in German speaking countries. I: General aspects].

The development of farm animals since the beginning of domestication is described. Modern breeds have existed since the end of the 18th century. Different efficiency with regard to what were topical breeding aims as well as manipulations by the government led to a decrease in the variety of breeds. The reasons of preserving endangered breeds are both genetic and cultural. There are some examples of breeds that once had little attention payed to and which now have obtained economic importance again. In recent years several institutions in West Germany have tried by financial advancement and other measures for a variety of breeds to avoid further curtailment of them.

Animal Welfare↗
PubMed1979

[Heritable defects in dogs (author's transl)].

The introduction to this report contains a description of the development of breeds of domestic animals. The change-over from natural to artificial selection gives rise to disturbances of morphological, physiological and behavioural traits. The origine, incidence and diagnosis of heritable defects in various canine breeds are discussed. On this basis two tables listing heritable defects in dogs are presented.

Animals↗
PubMed2003

When HIV-prevention messages and gender norms clash: the impact of domestic violence on women's HIV risk in slums of Chennai, India.

This paper examines how marital violence affects women's ability to protect themselves from HIV/AIDS. In-depth interviews (n = 48) and focus groups (n = 84, 3-7 per group) were conducted among men and women in two randomly selected slums of Chennai, India. The study showed that community gender norms tacitly sanction domestic violence that interferes with adopting HIV-preventive behaviors. Given the choice between the immediate threat of violence and the relatively hypothetical specter of HIV, women often resign themselves to sexual demands and indiscretions that may increase their risk of HIV acquisition. In conclusion, AIDS-prevention interventions must incorporate gender-related social contexts in settings where husbands strictly enforce their locus of control. HIV-prevention messages targeting men may effectively reduce women's exposure to HIV/AIDS.

Adult↗
PubMed1998

Delayed and selective motor neuron death after transient spinal cord ischemia: a role of apoptosis?

OBJECTIVE: The mechanism of spinal cord injury has been thought to be related to tissue ischemia, and spinal motor neuron cells are suggested to be vulnerable to ischemia. We hypothesized that delayed and selective motor neuron death is apoptosis. METHODS: Thirty-seven Japanese domesticated white rabbits weighing 2 to 3 kg were used in this study and were divided into two subgroups: a 15-minute ischemia group and a sham control group. Animals were allowed to recover at ambient temperature and were killed at 8 hours, and 1, 2, 4, and 7 days after reperfusion (n = 3 at each time point). By means of this model, cell damage was histologically analyzed. Detection of ladders of oligonucleosomal DNA fragment was investigated with gel electrophoresis up to 7 days of the reperfusion. Immunocytochemistry, in situ terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling staining was also performed. RESULTS: After 15 minutes of ischemia, most of the motor neurons showed selective cell death at 7 days of reperfusion. Typical ladders of oligonucleosomal DNA fragments were detected at 2 days of reperfusion. Immunocytochemistry showed in situ terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end staining was detected at 2 days of reperfusion selectively in the nuclei of motor neurons. CONCLUSION: These results suggest that delayed and selective death of the motor neuron cells after transient ischemia may not be necrotic but rather predominantly apoptotic.

Animals↗
PubMed1998

Snake bites recorded by veterinary practices in Australia.

OBJECTIVE: To determine the extent of the snake bite problem in domestic animals, its regional significance and the effects of antivenom treatment. DESIGN: A questionnaire was designed seeking information on the number and type of domestic animals referred, whether treated or untreated, type of snakes and management of the bite. PROCEDURE: The survey form was sent to 10% of veterinary surgeons, selected at random throughout Australia. RESULTS: The response of 106 veterinary surgeons revealed that snake bite in domestic animals is frequent, with an estimated 6200 cases reported annually. Bites were more prominent in rural (78%) than urban areas (22%) with brown, tiger and black snakes accounting for 76%, 113% and 6% of cases, respectively. Cats and dogs were the most frequently reported victims. Ninety-one percent of cats and 75% of dogs survived following the administration of antivenom whereas 66% of cats and 31% of dogs survived without antivenom. Overall, in 33% of cases antivenom was not used, and venom detection kits were used in only 1% of cases. A number of drugs were used in various combinations with or without antivenom and intravenous fluids in the treatment of animals with snake bite, but their role in reducing the severity of envenomations was not assessed. CLINICAL IMPLICATIONS: Antivenom significantly improves the chances of survival of domestic animals bitten by snakes.

Animals↗
PubMedDate not supplied

[Variability of home dietary habits of families living in Bamako (Mali) according to their socioeconomic status].

We investigated the influence of standard of living on the dietary and eating habits of families in Bamako (Mali). Family meals eaten at home at any time of day were studied. Families were selected for the study according to two criteria: the place of residence and the domestic commodities and urban investments. Thus, 24 families were included from affluent and 24 from moderately affluent neighborhoods, and 26 families from poor neighborhoods. All families ate three meals a day, each including staples and sauce. However, the dishes selected for the different meals and their ingredients varied considerably with the family's status. Cereals were the main component of breakfast, but the type varied from one category of family to another. All poor families and 79% of the intermediate group and only 54% of the affluent group ate millet/sorghum. Seventy-five % of the affluent, 13% of the intermediate and none of the poor families drank coffee at breakfast. Fifty % of the affluent, 29% of the intermediate and 19% of the poor families ate rice with nadji sauce at lunch. The quality of the nadji sauce varied with economic status. Tigadeguena sauce was eaten with rice in 17% of the affluent families, 50% of the intermediate group and 12% of the poor families. Very little millet/sorghum was eaten by the affluent at lunch, whereas it was included in lunch by over half the poor and one fifth of the intermediate families. The diversity of dishes was larger at supper, but only in the affluent families which had 2 to 4 different dishes or produce. They included garden vegetable salads and stews, with or without bread. Dinner for the intermediate and poor families was similar to lunch, that is a cereal base and a sauce. Home eating habits also differed according to status. In the affluent families breakfast was eaten alone, whereas in the poor families it was a communal meal. The intermediate group displayed both patterns. Affluent families tried to alternate and diversify their food intake from one meal to another, whereas the diet of the poor was monotonous. Most intermediate families tried to alternate a small range of staples (rice and traditional cereals) although this necessitated reducing the quality of the sauce. Our study shows that eating habits are affected by both cultural factors and standard of living.

Adolescent↗
PubMed1998

Selection at a P-glycoprotein gene in ivermectin- and moxidectin-selected strains of Haemonchus contortus.

Resistance to anthelmintics that are used to control parasite populations in domestic animals has become a serious problem worldwide. The development of resistance is an evolutionary process that leads to genetic changes in parasite populations in response to drug exposure. The anthelmintic ivermectin is known to bind to the human membrane transport protein, P-glycoprotein, and P-glycoprotein-deficient mice treated with ivermectin have shown signs of neurotoxicity. P-glycoprotein is believed to be involved in the multidrug resistance phenotype seen in some human cancers and for drug resistance in some protists. We have examined the genetic variation of a P-glycoprotein homologue from the nematode Haemonchus contortus to see if an association exists between specific alleles of this gene and survival to exposure to ivermectin or moxidectin. Two parasite strains passaged without drug treatment and three strains, subjected to anthelmintic selection and derived from the unselected strains, were examined. Allelic variation in the unselected strains showed this locus to be highly polymorphic. chi 2 analyses of allele frequencies showed significant differences between the unselected and the drug-selected derived strains. In all three drug-selected strains, an apparent selection for the same allele was observed. These findings suggest that P-glycoprotein may be involved in resistance to both ivermectin and moxidectin in H. contortus.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMedDate not supplied

Reproductive biotechnologies for endangered mammalian species.

Assisted reproductive techniques (gamete cryopreservation, artificial insemination, embryo transfer, and in vitro fertilization) allow to propagate small fragmented populations of wild endangered species or domestic breeds. There are the best way for producing several offspring from selected genitors in order to avoid inbreeding depression. However, few mammalian species have been well studied for their reproductive biology whereas huge differences have been observed between these species. Furthermore, materials, methods and experimental designs have to be adapted for each case and each limiting factor (wildness, poor quantity of biological material, disparate locations). Genome resource banking is currently arising and the most applied reproductive biotechnology remains artificial insemination. Assisted reproductive techniques currently developed in domestic species (intracytoplasmic sperm injection, nuclear transfer) may offer new opportunities for the propagation of endangered species.

Animals↗
PubMed2001

Consequences of genetic change in farm animals on food intake and feeding behaviour.

Selection in commercial populations on aspects of output, such as for growth rate in poultry. against fatness and for growth rate in pigs, and for milk yield in cows, has had very barge effects on such outputs over the past 50 years. Partly because of the cost of recording intake, there has been little or no selection for food intake or feeding behaviour. In order to predict the effects of such past, and future, selection on intake it is necessary to have some suitable theoretical framework. Intake needs to be predicted in order to make rational feeding and environmental decisions. The idea that an animal will eat 'to meet its requirements' has proved useful and continues to be fruitful. An important part of the idea is that the animal (genotype) can be described in a way that is sufficient for the accurate prediction of its outputs over time. Such descriptions can be combined with a set of nutritional constants to calculate requirements. There appears to have been no change in the nutritional constants under selection for output. Under such selection it is simplest to assume that changes in intake follow from the changes in output rates, so that intake changes become entirely predictable. It is suggested that other ways that have been proposed for predicting intake cannot be successful in predicting the effects of selection. Feeding behaviour is seen as being the means that the animal uses to attain its intake rather than being the means by which that intake can be predicted. Thus, the organisation of feeding behaviour can be used to predict neither intake nor the effects of selection on it.

Animals↗
PubMed2005

Genetic variation and evolution of Polaskia chichipe (Cactaceae) under domestication in the Tehuacán Valley, central Mexico.

Polaskia chichipe is a columnar cactus under artificial selection in central Mexico because of its edible fruits. Our study explored the effect of human manipulation on levels and distribution of genetic variation in wild, silviculturally managed and cultivated sympatric populations. Total genetic variation, estimated in nine populations with five microsatellite loci, was H(T) = 0.658 +/- 0.026 SE, which was mainly distributed within populations (H(S) = 0.646) with low differentiation among them (F(ST) = 0.015). Fixation index (F(IS)) in all populations was positive, indicating a deficit of heterozygous individuals with respect to Hardy-Weinberg expectations. When populations were pooled by management type, the highest expected heterozygosity (H(E) = 0.631 +/- 0.031 SE) and the lowest fixation index (F(IS) = 0.07) were observed in wild populations, followed by cultivated populations (H(E) = 0.56 +/- 0.03 SE, F(IS) = 0.14), whereas the lowest variation was found in silviculturally managed populations (H(E) = 0.51 +/- 0.05 SE, F(IS) = 0.17). Low differentiation among populations under different management types (F(ST) 0.005, P < 0.04) was observed. A pattern of migration among neighbouring populations, suggested from isolation by distance (r2 = 0.314, P < 0.01), may have contributed to homogenizing populations and counteracting the effects of artificial selection. P. chichipe, used and managed for at least 700 generations, shows morphological differentiation, changes in breeding system and seed germination patterns associated with human management, with only slight genetic differences detected by neutral markers.

Biological Evolution↗
PubMed1990

Alternative animal models with maternal effects and foster dams.

Effects of foster dams can be included in genetic evaluations using animal models with maternal effects in several ways. The alternatives discussed involve minor changes in computing strategies from strategies used with reduced animal models that predict breeding values for direct and maternal effects. The easiest alternative is to assign foster dams to groups by breed and time period and add equations for fixed effects of breed-period. Random and, assumed, independent effects of foster dams can be nested in breed-period groups. If foster dams do not repeat, then those effects can be absorbed into equations for other fixed effects, additive direct breeding value and breed-period effects by slightly modifying least squares contributions to coefficients of those equations. A third alternative for foster dams of the same breed is to add breeding values for foster dams for direct and maternal effects to solution vectors for breeding values. Equations are similar to those without foster dams, except that least squares contributions to coefficient matrix and right-hand sides are to equations for maternal breeding values and nongenetic maternal effects of foster dams rather than biological dams. Relationships and covariance between direct and maternal effects contribute mixed-model coefficients to direct and maternal breeding value equations of biological dams. This alternative basically requires only larger solution vectors for direct and maternal breeding values to accommodate foster dams that might not be included. The fourth alternative includes a vector of maternal breeding values for foster dams of each breed of foster dams and would require using rules of Westell to calculate coefficients due to relationships and fixed maternal genetic groups within each breed of foster dam. These alternatives do not require much additional computational effort compared with full or reduced animal model equations when the transformation to predict breeding values is used with Westell's rules to calculate coefficients due to relationships and genetic group effects due to prior genetic selection.

Animals↗
PubMed2001

Social environment, behavior, and schistosomiasis in an urban population in the northeast of Brazil.

The objective of our study was to gain greater insight into the pattern of water contact in relation to schistosomiasis among residents of São Lourenço da Mata, a town in Pernambuco, a state in the Northeast of Brazil. We had two primary objectives: 1) to identify water contact activities that were more likely to produce infection and 2) to examine the socioeconomic factors behind water contact activities. Using a sample of persons 10-25 years old, we carried out a population-based case-control study to investigate the first objective, and a cross-sectional study for the second objective. We found that leisure water contact with flowing water (stream or river) was significantly associated with schistosomiasis. Variables showing a statistically significant association with leisure water contact were economic sector, income, and level of education of the head of the household; type of housing; possessions inside the house; type of domestic water supply; and method of excreta collection. We introduced these variables into a multivariate model to select the ones that were most closely associated with leisure water contact. We used a stepdown procedure, and two variables were retained in the final model: type of domestic water supply and type of housing. We concluded that a decrease in leisure water contact was associated with better socioeconomic conditions. Our results suggest that with the subjects we studied in São Lourenço da Mata there was a socioeconomic determination for leisure water contact. Our data highlight the importance of a broad and integrated approach in studying water contact activities and in implementing behavioral interventions for schistosomiasis prevention and control.

Adolescent↗