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Biochemical, nutritional and genetic effects on boar taint in entire male pigs

Published online by Cambridge University Press:  17 December 2008

G. Zamaratskaia  and
E. J. Squires
G. Zamaratskaia*
Affiliation:
Department of Food Science, Swedish University of Agricultural Sciences, Box 7051, SE-750 07 Uppsala, Sweden
E. J. Squires
Affiliation:
Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1
*
E-mail: [email protected]
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Abstract

Pork odour is to a great extent affected by the presence of malodorous compounds, mainly androstenone and skatole. The present review outlines the current state of knowledge about factors involved in the regulation of androstenone and skatole in entire male pigs. Androstenone is a pheromonal steroid synthesised in the testes and metabolised in the liver. Part of androstenone accumulates in adipose tissue causing a urine-like odour. Skatole is produced in the large intestine by bacterial degradation of tryptophan and metabolised by hepatic cytochrome P450 enzymes and sulphotransferase. The un-metabolised part accumulates in adipose tissue, causing faecal-like odour. Androstenone levels are mostly determined by genetic factors and stage of puberty, whereas skatole levels in addition to genetic background and hormonal status of the pigs are also controlled by nutritional and environmental factors. To reduce the risk of tainted carcasses entering the market, male pigs are surgically castrated in many countries. However, entire males compared to castrates have superior production characteristics: higher growth rate, better feed efficiency and leaner carcasses. Additionally, animal welfare aspects are currently of particular importance in light of increasing consumers’ concerns. Nutrition, hormonal status, genetic influence on boar taint compounds and the methods to develop genetic markers are discussed. Boar taint due to high levels of skatole and androstenone is moderately heritable and not all market weight entire males have boar taint; it should thus be possible to select for pigs that do not have boar taint. In these studies, it is critical to assess the steroidogenic potential of the pigs in order to separate late-maturing pigs from those with a low genetic potential for boar taint. A number of candidate genes for boar taint have been identified and work is continuing to develop genetic markers for low boar taint. More research is needed to clarify the factors involved in the development of boar taint and to develop additional methods to prevent the accumulation of high concentrations of skatole and androstenone in fat. This review proposes those areas requiring further research.

Keywords

androstenoneentire male pigreviewskatole
Type
Full Paper
Information
animal , Volume 3 , Issue 11 , November 2009 , pp. 1508 - 1521
Copyright
Copyright © The Animal Consortium 2008

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References

Aldal, I, Andresen, O, Egeli, AK, Haugen, J-E, Grodum, A, Fjetland, O, Eikaas, JLH 2005. Levels of androstenone and skatole and the occurrence of boar taint in fat from young boars. Livestock Production Science 95, 121–129.CrossRefGoogle Scholar
Andresen, Ø 1975. 5α-Androstenone in peripheral plasma of pigs, diurnal variation in boars, effects of intravenous HCG administration and castration. Acta Endocrinologica (Copenhagen) 78, 385–391.Google ScholarPubMed
Angels Rius, M, Hortós, M, Garcia-Regueiro, JA 2005. Influence of volatile compounds on the development of off-flavours in pig back fat samples classified with boar taint by a test panel. Meat Science 71, 595–602.CrossRefGoogle Scholar
Babol, J, Squires, EJ 1995. Quality of meat from entire male pigs. Food Research International 28, 201–212.CrossRefGoogle Scholar
Babol, J, Squires, EJ 1999. Liver metabolic activities of intact male pigs injected with skatole. Canadian Journal of Animal Science 79, 549–552.CrossRefGoogle Scholar
Babol, J, Squires, EJ, Lundström, K 1998a. Hepatic metabolism of skatole in pigs by cytochrome P4502E1. Journal of Animal Science 76, 822–828.CrossRefGoogle ScholarPubMed
Babol, J, Squires, EJ, Lundström, K 1998b. Relationship between oxidation and conjugation metabolism of skatole in pig liver and concentrations of skatole in fat. Journal of Animal Science 76, 829–838.CrossRefGoogle ScholarPubMed
Babol, J, Squires, EJ, Lundstrøm, K 1999. Relationship between metabolism of skatole and andtrostenone in intact male pigs. Journal of Animal Science 77, 84–92.CrossRefGoogle ScholarPubMed
Babol, J, Zamaratskaia, G, Juneja, RK, Lundström, K 2004. The effect of age on distribution of skatole and indole levels in entire male pigs in four breeds: Yorkshire, Landrace, Hampshire and Duroc. Meat Science 67, 351–358.CrossRefGoogle ScholarPubMed
Baek, C, Hansen-Møller, J, Friiis, C, Cornett, C, Hansen, SH 1997. Identification of selected metabolites of skatole in plasma and urine from pigs. Journal of Agricultural and Food Chemistry 45, 2332–2340.CrossRefGoogle Scholar
Bañón, S, Andreu, C, Laencina, J, Garrido, M-D 2004. Fresh and eating pork quality from entire versus castrate heavy males. Food Quality and Preference 15, 293–300.CrossRefGoogle Scholar
Bonneau, M 1982. Compounds responsible for boar taint, with special emphasis on androstenone: a review. Livestock Production Science 9, 687–707.CrossRefGoogle Scholar
Bonneau, M 1987. Effects of age and live weight on fat 5 alpha-androstenone levels in young boars fed two planes of nutrition. Reproduction Nutrition Development 27, 413–422.CrossRefGoogle ScholarPubMed
Bonneau, M 1998. Use of entire males for pig meat in the European Union. Meat Science 49, S257–S272.CrossRefGoogle Scholar
Bonneau, M, Russeil, P 1985. The size of cowper’s (bulbo-urethral) glands as an estimate of boar taint on the slaughter line. Livestock Production Science 13, 169–178.CrossRefGoogle Scholar
Bonneau, M, Meusy-Dessolle, N, Léglise, PC, Claus, R 1982. Relationships between fat and plasma androstenone and plasma testosterone in fatty and lean young boars during growth and after hCG stimulation. Acta Endocrinologica (Copenhagen) 101, 119–128.Google ScholarPubMed
Bonneau, M, Carrié-Lemoine, J, Prunier, A, Garnier, DH, Terqui, M 1987. Age-related changes in plasma LH and testosterone concentration profiles and fat androstenone content in the young boar. Animal Reproduction Science 15, 241–258.CrossRefGoogle Scholar
Bonneau, M, LeDenmat, M, Vaudelet, JC, VelosoNunes, JR, Mortensen, AB, Mortensen, HP 1992. Contributions of fat androstenone and skatole to boar taint: I. Sensory attributes of fat and pork meat. Livestock Production Science 32, 63–80.CrossRefGoogle Scholar
Bonneau, M, Dufour, R, Chouvet, C, Roulet, C, Meadus, W, Squires, EJ 1994. The effects of immunization against luteinizing hormone-releasing hormone on performance, sexual development, and levels of boar taint-related compounds in intact male pigs. Journal of Animal Science 72, 14–20.CrossRefGoogle ScholarPubMed
Booth, WD 1987. Factors affecting the pheromone composition of voided boar saliva. Journal of Reproduction and Fertility 81, 427–431.CrossRefGoogle ScholarPubMed
Brennan, JJ, Shand, PJ, Fenton, M, Nicholls, LL, Aherne, FX 1986. Androstenone, androstenol and odor intensity in backfat of 100- and 130-kg boars and gilts. Canadian Journal of Animal Science 66, 615–624.CrossRefGoogle Scholar
Brophy, PJ, Gower, BD 1972. 16-unsaturated C 19 3-oxo steroids as metabolic intermediates in boar testis. Biochemical Journal 128, 945–952.CrossRefGoogle Scholar
Carlström, K, Malmfors, B, Lundström, K, Edqvist, LE, Gahne, B 1975. The effect of HCG on blood plasma levels of 5α-androstenone and testosterone in the boar. Swedish Journal of Agricultural Research 5, 15–21.Google Scholar
Chen, G, Zamaratskaia, G, Madej, A, Lundström, K 2006. Effect of hCG administration on the relationship between testicular steroids and indolic compounds in fat and plasma in entire male pigs. Meat Science 72, 339–347.CrossRefGoogle ScholarPubMed
Chen, G, Zamaratskaia, G, Andersson, HK, Lundström, K 2007. Effect of dietary supplement of raw potato starch and live weight on the levels of skatole, indole and androstenone measured by different methods. Food Chemistry 101, 439–448.CrossRefGoogle Scholar
Chen, G, Cue, R-A, Lundström, K, Wood, JH, Doran, O 2008. Regulation of cytochrome P450 2A6 protein expression by skatole, indole and testicular steroids in primary cultured porcine hepatocytes. Drug Metabolism and Disposition 36, 56–60.CrossRefGoogle Scholar
Claus, R, Hoffmann, B 1980. Oestrogens, compared to other steroids of testicular origin, in blood plasma of boars. Acta Endocrinologica (Copenhagan) 94, 404–411.Google ScholarPubMed
Claus, R, Raab, S 1999. Influences on skatole formation from tryptophan in the pig colon. Advances in Experimental Medicine and Biology 467, 679–684.CrossRefGoogle ScholarPubMed
Claus, R, Hoffmann, B, Karg, H 1971. Determination of 5-androst-16-en-3-one, a boar taint steroid in pigs, with reference to relationships to testosterone. Journal of Animal Science 33, 1293–1297.CrossRefGoogle ScholarPubMed
Claus, R, Dehnhard, M, Herzhog, A, Bernal-Barragan, H, Giménez, T 1993. Parallel measurements of indole and skatole (3-methylindole) in feces and blood plasma of pigs by HPLC. Livestock Production Science 34, 115–126.CrossRefGoogle Scholar
Claus, R, Weiler, U, Herzog, A 1994. Physiological aspects of androstenone and skatole formation in the boars – a review with experimental data. Meat Science 38, 289–305.CrossRefGoogle ScholarPubMed
Claus, R, Losel, D, Lacorn, M, Mentschel, J, Schenkel, H 2003. Effects of butyrate on apoptosis in the pig colon and its consequences for skatole formation and tissue accumulation. Journal of Animal Science 81, 239–248.CrossRefGoogle ScholarPubMed
Claus, R, Lacorn, M, Danowski, K, Pearce, MC, Bauer, A 2007. Short-term endocrine and metabolic reactions before and after second immunization against GnRH in boars. Vaccine 25, 4689–4696.CrossRefGoogle ScholarPubMed
Cooke, GM, Ferguson, SE, Rytina, E, Gower, DB 1983. Properties of porcine liver and testicular steroid sulphotransferases: reaction conditions and influence of naturally occurring steroids and steroid sulphates. Journal of Steroid Biochemistry 19, 1103–1109.CrossRefGoogle ScholarPubMed
Cronin, GM, Dunshea, FR, Butler, KL, McCauley, I, Barnett, JL, Hemsworth, PH 2003. The effects of immuno- and surgical-castration on the behaviour and consequently growth of group-housed, male finisher pigs. Applied Animal Behaviour Science 81, 111–126.CrossRefGoogle Scholar
Davis, SM, Squires, EJ 1999. Association of cytochrome b5 with 16-androstene steroid synthesis in the testis and accumulation in the fat of male pigs. Journal of Animal Science 77, 1230–1235.CrossRefGoogle ScholarPubMed
Dehnhard, M, Bernal-Barragan, H, Claus, R 1991. Rapid and accurate high-performance liquid chromatographic method for the determination of 3-methylindole (skatole) in faeces of various species. Journal of Chromatography 566, 101–107.CrossRefGoogle ScholarPubMed
Diaz, GJ, Squires, EJ 2000a. Metabolism of 3-methylindole by porcine liver microsomes: responsible cytochrome P450 enzymes. Toxicological Sciences 55, 284–292.CrossRefGoogle ScholarPubMed
Diaz, GJ, Squires, EJ 2000b. Role of aldehyde oxidase in the hepatic in vitro metabolism of 3-methylindole in pigs. Journal of Agricultural and Food Chemistry 48, 833–837.CrossRefGoogle ScholarPubMed
Diaz, GJ, Squires, EJ 2003. Phase II in vitro metabolism of 3-methylindole metabolites in porcine liver. Xenobiotica 33, 485–498.CrossRefGoogle Scholar
Diaz, GJ, Skordos, KW, Yost, GS, Squires, EJ 1999. Identification of Phase I metabolites of 3-methylindole produced by pig liver microsomes. Drug Metabolism and Disposition 27, 1150–1156.Google ScholarPubMed
Doran, E, Whittington, FM, Wood, JD, McGivan, JD 2002a. The relationship between adipose tissue skatole levels, rates of hepatic microsomal skatole metabolism and hepatic cytochrome P450IIE1 expression in two breeds of pig. Animal Science 74, 461–468.CrossRefGoogle Scholar
Doran, E, Whittington, FW, Wood, JD, McGivan, JD 2002b. Cytochrome P450IIE1 (CYP2E1) is induced by skatole and this induction is blocked by androstenone in isolated pig hepatocytes. Chemico-Biological Interactions 140, 81–92.CrossRefGoogle ScholarPubMed
Doran, E, Whittington, FM, Wood, JD, McGivan, JD 2004. Characterization of androstenone metabolism in pig liver microsomes. Chemico-Biological Interactions 147, 141–149.CrossRefGoogle ScholarPubMed
Draper, AJ, Madan, A, Parkinson, A 1997. Inhibition of coumarin 7-hydroxylase activity in human liver microsomes. Archives of Biochemistry and Biophysics 341, 47–61.CrossRefGoogle ScholarPubMed
Drochner, W 1993. Digestion of carbohydrates in the pig. Archives of Animal Nutrition 43, 95–116.Google ScholarPubMed
Dufort, I, Soucy, P, Lacoste, L, Luu-The, V 2001. Comparative biosynthetic pathway of androstenol and androgens. Journal of Steroid Biochemistry and Molecular Biology 77, 223–227.CrossRefGoogle ScholarPubMed
Dunshea, FR, Colantoni, C, Howard, K, McCauley, I, Jackson, P, Long, KA, Lopaticki, S, Nugent, EA, Simons, JA, Walker, J, Hennessy, DP 2001. Vaccination of boars with a GnRH vaccine (Improvac) eliminates boar taint and increases growth performance. Journal of Animal Science 79, 2524–2535.CrossRefGoogle ScholarPubMed
Einarsson, S 2006. Vaccination against GnRH: pros and cons. Acta Veterinaria Scandinavica 48 (suppl. 1), S10.CrossRefGoogle Scholar
Fish, DE, Cooke, GM, Gower, DB 1980. Investigation into the sulphoconjugation of 5 alpha-androst-16-en-3 beta-ol by porcine liver. FEBS Letters 117, 28–32.CrossRefGoogle ScholarPubMed
García-Regueiro, JA, Diaz, I 1989. Evaluation of the contribution of skatole, indole, androstenone and androstenols to boar-taint in back fat of pigs by HPLC and capillary gas chromatography (CGC). Meat Science 25, 307–316.CrossRefGoogle Scholar
Gillberg, M, Skaanild, MT, Friis, C 2006. Regulation of gender-dependent CYP2A expression in pigs: involvement of androgens and CAR. Basic and Clinical Pharmacology and Toxicology 98, 480–487.CrossRefGoogle ScholarPubMed
Gower, DB 1972. 16-Unsaturated C 19 steroids. A review of their chemistry, biochemistry and possible physiological role. Journal of Steroid Biochemistry 3, 45–103.CrossRefGoogle Scholar
Hansen, LL, Mejer, H, Thamsborg, SM, Byrne, DV, Roepstorff, A, Karlsson, AH, Hansen-Møller, J, Jensen, MT, Tuomola, M 2006. Influence of chicory roots (Cichorium Intybus L.) on boar taint in entire male and female pigs. Animal Science 82, 359–368.CrossRefGoogle Scholar
Hansson, I 1974. Effect of sex and weight on growth, feed efficiency and carcass characteristics of pigs. 1. Growth rate and feed efficiency of boars, barrows and gilts. Swedish Journal of Agricultural Research 4, 209–218.Google Scholar
Hawe, SM, Walker, N, Moss, BW 1992. The effect of dietary fibre, lactose and antibiotic on the levels of skatole and indole in faeces and subcutaneous fat in growing pigs. Animal Production 54, 413–419.Google Scholar
Hilbe, M, Jaros, P, Ehrensperger, F, Zlinszky, K, Janett, F, Hässig, M, Thun, R 2006. Histomorphological and immunohistochemical findings in testes, bulbourethral glands and brain of immunologically castrated male piglets. Schweizer Archiv für Tierheilkunde 148, 599–608.CrossRefGoogle ScholarPubMed
Hortos, M, Rius, MA, De Vries, A, Lacoste, A, Gispert, Mand Diestre, A 2000. Variation in boar taint compounds in backfat from divergent genetic lines. Proceedings of the 46th International Congress of Food Science and Technology, vol. 1 27 August–1 September 2000, Buenos Aires, Argentina, pp. 98–99.Google Scholar
Jaros, P, Bürgi, E, Stärk, KDC, Claus, R, Hennessy, D, Thun, R 2005. Effect of active immunization against GnRH on androstenone concentration, growth performance and carcass quality in intact male pigs. Livestock Production Science 92, 31–38.CrossRefGoogle Scholar
Jaturasitha, S, Pichitpantapong, S, Leangwunta, V, Khiaosaard, R, Suppadit, T, Kreuzer, M 2006. Increasing the slaughter weight of boars: effects on performance and pork quality. Journal of Applied Animal Research 30, 19–24.CrossRefGoogle Scholar
Jensen, MT, Hansen, LL 2006. Feeding with chicory roots reduces the amount of odorous compounds in colon and rectal contents of pigs. Animal Science 82, 369–376.CrossRefGoogle Scholar
Jensen, BB, Jensen, MT 1998. Microbial production of skatole in the digestive tract of entire male pigs. In Skatole and boar taint (ed. WK Jensen), pp. 41–75. Danish Meat Research Institute, Roskilde, Denmark.Google Scholar
Jensen, MT, Cox, RP, Jensen, BB 1995. 3-methylindole (skatole) and indole production by mixed population of pig fecal bacteria. Applied and Environmental Microbiology 61, 3180–3184.CrossRefGoogle ScholarPubMed
Knarreborg, A, Beck, J, Jensen, MT, Laue, A, Agergaard, N, Jensen, BB 2002. Effect of non-starch polysaccharides on production and absorption of indolic compounds in entire male pigs. Animal Science 74, 445–453.CrossRefGoogle Scholar
Kwan, TK, Orengo, C, Gower, DB 1985. Biosynthesis of androgens and pheromonal steroids in neonatal porcine testicular preparations. FEBS Letters 183, 359–364.CrossRefGoogle ScholarPubMed
Lanthier, F, Lou, Y, Terner, MA, Squires, EJ 2006. Characterizing developmental changes in plasma and tissue skatole concentrations in the prepubescent intact male pig. Journal of Animal Science 84, 1699–1708.CrossRefGoogle ScholarPubMed
Lanthier, F, Lou, Y, Squires, EJ 2007. Skatole metabolism in the intact pre-pubescent male pig: the relationship between hepatic enzyme activity and skatole concentrations in plasma and fat. Livestock Science 106, 145–153.CrossRefGoogle Scholar
Lee, GJ, Archibald, AL, Law, AS, Lloyd, S, Wood, J, Haley, CS 2005. Detection of quantitative trait loci for androstenone, skatole and boar taint between large white and Meishan pigs. Animal Genetics 36, 14–22.CrossRefGoogle ScholarPubMed
Lin, Z, Lou, Y, Squires, EJ 2004a. Molecular cloning, expression and functional characterization of cytochrome P450 2A6 gene in pig liver. Animal Genetics 35, 314–316.CrossRefGoogle ScholarPubMed
Lin, Z, Lou, Y, Squires, EJ 2004b. Molecular cloning and functional analysis of porcine SULT1A1 gene and its variant: a single mutation in SULT1A1 causes a significant decrease in sulfation activity. Mammalian Genome 15, 218–226.CrossRefGoogle ScholarPubMed
Lin, ZH, Lou, YP, Peacock, J, Squires, EJ 2005. A novel polymorphism in the 5′ untranslated region of the porcine cytochrome b5 (CYB5) gene is associated with decreased fat androstenone level. Mammalian Genome 16, 367–373.CrossRefGoogle ScholarPubMed
Lin, Z, Lou, Y, Squires, EJ 2006. Functional polymorphism in porcine CYP2E1 gene: Its association with skatole levels. Journal of Steroid Biochemistry and Molecular Biology 99, 231–237.CrossRefGoogle ScholarPubMed
Malmfors, B, Lundström, K, Hansson, I 1978. Fatty acid composition of porcine back fat and muscle lipids as affected by sex, weight and anatomical location. Swedish Journal of Agricultural Research 8, 25–38.Google Scholar
Meadus, WJ, Mason, JI, Squires, EJ 1993. Cytochrome P450c17 from porcine and bovine adrenal catalyses the formation of 5,16 androstadien-3β-ol from pregnenolone in the presence of cytochrome b5. Journal of Steroid Biochemistry and Molecular Biology 46, 565–572.CrossRefGoogle ScholarPubMed
Mentschel, J, Claus, R 2003. Increased butyrate formation in the pig colon by feeding raw potato starch leads to a reduction of colonocyte apoptosis and a shift to the stem cell compartment. Metabolism 52, 1400–1405.CrossRefGoogle Scholar
Metz, C, Hohl, K, Waidelich, S, Drochner, W, Claus, R 2002. Active immunization of boars against GnRH at an early age: consequences for testicular function, boar taint accumulation and N-retention. Livestock Production Science 74, 147–157.CrossRefGoogle Scholar
Moe, M, Grindflek, E, Doran, O 2007a. Expression of 3beta-hydroxysteroid dehydrogenase, cytochrome P450-c17, and sulfotransferase 2B1 proteins in liver and testis of pigs of two breeds: relationship with adipose tissue androstenone concentration. Journal of Animal Science 85, 2924–2931.CrossRefGoogle ScholarPubMed
Moe, M, Meuwissen, T, Lien, S, Bendixen, C, Wang, X, Conley, LN, Berget, I, Tajet, H, Grindflek, E 2007b. Gene expression profiles in testis of pigs with extreme high and low levels of androstenone. BMC Genomics 8, 405.CrossRefGoogle ScholarPubMed
Moss, BW, Hawe, SM, Walker, N 1993. Sensory thresholds for skatole and indole. In Measurement and prevention of boar taint in entire male pigs (ed. M. Bonneau), pp. 63–68. INRA Editions, Paris.Google Scholar
Mutembei, HM, Pesch, S, Schuler, G, Hoffmann, B 2005. Expression of oestrogen receptor and ß and of aromatase in the testis of immature and mature boars. Reproduction in Domestic Animals 40, 228–236.CrossRefGoogle Scholar
Naděje, B, Koucký, M, Ševčíková, S, Adamec, T, Laštovková, J 2000. Assessment of boar and barrow meat. Czech Journal of Animal Science 45, 539–544.Google Scholar
Nicolau-Solano, SI, Whittington, FM, Wood, JD, Doran, O 2007. Relationship between carcass weight, adipose tissue androstenone level and expression of the hepatic 3β-hydroxysteroid dehydrogenase in entire commercial pigs. Animal 1, 1053–1059.CrossRefGoogle ScholarPubMed
Oliver, WT, McCauley, I, Harrell, RJ, Suster, D, Kerton, DJ, Dunshea, FR 2003. A gonadotropin-releasing factor vaccine (Improvac) and porcine somatotropin have synergistic and additive effects on growth performance in group-housed boars and gilts. Journal of Animal Science 81, 1959–1966.CrossRefGoogle ScholarPubMed
Øverland, M, Berg, Jand Matre, T 1995. The effect of feed and feeding regime on skatole and androstenone levels and on sensory attributes of entire male and female pigs. In Proceedings of the Meeting EAAP Working Group, Production and Utilisation of Meat from Entire Male Pigs, Milton Keynes, UK, 6pp.Google Scholar
Patterson, RLS 1967. A possible contribution of phenolic components to boar odour. Journal of the Science of Food Agriculture 18, 8–10.CrossRefGoogle Scholar
Patterson, RLS 1968. 5α-androst-16-ene-3-one: compound responsible for taint in boar fat. Journal of the Science of Food Agriculture 19, 31–38.CrossRefGoogle Scholar
Peacock, J, Lou, Y, Lundström, K, Squires, EJ 2007. The effect of a ca. −8G>T polymorphism on the expression of cytochrome b5A and boar taint in pigs. Animal Genetics 39, 15–21.CrossRefGoogle Scholar
Pedersen, B 1998. Heritability of skatole in back fat. In Skatole and boar taint (ed. WK Jensen), pp. 129–136. Danish Meat Research Institute, Roskilde, Denmark.Google Scholar
Quintanilla, R, Demeure, O, Bidanel, JP, Milan, D, Iannuccelli, N, Amigues, Y, Gruand, J, Renard, C, Chevalet, C, Bonneau, M 2003. Detection of quantitative trait loci for fat androstenone levels in pigs. Journal of Animal Science 81, 385–394.CrossRefGoogle ScholarPubMed
Raeside, JI, Renaud, RL 1983. Estrogen and androgen production by purified Leydig cells of mature boars. Biology of Reproduction 28, 727–733.CrossRefGoogle ScholarPubMed
Rideout, TC, Fan, MZ, Cant, JP, Wagner-Riddle, CStonehouse, P 2004. Excretion of major odor-causing and acidifying compounds in response to dietary supplementation of chicory inulin in growing pigs. Journal of Animal Science 82, 1678–1684.CrossRefGoogle ScholarPubMed
Rius Sole, MA, García-Regueiro, JA 2001. Role of 4-phenyl-3-buten-2-one in boar taint: identification of new compounds related to sensorial descriptors in pig fat. Journal of Agricultural and Food Chemistry 49, 5303–5309.CrossRefGoogle ScholarPubMed
Robic, A, Larzul, C, Bonneau, M 2008. Genetic and metabolic aspects of androstenone and skatole deposition in pig adipose tissue: a review. Genetics Selection Evolution 40, 129–143.Google ScholarPubMed
Saat, YA, Gower, DB, Harrison, FA, Heap, RB 1974. Studies on the metabolism of 5alpha-androst-16-en-3-one in boar tests in vivo. Biochemical Journal 144, 347–352.CrossRefGoogle Scholar
Schwarzenberger, F, Toole, GS, Christie, HL, Raeside, JI 1993. Plasma levels of several androgens and estrogens from birth to puberty in male domestic pigs. Acta Endocrinologica (Copenhagen) 128, 173–177.Google ScholarPubMed
Sellier, P, Le Roy, P, Foilloux, MN, Gruand, J, Bonneau, M 2000. Responses to restricted index selection and genetic parameters for fat androstenone level and sexual maturity status of young boars. Livestock Production Science 63, 265–274.CrossRefGoogle Scholar
Sinclair, PA, Squires, EJ 2005. Testicular sulfoconjugation of the 16-androstene steroids by hydroxysteroid sulfotransferase: its effect on the concentrations of 5alpha-androstenone in plasma and fat of the mature domestic boar. Journal of Animal Science 83, 358–365.CrossRefGoogle ScholarPubMed
Sinclair, PA, Squires, EJ, Raeside, JI 2001. Early postnatal plasma concentrations of testicular hormones, pubertal development and carcass leanness as potential indicators of boar taint in market weight intact male pigs. Journal of Animal Science 79, 1868–1876.CrossRefGoogle ScholarPubMed
Sinclair, PA, Squires, EJ, Raeside, JI, Renaud, R 2005a. Synthesis of free and sulphoconjugated 16-androstene steroids by the Leydig cells of the mature domestic boar. Journal of Steroid Biochemistry and Molecular Biology 96, 217–228.CrossRefGoogle ScholarPubMed
Sinclair, PA, Hancock, S, Gilmore, WJ, Squires, EJ 2005b. Metabolism of the 16-androstene steroids in primary cultured porcine hepatocytes. Journal of Steroid Biochemistry and Molecular Biology 96, 79–87.CrossRefGoogle ScholarPubMed
Sinclair, PA, Gilmore, WJ, Lin, Z, Lou, Y, Squires, EJ 2006. Molecular cloning and regulation of porcine SULT2A1: relationship between SULT2A1 expression and sulfoconjugation of androstenone. Journal of Molecular Endocrinology 36, 301–311.CrossRefGoogle ScholarPubMed
Skinner, TM, Doran, E, McGivan, JD, Haley, CS, Archibald, AL 2005. Cloning and mapping of the porcine cytochrome-P450 2E1 gene and its association with skatole levels in the domestic pig. Animal Genetics 36, 417–422.CrossRefGoogle ScholarPubMed
Skinner, TM, Anderson, JA, Haley, CS, Archibald, AL 2006. Assessment of SULT2A1, CYP2A6 and CYPC18 as candidate genes for elevated backfat skatole levels in commercial and experimental pig populations. Animal Genetics 37, 521–522.CrossRefGoogle Scholar
Sonawane, BR, Coates, PM, Yaffe, SJ, Koldovsky, O 1983. Influence of dietary carbohydrates (alpha-saccharides) on hepatic drug metabolism in male rats. Drug Nutrition Interactions 2, 7–16.Google ScholarPubMed
Squires, EJ, Lundström, K 1997. Relationship between cytochrome P450IIE1 in liver and levels of skatole and its metabolites in intact male pigs. Journal of Animal Science 75, 2506–2511.CrossRefGoogle ScholarPubMed
Stewart, JD, Lou, Y, Squires, EJ, Coussens, PM 2005. Using human microarrays to identify differentially expressed genes associated with increased steroidogenesis in boars. Animal Biotechnology 16, 139–151.CrossRefGoogle ScholarPubMed
Tajet, H, Andresen, OMeuwissen, THE 2006. Estimation of genetic parameters for boar taint: skatole and androstenone and their correlations with sexual maturity. Acta Veterinaria Scandinavica 48(suppl. 1): S9.CrossRefGoogle Scholar
Tambyrajah, WS, Doran, E, Wood, JD, McGivan, JD 2004. The pig CYP2E1 promoter is activated by COUP-TF1 and HNF-1 and is inhibited by androstenone. Archives of Biochemistry and Biophysics 431, 252–260.CrossRefGoogle ScholarPubMed
Terner, MA, Gilmore, WJ, Lou, Y, Squires, EJ 2006. The role of CYP2A and CYP2E1 in the metabolism of 3-methylindole in primary cultured porcine hepatocytes. Drug Metabolism and Disposition 34, 848–854.CrossRefGoogle Scholar
Tuomola, M, Harpio, R, Knuuttila, P, Mikola, H, Lövgren, T 1997. Time-resolved fluoroimmunoassay for the measurement of androstenone in porcine serum and fat samples. Journal of Agricultural and Food Chemistry 45, 3529–3534.CrossRefGoogle Scholar
Van Oeckel, MJ, Warnants, N, De Paepe, M, Casteels, M, Boucqué, ChV 1998. Effect of fibre-rich diets on the backfat skatole content of entire male pigs. Livestock Production Science 56, 173–180.CrossRefGoogle Scholar
Varona, L, Vidal, O, Quintanilla, R, Gil, M, Sanchez, A, Folch, JM, Hortos, M, Rius, MA, Amills, M, Noguera, JL 2005. Baysean analysis of quantitative trait loci for boar taint in a Landrace population. Journal of Animal Science 83, 301–307.CrossRefGoogle Scholar
Vold, E 1970. Fleischproduktionseigenschaften bei Ebern und Kastraten IV: Organoleptische und gaschromatographische Untersuchungen wasserdampfflüchtiger Stoffe des Rückenspeckes von Ebern. Meldinger fra Norges Landbrukshøgskole 49, 1–25.Google Scholar
Walstra, Pand Maarse, G 1970. Onderzoek gestachlengen van mannelijke mestvarkens. Researchgroep voor Vlees en Vleeswaren TNO, IVO-rapport C-147, Rapport 2, p. 30.Google Scholar
Walstra, P, Claudi-Magnussen, C, Chevillon, P, von Seth, G, Diestre, A, Matthews, KR, Homer, DB, Bonneau, M 1999. An international study on the importance of androstenone and skatole for boar taint: levels of androstenone and skatole by country and season. Livestock Production Science 62, 15–28.CrossRefGoogle Scholar
Wang, JF, Zhu, YH, Li, DF, Wang, M, Jensen, BB 2004. Effect of type and level of dietary fibre and starch on ileal and faecal microbial activity and short-chain fatty acid concentrations in growing pigs. Animal Science 78, 109–117.CrossRefGoogle Scholar
Whittington, FM, Nute, GR, Hughes, SI, McGivan, JD, Lean, IJ, Wood, JD, Doran, E 2004. Relationships between skatole and androstenone accumulation, and cytochrome P4502E1 expression in Meishan × Large White pigs. Meat Science 67, 569–576.CrossRefGoogle Scholar
Willeke, H 1993. Possibilities of breeding for low 5α-androstenone content in pigs. Pig News and Information 14, 31–33.Google Scholar
Willeke, H, Claus, R, Müller, E, Pirchner, F, Karg, H 1987. Selection for high and low level of 5 α-androst-16-en-3-one in boars. I. Direct and correlated response of endocrinological traits. Journal of Animal Breeding and Genetics 104, 64–73.CrossRefGoogle Scholar
Wood, JD, Buxton, PJ, Whittington, FM, Enser, M 1986. The chemical composition of fat tissues in the pig: effects of castration and feeding treatment. Livestock Production Science 15, 73–82.CrossRefGoogle Scholar
Xue, J, Dial, GD, Holton, EE, Vickers, Z, Squires, EJ, Lou, Y, Godbout, D, Morel, N 1996. Breed differences in boar taint: relationship between tissue levels of boar taint compounds and sensory analysis of taint. Journal of Animal Science 74, 2170–2177.CrossRefGoogle ScholarPubMed
Zamaratskaia, G, Babol, J, Andersson, H, Lundström, K 2004a. Plasma skatole and androstenone levels in entire male pigs and relationship between boar taint compounds, sex steroids and thyroxine at various ages. Livestock Production Science 87, 91–98.CrossRefGoogle Scholar
Zamaratskaia, G, Babol, J, Madej, A, Squires, EJ, Lundström, K 2004b. Age-related variation of plasma concentrations of skatole in relation to androstenone, sex hormones, triiodothyronine and IGF-1 in six entire male pigs. Reproduction in Domestic Animals 39, 168–172.CrossRefGoogle ScholarPubMed
Zamaratskaia, G, Squires, EJ, Babol, J, Andersson, HK, Andersson, K, Lundström, K 2005a. Relationship between the activities of cytochromes P4502E1 and P4502A6 and skatole content in fat in entire male pigs fed with and without raw potato starch. Livestock Production Science 95, 83–88.CrossRefGoogle Scholar
Zamaratskaia, G, Babol, J, Andersson, HK, Andersson, K, Lundström, K 2005b. Effect of live weight and dietary supplement of raw potato starch on the levels of skatole, androstenone, testosterone and oestrone sulphate in entire male pigs. Livestock Production Science 93, 235–243.CrossRefGoogle Scholar
Zamaratskaia, G, Madej, A, Babol, J, Squires, EJ, Lundström, K 2005c. Free oestrone in adipose tissue and its relation to androstenone and skatole in entire male pigs. Reproduction in Domestic Animals 40, 156–160.CrossRefGoogle ScholarPubMed
Zamaratskaia, G, Rydhmer, L, Chen, G, Madej, A, Andersson, HK, Lundström, K 2005d. Boar taint is related to endocrine and anatomical changes at puberty but not to aggressive behaviour in entire male pigs. Reproduction in Domestic Animals 40, 500–506.CrossRefGoogle Scholar
Zamaratskaia, G, Chen, G, Lundström, K 2006. Effects of sex, weight, diet and hCG administration on levels of skatole and indole in the liver and hepatic activities of cytochromes P4502E1 and P4502A6 in pigs. Meat Science 72, 331–338.CrossRefGoogle ScholarPubMed
Zamaratskaia, G, Lou, Y, Chen, G, Andresen, Ø, Lundström, K, Squires, EJ 2007a. Effect of hCG stimulation on plasma androstenone concentrations and cytochrome b5 (CYB5) levels in testicular tissue. Reproduction in Domestic Animals 42, 105–108.CrossRefGoogle ScholarPubMed
Zamaratskaia, G, Gilmore, WJ, Lundström, K, Squires, EJ 2007b. Effect of testicular steroids on catalytic activities of cytochrome P450 enzymes in porcine liver microsomes. Food and Chemical Toxicology 45, 676–681.CrossRefGoogle ScholarPubMed
Zamaratskaia, G, Oskam, I, Ropstad, E, Tajet, H, Andresen, Ø 2008a. Effect of hCG stimulation on hepatic activities of cytochrome P4502E1 and P4502A in entire male pigs. Reproduction in Domestic Animals 43, 147–152.CrossRefGoogle Scholar
Zamaratskaia, G, Andersson, HK, Chen, G, Andersson, K, Madej, A, Lundström, K 2008b. Effect of a gonadotropin-releasing hormone vaccine (ImprovacTM) on steroid hormones, boar taint and performance in entire male pigs. Reproduction in Domestic Animals (doi:10.1111/j.1439-0531.2007.00914.x).CrossRefGoogle ScholarPubMed
Zamaratskaia, G, Rydhmer, L, Andersson, HK, Chen, G, Lowagie, S, Andersson, K, Lundström, K 2008c. Long-term effect of vaccination against gonadotropin-releasing hormone, using ImprovacTM mark, on hormonal profile and behaviour of male pigs. Animal Reproduction Science (doi:10.1016/j.anireprosci.2007.07.001).CrossRefGoogle Scholar
Zamaratskaia, G, Lou, Y, Peacock, J, Rydhmer, L, Andersson, HK, Juneja, RK, Chen, G, Lundström, K, Squires, EJ 2008d. Effect of polymorphism in the porcine cytochrome b5 (CYB5A) gene on androstenone and skatole concentrations and sexual development in Swedish swine populations. Animal 2, 190–196.CrossRefGoogle Scholar