Сельскохозяйственная биология, 2011, № 6, с. 54-59

УДК 636.4:636.082:575.174.015.3

EFFECT OF ESR AND IGF2 MARKER GENOTYPES ON THE BREEDING VALUES OF THE LARGE WHITE BOARS

O.V. Kostyunina¹, N.A. Svezhentseva², N.A. Zinovieva¹, A.V. Dotsev¹, A.V. Shahin¹, E.I. Sizareva², E.A. Gladyr’¹

The effect of complex genotype for estrogene receptor (ESR) and insulin-like growth factor (IGF2) DNA markers of the large white boars on the reproductive traits of their daughters in two parities and on estimated breeding values (EBV) for productive traits was studied. It was shown that the daughters of boars carrying QQ genotype for IGF2 had the total number of piglets born higher by 0.34-0.95 and the number of piglets born alive higher by 0.41-1.08 comparing to daughters of boars carrying Qq genotype of IGF2 and the same genotype of ESR. The increase of EBV for back fat (+0.44 mm) and EBV for loin muscle aria (+28.42 mm²) and decrease of EBV for days to 100 kg (-3.92 days) in boars carrying QQ/BB genotype for IGF2/ESR comparing to QQ/AA genotype was observed. The value of selection index MLI, including EBV for number of piglets born alive, 21 day weight, back fat and days to 100 kg was maximal in boars carrying QQ/BB genotype for IGF2/ESR that was by 6.9-15.3 points higher comparing to boars of the other genotypes.

Keywords: marker assisted selection, pigs, estimated breeding values (EBV), productive traits.

Today, molecular genetic techniques increase the efficiency of breeding programs owing to more accurate genetic evaluation and reduced generation interval (1, 2). According to M.F. Rothschild et al. (3), in pigs there have been mapped 67 quantitative trait loci (QTL) for reproductive traits, 224 QTLs for growth parameters and 89 QTLs for fat thickness. Currently, there are genetic tests allowing to detect more than 12 single nucleotide polymorphisms (SNP) of candidate genes associated with multiple fetation and number of piglets born alive (4). It has been shown that marker-assisted selection of pigs improves multiple fetation of sows by 0,3-1,0 piglet per litter (5-7). One of potentially important DNA markers associated with multiple fetation in pigs is a gene for estrogen receptor (ESR), whose products affect the expression of various transcription factors providing reproductive function in females (5). Along with it, DNA markers of meat and fattening productivity are widely used in breeding programs (8, 9). It has been also reported about the effect of a gene for insulin-like growth factor 2 (IGF2) polymorphism (10) on fat deposition and growth of muscle tissue in  pure-bred pigs (11, 12) of both different experimental crosses and industrial populations (9, 13 -15).
Using molecular markers in breeding pigs must consider the effects of marker genes for the full range of commercially important traits. Thus, some authors highlight the participation of IGF2 in reproductive function in mice and farm animals (16, 17). Selection for lean and subsequent reduce in body fat percentage can suppress multiple fetation because the intrauterine development of piglets and milk feeding of a large litter requires increased energy reserves in sows (18). Thus, selection of pigs using IGF2 aimed at lean meat can result in probable undesirable consequences for a multiple fetation and the number of live piglets at birth (5). Mendelian model of inheritance was used to prove a reliable effect of different polymorphisms in the gene IGF2 on litter size in pigs of Czech (19) and Poland (20) selection. Using the model of imprinting inheritance has shown a significant effect on paternal Q allele of IGF2 on multiple pregnancy in sows at the third and subsequent farrowings (21). Studying the synthetic line of pigs obtained by crossing Large White and Landrace breeds, it has been revealed the increased multiple fetation in sows carrying Q allele of IGF2 inherited from father (22). On the contrary, L.A. Rempel c et al. (23) has established no significant effects of IGF2 polymorphism on reproductive properties of synthetic pig lines.
There are many available reports on effects of individual marker genes studied in different populations of pigs, but still no data about integrated action of genotypes for IGF2 and ESR marker genes on productivity traits and estimated breeding value (EBV) used as the main evaluation criteria in foreign programs of genetic improvement pigs (24).
The purpose of this work was studying the effect of complex genotype for ESR and IGF2 of Large White boars on reproductive properties of sows-daughters and estimated breeding value for main commercially important traits.
Technique. The material for molecular genetic studies were tissue samples (ear notches) of Large White boars bred in the JSC “Znamensky selection-hybridization center” (n = 34) (Orel province). DNA extraction and PCR were performed using conventional techniques (25). Polymorphism of the studied DNA markers ESR and IGF2 (G3072A – mutation G → A at position 3072) was investigated according to the procedure developed in the Center of Biotechnology and Molecular Diagnostics of the All-Russia  Research and Development Institute of Livestock Husbandry. Reproductive properties of sows-daughters were estimated using the results of the 1st (n = 613) and 2nd (n = 463) farrowings by the following parameters: multiple fetation, number of piglets live at birth, weight of one piglet and a litter at birth, number of piglets at weaning, weight of a litter at weaning. Breeding value of boars was estimated by several economically valuable parameters of sows-daughters – number of piglets live at birth, milk production (weight of a litter on the 21st day after farrowing), age at 100 kg weight,  fat thickness, loin eye muscle area and MLI (an integrated index for a number of piglets born alive, milk production, fat thickness and age at 100 kg). The data were calculated using BLUP-model for multiple parameters in the computer program Herdsman 2000 (“S & S Programming Inc.”, USA) and the built-in module PEST (26).
Statistical analysis of results was performed according to standard techniques (27, 28).
Results. Reproductive traits of sows-daughters of boars-carriers of different genotypes for ESR and IGF2 were analyzed (Table 1). The daughters of boars heterozygous for these genes showed the minimum values of piglets born alive and multiple fetation at both farrowings. As expected, the daughters of boars with BB genotype for ESR exceeded the daughters of boars with AA genotype (while an identical genotype for IGF2) in the abovementioned parameters at the 1st farrowing – respectively, by 0,41 and 0,44 piglet per litter, at the 2nd farrowing – by 0,21 and 0,27 piglet.

The boars’ genotypes for IGF2 were found to affect reproductive traits of daughters as well. Boars with QQ genotype, in contrast to Qq (while a similar genotype for ESR), provided higher levels of multiple fetation and number of piglets born alive: respectively, at the 1st farrowing – by 0,39-0,95 and 0,46-1,08 piglets per litter, at the 2nd farrowing – by 0,34-0,57 and 0,41-0,53 piglet. Thus, the boars’ genotype QQ for IGF2 (“desirable” in terms of meat and fattening productivity) didn’t cause any negative effects on multiple fetation and number of piglets live at birth in sows-daughters compared with Qq genotype. Comparison of the progeny revealed significant differences in weight of piglets at birth at the 1st farrowing: in daughters of Qq/AB boars it was 80 g higher (p <0,05) than that in daughters of QQ/AB boars. Average weight of one piglet at birth was 40 g higher (p <0,05) in daughters of QQ/AA boars than that in daughters of QQ/BB boars. At the 2nd farrowing, daughters of QQ/AA boars reliably exceeded daughters of Qq/AA boars by litter weight (by 0,84 kg, p <0,05) and by number of piglets at weaning (by 0,42 piglet, p <0,05).
The described patterns and trends are completely consistent with estimated breeding values of boars carrying different genotypes for the markers IGF2 and ESR (Table 2).
Boars with BB genotype for ESR (Table 2) were given higher EBV in number of piglets live at birth compared with boars having AA genotype for ESR (while a similar QQ genotype for IGF2) (+0,23 piglet per litter). Assessing the breeding value of boars for meat and fattening productivity, it should be noted that BB genotype of boars (“desirable” for multiple fetation) was found to be associated with increased thickness of fat (+ 0,44 mm), lean muscle eye area (28,42 mm2) and earlier age at 100 kg live weight (-3,92 days) in contrast to AA genotype.  The performed calculations have revealed an insignificant dominant effect for milk production (0,24 kg), fat thickness (0,19 mm) and age at 100 kg live weight (0,34 days).

An additive component of fat thickness amounted to 0,22 mm. The analysis of relations between EBV and IGF2 using the data of Table 2 suggests that boars with QQ genotype for IGF2 were ranked by higher EBV in number of piglets born alive (by 0,06-0,08 piglet) than boars with Qq genotype (while similar genotypes for ESR). The highest total breeding value for the integrated parameter MLI was observed in boars with QQ/BB genotype for IGF2/ESR exceeding the boars with other genotypes by 6,9-15,3 points.
So, the authors have established the absence of negative effects of Q allele of IGF2 gene (“desirable” in terms of meat and fattening productivity) on reproductive traits of Large White pigs. At the same time, the genotype BB for ESR (“desirable” in terms of multiple fetation) was found to reduce the age at 100 kg and increase lean muscle eye area. In this regard, estimating the genotypes of Large White boars for the markers IGF2 and ESR can be suggested as an additional criterion for selecting individuals with high breeding value for reproductive, fattening and meat quality.

REFERENCES

1. Dekkers J.C., Commercial Application of Marker- and Gene-Assisted Selection in Livestock: Atrategies and Lessons, J. Anim. Sci., 2004, vol. 82, pp. 313-328.
2. Proskurina N.V., Tikhomirova T.I., Gladyr’ E.A., Larionova P.V. and Zinovyeva N.A., Comparative Analysis of Informativeness of Erythrocytes Antigens and DNA-Microsatellites as Genetic Markers in Breeding-Pedigree Work with Pigs of Canadian Selection, S.-kh. biol., 2007, no. 6, pp. 41-47.
3. Rothschild M.F., Hu Z.L. and Jiang Z.H., Advances in QTL Mapping in Pigs, Int. J. Biol. Sci., 2007, no. 3, pp. 192-197.
4. Distl O., Mechanisms of Regulation of Litter Size in Pigs on the Genome Level, Reprod. Domest. Anim., 2007, vol. 42, no. 2, pp. 10-16.
5. Rothschild M.F., Porcine Genomics Delivers New Tools and Results: This Little Piggy Did More than Just Go to Market, Genet. Res., 2004, vol. 83, pp. 1-6.
6. Zinovyeva N.A., Molecular-Genetic Techniques and Their Use in Pig Breeding, Dostizheniya nauki i tekhniki APK, 2008, no. 10, pp. 37-39.
7. Zinovyeva N.A., Kostyunina O.V., Gladyr’ E.A., Bannikova A.D., Kharzinova V.R., Larionova P.V., Shavyrina K.M. and Ernst L.K., Role of DNA-Markers of Farm Animals Productivity Traits, Zootekhniya, no. 1, pp. 8-10.
8. Kostyunina O., Zinovyeva N., Letvichenkov A. and Gogolev A., Selection Based on DNA-Techniques, Zhivotnovodstvo Rossii, 2008, no. 4, pp. 39-42.
9. Loban N.A., Kostyunina O.V., Vasilyuk O.Ya., Bannikova A.D., Chernov A.S., Zinovyeva N.A. and Ernst L.K., The Influence of the Polymorphism of Igf2 Gene on Feeding and Meat Qualities of Belarusian Large White Breed of Pigs, S.-kh. biol., 2009, no. 2, pp. 27-30.
10. Van Laere A.S., Nguyen M., Braunschweig M., Nezer C., Collette C., Moreau L., Archibald A.L., Haley C.S., Buys N., Tally M., Andersson G., Georges M. and Andersson L., A Regulatory Mutation in IGF2 Causes a Major QTL Effect on Muscle Growth in the Pig, Nature, 2003, vol. 425, pp. 832-836.
11. Jeon J.T., Carlborg O., Tornsten A., Giuffra E., Amarger V., Chardon P., Andersson-Eklund L., Andersson K., Hansson I., Lundstrom K. and Andersson L., A Paternally Expressed QTL Affecting Skeletal and Cardiac Muscle Mass in Pigs Maps to the IGF2 Locus, Nat. Genet., 1999, vol. 21, pp. 157-158.
12. Nezer C., Moreau L., Brouwers B., Coppieters W., Detilleux J., Hanset R., Karim L., Kvasz A., Leroy P. and Georges M., An Imprinted QTL with Major Effect on Muscle Mass and Fat Deposition Maps to the IGF2 Locus in Pigs, Nat. Genet., 1999, vol. 21, pp. 155-156.
13. Jungerius B.J., Van Laere A.S., Te Pas M.F., Van Oost B.A., Andersson L. and Groenen M.A., The IGF2-Intron3-G3072A Substitution Explains a Major Imprinted QTL Effect on Backfat Thickness in a Meishan Ѕ European White Pig Intercross, Genet. Res., 2004, vol. 84, pp. 95-101.
14. Estelle J., Mercade A., Noguera J.L., Perez-Enciso M., Ovilo C., Sanchez A. and Folch J.M., Effect of the Porcine IGF2-Intron3-G3072A Substitution in an Outbreed Large White Population and in an Iberian Ѕ Landrace Cross, J. Anim. Sci., 2005, vol. 83, pp. 2723-2728.
15. Heuven H.C.M. and Bovenhuis H., Effect of IGF2 on Growth Characteristics of F2 Meishan Ѕ White, Proc. 56th Annual Meeting of the European Association for Animal Production, Upssala, 2005, vol. G6.10, pp. 1-4.
16. Badinga L., Song S., Simmen R.C., Clarke J.B., Clemmons D.R. and Simmen F.A., Complex Mediation of Uterine Endometrial Epithelial Cell Growth by Insulin-Like Growth Factor-II (IGF-II) and IGF-Binding Protein-2, J. Mol. Endocrinol., 1999, vol. 23, pp. 277-285.
17. Schams D., Berisha B., Kosmann M., Einspanier R. and Amselgruber W.M., Possible Role of Growth Hormone, IGFs, and IGF-Binding Proteins in the Regulation of Ovarian Function in Large Farm Animals, Domest. Anim. Endocrinol., 1999, vol. 17, pp. 279-285.
18. Mathur P. and Liu Y., Marker Assisted Selection for the Canadian Swine Industry, Proc. 28th Annual National Swine Improvement Federation, Des Moines, 2003, pp. 146-149.
19. Horak P., Mikova G., Urban T., Putnova L., Knoll A. and Dvorak J., Association of Polymorphism in the IGF2 Gene with Litter Size in Black Pied Prestice Pigs, Czech. J. Anim. Sci., 2001, vol. 46, no. 11, pp. 505-508.
20. Katska-Ksiazkiewicz L., Lechniak-Cieslak D., Korwin-Kossakowska A., Alm H., Rynska B., Warzych E., Sosnowski J. and Sender G., Genetical and Biotechnological Methods of Utilization of Female Reproductive Potential in Mammals, Reprod. Biol., 2006, vol. 6, suppl. 1, pp. 21-36.
21. Munoz G., Ovilo C., Estelle J., Silio L., Fernandez A. and Rodriguez C., Association with Litter Size of New Polymorphisms on ESR1 and ESR2 Genes in a Chinese-European Pig Line, Genet. Sel. Evol., 2007, vol. 39, pp. 195-206.
22. Buys N., Van den Abeele A., Stinckens A., Deley J. and Georges M., Effect of the IGF2-Intron3-G3072A Mutation on Prolificacy in Sows, Proc. 8th Congress on Genetic Applied to Livestock Production, Belo Horizonte, 2006, pp. 6-22.
23. Rempel L.A., Nonneman D.J., Wise T.H., Erkens T., Peelman L.J. and Rohrer G.A., Association Analyses of Candidate SNP on Reproductive Traits in Swine, J. Anim. Sci., 2010, vol. 88, no. 1, pp. 1-15.
24. Chinarov Yu.I., Zinovyeva N.A. and Erns L.K., Method of Breeding Evaluation of Pigs on the Basis of BLUP, Zhivotnovodstvo Rossii, 2007, no. 2, pp. 45-46.
25. Zinovyeva N.A., Popov A.N., Ernst L.K. et al., Metodicheskie rekommendatsii po ispol’zovaniyu metoda polimeraznoi tsepnoi reaktcii v zhivotnovodstvo (Methodological Recommendations on Using PCR in Animal Husbandry), Dubrovitsy, 1998.
26. Grоеneveld E., PEST User’s Manual, Neustadt: Institute of Animal Science, Germany, 2006, p. 77.
27. Merkuryeva E.A., Abramova Z.V., Bakai A.V. et al., Genetika (Genetics), Moscow, 1991.
28. Mather K. and Jinks J., Biometricheskaya genetika (Biometrical Genetics), Moscow, 1985.