ASSOCIATION OF MITOCHONDRIAL HAPLOTYPES WITH PHENOTYPIC SIGNS OF FATTENING PRODUCTIVITY IN HYBRID PIGS

Abstract

The results of the study indicate that the variability of mtDNA of pigs is one of the ways to assess and predict the productivity of hybrid pigs by phenotypic characteristics. The purpose of the study was to conduct zootechnical analysis to determine the presence of an association of mtDNA haplotypes with signs of fattening productivity in hybrid pigs (Large White × Landrace). The study was conducted on an experimental sample of pigs (n = 18), which are the result of direct (Large White × Landrace) and reciprocal crossing (Landrace × Large White). DNA extraction was performed from epithelial tissue using a kit DNA-sorb-B nucleic acid extraction kit from “InterLabService-Ukraine” LLC. A previous study identified 4 mtDNA haplotypes among hybrid pigs of Irish selection, three of which are grouped with pigs of European origin clade “E” – С (Landrace, Hampshire, Wales, wild pig); G (Wales, wild pig); O (Landrace, wild pig). Pigs with haplotype N (Large White, Berkshire, Asian wild pig) grouped with pigs of Asian origin. Asian-type pigs with mitochondrial haplotype N belong to the Asian cluster «clade A». The common origin of hybrid pigs has been determined and it has been clarified and how these mitochondrial haplotypes affect fattening productivity has been identified. The estimated main phenotypic indicators are the following average values for relation to mitochondrial haplotypes in pigs. (С, G, O, N): а) average daily weight gain for the fattening period, kg/g – haplotype C (867 g), N (835 g) 77%; for haplotype G (761 g) 74% and 75% (789 g) for haplotype O. b) the time spent in the fattening group, days, is 10% (107 days) for all haplotypes (C, G, O, N). c) Wet weight attainment, 100 kg/day, for haplotype C (144 days), N (141 days) 13 percent; 16% (165 days) for haplotype G and 15% (156 days) for haplotype O. Transfer to the rearing group was carried out at the same age of 63 days, but with a fairly large difference in weight of 5 and 9.2 kg, after all, the average value when fattening should be 30 kg. This also indicates an uneven growth of the studied sample of hybrid pigs. This is clearly reflected throughout the life of the studied pigs in the following indicators: the age of achievement of live weight is 100 kg/ day for the accounting period from birth before slaughter, for haplotype C – 144 and N – 141 days compared to pigs with haplotype O – 156 and G – 165 days with a difference of 13 and 22 days. The age of achievement of live weight is 100 kg/day for the accounting period from days of fattening before slaughter, for haplotype C – 150 and N – 145 days compared to pigs with haplotype O – 159 and G – 166 days with a difference of 11 and 18 days. Pigs with haplotypes C and N are characterized by a uniform average daily gain over the fattening period with an average of 851 g with a difference of -76 g with haplotypes O and G. It is worth noting that only all pigs with haplotypes C (0.696 g), G (0.605 g), O (0.642 g), N (0.715 g) – are characterized by a uniformly low average daily gain for the entire period of cultivation (from birth to removal from fattening). A logical assumption is that there are advantages of life priority for born pigs, who have an adequate birth weight to be profitable. These facts confirm the prospect of continuing research on the association of mtDNA haplotypes as determinantspig of productivity.