Chalcones with potential antibacterial and antibiofilm activities against periodontopathogenic bacteria.

OBJECTIVES: Periodontitis is a pathology resulting from complex interaction of microorganisms in the dental biofilm with the host's immune system. Increased use of antibiotics associated with their inappropriate use has increased resistance levels in anaerobic bacteria. Therefore, identifying new antimicrobial compounds, such as chalcones, is urgent. This study evaluates the antibacterial activity and the antibiofilm activity of 15 chalcones against the periodontopathogenic bacteria Prevotella nigrescens (ATCC 33563), P. oralis (ATCC 33269), Peptostreptococcus anaerobius (ATCC 27337), Actinomyces viscosus (ATCC 43146), Porphyromonas asaccharolytica (ATCC 25260), and Fusobacterium nucleatum (ATCC 25586). METHODS: The compounds were evaluated by minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC) tests. RESULTS: Compounds 1-6 showed good antibacterial and antibiofilm activities against most of the evaluated bacteria: MIC was lower than or equal to 6.25 µg/mL, biofilm biomass was reduced by 95%, and the compounds at concentrations between 0.78 and 100 µg/mL totally inhibited cell viability. Among the tested chalcones, 3 stood out: it was effective against all the bacteria, as revealed by the MIC and MBIC results. CONCLUSIONS: Our results have consolidated a base for the development of new studies on the effects of the tested chalcones as agents to combat and to prevent periodontitis.

Prediction model to discriminate leptospirosis from hantavirus.

OBJECTIVE: The aim of this study was to build a prediction model to discriminate precociously hantavirus infection from leptospirosis, identifying the conditions and risk factors associated with these diseases. METHODS: A logistic regression model in which the response variable was the presence of hantavirus or leptospirosis was adjusted. RESULTS: As a result, the method selected the following variables that influenced the prediction formula: sociodemographic variables, clinical manifestations, and exposure to environmental risks. All variables considered in the model presented statistical significance with a p<0.05 value. The accuracy of the model to differentiate hantavirus from leptospirosis was 88.7%. CONCLUSIONS: Concluding that the development of statistical tools with high potential to predict the disease, and thus differentiate them precociously, can reduce hospital costs, speed up the patient's care, reduce morbidity and mortality, and assist health professionals and public managers in decision-making.

Learning curve for the laparoscopy-guided kidney biopsy procedure in small corpses of dogs and pigs.

The use of renal biopsy through laparoscopy is increasingly present both in human and veterinary medicine. However, both techniques require skill and training to make the operator capable to do it. The learning curve allows the quantitative and qualitative assessment of the number of attempts and minimum time for the surgical procedure. The objective included establish the learning curve for laparoscopy-guided kidney biopsy procedures in dog and pig corpses. Six dogs and six pigs corpses weighing less than 10 kg were used for this study. All corpses underwent kidney biopsy performed through laparoscopy. Twenty-four operators, two per animal, performed 20 renal biopsies each (10 for each kidney), with 480 collection-procedures in total. Duration and difficulty of the procedure and the biopsy sample quality were evaluated and statistical analysis was performed using a mixed regression model with a random effect of individuals and multivariate analysis of data. There were 91.5% of the samples that were adequate for evaluation. There was no significant difference in the number of glomeruli or cortex percentage considering the attempts in either species, demonstrating the operator's ability since first collection. Swine samples showed higher amounts of renal cortex than canine samples. The procedure duration was shorter as more attempts were performed in dogs and pigs. From the fourth repetition, the professional reached a plateau for the variable related to 'collection', and from the second, the professional presented uniform duration for 'sample storage'. Operators of the swine model acquired more agility than the dog ones. The variable 'difficulty' decreased as more repetitions were performed, reaching a plateau in the sixth attempt. Seven renal biopsies laparoscopy-guided are required for an operator to be considered 'capable' to perform the procedure in the referred species included. The learning curve for image-guided kidney biopsy procedures improves the implementation of this technique and benefits patients that undergo this procedure.

Prediction model to discriminate leptospirosis from hantavirus

SUMMARY OBJECTIVE: The aim of this study was to build a prediction model to discriminate precociously hantavirus infection from leptospirosis, identifying the conditions and risk factors associated with these diseases. METHODS: A logistic regression model in which the response variable was the presence of hantavirus or leptospirosis was adjusted. RESULTS: As a result, the method selected the following variables that influenced the prediction formula: sociodemographic variables, clinical manifestations, and exposure to environmental risks. All variables considered in the model presented statistical significance with a p<0.05 value. The accuracy of the model to differentiate hantavirus from leptospirosis was 88.7%. CONCLUSIONS: Concluding that the development of statistical tools with high potential to predict the disease, and thus differentiate them precociously, can reduce hospital costs, speed up the patient's care, reduce morbidity and mortality, and assist health professionals and public managers in decision-making.

Assessment of the antibacterial, antivirulence, and action mechanism of Copaifera pubiflora oleoresin and isolated compounds against oral bacteria.

The microorganisms that constitute the oral microbiome can cause oral diseases, including dental caries and endodontic infections. The use of natural products could help to overcome bacterial resistance to the antimicrobials that are currently employed in clinical therapy. This study assessed the antimicrobial activity of the Copaifera pubiflora oleoresin and of the compounds isolated from this resin against oral bacteria. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays provided values ranging from 6.25 to > 400 µg/mL for the C. pubiflora oleoresin and its isolated compounds. The fractional inhibitory concentration index (FICI) assay showed that the oleoresin and chlorhexidine did not act synergistically. All the tested bacterial strains formed biofilms. MICB50 determination revealed inhibitory action: values varied from 3.12-25 µg/mL for the oleoresin, and from 0.78 to 25 µg/mL for the ent-hardwickiic acid. Concerning biofilm eradication, the C. pubiflora oleoresin and hardwickiic acid eradicated 99.9 % of some bacterial biofilms. Acid resistance determination showed that S. mutans was resistant to acid in the presence of the oleoresin and ent-hardwickiic acid at pH 4.0, 4.5, and 5.0 at all the tested concentrations. Analysis of DNA/RNA and protein release by the cell membrane demonstrated that the oleoresin and hardwiickic acid damaged the bacterial membrane irreversibly, which affected membrane integrity. Therefore, the C. pubiflora oleoresin and ent-hardwickiic acid have potential antibacterial effect and can be used as new therapeutic alternatives to treat oral diseases such as dental caries and endodontic infections.

Apoio e rede social no contexto urbano: percepções de mães de crianças prematuras / Support and social network in the urban context: Perceptions of mothers of premature children

Pesquisa transversal de abordagem quantitativa e qualitativa com objetivo de analisar pelo referencial da Promoção da Saúde a percepção de apoio e rede social no contexto urbano. Aplicou-se escala de MOS-SSS e um questionário a 75 mães de crianças com até 24 meses de idade, nascidas prematuras e seguidas em ambulatório especializado de crianças de risco. A rede social da maioria tem no máximo três pessoas, sendo que 33% não tem amigos. A dimensão afetiva da família foi o apoio mais percebido (86,66%). Da cidade de moradia apontaram potencialidades (família, acesso aos serviços de saúde, segurança) e fragilidades (lazer, áreas públicas), elementos que subsidiam a implementação de ações e políticas em Promoção da Saúde. Conclui-se que a percepção positiva do apoio e rede social no contexto urbano, além de favorecer o desenvolvimento e qualidade de vida dos prematuros, infere um alto suporte social, quesito necessário para um município saudável.

Cross-sectional research of a quantitative and qualitative approach with the objective of analyzing, through the Health Promotion referential, the perception of support and social network in the urban context. A MOS-SSS scale and a questionnaire were applied to 75 mothers of children up to 24 months of age, born prematurely and followed up in a specialized clinic of risk children. The social network of the majority has a maximum of three people, and 33% have no friends. The affective dimension of the family was the most perceived support (86.66%). From the city of housing they pointed out potentialities (family, access to health services, safety) and fragilities (leisure, public areas) which support the implementation of Health Promotion actions and policies. It is concluded that social network in the urban context, besides promoting the development and quality of life of premature infants, infers a high social support, necessary for a healthy municipality.

Apoio e rede social no contexto urbano: percepções de mães de crianças prematuras / Support and social network in the urban context: Perceptions of mothers of premature children

Pesquisa transversal de abordagem quantitativa e qualitativa com objetivo de analisar pelo referencial da Promoção da Saúde a percepção de apoio e rede social no contexto urbano. Aplicou-se escala de MOS-SSS e um questionário a 75 mães de crianças com até 24 meses de idade, nascidas prematuras e seguidas em ambulatório especializado de crianças de risco. A rede social da maioria tem no máximo três pessoas, sendo que 33% não tem amigos. A dimensão afetiva da família foi o apoio mais percebido (86,66%). Da cidade de moradia apontaram potencialidades (família, acesso aos serviços de saúde, segurança) e fragilidades (lazer, áreas públicas), elementos que subsidiam a implementação de ações e políticas em Promoção da Saúde. Conclui-se que a percepção positiva do apoio e rede social no contexto urbano, além de favorecer o desenvolvimento e qualidade de vida dos prematuros, infere um alto suporte social, quesito necessário para um município saudável.

Cross-sectional research of a quantitative and qualitative approach with the objective of analyzing, through the Health Promotion referential, the perception of support and social network in the urban context. A MOS-SSS scale and a questionnaire were applied to 75 mothers of children up to 24 months of age, born prematurely and followed up in a specialized clinic of risk children. The social network of the majority has a maximum of three people, and 33% have no friends. The affective dimension of the family was the most perceived support (86.66%). From the city of housing they pointed out potentialities (family, access to health services, safety) and fragilities (leisure, public areas) which support the implementation of Health Promotion actions and policies. It is concluded that social network in the urban context, besides promoting the development and quality of life of premature infants, infers a high social support, necessary for a healthy municipality.

Antibacterial, Preservative, and Mutagenic Potential of Copaifera spp. Oleoresins Against Causative Agents of Foodborne Diseases.

Foodborne diseases (FBDs) are a serious public health concern worldwide. In this scenario, preservatives based on natural products, especially plants, have attracted researchers' attention because they offer potential antimicrobial action as well as reduced health impact. The genus Copaifera spp., which is native of tropical South America and West Africa, contains several species for which pharmacological activities, including antibacterial effects, have been described. On the basis of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), antibiofilm activity (inhibition and eradication), preservative capacity, and Ames test, we evaluated the antibacterial, preservative, and mutagenic potential of Copaifera spp. oleoresins against the causative agents of FBDs. The Copaifera duckei, Copaifera reticulata, Copaifera paupera, and Copaifera pubiflora oleoresins displayed promising MIC/MBC values-from 12.5 to 100 µg/mL-against Staphylococcus aureus (American Type Culture Collection [ATCC] 29213), Listeria monocytogenes (ATCC 15313), and Bacillus cereus (ATCC 14579). C. duckei, C. reticulata, C. paupera, and C. pubiflora oleoresin concentrations ranging from 25 to 200 µg/mL and from 100 to 400 µg/mL inhibited biofilm formation and eradicated biofilms, respectively. The oleoresins did not exert mutagenic effects and had superior food preservative action to sodium benzoate (positive control). In conclusion, Copaifera oleoresins exhibit potential antibacterial activity and are not mutagenic, which makes them a promising source to develop novel natural food preservatives to inhibit foodborne pathogens.

Análise multivariada da esquistossomose no estado de Minas Gerais: análise de componentes principais / Multivariate analysis of schistosomiasis in the state of Minas Gerais: principal component analysis

INTRODUÇÃO: A esquistossomose mansônica é uma doença negligenciada no Brasil, logo, relacionada à pobreza e ausência de condições sanitárias. Ocorre na região litorânea do nordeste e se interioriza a partir do estado da Bahia, chegando a Minas Gerais. OBJETIVO: Agrupar, por meio da análise de componentes principais, as principais variáveis relacionadas à esquistossomose em fatores que possam explicar a variância dos dados. MÉTODOS: Foram avaliadas as notificações de esquistossomose entre os anos de 2007 a 2014, considerando a média por 100 mil habitantes. As variáveis: educação, saúde, economia, infraestrutura e saneamento, População, altimetria e Índice de Desenvolvimento Humano (IDH), foram obtidas no Atlas Brasil; os dados das notificações de esquistossomose foram obtidos no Sistema de Informação de Agravos e Notificação (SINAN). A análise estatística foi realizada a partir da análise de componentes principais, visando identificar os principais fatores que contribuem de forma mais significativa, com a variância dos dados. RESULTADOS: Considerando os critérios propostos, três fatores explicaram mais de 76% da variância, sendo o primeiro relacionado às variáveis: taxa de analfabetismo em 18 anos ou mais, sem ensino fundamental, mortalidade infantil, extremamente pobre, vulnerável a pobreza, esgotamento sanitário inadequado e população rural. O segundo foi relacionado à variável esgotamento sanitário e o terceiro fator à variável altitude. CONCLUSÃO: As variáveis associadas aos fatores, principalmente aquelas pautadas nos determinantes sociais de saúde, demonstram uma forte relação com a ocorrência da esquistossomose. A contribuição do estudo nos remete a possibilidade de agrupar variáveis em fatores que comportam de forma sinérgica e favorecem a incidência da parasitose.

INTRODUCTION: Schistosomiasis mansoni is a neglected disease in Brazil, therefore, related to poverty and lack of sanitary conditions. Occurs in the coastal region of the northeast and spreads inland from the state of Bahia, reaching Minas Gerais. OBJECTIVE: To group, through component analysis, the main variables related to schistosomiasis in factors that may explain data variance. METHODS: Reports of schistosomiasis between the years 2007 to 2014 were evaluated, considering averages per 100 thousand inhabitants. The variables: education, health, economy, infrastructure and sanitation, population, altimetry and Human Development Index (HDI), were obtained from Atlas Brazil; the schistosomiasis notification data were obtained from the injury and notification information system (SINAN). Statistical analysis was based on the analysis of main components, aiming to identify the key factors that contribute most significantly to data variance. RESULTS: Considering the proposed criteria, three factors explained more than 76% of the variance, the first one related to the following variables: illiteracy rate at 18 years of age or more, no elementary education, child mortality, extremely poor, vulnerable to poverty, inadequate sanitary sewage and rural population. The second was related to the sanitary sewage variable and the third factor to the altitude variable. CONCLUSION: The variables associated with factors, especially those based on the social determinants of health; show a strong relation with the occurrence of schistosomiasis. The contribution of the study reminds us of the possibility of grouping variables into factors that behave synergistically and favor the incidence of parasitosis.

Use of Copaifera multijuga for acute corneal repair after chemical injury: A clinical, histopathological and toxicogenetic study.

Copaiba oil is widely used in medicine, but there are no reports regarding its application in ophthalmology. Therefore, the objective of this study was to evaluate the clinical, histopathological and toxicogenetic effects of eye drops containing 0.1 and 0.5% of Copaifera multijuga Hayne oil on superficial corneal ulcers induced with alkali in the left eye of rats. For histological analysis, the percent reduction in ulcers and thickness of the corneal epithelium and stroma were evaluated 48 and 72 h after ulcer induction. Additionally, neovascularization and polymorphonuclear infiltration were classified in the stroma. The bone marrow micronucleus test was used for toxicogenetic assessment. None of the animals exhibited clinical signs of immediate ocular discomfort after instillation and the eye drops were harmless to the ocular surface. There was a significant difference in percent ulcer reduction and corneal stroma thickness between animals treated with the C. multijuga eye drops and untreated animals with corneal injury and the negative control, respectively, suggesting a healing effect of the oleoresin. Analysis of the thickness of the corneal epithelium at the two time points showed that the eye drops formulated did not significantly reduce the damage caused by alkali. The same was observed for the treatments with the reference drugs. No difference in stromal neovascularization or inflammatory infiltration was observed between the treated groups. The toxicogenetic results revealed the absence of cytotoxicity and genotoxicity of the treatments. In conclusion, the C. multijuga eye drops did not cause damage to the ocular surface under the present experimental conditions and corneal epithelization was similar to the conventional treatments. These results indicate that eye drops containing C. multijuga oleoresin are a promising option for the treatment of superficial keratitis.

Qualidade de vida relacionada à saúde de pacientes com câncer de próstata / Quality of life related to the health of patients with prostate cancer / Calidad de vida relacionada con la salud de los pacientes con cáncer de próstata

INTRODUÇÃO: O diagnóstico e o tratamento do câncer de próstata podem provocar modificações significativas na vida dos homens, alterando a sua qualidade de vida. O objetivo deste estudo foi avaliar a qualidade de vida relacionada à saúde de pacientes com câncer de próstata em tratamento de hormonioterapia e radioterapia. MATERIAIS E MÉTODOS: Estudo descritivo, transversal, com dados sociodemográficos, clínicos e de avaliação da qualidade de vida de 213 pacientes, obtidos por roteiro de entrevista e pelo questionário Expanded Prostate Cancer Index Composite. Utilizou-se estatística descritiva. RESULTADOS: Houve predominância de homens acima de 50 anos, brancos, casados, com baixa escolaridade e aposentados, com diagnóstico inicial obtido pelas alterações no exame de Antígeno Prostático Específico e estadiamento II. As médias dos escores obtidos no domínio da função sexual indicaram queda na qualidade de vida, para ambos os tratamentos. DISCUSSÃO: Tanto a hormonioterapia como a radioterapia podem causar algum tipo de efeito na função sexual, diretamente relacionado a um significativo impacto na qualidade de vida relacionada à saúde para muitos homens. CONCLUSÕES: Ainda que os resultados tenham sido obtidos e analisados pela primeira vez no hospital do estudo, oferecem subsídios para o conhecimento da realidade local e corroboram com os achados de outros estudos realizados em locais e realidades diferentes.

INTRODUCTION: The diagnosis and treatment of prostate cancer can cause significant modifications in the lives of men, altering their quality of life. The aim of this study was to assess the health-related quality of life of patients with prostate cancer in hormone therapy and radiotherapy treatment. MATERIALS AND METHODS: Descriptive, cross-sectional study with sociodemographic, clinical data and quality of life evaluation of 213 patients, obtained from the interview script and through the questionnaire Expanded Prostate Cancer Index Composite. Descriptive statistics were used. RESULTS: There was a predominance of white men over 50 years of age, married, with low schooling, and retirees with initial diagnosis obtained by alterations on the specific prostatic antigen test and stage II. The mean scores obtained in the sexual function domain indicated a decrease in quality of life for both treatments. DISCUSSION: Hormone therapy and radiotherapy can cause some type of type of effect on the sexual function, directly related to a significant impact on the quality of life related to health for many men. CONCLUSIONS: Although the results were obtained and analyzed for the first time in the study hospital, they offer subsidies for the knowledge of the local reality and corroborate with findings from other studies carried out in different places and realities.

INTRODUCCIÓN: El diagnóstico y el tratamiento del cáncer de próstata pueden provocar cambios significativos en la vida de los hombres, alterando su calidad de vida. El objetivo de este estudio fue evaluar la calidad de vida relacionada con la salud de pacientes con cáncer de próstata en tratamiento de hormonioterapia y radioterapia. MATERIALES Y MÉTODOS: Estudio descriptivo, transversal, con datos sociodemográficos, clínicos y de evaluación de la calidad de vida de 213 pacientes, obtenidos por un guión de entrevista y por el cuestionario Expanded Prostate Cancer Index Composite. Se utilizó estadística descriptiva. RESULTADOS: Hubo predominio de hombres mayores de 50 anos, blancos, casados, con baja escolaridad y jubilados, con diagnóstico inicial obtenido por las alteraciones en el examen de Antígeno Prostático Específico y estadio II. Las medias de las puntuaciones obtenidas en el dominio de la función sexual indicaron caída en la calidad de vida, para ambos tratamientos. DISCUSIÓN: Tanto la hormonioterapia como la radioterapia pueden causar algún tipo de efecto en la función sexual, directamente relacionado con un significativo impacto en la calidad de vida relacionada con la salud para muchos hombres. CONCLUSIONES: Aunque los resultados han sido obtenidos y analizados por primera vez en el hospital del estudio, ofrecen subsidios para el conocimiento de la realidad local y corroboran los resultados con otros estudios realizados en locales y realidades diferentes.

Influência de fatores de risco na mortalidade por doenças infecciosas e parasitárias / Influence of mortality risk factors by infectious and parasite diseases

O Brasil tem grande extensão e características socioeconômicas, demográficas e culturais distintas. Sendo assim, em algumas regiões, as doenças infecciosas e parasitárias (DIPs) ainda fazem parte do cotidiano da população. Desse modo, objetivou-se avaliar se as DIPs, nos municípios que constituem a Superintendência Regional de Saúde (SRS) de Alfenas (MG), têm relação com fatores de risco selecionados. Trata-se de um estudo transversal de base populacional, de caráter descritivo e abordagem quantitativa, utilizando-se dados secundários obtidos no censo demográfico (2010) e empregando-se a análise de correlação de Pearson. Todos os indicadores de saúde e educação estudados, correlacionaram-se significativamente com a mortalidade por DIPs. O sistema de abastecimento de água por rede geral de distribuição, juntamente com o número de esgotamento sanitário por rede geral de esgoto ou pluvial, foram as variáveis dos indicadores de saneamento básico que demonstraram os mais elevados índices de correlação. Dentre os indicadores relativos à economia, o rendimento nominal mensal até » de salário mínimo ou sem rendimento mensal influenciaram significativamente a mortalidade por DIPs e, entre os indicadores de mortalidade infantil, somente o número de nascidos com peso inferior a 2500g demonstrou relação com as DIPs. Os resultados mostraram que as condições ambientais e de saneamento assim como as condições socioeconômicas dos residentes nos domicílios servidos por esses bens, aliadas à divulgação de medidas básicas de higiene pessoal, doméstica e comunitária impactam na saúde da população, refletindo na morbidade e mortalidade por enfermidades de diferentes etiologias, incluindo-se às DIPs. Dessa maneira, o conhecimento da prevalência e das principais variáveis associadas pode fornecer subsídio para dimensão do problema, planejamento e implementação de ações de promoção à saúde e à prevenção de agravos do processo saúde-doença.

Due to Brazil´s huge extension and to different social, economic, demographic and cultural conditions, several regions in Brazil feature infectious and parasite diseases (IPDs). Current analysis assesses whether IPDs in the municipalities of the Health Regional Superintendence of Alfenas MG Brazil are related to specific risk factors. Current populated-based transversal, descriptive and quantitative study employs secondary data from the 2010 demographic census, by Pearson´s co-relationship. All health and educational indicators significantly co-relate themselves with mortality due to IPDs, The water supply system and the number of sewerage and rainwater per network unit were the variables of basic sanitation indexes with the highest co-relation scores. In the case of economic indicators, the monthly income of half the minimum wage or without any monthly earnings significantly affected IPD-based mortality. Only the number of births weighing less than 2500g had any relationship to IPDs. Results showed environmental and sanitation conditions, coupled to the social and economic factors of residents in homes with such characteristics, plus the dissemination of basic measures for personal, home and community hygiene impact population´s health. The latter influences morbidity and mortality by diseases of different etiologies, including IPDs. Knowledge on the prevalence and main associated variables may be a help in evaluating the problem and the planning and implementation of activities for the health and prevention of health-disease relationships.

Genetic parameters for body weight, carcass chemical composition and yield in a broiler-layer cross developed for QTL mapping.

The objective of this study was to estimate genetic and phenotypic correlations of body weight at 6 weeks of age (BW6), as well as final carcass yield, and moisture, protein, fat and ash contents, using data from 3,422 F2 chickens originated from reciprocal cross between a broiler and a layer line. Variance components were estimated by the REML method, using animal models for evaluating random additive genetic and fixed contemporary group (sex, hatch and genetic group) effects. The heritability estimates (h(2)) for BW6, carcass yield and percentage of carcass moisture were 0.31 ± 0.07, 0.20 ± 0.05 and 0.33 ± 0.07, respectively. The h(2) for the percentages of protein, fat and ash on a dry matter basis were 0.48 ± 0.09, 0.55 ± 0.10 and 0.36 ± 0.08, respectively. BW6 had a positive genetic correlation with fat percentage in the carcass, but a negative one with protein and ash contents. Carcass yield, thus, appears to have only low genetic association with carcass composition traits. The genetic correlations observed between traits, measured on a dry matter basis, indicated that selection for carcass protein content may favor higher ash content and a lower percentage of carcass fat.

Heterogeneidade dos componentes de variância na produção de leite e seus efeitos nas estimativas de herdabilidade e repetibilidade / Heterogeneity of variance components in milk production and their effects on estimates of heritability and repeatability

Avaliou-se a heterogeneidade dos componentes de variância e seu efeito nas estimativas de herdabilidade e repetibilidade da produção de leite de bovinos da raça Holandesa. Os rebanhos foram agrupados de acordo com o nível de produção (baixo, médio e alto) e avaliados na escala não transformada, raiz quadrada e logarítmica. Os componentes de variância foram estimados pelo método de máxima verossimilhança restrita. O modelo animal incluiu os efeitos fixos de rebanho-ano-estação e das covariáveis duração da lactação (efeito linear) e idade da vaca ao parto (efeito linear e quadrático) e os efeitos aleatórios genético aditivo direto, de ambiente permanente e residual. Na escala não transformada, todos os componentes de variância foram heterogêneos entre os três níveis de produção. Nesta escala, a variância residual e a fenotípica estavam associadas positivamente com o nível de produção enquanto que na escala logarítmica a associação foi negativa. A heterogeneidade da variância fenotípica e de seus componentes afetou mais as estimativas de herdabilidade que as da repetibilidade. A eficiência do processo de seleção para produção de leite poderá ser afetada pelo nível de produção em que forem estimados os parâmetros genéticos.

It was evaluated the heterogeneity of components of phenotypic variance and its effects on the heritability and repeatability estimates for milk yield in Holstein cattle. The herds were grouped according to their level of production (low, medium and high) and evaluated in the non-transformed, square-root and logarithmic scale. Variance components were estimated using a restricted maximum likelihood method based on an animal model that included fixed effects of herd-year-season, and as covariates the linear effect of lactation duration and the linear and quadratic effects of cow's age at calving and the random direct additive genetic, permanent environment and residual effects. In the non-transformed scale all the variance components were heterogeneous. On this scale, residual and phenotypic variance components were associated positively with the level of production while in logarithmic scale that association was negative. Estimates of heritability were more affected than the repeatability for the phenotypic variance heterogeneity and their components. The of selection process efficiency for milk production could be affected by the level of production which was considered for genetic parameters estimation.

Genetic parameters for body weight, carcass chemical composition and yield in a broiler-layer cross developed for QTL mapping

The objective of this study was to estimate genetic and phenotypic correlations of body weight at 6 weeks of age (BW6), as well as final carcass yield, and moisture, protein, fat and ash contents, using data from 3,422 F2 chickens originated from reciprocal cross between a broiler and a layer line. Variance components were estimated by the REML method, using animal models for evaluating random additive genetic and fixed contemporary group (sex, hatch and genetic group) effects. The heritability estimates (h²) for BW6, carcass yield and percentage of carcass moisture were 0.31 ± 0.07, 0.20 ± 0.05 and 0.33 ± 0.07, respectively. The h² for the percentages of protein, fat and ash on a dry matter basis were 0.48 ± 0.09, 0.55 ± 0.10 and 0.36 ± 0.08, respectively. BW6 had a positive genetic correlation with fat percentage in the carcass, but a negative one with protein and ash contents. Carcass yield, thus, appears to have only low genetic association with carcass composition traits. The genetic correlations observed between traits, measured on a dry matter basis, indicated that selection for carcass protein content may favor higher ash content and a lower percentage of carcass fat.