Impact of Sow Milk Protein Polymorphism on Piglet Rearing
The aim of the investigations was to ascertain interrelationships between polymorphic fractions of milk proteins and rearing results of piglets from Złotnicka White sows. The experimental material comprised 20 sows of the native Złotnicka White breed. Pigs of this breed are included in the National Genetic Resources Conservation Programme. Investigations included two successive (2nd and 3rd) lactations of sows during which the following parameters were determined: number and weight of piglets on days 1, 7, 14, 21 and 28; weight gains of individual piglets during the period from day 1 to 7, from day 8 to 14, from day 15 to 21 and from day 22 to 28; as well as mortality for the entire period of rearing, i.e. from day 1 to day 28 of age. A total of 425 piglets born in 40 litters (20 sows x 2 lactations) were investigated. As a result of electrophoretic separations, the following four protein fractions were isolated from sow milk: αs1-casein (CSN1S1), genotypes AA, AB, BB and BC; β-casein (CSN2), genotypes AA, AB and BB; κ-casein (CSN3), genotypes AA, AB and BB; β-lactoglobulin (LGB), genotypes AA and BB. The present study showed that milk from sows of AA CSN1S1 and AA LGB genotypes appeared to be more valuable and nourishing, as indicated by the fact that these sows reared piglets which were characterized by the best production results, i.e. body weight, weight gains and the lowest percentage mortality. The least dynamic results were obtained by piglets originating from litters of sows of the AA-CSN3 genotype.