RESUMO

Biological information regarding markers and gene association may be used to attribute different weights for single nucleotide polymorphism (SNP) in genome-wide selection. Therefore, we aimed to evaluate the predictive ability and the bias of genomic prediction using models that allow SNP weighting in the genomic relationship matrix (G) building, with and without incorporating biological information to obtain the weights. Firstly, we performed a genome-wide association studies (GWAS) in data set containing single- (SL) or a multi-line (ML) pig population for androstenone, skatole and indole levels. Secondly, 1%, 2%, 5%, 10%, 30% and 50% of the markers explaining the highest proportions of the genetic variance for each trait were selected to build gene networks through the association weight matrix (AWM) approach. The number of edges in the network was computed and used to derive weights for G (AWM-WssGBLUP). The single-step GBLUP (ssGBLUP) and weighted ssGBLUP (WssGBLUP) were used as standard scenarios. All scenarios presented predictive abilities different from zero; however, the great overlap in their confidences interval suggests no differences among scenarios. Most of scenarios of based on AWM provide overestimations for skatole in both SL and ML populations. On the other hand, the skatole and indole prediction were no biased in the ssGBLUP (S1) in both SL and ML populations. Most of scenarios based on AWM provide no biased predictions for indole in both SL and ML populations. In summary, using biological information through AWM matrix and gene networks to derive weights for genomic prediction resulted in no increase in predictive ability for boar taint compounds. In addition, this approach increased the number of analyses steps. Thus, we can conclude that ssGBLUP is most appropriate for the analysis of boar taint compounds in comparison with the weighted strategies used in the present work.

Assuntos

RESUMO

The objective of this research was to study the effect of immunocastration on the morphometric characteristics of sex glands in male Swallow-bellied Mangalitsa pigs. The study included 24 animals (13 entire and 11 immunocastrated males). The research focused on the following traits: age at slaughter (days), live weight at slaughter (kg), growth rate (kg day−1), and morphometric testicle traits (volume, cm3; weight, g; length, width, thickness, and circumference, mm). The efficacy of immunocastration was determined based on androstenone and skatole levels in adipose tissue. The group of immunocastrated animals had higher body weight at slaughter (+18.8 kg) due to higher average daily live gain (+87 g). Immunocastration resulted in reduced morphometric measures of testes. The volumes and weight of testes/epididymes were reduced by 28.9-54.4 and 32.1-53.3%, respectively. Testis length and other size-related traits were significantly reduced by 17.4-27.6%. The linear regression effect of live body weight at slaughter within the immunocastrated group on testis measurements was not significant. Within the entire group of males, the increase of live body weight at slaughter by 1 kg had an effect on the increase of volume and weight of testes/epididymes by 0.55-2.24 cm3 and 0.52-2.28 g, respectively. Other size-related testis traits increased by 0.04-0.55 mm for each kg of body weight. Immunocastration also resulted in 79.6% decrease in the weight of accessory sex glands. The present study is the first to demonstrate that immunocastration could be a method of choice for castration of the local fatty pig breed, Mangulica (Swallow-bellied Mangalitsa).(AU)

Assuntos

RESUMO

A non-surgical sterilant (NSS) was used with the objective of assessing the zootechnical performance, carcass and meat quality, and hormone levels. 90 male piglets were selected with birthweights varying between 1.5kg to 2.0kg. The control group was constituted of 45 males castrated by the conventional surgical method, at the seventh day of age, and the treated group was constituted of 45 males castrated with NSS (active principle of zinc gluconate in the concentration of 26.2mg/mL associated to the dimethyl sulfoxide at 0.5%), with the application of the first dose on the seventh day of age and the second dose on the fourteenth day of age. The zootechnical assessments were carried out on the farm and consisted: weight gain in the periods per animal and feed conversion. The slaughter of the animals and the assessment of the carcass and meat quality and hormone levels were carried out in a slaughterhouse and the municipality of Campinas (SP). The study demonstrated that the use of NSS was a viable alternative in relation to the zootechnical performance and the carcass quality. In relation to the meat quality there was no significant difference in the majority of the assessed parameters.(AU)

Foi utilizado esterilizante não cirúrgico (ENC) com o objetivo de se avaliar o desempenho zootécnico e a qualidade de carcaça, de carne e de níveis hormonais. Foram selecionados 90 leitões machos de peso entre 1,5kg e 2,0kg ao nascimento. O grupo controle foi constituído por 45 machos castrados pelo método cirúrgico convencional, ao sétimo dia de idade, e o grupo tratado foi constituído por 45 machos castrados com ENC (princípio ativo de gluconato de zinco na concentração de 26,2mg/mL associado ao dimetil sulfóxido a 0,5%), com primeira dose de aplicação ao sétimo dia de idade e a segunda dose ao 14° dia de idade. As avaliações consistiram de: ganho de peso nos períodos por animal e conversão alimentar. O abate dos animais e a avaliação da carne e de níveis hormonais foram realizados em um frigorífico, na cidade de Campinas (SP). O uso de ENC foi uma alternativa viável em relação ao desempenho zootécnico e à qualidade da carcaça. Em relação à qualidade da carne, não houve diferença significativa na maioria dos parâmetros avaliados.(AU)

Assuntos

RESUMO

A non-surgical sterilant (NSS) was used with the objective of assessing the zootechnical performance, carcass and meat quality, and hormone levels. 90 male piglets were selected with birthweights varying between 1.5kg to 2.0kg. The control group was constituted of 45 males castrated by the conventional surgical method, at the seventh day of age, and the treated group was constituted of 45 males castrated with NSS (active principle of zinc gluconate in the concentration of 26.2mg/mL associated to the dimethyl sulfoxide at 0.5%), with the application of the first dose on the seventh day of age and the second dose on the fourteenth day of age. The zootechnical assessments were carried out on the farm and consisted: weight gain in the periods per animal and feed conversion. The slaughter of the animals and the assessment of the carcass and meat quality and hormone levels were carried out in a slaughterhouse and the municipality of Campinas (SP). The study demonstrated that the use of NSS was a viable alternative in relation to the zootechnical performance and the carcass quality. In relation to the meat quality there was no significant difference in the majority of the assessed parameters.(AU)

Foi utilizado esterilizante não cirúrgico (ENC) com o objetivo de se avaliar o desempenho zootécnico e a qualidade de carcaça, de carne e de níveis hormonais. Foram selecionados 90 leitões machos de peso entre 1,5kg e 2,0kg ao nascimento. O grupo controle foi constituído por 45 machos castrados pelo método cirúrgico convencional, ao sétimo dia de idade, e o grupo tratado foi constituído por 45 machos castrados com ENC (princípio ativo de gluconato de zinco na concentração de 26,2mg/mL associado ao dimetil sulfóxido a 0,5%), com primeira dose de aplicação ao sétimo dia de idade e a segunda dose ao 14° dia de idade. As avaliações consistiram de: ganho de peso nos períodos por animal e conversão alimentar. O abate dos animais e a avaliação da carne e de níveis hormonais foram realizados em um frigorífico, na cidade de Campinas (SP). O uso de ENC foi uma alternativa viável em relação ao desempenho zootécnico e à qualidade da carcaça. Em relação à qualidade da carne, não houve diferença significativa na maioria dos parâmetros avaliados.(AU)

Assuntos