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

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: 79%

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

Zamaratskaia

Squires

2009

191

179

“…The higher levels of valerianic acid when inulin-type fructans was added in the diet are in agreement with a study by Øverland et al (2011), adding chicory-inulin in diets to entire male pigs. Earlier studies report that feeding easily fermentable carbohydrates as raw potato starch to pigs results in higher butyrate production in the hindgut Mentschel and Claus, 2003). Increased butyrate in the hindgut has been suggested to inhibit apoptosis of colonic mucosal cells (Hass et al, 1997;Mentschel and Claus, 2003), and is implied as an explanation to lower skatole production in the hindgut due to less substrate for skatole production .…”

Section: Discussionmentioning

confidence: 99%

Feeding Jerusalem artichoke reduced skatole level and changed intestinal microbiota in the gut of entire male pigs

Vhile

Kjos

Sørum

et al. 2012

Different levels of dried Jerusalem artichoke were fed to entire male pigs 1 week before slaughter. The objective was to investigate the effect on skatole level in the hindgut and in adipose tissue, as well as the effect on microflora and short-chain fatty acids (SCFA) in the hindgut. Five experimental groups (n 5 11) were given different dietary treatments 7 days before slaughtering: negative control (basal diet), positive control (basal diet 1 9% chicory-inulin), basal diet 1 4.1% Jerusalem artichoke, basal diet 1 8.1% Jerusalem artichoke and basal diet 1 12.2% Jerusalem artichoke. Samples from colon, rectum, faeces and adipose tissue were collected. Effect of dietary treatment on skatole, indole and androstenone levels in adipose tissue and on skatole, indole, pH, dry matter (DM), microbiota and SCFA in the hindgut was evaluated. Feeding increasing levels of Jerusalem artichoke to entire male pigs reduced skatole in digesta from colon and in faeces (linear, P , 0.01). There was also a tendency towards a decreased level of skatole in adipose tissue (linear, P 5 0.06). Feeding Jerusalem artichoke decreased DM content in colon and faeces and pH in colon (linear, P , 0.01). Increasing levels of Jerusalem artichoke resulted in a reduced level of Clostridium perfringens in both colon and rectum (linear, P , 0.05) and a tendency towards decreased levels of enterobacteria in colon (linear, P 5 0.05). Further, there was an increase in total amount of SCFA (linear, P , 0.05), acetic acid (linear, P , 0.05) and valerianic acid (linear, P , 0.01) in faeces. In conclusion, adding dried Jerusalem artichoke to diets for entire male pigs 1 week before slaughter resulted in a dose-dependent decrease in skatole levels in the hindgut and adipose tissue. The reduced skatole levels might be related to the decrease in C. perfringens and the increase in SCFA with subsequent reduction in pH.

“…The production of skatole greatly depends on the composition of the diet and the intestinal microflora (Jensen et al, 1995;Claus et al, 2003). Important quantities of butyrate are produced when RPS is fermented in the large intestine (Martin et al, 2000;Mentschel and Claus, 2003), which reduces epithelial cell apoptosis . Because tryptophan from cell debris is a substrate for skatole formation, lower skatole tissue and plasma levels can be expected.…”

Section: Discussionmentioning

confidence: 99%

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.