Genetic determination of piglets postweaning survival
The genetic potential of contemporary swine breeds can be disturbed if animal welfare and management systems don’t meet standard requirements. Environmental conditions, housing and feeding systems as well as veterinary inspection, molecular genetics for testing the presence of expression genes in pigs, responsible for the performance and health condition of these animals. Directional selection aimed at improving productive traits in pigs has caused limitations in adaptive mechanisms, affecting also to the health of these animals. It also refers to results obtained in studies within molecular genetics, cytogenetics and immunogenetics, showing an improvement in genotypes, and to some methods for prevention and control of oodema disease and postweaning diarrhea.
Each year about 10 million piglets die all over the world because of postweaning diarrhea. Huge losses in pigs are due to the diarrhea of piglets caused by F4 and F18 Escherichia coli. The presence of the receptors is conditioned by genes ECR F4 and ECR F18. Loci ECR F4 and F18 are closely linked and located very close to the swine MUC4 and FUT1 genes. Molecular tests identifying alleles of the MUC4 and FUT1 gene are used for determining the genotypes of pigs susceptible (dominant homozygotes and heterozygotes) and resistant (recessive homozygotes) to F4 and F18 E. coli strains.
Sequencing of the FUT1 gene of pigs of dominant and recessive genotypes in ECF18R locus showed that these genotypes differ in the exchange of adenine (A) for guanine (G) in 307 nucleotide. The genotype of resistance to diarrhea (bb in ECF18R locus) is equal to the AA genotype in FUT1 locus and BB and Bb (in ECF18R locus) genotypes are equal to GG and GA (in FUT1 locus), respectively. It was found that the level of the FUT1 enzyme (α-(1,2) fucosyltransferase) was 28- to 45-fold higher in piglets resistant to diarrhea as compared to the susceptible ones. According to the results of study of the polymorphism of ECR F4 (MUC 4) gene guanine (G) for cytosine (C) transitions at 1849 nucleotide position is identified.Presence of C allele in the genotype of both mother and father (CG x CG) authentically lowered the viability of suckling piglets and accordingly the output of weaning piglets in comparison with parents posterity carrying G allele in the genotype.
Polymorphism of ECR F4 (MUC 4) and ECR F18 (FUT1) gene don’t render influence on the reproductive function of soar boars. Positive influence of desirable genotypes of parental forms and combinations in schemes of pairing on genes FUT1 and MUC4 on safety and an output of business pigs has been revealed. Thus, it would be appropriate to realize the genetic testing of parental combinations for the determination of the polymorphism of MUC4 and FUT1 genes and realize the selection of parents taking into consideration the genotypes carrying only G and A allele, respectively.
Источник: Genetic determination of piglets postweaning survival / Syrovnev G. I. // Хімія та сучасні технології: тези доповідей V міжнародної науково-технічної конференції студентів, аспірантів та молодих вчених (Дніпропетровськ, 20-22 квітня 2011р.) - Дніпропетровськ, 2011. - С. 457.