Marek Babicz
Polymorphism of chosen genes potentially associated with reproduction performance of Pulawska breed pigs
Implementation of traditional selection methods to improve female reproductive traits in swine appears to be less effective than selection protocols aimed to improve pig fattening and slaughter value. Therefore, novel methods for the achievement of worthwhile swine utility traits improvement have been still under study. One of the these methods involves the typing of genes directly affecting pig breeding performance traits.
The objective of the research was to determine the impact of polymorphism of chosen genes and body fluid leptin concentration on reproduction performance parameters of gilts and sows of Pulawska breed.
The studies included 300 dams (50 gilts and 250 sows) of Pulawska breed, obtained from seven family groups (Akra, Dazerka, Fajka, Fuka, Fura, Multa, Sama) managed in 2005–2008 in 12 breeding herds under the conservation breeding program.
A group of chosen gene candidates whose effects are associated with gilt performance as well as piglet growth and development, i.e. ESRFSTGHLEPMYF4PRLRYR1 was studied by the PCR-RFLP molecular technique.
To determine swine breeding performance, the in vivo and post mortem measurements were made. A total of 50 gilts were slaughtered between 5–10 day after estrous signs completion at the third spontaneous sexual cycle. Data illustrating sow reproductive value was gathered over five consecutive farrowings time (1–5 litters).
There was statistical analysis performed on the effect of gene polymorphisms of each gene on the following utility traits of gilts and sows: age and body weight at onset of second and third estrus, duration of tolerance reflex (sexually receptive behavior) in second and third estrus, intensity of estrus signs in second and third estrus, uterus weight, ovary weight, length of uterine horns, corpus luteum number, age at first farrowing, length of inter-litter period, number of piglet teats, number of live-born piglets in a litter, number of piglets raised up to 21st day, number of young boars and gilts raised up to 21st day of age, individual body weight of piglets (mean of the litter), a content of major chemical components of colostrum and milk, leptin concentration in body fluids. A leptin level was established in blood plasma, colostrum and milk using Multi-species Leptin RIA kit by Linco Research according to the manufacturer’s instructions. Blood was collected from the gilts during the tolerance reflex time in I, II and III sexual cycle at estrus phase (in heat). Colostrum and milk samples were taken on 1st, 3rd, 7th, 14th, 21st and 35th lactation day of the successive second and third breeding cycle. A leptin level was referred to the parameters of gilt potential fertility and body weight of piglets from the second and third litters.
Statistical analysis was performed with SAS statistical software application. A level of the studied traits was presented as the mean of the least squares (LSM) with standard error values (SE) defining reliability of estimates. A genotype influence on parameters of the analyzed traits was established using the mixed models. Significance of differences of a leptin concentration level and the investigated traits was determined by multifactorial analysis of variance, the least square method.
The studies of the genetic structure allowed to determine a value of the main indices of genetic variation. The obtained numerical data proved to be characteristic of a regional low population size.