Eating Quality of Pork from Entire Male Pigs after Dietary Supplementation with Hydrolysable Tannins

Simple Summary The European pig industry needs to adapt to growing social interest regarding animal welfare. One of these concerns is the surgical castration of male piglets-a common practice primarily performed to avoid the risk of boar taint released from the meat of uncastrated males, especially during heat treatment. Several EU countries are trying to stop the surgical castration of pigs. The European Commission (EC) strongly supports these activities. One of the two currently feasible alternatives to the production of castrates is the fattening of entire male pigs. It is well known that skatole, one of two main compounds responsible for boar taint, can be eliminated or reduced by feeding additives. Recently, some promising results have been achieved using hydrolysable tannins in the diet of entire males. However, it should be mentioned that these studies focused on the influence of tannins on fattening, carcass value, meat quality and the deposition of androstenone and skatole in adipose tissue but not their influence on sensory characteristics. Therefore, the objective of this study was, in addition to determining the effects of tannins on skatole and androstenone accumulation in fatty tissue, to assess the sensory attributes of pork from entire males after supplementation of the diet with 1-4% tannins. The results showed that 2-4% supplementation of tannins in the feed reduced the accumulation of skatole in fatty tissue. The odour and flavour of pork were not influenced by tannin supplementation, but higher doses of tannins decreased the juiciness and tenderness of pork from entire males but only in men's evaluation. The effect of the sex of the panellists on both of these sensory traits was observed in both the control and tannin-supplemented groups. Boar taint is an unpleasant odour and flavour released during heat treatment of pork from uncastrated male pigs. The two main compounds responsible for boar taint are androstenone and skatole. Androstenone is a steroid hormone formed in the testis during sexual maturity. Skatole is a product of microbial degradation of the amino acid tryptophan in the hindgut of pigs. Both of these compounds are lipophilic, which means that they can be deposited in adipose tissue. Several studies have reported heritability estimates for their deposition from medium (skatole) to high magnitudes (androstenone). In addition to efforts to influence boar taint through genetic selection, much attention has also been paid to reducing its incidence using various feeding strategies. From this point of view, research has focused especially on the reduction in skatole content by supplementation of feed additives into the nutrition of entire male pigs. Promising results have been achieved using hydrolysable tannins in the diet. To date, most studies have investigated the effects of tannins on the production and accumulation of skatole in adipose tissue, intestinal microbiota, growth rate, carcasses and pork quality. Thus, the objective of this study was, in addition to determining the effects of tannins on androstenone and skatole accumulation, to assess the effects of tannins on the sensory traits of meat from entire males. The experiment was performed on 80 young boars-progeny of several hybrid sire lines. Animals were randomly assigned to one control and four experimental groups (each numbering 16). The control group (T0) received a standard diet without any tannin supplementation. Experimental groups were supplemented with 1% (T1), 2% (T2), 3% (T3) or 4% (T4) SCWE (sweet chestnut wood extract) rich in hydrolysable tannins (Farmatan). Pigs received this supplement for 40 days prior to slaughter. Subsequently, the pigs were slaughtered, and sensory analysis was applied to evaluate the odour, flavour, tenderness and juiciness of the pork. The results showed a significant effect of tannins on skatole accumulation in adipose tissue (p = 0.052-0.055). The odour and flavour of the pork were not affected by tannins. However, juiciness and tenderness were reduced by higher tannin supplementation (T3-T4) compared to the controls (p < 0.05), but these results were sex-dependent (in favour of men compared to women). Generally, women rated tenderness and juiciness worse than men regardless of the type of diet.