Effects of raw potato starch and live weight on fat and plasma skatole, indole and androstenone levels measured by different methods in entire male pigs

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191

179

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.

Section: Biochemical Nutritional and Genetic Effects On Boar Taintmentioning

confidence: 81%

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

Zamaratskaia

Squires

2009

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191

179

“…Indole synthesis in the large intestine is mediated by many types of bacteria, whereas skatole production requires the presence of highly specific bacterial populations. Feeding RPS affected skatoleproducing bacteria; however, indole-producing bacteria remain unaffected (Chen et al, 2007).…”

Section: Discussionmentioning

confidence: 96%

Performances, meat quality and boar taint of castrates and entire male pigs fed a standard and a raw potato starch-enriched diet

Pauly

Spring

O’Doherty

et al. 2008

In Europe there is increasing concern about the common practice of surgical castration of piglets without anaesthesia. One possible alternative to completely avoid castration is entire male pig production. Thus, the objective of the study was to compare the growth performance, carcass characteristics, organ weights, meat quality traits, fat score and boar taint compounds in the adipose tissue of group-penned entire male pigs and castrates. Furthermore, the effect of raw potato starch (RPS) fed for 7 days prior to slaughter was determined. Pigs (n= 36) were blocked by BW into 12 blocks (3 littermates/block) and assigned to three experimental groups: surgical castrates (C); entire males (EM); and entire males offered RPS (30 g RPS/100 g diet) for 7 days prior to slaughter (EM+). Pigs hadad libitumaccess to the feed from 22 to 107 kg, individual feed intake was recorded daily and BW once a week. Entire males grew slower (EM: 771, EM+: 776v. C: 830 g/day;P< 0.01), consumed less feed (EM: 1.87, EM+: 1.89v. C: 2.23 kg/day;P< 0.01) and were more efficient (feed conversion ratio: EM: 2.42, EM+: 2.44v. C: 2.69 kg/kg;P< 0.01) than C. Compared to C, carcass dressing percentage was lower (EM: 79.4, EM+: 79.4v. C: 81.6%;P< 0.01) and percentage of valuable cuts was higher (EM: 57.3, EM+: 56.5v. 52.6%;P< 0.01) in entire males. The hearts (EM: 426, EM+: 425v. C: 378 g), kidneys (EM: 387, EM+: 378v. C: 311 g), bulbourethral (EM: 200, EM+: 195v. C: 7 g) and salivary glands (EM: 99, EM+: 94v. C: 42 g) were heavier (P< 0.001) in entire males than in C. Meat quality traits did not (P> 0.05) differ among experimental groups but the adipose tissue was more unsaturated in entire males than in C as indicated by the higher fat scores (EM: 69.1, EM+: 67.2v. C: 63.6;P< 0.01). Feeding RPS reduced (P= 0.04) the skatole tissue concentrations (expressed in μg/g lipid) in EM+ (0.22) compared to EM (0.85), whereas androstenone and indole levels were not (P⩾ 0.60) affected (EM: 1.7 and 0.10, EM+: 2.0 and 0.09, respectively). Although the current results confirmed the high efficiency of entire males compared to castrates, the observed high androstenone levels represent a major challenge to implement entire males production.

“…This pig had an androstenone level of 0.52 mg/g, as obtained by the ELISA method. Given that the ELISA method can overestimate the androstenone concentration, especially at low concentrations (Chen et al, 2007a), an additional analysis by HPLC was performed. An androstenone level 0.15 mg/g obtained by HPLC is probably more reliable.…”

Section: Discussionmentioning

confidence: 99%

“…Subsequently, 33 out of 76 (trial 1) and 34 out of 69 (trial 2) pigs slaughtered at around 115 kg received, in addition to the ordinary diet, raw potato starch (Lyckeby Culminar AB, Karlshamn, Sweden), 0.6 kg/day for 2 weeks prior to slaughter. This has previously been shown to have a skatole-reducing effect (Zamaratskaia et al, 2005b;Chen et al, 2007a). Polymorphism in CYB5A gene in Swedish pig populations Testes and bulbourethral (Cowper's) glands were removed from entire male pigs at slaughter, and dissected from extraneous tissue.…”

Section: Animal and Samplingmentioning

confidence: 99%

“…Androstenone levels in plasma and fat were determined with an ELISA method (Sinclair et al, 2001). Additionally, androstenone in the fat sample from the pig with T/T genotype was analysed by HPLC, since the ELISA method was shown to overestimate androstenone concentrations in fat (Chen et al, 2007a). Total testosterone and oestrone sulphate concentrations were measured with radio-immunoassay (RIA) procedures (Diagnostic Products Corporation, Los Angeles, CA, USA), according to manufacturer's instructions.…”

Section: Chemical Analysesmentioning

confidence: 99%

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Effect of polymorphism in the porcine cytochrome b5 (CYB5A) gene on androstenone and skatole concentrations and sexual development in Swedish pig populations

Zamaratskaia

Lou

Peacock

et al. 2008

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The present study investigated the presence of a single-nucleotide polymorphism (G . T) at base 28 upstream of ATG in 5 0 untranslated region of cytochrome b5 (CYB5A) gene in Swedish pig populations and evaluated the significance of this polymorphism for androstenone and skatole levels, sexual development and performance parameters in pigs. Frequencies of the T allele were 6.7% for Swedish Yorkshire 3 Landrace crossbred pigs (n 5 245), 6.5% for Swedish Yorkshire (n 5 99) and 12.8% for Landrace breed (n 5 74). No deviations from Hardy-Weinberg equilibrium were observed in the investigated populations. In Swedish Yorkshire 3 Landrace crossbred entire male pigs (n 5 193), plasma samples were analysed for skatole, androstenone, testosterone and oestrone sulphate, and fat samples were analysed for androstenone, skatole and free oestrone. Additionally, testis weight and bulbourethral gland length for crossbred pigs were recorded. Plasma androstenone levels were significantly lower in the G/T genotype at 90 kg live weight compared with the wild G/G genotype at the same live weight (P 5 0.006). In heavier pigs, plasma androstenone levels did not differ between genotypes (P 5 0.382). Fat androstenone levels were not affected by CYB5A genotype (P 5 0.252). Skatole levels in the G/T genotype at 115 kg live weight were lower compared with those in the G/G genotype in plasma (P 5 0.048) and fat (P 5 0.028), although no differences were observed in lighter pigs. Testis weight, bulbourethral gland length, testosterone and oestrone sulphate levels in plasma, and oestrone levels in fat were not affected by genotype. We concluded that the presence of the T allele in the CYB5A gene resulted in lower androstenone levels in plasma, and lower skatole levels in fat and plasma; this reduction, however, was dependent on the live weight of the animals. Reproductive hormones and growth rate did not differ between the pigs of different genotypes, whereas a higher lean meat content was found in the G/T genotype in comparison with the G/G genotype. The practical application of those results in Sweden is doubtful because of lack of the effect on androstenone in fat and the low frequency of the T allele in the studied Swedish pig populations.