Study of genetic variability in pigs after the traditional breeding program.

Molecular markers are tools used to improve genetic gains. The objective of this study was to analyze the security of alleles of molecular marker genes for characteristics of economic interest in a pure population of pigs. After the extraction of DNA from the hair of 272 Large White matrices, the allele and genotype frequency of single nucleotide polymorphism was performed using the ARMS-PCR Multiplex technique in the DGAT1, LEPR, H-FABP, MC4R, and SREBF1 genes using RFLP-PCR for the GH gene. After capillary electrophoresis in an automated DNA sequencing of the DGAT1, LEPR, H-FABP, and SREBF1 genes, no polymorphisms were found. Only the MC4R marker presented 100% heterozygosity. For the GH gene, 209 of the initial population samples were genotyped. The PCR product (605 bp) was digested with the restriction enzyme DdeI, with fragments being of 335, 148, and 122 bp for the D1 allele and 457 and 148 bp for the D2 allele. The genotypic frequency obtained of D1D2 was 88% and of D2D2 was 22%. The D1 allele presented a frequency of 11% and the D2 allele of 89%. The high intensity of selection for commercial breeds justifies the absence or the low number of polymorphisms for the genes studied.

Utilização da técnica in vitro semiautomática de produção de gases na avaliação da fermentação microbiana do ceco de suínos / Use of the semi-automatic in vitro gas production technique for the evaluation of swine cecal microbial fermentation

O presente estudo teve como objetivo avaliar o os padrões de fermentação microbiana do ceco de suínos, utilizando-se um modelo aplicado na técnica in vitro de produção de gases para ruminantes. Três tipos de inóculo foram utilizados: ceco de suínos criados ao ar livre (CSF), ceco de suínos criados confinados (CSC) e líquido ruminal de bovino (LRB). Os substratos utilizados derivaram de uma dieta de suínos à base de farelo de soja e de grãos de milho, atendendo as exigências nutricionais dos suínos. Para composição dos substratos, foram estabelecidos diferentes níveis de substituição da dieta basal pela torta da amêndoa da Acrocomia aculeata (AA), coproduto da produção do biodiesel, sendo: BAS - 100% de dieta basal; M10 - 90% de dieta basal e 10% AA; M20 - 80% de dieta basal e 20% AA e o TF - feno de Tifton 85 (Cynodon spp.). A produção de gases foi avaliada nos tempos zero, três, seis, nove, 12, 16, 24, 48, 72 e 96 horas após a incubação. Foram analisados o potencial máximo de produção de gás (A) e o tempo de colonização (L). O delineamento experimental utilizado foi inteiramente ao acaso, em arranjo fatorial 4 x 3. Os dados de A e L foram submetidos à análise de variância, e as médias comparadas pelo teste de Tukey a 5%. Comparando os inóculos para A (mL/gMS), LRB e CSF apresentaram valores similares, diferindo apenas para TF. O tempo de colonização (L) entre inóculos, o CSC e o CSF apresentaram os menores tempos de colonização quando a ração foi BAS. Com os substratos M10 e M20, o inóculo LRB apresentou o menor tempo, CSF o maior tempo e CSC não diferiu de ambos. Não houve diferença significativa entre os inóculos para o substrato TF. A técnica de produção de gases utilizada para o ceco de suínos apresentou resultados semelhantes aos encontrados para ruminantes. O modelo matemático usado foi adequado para descrever a curva de fermentação no ceco de suínos, mostrando semelhanças entre as microbiotas do ceco e do rúmen.(AU)

This study aimed to evaluate the microbial fermentation patterns of the pig ceca using the technique of in vitro gas production for ruminants. Three types of inoculums were used: swine ceca raised in a free range system (CSF), swine ceca raised in a conventional confined system (CSC) and bovine rumen fluid (LRB). The substrates used were derived from pig's diet with soybean meal and corn grits, according to the nutritional requirements of swine. The substrates were composed by different set levels of substitution of basal diet by meal almond Acrocomia aculeata (AA), as: BAS - 100% of basal diet; M10 - 90% of basal diet and 10% AA (M10); M20 - 80% of basal diet and 20% AA (M20) and TF - Tifton 85 hay (Cynodon spp.).The gas production was evaluated at times 0, 3, 6, 9, 12, 16, 24, 48, 72 and 96 hours after incubation. The study analyzed the maximum potential of gas production (A) and lag time (L). The experimental design was completely randomized in a 4 x 3 factorial arrangement. The A and L data were submitted to analysis of variance and the averages compared by Tukey 5% test. Comparing the inoculum for A (ml / gDM), LRB, and CS, they showed similar values, differing only for TF. The lag time (L) between inoculum, the CSC and CSF had the lowest colonization times when the meal was BAS. With M10 and M20 substrates, the LRB inoculum showed the lowest time, CSF had the longest time and CSC did not differ from both. There was no significant difference between the inoculum for TF substrate. The gas production technique used for the ceca of pigs showed similar results to those for ruminants. The mathematical model used was adequate to describe the fermentation curve in the ceca of pigs, showing similarities between the microbiota of the ceca and the rumen.(AU)

PIT1 gene polymorphism in Pietrain and Large White pigs after divergent selection.

We examined the polymorphisms in the PIT1 gene of 103 pigs and compared their frequencies in the maternal and paternal lineages of the Pietrain and Large White breeds, which have undergone divergent selection for over 30 years. DNA samples extracted from the blood of these animals were amplified by PCR and genotyped by RFLP, using the restriction enzyme RsaI. The data were analyzed with the chi-square test. We found that 57.3% of the animals were genotype AB, among which 26.2% were of the Large White paternal lineage, 18.5% the Pietrain paternal lineage and 12.6% the Pietrain maternal lineage. The AA genotype appeared in 20.4%, of which 7.8% were Large White, 4.8% the Pietrain paternal lineage and 7.8% the Pietrain maternal lineage. BB was observed in 22.3% (6.8% were of the Large White paternal lineage, 9.7% of the Pietrain paternal lineage and 5.8% of the Pietrain maternal lineage). The allele frequencies were 49.0% A and 51.0% B allele. When we examined the Pietrain maternal and paternal lineages, we found that the PIT1 gene had been fixed in the paternal lineage, suggesting that the B allele is associated with low body fat and improved muscle development when compared to the maternal lineage. However, no significant differences were found between the Pietrain and Large White paternal lineages.

Obese gene polymorphism in Pietrain and Large White pigs after a divergent selection.

The aim of the present study was to identify polymorphisms in the leptin gene of 112 pigs and compare the maternal and paternal lineage of Pietrain and Large White breeds that underwent a divergent selection for over 30 years. DNA samples extracted from the blood of these animals were amplified by polymerase chain reaction and genotyped by restriction fragment length polymorphism using the restriction enzyme HinfI. The data were statistically analyzed by the chi-square test. The results showed that 87.5% of the animals were genotype TT, where 31.25% were Large White paternal lineage, 31.25% were Pietrain paternal lineage and 25% were Pietrain maternal lineage. The TC genotype appeared in 12.5%, where 10% were Large White, 0.5% were Pietrain paternal lineage and 2% were of the same maternal lineage breed; CC was not observed. As for the allele frequency, 93.75% of the T and 6.25% of the C allele were found. In Pietrain maternal and paternal lineages, it could not be determined that the Obese gene had been fixed in the maternal lineage. However, in the Pietrain and Large White paternal lineages there was a statistically significant difference, suggesting that the C allele is associated with growth and daily weight gain and that the low frequency of C in the Pietrain lineage is related to low rate of body fat, a typical feature of this breed.