ESR1andESR2gene markers are not associated with number of piglets born alive in Italian Large White sows

Abstract

Many studies have reported that markers in the estrogen receptor 1 (ESR1) and estrogen receptor 2 (ESR2) genes are associated with litter size in pigs, even if inconsistent results have been obtained in different populations. We analysed the ESR1 PvuII and the ESR2 AF164957:c.949G>A polymorphisms in Italian Large White (ITLW) sows to evaluate if these markers are associated with number of piglets born alive at first litter (NBA1). First, both polymorphisms were genotyped by selective genotyping in a total of 440 sows chosen according to the extreme and divergent estimated breeding value (EBV) for NBA1 (220 sows with low EBV and 220 sows with high EBV). For the ESR1 polymorphism, no allele and genotype frequency differences were observed between the two groups (allele A=0.62 and allele B=0.38 in both two groups). For the ESR2 polymorphism, a trend of different allele frequency between the two tails was identified (P=0.052). However, no significant association between the same ESR2 marker and EBV NBA1 was detected analyzing 1772 ITLW sows (allele A=0.59 and allele G=0.41). As the two investigated polymorphisms were not associated with NBA1 EBVs, they seem not useful for marker assisted selection to improve this trait in the ITLW breed.

Maximum number of total born piglets in a parity and individual ranges in litter size expressed as specific characteristics of sows

“…For a deeper insight into the genetics of litter size and related traits, SNP technology is being widely adapted. Such studies have been reviewed [10], and candidate genes of reproduction traits in sows were reported based on different pig populations, partly with contradictory results [11][12][13].…”

Allelic to genome wide perspectives of swine genetic variation to litter size and its component traits

“…Contrarily, in Chinese-European pigs non-signi cant association of PvuII polymorphism with litter size but signi cant association with TNB was observed [16]. Also, in Italian Large White population, genetic variation of the gene was not observed and hence was not associated with litter size in the target breed [17]. In another study, a polymorphism of ESR2 at telomere of q arm of SCC1 was identi ed and no signi cant association with litter size of Iberian pig population was found [13].…”

The Influence of Fattening and Slaughter Traits on Reproduction in Polish Large White Sows

“…Together with the Landrace, the PLW, similar to the Italian Large White (ITLW) in Italy, is the basic maternal breed of pigs reared in Poland (Dall'Olio et al, 2011;Schwarz et al, 2009). In the year 2010, sows of the Polish Large White breed accounted for 33.01% of the Polish national pig population (Orzechowska and Mucha, 2011).…”