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

Animal

Volumn 3, Issue 11, 2009, Pages 1508-1521

  Zamaratskaia, G ^a   Squires, E J ^b  

^a SWEDISH UNIVERSITY OF AGRICULTURAL SCIENCES   (Sweden)

^b UNIVERSITY OF GUELPH   (Canada)

Author keywords

Androstenone; Entire male pig; Review; Skatole

Indexed keywords

ANIMALIA; BACTERIA (MICROORGANISMS); SUIDAE;

EID: 70449382263     PISSN: 17517311     EISSN: 1751732X     Source Type: Journal    
DOI: 10.1017/S1751731108003674     Document Type: Article

References (133)

1. Aldal I, Andresen O, Egeli AK, Haugen J-E, Grodum A, Fjetland O and 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.
2. Angels Rius M, Hortó s M and 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.
3. Babol J and Squires EJ 1995. Quality of meat from entire male pigs. Food Research International 28, 201-212.
4. Babol J and Squires EJ 1999. Liver metabolic activities of intact male pigs injected with skatole. Canadian Journal of Animal Science 79, 549-552.
5. Babol J, Squires EJ and Lundström K 1998a. Hepatic metabolism of skatole in pigs by cytochrome P4502E1. Journal of Animal Science 76, 822-828.
6. Babol J, Squires EJ and 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.
7. Babol J, Squires EJ and Lundstrøm K 1999. Relationship between metabolism of skatole and andtrostenone in intact male pigs. Journal of Animal Science 77, 84-92.
8. Babol J, Zamaratskaia G, Juneja RK and 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.
9. Baek C, Hansen-Møller J, Friiis C, Cornett C and Hansen SH 1997. Identification of selected metabolites of skatole in plasma and urine from pigs. Journal of Agricultural and Food Chemistry 45, 2332-2340.
10. Bañó n S, Andreu C, Laencina J and Garrido M-D 2004. Fresh and eating pork quality from entire versus castrate heavy males. Food Quality and Preference 15, 293-300.
11. Bonneau M 1982. Compounds responsible for boar taint, with special emphasis on androstenone: a review. Livestock Production Science 9, 687-707.
12. 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.
13. Bonneau M 1998. Use of entire males for pig meat in the European Union. Meat Science 49, S257-S272.
14. Bonneau M and 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.
15. Bonneau M, Meusy-Dessolle N, Lé glise PC and 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.
16. Bonneau M, Carrié -Lemoine J, Prunier A, Garnier DH and Terqui M 1987. Agerelated changes in plasma LH and testosterone concentration profiles and fat androstenone content in the young boar. Animal Reproduction Science 15, 241-258.
17. Bonneau M, LeDenmat M, Vaudelet JC, VelosoNunes JR, Mortensen AB and 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.
18. Bonneau M, Dufour R, Chouvet C, Roulet C, Meadus W and 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.
19. Booth WD 1987. Factors affecting the pheromone composition of voided boar saliva. Journal of Reproduction and Fertility 81, 427-431.
20. Brennan JJ, Shand PJ, Fenton M, Nicholls LL and 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.
21. Brophy PJ and Gower BD 1972. 16-unsaturated C 19 3-oxo steroids as metabolic intermediates in boar testis. Biochemical Journal 128, 945-952.
22. Carlström K, Malmfors B, Lundström K, Edqvist LE and Gahne B 1975. The effect of HCG on blood plasma levels of 5a-androstenone and testosterone in the boar. Swedish Journal of Agricultural Research 5, 15-21.
23. Chen G, Zamaratskaia G, Madej A and 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.
24. Chen G, Zamaratskaia G, Andersson HK and 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.
25. Chen G, Cue R-A, Lundström K, Wood JH and 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.
26. Claus R and Hoffmann B 1980. Oestrogens, compared to other steroids of testicular origin, in blood plasma of boars. Acta Endocrinologica (Copenhagan) 94, 404-411.
27. Claus R and Raab S 1999. Influences on skatole formation from tryptophan in the pig colon. Advances in Experimental Medicine and Biology 467, 679-684.
28. Claus R, Hoffmann B and 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.
29. Claus R, Dehnhard M, Herzhog A, Bernal-Barragan H and Gimé nez 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.
30. Claus R, Weiler U and Herzog A 1994. Physiological aspects of androstenone and skatole formation in the boars - a review with experimental data. Meat Science 38, 289-305.
31. Claus R, Losel D, Lacorn M, Mentschel J and 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.
32. Claus R, Lacorn M, Danowski K, Pearce MC and Bauer A 2007. Short-term endocrine and metabolic reactions before and after second immunization against GnRH in boars. Vaccine 25, 4689-4696.
33. Cooke GM, Ferguson SE, Rytina E and 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.
34. Cronin GM, Dunshea FR, Butler KL, McCauley I, Barnett JL and 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.
35. Davis SM and 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.
36. Dehnhard M, Bernal-Barragan H and 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.
37. Diaz GJ and Squires EJ 2000a. Metabolism of 3-methylindole by porcine liver microsomes: responsible cytochrome P450 enzymes. Toxicological Sciences 55, 284-292.
38. Diaz GJ and 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.
39. Diaz GJ and Squires EJ 2003. Phase II in vitro metabolism of 3-methylindole metabolites in porcine liver. Xenobiotica 33, 485-498.
40. Diaz GJ, Skordos KW, Yost GS and Squires EJ 1999. Identification of Phase I metabolites of 3-methylindole produced by pig liver microsomes. Drug Metabolism and Disposition 27, 1150-1156.
41. Doran E, Whittington FM, Wood JD and 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.
42. Doran E, Whittington FW, Wood JD and 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.
43. Doran E, Whittington FM, Wood JD and McGivan JD 2004. Characterization of androstenone metabolism in pig liver microsomes. Chemico-Biological Interactions 147, 141-149.
44. Draper AJ, Madan A and Parkinson A 1997. Inhibition of coumarin 7-hydroxylase activity in human liver microsomes. Archives of Biochemistry and Biophysics 341, 47-61.
45. Drochner W 1993. Digestion of carbohydrates in the pig. Archives of Animal Nutrition 43, 95-116.
46. Dufort I, Soucy P, Lacoste L and Luu-The V 2001. Comparative biosynthetic pathway of androstenol and androgens. Journal of Steroid Biochemistry and Molecular Biology 77, 223-227.
47. Dunshea FR, Colantoni C, Howard K, McCauley I, Jackson P, Long KA, Lopaticki S, Nugent EA, Simons JA, Walker J and 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.
48. Einarsson S 2006. Vaccination against GnRH: pros and cons. Acta Veterinaria Scandinavica 48(suppl. 1), S10.
49. Fish DE, Cooke GM and Gower DB 1980. Investigation into the sulphoconjugation of 5 alpha-androst-16-en-3 beta-ol by porcine liver. FEBS Letters 117, 28-32.
50. Garc?́a-Regueiro JA and 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.
51. Gillberg M, Skaanild MT and 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.
52. 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.
53. Hansen LL, Mejer H, Thamsborg SM, Byrne DV, Roepstorff A, Karlsson AH, Hansen-Møller J, Jensen MT and Tuomola M 2006. Influence of chicory roots (Cichorium Intybus L.) on boar taint in entire male and female pigs. Animal Science 82, 359-368.
54. 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.
55. Hawe SM, Walker N and 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.
56. Hilbe M, Jaros P, Ehrensperger F, Zlinszky K, Janett F, Hässig M and 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.
57. Hortos M, Rius MA, De Vries A, Lacoste A, Gispert Mand and 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.
58. Jaros P, Bürgi E, Stärk KDC, Claus R, Hennessy D and 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.
59. Jaturasitha S, Pichitpantapong S, Leangwunta V, Khiaosaard R, Suppadit T and Kreuzer M 2006. Increasing the slaughter weight of boars: effects on performance and pork quality. Journal of Applied Animal Research 30, 19-24.
60. Jensen MT and 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.
61. Jensen BB and 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.
62. Jensen MT, Cox RP and Jensen BB 1995. 3-methylindole (skatole) and indole production by mixed population of pig fecal bacteria. Applied and Environmental Microbiology 61, 3180-3184.
63. Knarreborg A, Beck J, Jensen MT, Laue A, Agergaard N and Jensen BB 2002. Effect of non-starch polysaccharides on production and absorption of indolic compounds in entire male pigs. Animal Science 74, 445-453.
64. Kwan TK, Orengo C and Gower DB 1985. Biosynthesis of androgens and pheromonal steroids in neonatal porcine testicular preparations. FEBS Letters 183, 359-364.
65. Lanthier F, Lou Y, Terner MA and 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.
66. Lanthier F, Lou Y and Squires EJ 2007. Skatole metabolism in the intact prepubescent male pig: the relationship between hepatic enzyme activity and skatole concentrations in plasma and fat. Livestock Science 106, 145-153.
67. Lee GJ, Archibald AL, Law AS, Lloyd S, Wood J and 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.
68. Lin Z, Lou Y and Squires EJ 2004a. Molecular cloning, expression and functional characterization of cytochrome P450 2A6 gene in pig liver. Animal Genetics 35, 314-316.
69. Lin Z, Lou Y and 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.
70. Lin ZH, Lou YP, Peacock J and Squires EJ 2005. A novel polymorphism in the 50 untranslated region of the porcine cytochrome b5 (CYB5) gene is associated with decreased fat androstenone level. Mammalian Genome 16, 367-373.
71. Lin Z, Lou Y and Squires EJ 2006. Functional polymorphism in porcine CYP2E1 gene: Its association with skatole levels. Journal of Steroid Biochemistry and Molecular Biology 99, 231-237.
72. Malmfors B, Lundström K and 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.
73. Meadus WJ, Mason JI and Squires EJ 1993. Cytochrome P450c17 from porcine and bovine adrenal catalyses the formation of 5,16 androstadien-3b-ol from pregnenolone in the presence of cytochrome b5. Journal of Steroid Biochemistry and Molecular Biology 46, 565-572.
74. Mentschel J and 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.
75. Metz C, Hohl K, Waidelich S, Drochner W and 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.
76. Moe M, Grindflek E and 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.
77. Moe M, Meuwissen T, Lien S, Bendixen C, Wang X, Conley LN, Berget I, Tajet H and Grindflek E 2007b. Gene expression profiles in testis of pigs with extreme high and low levels of androstenone. BMC Genomics 8, 405.
78. Moss BW, Hawe SM and 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.
79. Mutembei HM, Pesch S, Schuler G and 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.
80. Nadě je B, Koucký M, Sevč́ková S, Adamec T and Laštovková J 2000. Assessment of boar and barrow meat. Czech Journal of Animal Science 45, 539-544.
81. Nicolau-Solano SI, Whittington FM, Wood JD and Doran O 2007. Relationship between carcass weight, adipose tissue androstenone level and expression of the hepatic 3b-hydroxysteroid dehydrogenase in entire commercial pigs. Animal 1, 1053-1059.
82. Oliver WT, McCauley I, Harrell RJ, Suster D, Kerton DJ and 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.
83. Overland M, Berg Jand and 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.
84. Patterson RLS 1967. A possible contribution of phenolic components to boar odour. Journal of the Science of Food Agriculture 18, 8-10.
85. Patterson RLS 1968. 5a-androst-16-ene-3-one: compound responsible for taint in boar fat. Journal of the Science of Food Agriculture 19, 31-38.
86. Peacock J, Lou Y, Lundström K and Squires EJ 2007. The effect of a ca. 28G.T polymorphism on the expression of cytochrome b5A and boar taint in pigs. Animal Genetics 39, 15-21.
87. 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.
88. Quintanilla R, Demeure O, Bidanel JP, Milan D, Iannuccelli N, Amigues Y, Gruand J, Renard C, Chevalet C and Bonneau M 2003. Detection of quantitative trait loci for fat androstenone levels in pigs. Journal of Animal Science 81, 385-394.
89. Raeside JI and Renaud RL 1983. Estrogen and androgen production by purified Leydig cells of mature boars. Biology of Reproduction 28, 727-733.
90. Rideout TC, Fan MZ, Cant JP, Wagner-Riddle C and Stonehouse 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.
91. Rius Sole MA and Garc?́a-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.
92. Robic A, Larzul C and Bonneau M 2008. Genetic and metabolic aspects of androstenone and skatole deposition in pig adipose tissue: a review. Genetics Selection Evolution 40, 129-143.
93. Saat YA, Gower DB, Harrison FA and Heap RB 1974. Studies on the metabolism of 5alpha-androst-16-en-3-one in boar tests in vivo. Biochemical Journal 144, 347-352.
94. Schwarzenberger F, Toole GS, Christie HL and Raeside JI 1993. Plasma levels of several androgens and estrogens from birth to puberty in male domestic pigs. Acta Endocrinologica (Copenhagen) 128, 173-177.
95. Sellier P, Le Roy P, Foilloux MN, Gruand J and 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.
96. Sinclair PA and 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.
97. Sinclair PA, Squires EJ and 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.
98. Sinclair PA, Squires EJ, Raeside JI and 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.
99. Sinclair PA, Hancock S, Gilmore WJ and Squires EJ 2005b. Metabolism of the 16-androstene steroids in primary cultured porcine hepatocytes. Journal of Steroid Biochemistry and Molecular Biology 96, 79-87.
100. Sinclair PA, Gilmore WJ, Lin Z, Lou Y and 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.
101. Skinner TM, Doran E, McGivan JD, Haley CS and 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.
102. Skinner TM, Anderson JA, Haley CS and 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.
103. Sonawane BR, Coates PM, Yaffe SJ and Koldovsky O 1983. Influence of dietary carbohydrates (alpha-saccharides) on hepatic drug metabolism in male rats. Drug Nutrition Interactions 2, 7-16.
104. Squires EJ and 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.
105. Stewart JD, Lou Y, Squires EJ and Coussens PM 2005. Using human microarrays to identify differentially expressed genes associated with increased steroidogenesis in boars. Animal Biotechnology 16, 139-151.
106. Tajet H, Andresen O and Meuwissen 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.
107. Tambyrajah WS, Doran E, Wood JD and 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.
108. Terner MA, Gilmore WJ, Lou Y and 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.
109. Tuomola M, Harpio R, Knuuttila P, Mikola H and Lö vgren 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.
110. Van Oeckel MJ, Warnants N, De Paepe M, Casteels M and Boucqué ChV 1998. Effect of fibre-rich diets on the backfat skatole content of entire male pigs. Livestock Production Science 56, 173-180.
111. Varona L, Vidal O, Quintanilla R, Gil M, Sanchez A, Folch JM, Hortos M, Rius MA, Amills M and Noguera JL 2005. Baysean analysis of quantitative trait loci for boar taint in a Landrace population. Journal of Animal Science 83, 301-307.
112. Vold E 1970. Fleischproduktionseigenschaften bei Ebern und Kastraten IV: Organoleptische und gaschromatographische Untersuchungen wasserdampfflü chtiger Stoffe des Rückenspeckes von Ebern. Meldinger fra Norges Landbrukshøgskole 49, 1-25.
113. Walstra Pand and Maarse G 1970. Onderzoek gestachlengen van mannelijke mestvarkens. Researchgroep voor Vlees en Vleeswaren TNO, IVO-rapport C-147, Rapport 2, p. 30.
114. Walstra P, Claudi-Magnussen C, Chevillon P, von Seth G, Diestre A, Matthews KR, Homer DB and 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.
115. Wang JF, Zhu YH, Li DF, Wang M and 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.
116. Whittington FM, Nute GR, Hughes SI, McGivan JD, Lean IJ, Wood JD and Doran E 2004. Relationships between skatole and androstenone accumulation, and cytochrome P4502E1 expression in Meishan 3Large White pigs. Meat Science 67, 569-576.
117. Willeke H 1993. Possibilities of breeding for low 5a-androstenone content in pigs. Pig News and Information 14, 31-33.
118. Willeke H, Claus R, Müller E, Pirchner F and Karg H 1987. Selection for high and low level of 5 a-androst-16-en-3-one in boars. I. Direct and correlated response of endocrinological traits. Journal of Animal Breeding and Genetics 104, 64-73.
119. Wood JD, Buxton PJ, Whittington FM and Enser M 1986. The chemical composition of fat tissues in the pig: effects of castration and feeding treatment. Livestock Production Science 15, 73-82.
120. Xue J, Dial GD, Holton EE, Vickers Z, Squires EJ, Lou Y, Godbout D and 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.
121. Zamaratskaia G, Babol J, Andersson H and 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.
122. Zamaratskaia G, Babol J, Madej A, Squires EJ and Lundström K 2004b. Agerelated 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.
123. Zamaratskaia G, Squires EJ, Babol J, Andersson HK, Andersson K and 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.
124. Zamaratskaia G, Babol J, Andersson HK, Andersson K and 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.
125. Zamaratskaia G, Madej A, Babol J, Squires EJ and 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.
126. Zamaratskaia G, Rydhmer L, Chen G, Madej A, Andersson HK and 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.
127. Zamaratskaia G, Chen G and 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.
128. Zamaratskaia G, Lou Y, Chen G, Andresen O, Lundström K and 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.
129. Zamaratskaia G, Gilmore WJ, Lundström K and 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.
130. Zamaratskaia G, Oskam I, Ropstad E, Tajet H and Andresen O 2008a. Effect of hCG stimulation on hepatic activities of cytochrome P4502E1 and P4502A in entire male pigs. Reproduction in Domestic Animals 43, 147-152.
131. Zamaratskaia G, Andersson HK, Chen G, Andersson K, Madej A and 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).
132. Zamaratskaia G, Rydhmer L, Andersson HK, Chen G, Lowagie S, Andersson K and Lundström K 2008c. Long-term effect of vaccination against gonadotropinreleasing hormone, using ImprovacTM mark, on hormonal profile and behaviour of male pigs. Animal Reproduction Science (doi:10.1016/ j.anireprosci.2007.07.001).
133. Zamaratskaia G, Lou Y, Peacock J, Rydhmer L, Andersson HK, Juneja RK, Chen G, Lundström K and 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.