Comparison of genetic parameters and estimated breeding values for worm resistance in meat sheep obtained using traditional and genomic models.

Gastrointestinal nematode infections have caused expressive losses in sheep production worldwide. The improvement of host genetic resistance to worms has been used as a strategy to mitigate this problem. In this sense, the inclusion of genomic information has shown potential to increase the accuracy of prediction of breeding values and speed up selection. In this study, we aimed to compare estimates of genetic parameters and breeding values for traits that indicate the resistance to gastrointestinal nematode infection in Santa Inês sheep using the pedigree-based BLUP or including genomic information. There were 1478 animals in the pedigree, of which 271 were genotyped using the OvineSNP50 BeadChip (Illumina, Inc.). The host resistance was assessed using the following traits: fecal nematode egg counts (FEC); FAMACHA score (FAMACHA); and resistance to gastrointestinal nematode infection (RGNI) as a combination of FEC, FAMACHA, body condition score, and hematocrit. The genetic parameters and breeding values were estimated using single- and multi-trait analyses. For RGNI, the heritability estimates ranged from 0.25 using the single-trait genomic model (S-H) to 0.54 using the traditional multi-trait model (M-A). The heritability estimates for FEC ranged from 0.06 to 0.36, using the single-trait pedigree-based model (S-A) and the multi-trait genomic model (M-H), respectively. For FAMACHA, the heritability estimates ranged from 0.46 (M-H) to 0.54 (M-A). Estimates of genetic correlation ranged from 0.22 to 0.69. The inclusion of genomic information provided gain in accuracy for all traits. All estimates of predictive ability obtained using genomic data in a multi-trait setting were higher than those obtained using single-trait models. The estimates of predictive ability ranged from 0.03 (S-A) to 0.46 (M-H). The heritability estimates obtained using genomic information showed that all traits evaluated are suitable for genomic selection. Despite the low accuracies obtained, the use of the genomic model provided more accurate estimates of breeding values in comparison to the pedigree-based model.

Genetic parameters for worm resistance in Santa Inês sheep using the Bayesian animal model.

OBJECTIVE: The objective of this study was to estimate the genetic parameters for worm resistance (WR) and associated characteristics, using the linear-threshold animal model via Bayesian inference in single- and multiple-trait analyses. METHODS: Data were collected from a herd of Santa Inês breed sheep. All information was collected with animals submitted to natural contamination conditions. All data (number of eggs per gram of feces [FEC], Famacha score [FS], body condition score [BCS], and hematocrit [HCT]) were collected on the same day. The animals were weighed individually on the day after collection (after 12-h fasting). The WR trait was defined by the multivariate cluster analysis, using the FEC, HCT, BCS, and FS of material collected from naturally infected sheep of the Santa Inês breed. The variance components and genetic parameters for the WR, FEC, HCT, BCS, and FS traits were estimated using the Bayesian inference under the linear and threshold animal model. RESULTS: A low magnitude was obtained for repeatability of worm-related traits. The mean values estimated for heritability were of low-to-high (0.05 to 0.88) magnitude. The FEC, HCT, BCS, FS, and body weight traits showed higher heritability (although low magnitude) in the multiple-trait model due to increased information about traits. All WR characters showed a significant genetic correlation, and heritability estimates ranged from low (0.44; single-trait model) to high (0.88; multiple-trait model). CONCLUSION: Therefore, we suggest that FS be included as a criterion of ovine genetic selection for endoparasite resistance using the trait defined by multivariate cluster analysis, as it will provide greater genetic gains when compared to any single trait. In addition, its measurement is easy and inexpensive, exhibiting greater heritability and repeatability and a high genetic correlation with the trait of resistance to worms.

Genetic evaluation of sheep for resistance to gastrointestinal nematodes and body size including genomic information.

OBJECTIVE: The genetic evaluation of Santa Inês sheep was performed for resistance to gastrointestinal nematode infection (RGNI) and body size using different relationship matrices to assess the efficiency of including genomic information in the analyses. METHODS: There were 1,637 animals in the pedigree and 500, 980, and 980 records of RGNI, thoracic depth (TD), and rump height (RH), respectively. The genomic data consisted of 42,748 SNPs and 388 samples genotyped with the OvineSNP50 BeadChip. The (co)variance components were estimated in single- and multi-trait analyses using the numerator relationship matrix (A) and the hybrid matrix H, which blends A with the genomic relationship matrix (G). The BLUP and single-step genomic BLUP methods were used. The accuracies of estimated breeding values and Spearman rank correlation were also used to assess the feasibility of incorporating genomic information in the analyses. RESULTS: The heritability estimates ranged from 0.11±0.07, for TD (in single-trait analysis using the A matrix), to 0.38±0.08, for RH (using the H matrix in multi-trait analysis). The estimates of genetic correlation ranged from -0.65±0.31 to 0.59±0.19, using A, and from -0.42±0.30 to 0.57±0.16 using H. The gains in accuracy of estimated breeding values ranged from 2.22% to 75.00% with the inclusion of genomic information in the analyses. CONCLUSION: The inclusion of genomic information will benefit the direct selection for the traits in this study, especially RGNI and TD. More information is necessary to improve the understanding on the genetic relationship between resistance to nematode infection and body size in Santa Inês sheep. The genetic evaluation for the evaluated traits was more efficient when genomic information was included in the analyses.

Aspectos higienicossanitários dos boxes de comercialização de pescado no Mercado Municipal José Emídio em Timon, MA / Sanitary aspects of fish marketing boxes in the Jose Emidio Municipal Market in Timon, MA

Objetivou-se verificar as condições higienicossanitárias dos boxes de comercialização de pescado no Mercado Público José Emídio, localizado no município de Timon, Maranhão. Foram aplicados checklists considerando os aspectos higiênicos e sanitários dos proprietários dos boxes e realizou-se a coleta de amostras dos alimentos comercializados nesses estabelecimentos para avaliação microbiológica, bem como amostras, por meio de swab, das mãos, realizando a determinação do número mais provável de coliformes a 35º e a 45º C. Tais procedimentos foram posteriores a apresentação, leitura e assinatura do Termo de Consentimento Livre e Esclarecido. Por meio da porcentagem de "SIM" às respostas dos itens do checklist, os boxes foram diagnosticados com 24,14; 31,03 e 48,00% para A, B e C, respectivamente, sendo os três estabelecimentos classificados como irregulares. Nas análises microbiológicas verificou-se que há presença de coliformes totais na maioria das amostras de pescado, indicando condições higienicossanitárias insatisfatórias dos alimentos comercializados nos boxes pesquisados. Todavia, nas análises referentes aos manipuladores, verificou-se que somente um apresentou resultado de contaminação microbiológica. Tais resultados evidenciam a necessidade de análise microbiológica dos alimentos, auxiliando a identificação de qual momento está ocorrendo o processo de contaminação do pescado. A aplicação somente do checklist é ineficiente para avaliação das condições higienicossanitárias de estabelecimento comercializadores de pescado.(AU)

It was aimed to verify the hygienic-sanitary conditions of fish comercilizers boxes in the José Emídio Public Market, located in the Timon city, Maranhão. They were applied "checklist" considering the hygienic-sanitary aspects of the Manipulators of the boxes and the samples of the foods commercialized collected in out for microbiological evaluation, as well as samples by hand swab, making the determination of the most probable number of coliforms at 35º and 45º C. Such procedures were subsequent to the presentation, reading and signing of the Termod and Free and Scantily Consented. Through the "YES" percentage of responses to Checklist items, the boxes were diagnosed with 24,14, 31,03 and 48,00% for A, B and C, respectively, and the three establishments were classified as irregular. In the microbiological analyzes it was verified that there is presence of total coliforms in the majority of fish samples, indicating unsatisfactory hygienic-sanitary conditions of the foods commercialized in the researched boxes. However, in the analyzes referring to the manipulators, it was verified that only one presented a result of microbiological contamination. These results evidenced the need for microbiological analysis of the food, helping to identify which moment the process of fish contamination is occurring. The only application of the "checklist" is inefficient to evaluate the hygienicsanitary conditions of fish traders.

Genetic parameters for marbling and body score in Anglonubian goats using Bayesian inference via threshold and linear models.

OBJECTIVE: The aim of this study was to estimate (co) variance components and genetic parameters for categorical carcass traits using Bayesian inference via mixed linear and threshold animal models in Anglonubian goats. METHODS: Data were obtained from Anglonubian goats reared in the Brazilian Mid-North region. The traits in study were body condition score, marbling in the rib eye, ribeye area, fat thickness of the sternum, hip height, leg perimeter, and body weight. The numerator relationship matrix contained information from 793 animals. The single- and two-trait analyses were performed to estimate (co) variance components and genetic parameters via linear and threshold animal models. For estimation of genetic parameters, chains with 2 and 4 million cycles were tested. An 1,000,000-cycle initial burn-in was considered with values taken every 250 cycles, in a total of 4,000 samples. Convergence was monitored by Geweke criteria and Monte Carlo error chain. RESULTS: Threshold model best fits categorical data since it is more efficient to detect genetic variability. In two-trait analysis the contribution of the increase in information and the correlations between traits contributed to increase the estimated values for (co) variance components and heritability, in comparison to single-trait analysis. Heritability estimates for the study traits were from low to moderate magnitude. CONCLUSION: Direct selection of the continuous distribution of traits such as thickness sternal fat and hip height allows obtaining the indirect selection for marbling of ribeye.

Genetic parameters for carcass traits and body size in sheep for meat production.

The aim was to estimate the covariance components and genetic parameters of carcass traits and body size of meat sheep by employing animal models for single and multi-trait analyses. Data were collected from herds of adult Santa Ines sheep. The ribeye area, subcutaneous fat thickness, and rump fat thickness, evaluated in vivo by ultrasound images of the carcass; and morphometric traits: fat depth, rump height, chest circumference, chest depth, body length, and rump length were measured. The covariance components and genetic parameters for these traits were estimated by restricted maximum likelihood methodology, considering the random additive direct-genetic effects of the animal and errors associated with each observation, and the fixed effects of the contemporary group, the type of birth, and the age of the animal classes. Heritability estimates for carcass traits and animal size were higher in the three-trait analyses than in the single-trait analyses. The magnitudes of the values obtained indicate that genetic progress can be achieved by selection based on the traits studied.