Physiological and hematological parameters of sheep reared in the tropics and subtropics / [Parâmetros fisiológicos e hematológicos de ovinos criados nos trópicos e nos subtrópicos]

This study aimed to determine the physiological and hematological parameters of sheep in Brazil. Therefore, 5,081 observations were used from previous experiments with animals from different Brazilian regions with the time of day, gender, breed, age, physiological characteristics, hematological and climatic variables. The animals were classified according to their stress level, and only data of non-stressed animals were used to calculate the reference values. Respiratory rate was the parameter that most differed from the normal range, with values ​​above the limits usually reported for the species, being higher in commercial wool sheep. For hematological variables, differences were observed between the present results and the previously reported values in the literature. A higher number of red blood cells (RBC), lower hemoglobin and mean corpuscular hemoglobin concentration (MCHC) were observed in young animals. A higher number of RBC and MCHC were noted in sheep crossed with local breeds. Considering that physiological and hematological parameters are indicators of the animal's pathological or physiological state, for a correct interpretation of the results, the use of reference values based on animals with similar racial characteristics and subjected to similar environmental conditions is recommended.(AU)

O objetivo deste estudo foi determinar parâmetros fisiológicos e hematológicos de ovinos no Brasil. Portanto, foram utilizadas 5.081 observações de experimentos anteriores com animais de diversas regiões do Brasil, com diferentes horário, sexo, raça, idade, características fisiológicas, variáveis ​​hematológicas e climáticas. Os animais foram classificados de acordo com o nível de estresse, e apenas os dados dos animais não estressados ​​foram utilizados para o cálculo dos valores de referência. A frequência respiratória foi o parâmetro que mais diferiu em relação à normalidade, com valores acima dos limites usualmente relatados para a espécie, sendo maior em ovinos de lã comercial. Para as variáveis ​​hematológicas, também foram verificadas diferenças entre os resultados observados e os valores previamente relatados na literatura. Maior número de hemácias, menor hemoglobina e concentração de hemoglobina corpuscular média (CHbCM) foram observados em animais jovens e maior número de hemácias e CHbCM em ovinos cruzados com raças locais. Considerando que os parâmetros fisiológicos e hematológicos são indicadores do estado patológico ou fisiológico do animal, para uma correta interpretação dos resultados recomenda-se a utilização de valores de referência baseados em animais com características raciais semelhantes e submetidos a condições ambientais também semelhantes.(AU)

Spatial distribution of Brazilian bovine taurine breeds associated with climatic, physical and socioeconomic variables / [Distribuição espacial de raças taurinas bovinas brasileiras associada a variáveis climáticas, físicas e socioeconômicas]

The objective of this study was to evaluate the spatial distribution of purebred Bos taurus taurus bovine breeds raised in Brazil in association with climatic, physical and socioeconomic variables. The breeds Aberdeen Angus, Ayrshire, Braford, Brangus, Charolais, Devon, Flemish, Hereford, Pinzgauer, Shorthorn and Simental were classified according to their aptitude (milk, meat or dual-purpose). They were spatialized according to their aptitude using state and municipal information. The milk breeds were found in the states of Rio Grande do Sul and Santa Catarina, while the dual-purpose breeds were found in Minas Gerais and Rio Grande do Sul states and the beef breeds were concentrated in the southern region. Only the Aberdeen Angus meat breed showed higher dispersion in other regions. Meat and dual-purpose breeds tended to be raised in regions with lower maximum temperature, average temperature, thermal amplitude and temperature-humidity index. Dual-purpose breeds were found in municipalities with high humidity and altitude, but with a low gross domestic product, little technical guidance received from cooperatives and the government, low control of diseases and parasites, as well as low use of pasture rotation systems. The spatial distribution of Brazilian bovine taurine breeds, regardless of aptitude, was related to climatic, physical and socioeconomic factors.(AU)

O objetivo deste estudo foi avaliar a distribuição espacial de raças bovinas puras Bos taurus taurus criadas no Brasil, associadas a variáveis climáticas, físicas e socioeconômicas. As raças Aberdeen Angus, Ayrshire, Braford, Brangus, Charolês, Devon, Flamenga, Hereford, Pinzgauer, Shorthorn e Simental foram classificadas de acordo com sua aptidão (leite, carne ou duplo-propósito). Elas foram espacializadas de acordo com sua aptidão a partir de informações estaduais e municipais. As raças leiteiras foram encontradas nos estados do Rio Grande do Sul e de Santa Catarina, enquanto as raças de duplo-propósito foram encontradas nos estados de Minas Gerais e Rio Grande do Sul, e as raças de carne concentraram-se na região Sul. Apenas a raça de carne Aberdeen Angus apresentou maior dispersão nas demais regiões. As raças de carne e de duplo-propósito tendem a ser criadas em regiões com menores temperatura máxima, temperatura média, amplitude térmica e índice de temperatura e umidade. As raças de duplo-propósito foram encontradas em municípios com alta umidade e altitude, mas com baixo produto interno bruto, pouca orientação técnica recebida de cooperativas e do governo, baixo controle de doenças e de parasitas e baixo uso de sistema de rotação de pastagens. A distribuição espacial das raças taurinas bovinas brasileiras, independentemente da aptidão, foi relacionada a fatores climáticos, físicos e socioeconômicos.(AU)

Different methods of assessing udder temperature through thermography and their relation with rectal temperature.

Infrared thermography of the lateral side portion of the udder was taken from 38 lactating cows in a 6-day experiment. Thermograms were analyzed using specific software with the use of eight different methods. The experiment was aimed at correlating the different methods with each other and with rectal temperature (RT), in order to suggest a method to assess udder side temperature, and also at creating regression equations to enable RT calculation through the use of thermographic data. All methods of analyzing thermograms were highly correlated; correlations between thermograms and RT were significant (P < 0.01) and above 0.840. The highest correlation was between RT and the maximum temperature obtained using a horizontal rectangle placed within the lateral (side) portion of the udder (maximum temperature in a horizontal rectangle (MHR), 0.897). With the exception of the average temperature of a horizontal rectangle, linear regression coefficients were significant (P < 0.05) and coefficients of determination were higher than 75.51%. We suggest the use of MHR to evaluate udder side temperature. The ease of accessing the side of the udder, the welfare advantages of non-invasive observations, and the high correlation with RT suggest the use of thermograms in the lateral portion of the udder to assess animals' temperature.

Access to shade changes behavioral and physiological attributes of dairy cows during the hot season in the subtropics.

The effect of shade on behavior and physiological attributes of grazing cows in a high altitude subtropical zone is not well established. This work aimed to investigate how social and ingestive behaviors, as well as physiological and other attributes of dairy cows such as milk production, change in a subtropical environment during the hot season either with or without free access to shade. Fourteen lactating cows were kept on pasture either with no shade or with free access to shade for 5 days and their behavior was recorded with instantaneous scan sampled every 10 min, from sunrise, 0530 h (Greenwich mean time, GMT-0200 h) to sunset, 2100 h (GMT-0200 h). Behavior traits included (1) time spent in activities such as grazing, ruminating, resting, lying, standing, walking, seeking shade and staying in the proximity to the water trough and (2) number of events such as water ingestion, aggressive interactions, as well as competition for shade and water. Physiological attributes such as heart and respiratory rates, rectal temperature, number of rumen movements, panting score, as well as milk yield, were evaluated. Time spent in behavioral activities, number of behavioral events and physiological attributes varied between groups (with and without access to shade). Cows with no shade showed increased respiratory and heart rates and panting score at 1300 h, higher values for time of permanence near the water trough, number of competition and aggression events for shade. On the other hand, they showed lower values for time spent resting while lying, ruminating while standing, seeking shade. Access to shade did not change time spent lying, standing, walking with the head up, ruminating while lying, resting while standing, as well as milk yield and number of ruminal movements. Significant interactions between access to shade and days of measurements were detected for time spent walking, ruminating, grazing, resting, number of water ingestion events, competition events near the water trough and for shade, as well as for rectal temperature and panting score measured at 1700 h. In the high altitude subtropical region, access to shade minimizes negative heat stress effects on behavior and physiological aspects of dairy cows.

Georeferenced evaluation of genetic breeding value patterns in Brazilian Holstein cattle.

The aim of this study was to analyze the relationship between environmental and genetic values for milk production and type traits in Holstein cattle in Brazil. The genetic value of 65,383 animals for milk production and 53,626 for type classification were available. Socioeconomic and environmental data were obtained from the Brazilian Institute of Geography and Statistics, the Food and Agriculture Organization of the United Nations, the National Aeronautics and Space Administration, and the National Institute of Meteorology. Five to six clusters were generated for each of the groups of type traits and production levels. The relationships between these traits were assessed using the STEPDISC, DISCRIM and CANDISC procedures in SAS(®). Traits within the clusters behaved differently, but, in general, animals with lower genetic values were found in environments that were more stressful for animal production. These differences were mainly associated with temperature, humidity, precipitation and the Normalized Difference Vegetative Index. Genetic values for milk production showed best discrimination between different environments, while type traits showed poor discrimination, possibly because farmers mainly select for milk production. Environmental variations for genetic values in dairy cattle in Brazil should be further examined.

Quality assessment of corn batches received at a feed mill in the brazilian cerrado

This study aimed at investigating factors that contribute to changes in the quality of corn used in compound poultry feeds. Samples were collected from 6488 bulk cargos received at a feed mill located close to Brasília, Brazil. The parameters studied were divided into two groups: those related to corn chemical composition, including crude protein (% CP), ether extract (% EE), crude fiber (% CF), nitrogen-free extract (% NFE), and estimated metabolizable energy (ME), and corn physical characteristics, including density, moisture, and grain physical damage. High coefficients of determination (R²) and low coefficients of variation (CV) were determined for the chemical and physical parameters. The analysis of variance showed low to medium R². Month, year, supplier, and their interactions influenced (p 0.05) all chemical properties, as well as density, moisture, and ME. Physical characteristics were less affected by those factors, except for quantity of damaged grains. The principal component analysis separated the physical and chemical factors. The coefficients of the first component explained 54% of the total variation between variables. The first principal component showed that NFE and ME increased as humidity decreased. The second component also showed a decrease of physical problems due to reduction in humidity. Results indicate that the feed mills should take preventive measures when selecting suppliers, and diets should be formulated according to the differences in chemical and physical composition of corn supplied in different months and years.(AU)

Genetic diversity and population structure of different varieties of Morada Nova hair sheep from Brazil.

The aim of this study was to analyze genetic diversity and population structure among varieties of White (N = 40), Red (N = 32), and Black (N = 31) Morada Nova hair sheep from flocks in the northeastern Brazilian semiarid region. Fifteen nuclear microsatellite markers and two regions of mitochondrial DNA were used. The intra-population analysis demonstrated that the White variety had higher diversity, while the Red variety had the lowest values. The Bayesian analysis to assess the genetic population structure allowed differentiation between White, Red, and Black varieties, and revealed a tendency towards sub-structuring in the White variety flocks from the States of Ceará and Paraíba. The results of analyses of molecular variance showed that the greatest genetic structure was found when comparing flocks rather than varieties (8.59 vs 6.64% of the total variation, P < 0.001). Based on genetic distance, Dtl, both the dendrogram analysis and the principal coordinate analysis showed the formation of two main groups: one composed of White and another of Black and Red individuals. Five and two haplotypes were found for the D-loop region and the ND5 gene, respectively. A haplotype unique to the Red variety was found in the D-loop region and a variety haplotype unique to the Black variety was found in the ND5 gene; however, these frequencies were low and therefore require further validation. These results support the existence of substantial differences between the Red and White varieties and should be used as separate genetic resources and to improve conservation programs.

Origins and genetic diversity of British cattle breeds in Brazil assessed by pedigree analyses.

Pedigree information available for Angus (ANG), Devon (DEV), Hereford (HER), and Shorthorn (SHO) cattle in Brazil was analyzed to appraise the genetic diversity and population structure of these breeds. Pedigree records collected from the beginning of the 20th century until 2010 were used in the analyses. Over time, the number of herdbook registrations declined in HER after a peak in the 1970s, remained low in DEV and SHO, and increased steadily in ANG since the 1990s, such that it the latter is now the leading British cattle breed in Brazil. The average number of offspring registered per sire ranged from about 12 (SHO) to 20 (DEV) and the mean generation interval ranged from about 6.0 (HER and SHO) to 6.4 (ANG) years. In the reference population (calves born in 2009 and 2010, plus those born in 2008 for SHO) the mean equivalent number of generations known ranged from about 7 (SHO) to 9 (HER). In the 4 breeds studied, nearly all animals born over the last few years are inbred, even though the mean level of inbreeding in the reference population is below 4% in all breeds. The rate of inbreeding per generation, computed from the individual increase in inbreeding, ranged from about 0.2 (ANG) to 0.5% (DEV), with a corresponding effective population size of 245 and 92, respectively, which is above the recommended minimum critical threshold. The number of founders/ancestors contributing with 50% of the reference population gene pool was 211/26 for ANG, 41/14 for DEV, 164/25 for HER, and 79/10 for SHO, with effective number of founders/ancestors/founder genomes of 470/68/36, 89/33/16, 289/59/30, and 200/28/18 for ANG, DEV, HER, and SHO, respectively. The genetic contribution of different countries to the gene pool of each breed indicated that, throughout the period studied, DEV genes originated predominantly from the United Kingdom, while for the other breeds there was a changing pattern over time. Until the 1970s Argentina was the major supplier of ANG, while HER and SHO genes were mostly from Uruguay, but since then the United States took the leading role as supplier of ANG, HER, and SHO genes to Brazil. Our results reveal a mild increase in inbreeding in all breeds studied, with effective population size estimates indicating that reasonable levels of genetic diversity have been maintained in all 4 breeds. Continuous monitoring of inbreeding trends and of parameters derived from probability of gene origin should be ensured to warrant the long-term maintenance of genetic diversity.

Platelet rich plasma associated with heterologous fresh and thawed chondrocytes on osteochondral lesions of rabbits / Associação de plasma rico em plaquetas e condrócitos heterólogos frescos e descongelados em lesão osteocondral de coelhos

Chondrocytes obtained from stifle joint of New Zealand White rabbits were cultivated. Half of cells were maintained in culture for later implantation and the others frozen during six months to evaluate viability. A circular osteochondral defect was created in the right stifle of other twenty seven rabbits. The control group (CG) received no treatment. The thawed (TH) and fresh (FH) heterologous groups received, respectively, an implant of cultivated thawed or fresh heterologous chondrocytes associated with platelet rich plasma (PRP). The CG group showed greatest pain and lameness compared to the other groups seven days after the implantation. Microscopically, at 45 and 90 days, the TH and FH groups showed filling with cartilaginous tissue containing chondrocytes surrounded by a dense matrix of glycosaminoglycans. In the CG group, healing occurred with vascularized fibrous connective tissue without integration to the subchondral bone. Cryopreserved heterologous chondrocytes were viable for implantation and healing of osteochondral lesions; the association with PRP allows the fixation of cells in the lesion and offers growth factors which accelerates repair with tissue similar to articular hyaline cartilage.

Cultivaram-se condrócitos obtidos da articulação do joelho de coelhos. Metade das células foi mantida em cultura para posterior implantação, e a outra metade foi congelada durante seis meses com a finalidade de avaliar a viabilidade. Criou-se um defeito circular osteocondral no joelho direito de outros vinte e sete coelhos. O grupo controle (GC) não recebeu tratamento. Os grupos descongelado (TH) e fresco (FH) receberam, respectivamente, implantes heterólogos de condrócitos cultivados descongelados e frescos, associados com PRP. O grupo GC apresentou maior dor e claudicação em comparação com os outros grupos aos sete dias após o implante. Microscopicamente, aos 45 e 90 dias, os grupos TH e FH mostraram preenchimento da falha com tecido cartilaginoso contendo condrócitos circundados por uma matriz densa de glicosaminoglicanos. Nesse período, no grupo CG, a cura ocorreu com tecido conjuntivo fibroso vascularizado e sem integração com o osso subcondral. Condrócitos heterólogos criopreservados foram viáveis para implantação e tratamento de lesões osteocondrais; a associação com o PRP permitiu a fixação de células na lesão e ofereceu fatores de crescimento que aceleraram a reparação com o tecido semelhante à cartilagem hialina articular.

Bioeconomic model and selection indices in Aberdeen Angus cattle.

A bioeconomic model was developed to calculate economic values for biological traits in full-cycle production systems and propose selection indices based on selection criteria used in the Brazilian Aberdeen Angus genetic breeding programme (PROMEBO). To assess the impact of changes in the performance of the traits on the profit of the production system, the initial values ​​of the traits were increased by 1%. The economic values for number of calves weaned (NCW) and slaughter weight (SW) were, respectively, R$ 6.65 and R$ 1.43/cow/year. The selection index at weaning showed a 44.77% emphasis on body weight, 14.24% for conformation, 30.36% for early maturing and 10.63% for muscle development. The eighteen-month index showed emphasis of 77.61% for body weight, 4.99% for conformation, 11.09% for early maturing, 6.10% for muscle development and 0.22% for scrotal circumference. NCW showed highest economic impact, and SW had important positive effect on the economics of the production system. The selection index proposed can be used by breeders and should contribute to greater profitability.

Humoral and cellular immunity in chromium picolinate-supplemented lambs.

The effects of oral supplementation of chromium picolinate (CrPic) on humoral and cellular immunity in sheep were investigated. Twenty-four male lambs divided into four treatments and received different dosages of CrPic: placebo (0), 0.250, 0.375, and 0.500 mg of chromium/animal/day during 84 days. The base ration was Panicum maximum cv Massai hay and concentrate. Blood samples were collected fortnightly for total and differential leukocyte counts. On days 28 and 56, the lambs were challenged with chicken ovalbumin I.M. Serum samples were collected on days 46 and 74 and subjected to an indirect enzyme-linked immunosorbent assay to measure IgG anti-ovalbumin. The cell-mediated immune response was determined by a delay-type hypersensitivity test using phytohemagglutinin. CrPic did not significantly affect humoral immunity in lambs but there was a negative effect on cellular immunity (P < 0.05) as Cr supplementation increased. Therefore, the level of Cr supplementation for lambs must be better studied to address its effect on stressed animals or the possible toxic effects of Cr on the animal itself or its immune system.

Severe feed restriction increases permeability of mammary gland cell tight junctions and reduces ethanol stability of milk.

A total of twelve lactating Jersey cows were used in a 5-week experiment to determine the effects of severe feed restriction on the permeability of mammary gland cell tight junctions (TJs) and its effects on milk stability to the alcohol test. During the first 2 weeks, cows were managed and fed together and received the same diet according to their nutritional requirements (full diet: 15 kg of sugar cane silage; 5.8 kg of alfalfa hay; 0.16 kg of mineral salt and 6.2 kg of concentrate). In the 3rd week, animals were distributed into two groups of six cows each. One group received the full diet and the other a restricted diet (50% of the full diet). In the 4th and 5th weeks, all animals received the full diet again. Milk composition and other attributes, such as titratable acidity, ethanol stability, pH, density and somatic cell count (SCC) were evaluated. Cortisol levels indicated the stress condition of the cows. Plasma lactose and milk sodium were measured to assess mammary TJ leakiness. Principal factor analysis (PFA) showed that the first two principal factors (PFs) contributed with 44.47% and 20.57% of the total variance in the experiment and, as feeding levels increased, milk stability to the ethanol test became higher and plasma lactose levels decreased, which indicates lower permeability of the mammary gland cell TJ. Correspondence analyses were consistent with PFA and also showed that lower feeding levels were related to reduced milk stability, high plasma lactose, high sodium in milk, low milk lactose (another parameter used to assess TJ permeability) and higher cortisol levels, indicating the stress to which animals were submitted. All observations were grouped in three clusters, with some of the above-mentioned patterns. Feeding restriction was associated with higher permeability of TJ, decreasing milk stability to the ethanol test.

Genetic variability in local Brazilian horse lines using microsatellite markers.

Genetic variability at 11 microsatellite markers was analyzed in five naturalized/local Brazilian horse breeds or genetic groups. Blood samples were collected from 328 animals of the breeds Campeira (Santa Catarina State), Lavradeira (Roraima State), Pantaneira (Pantanal Mato-Grossense), Mangalarga Marchador (Minas Gerais State), as well as the genetic group Baixadeiro (Maranhão State), and the exotic breeds English Thoroughbred and Arab. We found significant genetic variability within evaluated microsatellite loci, with observed heterozygosis varying between 0.426 and 0.768 and polymorphism information content values of 0.751 to 0.914. All breeds showed high inbreeding coefficients and were not in Hardy-Weinberg equilibrium. The smallest genetic distance was seen between the Pantaneira and Arab breeds. The principal component analyzes and Bayesian approach demonstrated that the exotic breeds have had a significant influence on the genetic formation of the local breeds, with introgression of English Throroughbred in Pantaneira and Lavradeira, as well as genetic proximity between the Arab, Pantaneira and Mangalarga Marchador populations. This study shows the need to conserve traits acquired by naturalized horse breeds over centuries of natural selection in Brazil due to the genetic uniqueness of each group, suggesting a reduced gene flow between them. These results reinforce the need to include these herds in animal genetic resource conservation programs to maximize the genetic variability and conserve useful allele combinations.

Genetic diversity and assessment of 23 microsatellite markers for parentage testing of Santa Inês hair sheep in Brazil.

Santa Inês is the most common hair sheep breed in Brazil and probably has the highest genetic diversity among sheep breeds in this country. Successful breeding programs for Brazilian sheep breeds are not common for various reasons, including a lack of control of parentage in the flocks. We developed an allele frequency database for 23 STR loci for the Santa Inês breed based on 285 animals sampled from five populations distributed across the central-western and north-eastern regions of Brazil. The marker set included seven microsatellites used in the 2011 International Society for Animal Genetics sheep genotyping comparison tests and all eight microsatellites currently approved by the Brazilian Agricultural Ministry laboratory accreditation guidelines for sheep identification. The microsatellites had an average of 10 alleles and a mean expected heterozygosity of 0.745. Combined paternity exclusion probabilities when no parent or one parent was known were >99.99%. A small proportion (5.8%) of the existing genetic variation was found to be among the Santa Inês populations, possibly derived from genetic drift and selection. We found that the marker panel proposed by the Agricultural Ministry, although generally useful, should be enhanced by including more markers for improved exclusionary power in parentage testing. This database provides a useful tool for parentage testing of this major Brazilian breed, contributing to improved management and breeding of existing herds.

PRNP haplotype and genotype frequencies in Brazilian sheep: issues for conservation and breeding programs.

Polymorphisms of PRNP gene have been strongly correlated to the susceptibility/resistance to scrapie in sheep. Variants at the coding positions 136, 154 and 171 have been the most frequently associated to susceptibility to classical scrapie. The aim of this study was to estimate PRNP haplotype and genotype frequencies in a sample of 1400 sheep from 13 different breeds that are representative of the main production regions in Brazil. A total of four different alleles (ARR, ARQ, AHQ and VRQ) and nine genotypes were observed at different frequencies among the investigated breeds. There were distinct patterns of allelic distribution between naturalized and commercial/specialized breeds and different geographic regions. These results will influence the development and management of breeding and conservation programs and will help to develop Brazilian efforts to avoid scrapie epidemics.

Adaptation of a low-cost medium-throughput genotyping system for ovine prion protein gene polymorphims associated with scrapie.

Resistance and susceptibility to scrapie in sheep have been associated with SNPs located at codons 136, 154 and 171 of the prion protein (PRNP) gene. Many countries have sheep breeding programs selecting for resistance to scrapie based on the genotyping of these SNPs. We adapted a fast and robust method for genotyping sheep flocks for these polymorphisms, with reduced costs. Ninety-six samples were genotyped using an adapted SNaPshot PRNP assay, and the results were checked by resequencing. The results showed 100% concordance, using a method that reduces genotyping costs by 70%, by reducing reagent concentrations in the three main steps of the assay (amplicon purification, base extension and final cleanup). This cost reduction should contribute to the development of selection criteria based on PRNP genotyping in countries where assay costs are an important limiting factor.

Efeitos do congelamento sobre condrócitos cultivados de coelhos / Effect of freezing on rabbit cultured chondrocytes

This work evaluated the effect of freezing on chondrocytes maintained in culture, aiming the establishment of a cell bank for future application as heterologous implant. Chondrocytes extracted from joint cartilage of nine healthy New Zealand White rabbits were cultivated and frozen with the cryoprotector 5 percent dimethylsulfoxide for six months. Phenotypic and scanning electron microscopy analyses were carried out to identify morphological and functional differences between fresh and thawed cells. After enzymatic digestion, a total of 4.8x10(5)cells per rabbit were obtained. Fresh chondrocytes showed a high mitotic rate and abundant matrix was present up to 60 days of culture. Loss of phenotypic stability was notable in the thawed chondrocytes, with a low labeling of proteoglycans and weak immunostaining of type II collagen. The present study showed important loss of chondrocyte viability under the freezing conditions. For future in vivo studies of heterologous implant, these results suggests that a high number of cells should be implanted in the host site in order to achieve an adequate number of viable cells. Furthermore, the chondrocytes should be implanted after two weeks of culture, when the highest viability rate is found.

Avaliaram-se os efeitos do congelamento sobre condrócitos mantidos em cultura, com o objetivo de se estabelecer um banco celular para futura aplicação como implante heterólogo. Condrócitos extraídos da cartilagem articular de nove coelhos saudáveis, da raça Nova Zelândia Branca, foram cultivados e submetidos ao congelamento, com o citoprotetor sulfóxido de dimetila a 5 por cento, por um período de seis meses. Análises fenotípicas e de microscopia eletrônica de varredura foram realizadas com o objetivo de identificar diferenças morfológicas e funcionais entre as células frescas e as descongeladas. Após a digestão enzimática, foram obtidas 4,8x10(5) células por coelho. Os condrócitos frescos apresentaram elevada taxa mitótica e abundante presença de matriz até os 60 dias de cultura. Nas culturas dos condrócitos descongelados, a perda de estabilidade fenotípica foi marcante, o que foi demonstrado pela baixa intensidade da coloração dos proteoglicanos e pela fraca imunomarcação do colágeno tipo II. Sob as condições de congelamento utilizadas, houve importante perda de viabilidade condrocítica. Para futuros estudos in vivo de implante heterólogo, estes resultados sugerem que o elevado número de células deve ser implantado no sítio hospedeiro, com o objetivo de se obter maior quantidade de células viáveis, e que os condrócitos deverão ser implantados com duas semanas de cultivo, período em que apresentam melhor taxa de viabilidade.

Effect of freezing on rabbit cultured chondrocytes / Efeitos do congelamento sobre condrócitos cultivados de coelhos

This work evaluated the effect of freezing on chondrocytes maintained in culture, aiming the establishment of a cell bank for future application as heterologous implant. Chondrocytes extracted from joint cartilage of nine healthy New Zealand White rabbits were cultivated and frozen with the cryoprotector 5 percent dimethylsulfoxide for six months. Phenotypic and scanning electron microscopy analyses were carried out to identify morphological and functional differences between fresh and thawed cells. After enzymatic digestion, a total of 4.8x10(5)cells per rabbit were obtained. Fresh chondrocytes showed a high mitotic rate and abundant matrix was present up to 60 days of culture. Loss of phenotypic stability was notable in the thawed chondrocytes, with a low labeling of proteoglycans and weak immunostaining of type II collagen. The present study showed important loss of chondrocyte viability under the freezing conditions. For future in vivo studies of heterologous implant, these results suggests that a high number of cells should be implanted in the host site in order to achieve an adequate number of viable cells. Furthermore, the chondrocytes should be implanted after two weeks of culture, when the highest viability rate is found.(AU)

Avaliaram-se os efeitos do congelamento sobre condrócitos mantidos em cultura, com o objetivo de se estabelecer um banco celular para futura aplicação como implante heterólogo. Condrócitos extraídos da cartilagem articular de nove coelhos saudáveis, da raça Nova Zelândia Branca, foram cultivados e submetidos ao congelamento, com o citoprotetor sulfóxido de dimetila a 5 por cento, por um período de seis meses. Análises fenotípicas e de microscopia eletrônica de varredura foram realizadas com o objetivo de identificar diferenças morfológicas e funcionais entre as células frescas e as descongeladas. Após a digestão enzimática, foram obtidas 4,8x10(5) células por coelho. Os condrócitos frescos apresentaram elevada taxa mitótica e abundante presença de matriz até os 60 dias de cultura. Nas culturas dos condrócitos descongelados, a perda de estabilidade fenotípica foi marcante, o que foi demonstrado pela baixa intensidade da coloração dos proteoglicanos e pela fraca imunomarcação do colágeno tipo II. Sob as condições de congelamento utilizadas, houve importante perda de viabilidade condrocítica. Para futuros estudos in vivo de implante heterólogo, estes resultados sugerem que o elevado número de células deve ser implantado no sítio hospedeiro, com o objetivo de se obter maior quantidade de células viáveis, e que os condrócitos deverão ser implantados com duas semanas de cultivo, período em que apresentam melhor taxa de viabilidade.(AU)

Performance and ruminal protozoa in lambs with chromium supplementation.

The effects of chromium picolinate (CrPic) oral supplementation on the performance and ruminal protozoa population in sheep was investigated. Twenty-four male lambs were treated with four different levels of CrPic: placebo, 0.250, 0.375 and 0.500mg of chromium/animal/day during 84 days. The base ration was Panicum maximum cv Massai hay and concentrate. Feed intake was measured three times a week. Lambs were weighed every 2 weeks. Ruminal content was sampled five times during the trial to quantify ruminal protozoa. No difference (p>0.05) between treatments was recorded for any parameter measured: initial and final mean body weight, dry matter intake, daily gain and total body weight gain. There was a negative linear relationship between Cr supplementation and protozoa count (p=0.0013) with no additional decrease when CrPic supplemental levels were higher than 0.375mg/day. Therefore, Cr supplementation must be carried out carefully and more studies need to address stressed animals or possible toxic effects of Cr in the animal itself or to the ruminal protozoa population.

Number of flocks on the same litter and carcase condemnations due to cellulitis, arthritis and contact foot-pad dermatitis in broilers.

1. This study was conducted to verify the impact of different kinds of material and the number of times of litter reuse on the incidence of chicken pathologies. Approximately 4·5 million broilers from conventional Brazilian farms were evaluated in the abattoir for cellulitis, arthritis and contact foot-pad dermatitis. 2. Four different kinds of litter material, Brachiaria grass, corncob, sawdust and rice shell, were used. Brachiaria grass litter showed the highest incidence of contact foot-pad dermatitis. Corncob litter also showed some negative effects on foot quality. Broilers raised on rice shell litter showed good results in terms of the incidence of contact foot-pad dermatitis. The best results were obtained with sawdust litter, because the incidence of cellulitis and arthritis were the lowest and the incidence of contact foot-pad dermatitis was also very low.