Revealing genetic relationships between compounds affecting boar taint and reproduction in pigs

NORSVIN (The Norwegian Pig Breeders Association), PO Box 504, 2304 Hamar, Norway.
Journal of Animal Science (Impact Factor: 2.11). 03/2011; 89(3):680-92. DOI: 10.2527/jas.2010-3290
Source: PubMed


Boar taint is characterized by an unpleasant taste or odor in intact male pigs and is primarily attributed to increased concentrations of androstenone and skatole and to a lesser extent by increased indole. The boar taint compounds skatole and indole are produced by gut bacteria, metabolized in the liver, and stored in the fat tissue. Androstenone, on the other hand, is synthesized in the testis along with testosterone and estrogens, which are known to be important factors affecting fertility. The main goal of this study was to investigate the relationship between genetic factors involved in the primary boar taint compounds in an attempt to discover ways to reduce boar taint without decreasing fertility-related compounds. Heritabilities and genetic correlations between traits were estimated for compounds related to boar taint (androstenone, skatole, indole) and reproduction (testosterone, 17β-estradiol, and estrone sulfate). Heritabilities in the range of 0.47 to 0.67 were detected for androstenone concentrations in both fat and plasma, whereas those for skatole and indole were slightly less (0.27 to 0.41). The genetic correlations between androstenone in plasma and fat were extremely high (0.91 to 0.98) in Duroc and Landrace. In addition, genetic correlations between androstenone (both plasma and fat) and the other sex steroids (estrone sulfate, 17β-estradiol, and testosterone) were very high, in the range of 0.80 to 0.95. Furthermore, a genome-wide association study (GWA) and a combined linkage disequilibrium and linkage analysis (LDLA) were conducted on 1,533 purebred Landrace and 1,027 purebred Duroc to find genome regions involved in genetic control of the boar taint compounds androstenone, skatole, and indole, and sex hormones related to fertility traits. Up to 3,297 informative SNP markers were included for both breeds, including SNP from several boar taint candidate genes. From the GWA study, we found that altogether 27 regions were significant at a genome-wide level (P < 0.05) and an additional 7 regions were significant at a chromosomal level. From the LDLA study, 7 regions were significant on a genome-wide level and an additional 7 regions were significant at a chromosomal level. The most convincing associations were obtained in 6 regions affecting skatole and indole in fat on chromosomes 1, 2, 3, 7, 13, and 14, 1 region on chromosome 6 affecting androstenone in plasma only, and 5 regions on chromosomes 3, 4, 13, and 15 affecting androstenone, testosterone, and estrogens.

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    • "The effect of animal gender on meat flavor is highly related to testosterone and skatole that are produced in intact males and females, respectively. Boar taint in pork from intact males is an unpleasant urine-like and sweaty odor that is related to the presence of androstenone (5α-androst-16-en-3-one) and skatole (3-methylindole) (Grindflek et al., 2011). Androstenone is a metabolite of testosterone, and skatole is the major contributor to pastoral-flavor (Teixeira, Batista, Delfa, & Cadavez, 2005). "
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    ABSTRACT: Our objective was to determine the influence of mitochondria on metabolites and pH decline using an in vitro model of postmortem muscle metabolism. Mitochondria were isolated from porcine longissimus lumborum and added (0, 0.5, or 2.0mg) to powdered muscle in reaction media containing either a combination of inhibitors for mitochondria complexes (I, IV, and V) or diluent (without inhibitors). In the absence of inhibitors, adding mitochondria (0.5 and 2.0mg) reduced ATP loss from 30 to 120min, but did not alter glycogen or lactate during this time. In reactions with mitochondria, inhibitors decreased ATP levels by 30min and increased glycogen degradation by 60min. Regardless of mitochondria content, inhibitors enhanced lactate accumulation from 15 to 240min, and decreased pH from 15min to 1440min. In the in vitro model, mitochondria influence the maintenance of ATP, and inhibition of mitochondria enzyme activity contributes to accelerated metabolism and pH decline. Copyright © 2015. Published by Elsevier Ltd.
    Full-text · Article · Jul 2015 · Meat Science
    • "The correlation between the different sex steroids and boar taint compounds in male pigs has been studied extensively (Zamaratskaia et al., 2004; Grindflek et al., 2011; Strathe et al., 2013). However, correlations differ considerably between studies, which can be partly explained by the effect of breed on the occurrence of boar taint (Aluwé et al., 2011b). "
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    ABSTRACT: Societal pressure to ban surgical castration of male piglets is rising due to animal welfare concerns, thus other methods to prevent boar taint need to be explored. Genetic selection against boar taint appears to be a long-term sustainable alternative. However, as boar taint is linked to reproductive hormones, it is important to consider possible negative side effects such as delayed sexual maturity or changes in behaviour. We reported earlier that the melanocortin-4 receptor (MC4R) marker can be used to reduce boar taint levels in fat of boars. The objective of this study was to evaluate whether MC4R marker-assisted selection for lower boar taint prevalence affects plasma levels of boar taint compounds and testosterone; sexual maturity; behaviour; skin lesions; and lameness in boars and gilts. Using an intervention study with a 2×2 design, 264 boars and gilts differing on position 893 of the MC4R gene (AA v. GG) were compared. The MC4R polymorphism did not affect the plasma concentration of either androstenone or testosterone at different time points, whereas the concentration of skatole was significantly lower (P=0.003) and the concentration of indole tended to be lower (P=0.074) in GG compared with AA boars. A higher percentage of gilts of the GG genotype were in puberty at slaughter age compared with AA gilts (P<0.001). The age of the boars at sexual maturity (as indicated by the first positive preputial smear test) did not differ between AA and GG boars. In contrast, weight of GG boars at sexual maturity tended to be lower (P=0.065). During the period from 6 weeks of age to slaughter, boars and gilts of the GG genotype showed more playing behaviour (P=0.015) and less passive and feeding behaviour (P=0.003). They showed more skin lesions on their back and caudal area (P=0.022), and tended to show more skin lesions on their head and anterior area (P=0.093) compared with AA animals. In conclusion, the polymorphism in the MC4R gene can be used as a marker without negative effects on reproduction characteristics in boars and gilts. Genetic selection towards a lower prevalence of boar taint will lead to more active pigs with more skin lesions. Management strategies may therefore be necessary to reduce skin lesions in the selected animals.
    No preview · Article · Jul 2015 · animal
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    • "To assess the ability of treatments (surgical vs vaccination) to inhibit the formation of two chemical substances typically tied to boar taint offflavour in entire males (Grindflek et al., 2011), samples were removed from belly fat tissue just after carcass sectioning and quantitatively analysed for skatole and androstenone by HPLC and GC–MS, respectively (Rius, Hortós, & García-Reguiero, 2005). "
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    ABSTRACT: The aim of this study was to evaluate immunocastration (vaccination against GnRH using Improvac® vaccine), as an alternative to surgical castration in heavy male pigs (average live weight 165±10kg), used in the production of Italian typical dry-cured ham. A total of 60 Landrace×Large White male pigs were assigned to three groups of 20 units, including one group of surgically castrated (SC), and two of immunocastrated pigs, with two (IC2) or three (IC3) vaccine treatments, respectively. The groups were compared for green ham traits, processing weight losses, chemo-physical, and sensory properties of dry-cured hams. While IC3 were not different (P>0.05) from SC group, IC2 hams were found to differ (P<0.05) both from SC and IC3 groups in ham traits, final weight losses, texture and sensory boar taint in finished hams. Therefore, vaccination with three doses could be taken into account to control boar taint in the manufacturing of typical Italian dry-cured ham. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Full-text · Article · Jul 2015 · Meat Science
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