Influence of type and dietary rate of inclusion of non-starch polysaccharides on skatole content and meat quality of finishing pigs

Abstract

Abstract The effect of feeding different sources of dietary fibre at varying rates of inclusion on the concentrations of skatole and indole in the backfat of finishing pigs and their subsequent carcass quality was studied. Sugar-beet pulp (SBP) and straw (S) were selected because of their assumed widely differing hind-gut fermentability characteristics. They were individually and in combination added to a diet at three rates of inclusion designed to provide concentrations of 40, 80 and 120 g non-starch polysaccharide (NSP) per kg. The digestible energy (DE) contents varied between the three levels of inclusion of NSP but were formulated to a lysine: energy ratio of 0.625 g: MJ DE with other amino acids being in the same individual proportion to lysine. The nine experimental diets were offered to 10 replicate (five entire males and five females) pigs of initial live weight 55 kg. Food intakes were adjusted between treatment to ensure that energy and nutrient intakes were common. Animals were slaughtered on reaching 85 kg live weight. Adipose tissue was analysed for skatole and indole and meat quality characteristics assessed. No significant differences in performance were detected although carcasses from animals given sugar-beet pulp were significantly fatter. There were significant correlations between the level of skatole in the backfat and the following eating quality characteristics: skatole odour intensity of the fat, abnormal odour intensity of fat, abnormal odour intensity of lean and abnormal flavour intensity of lean with correlations coefficients of 0·656 , 0·709 , 0·496 and 0·523 respectively (coefficients >0.276; P < 0·05). The range in skatole levels in the backfat were attributable substantially to very high levels found in three boars. No significant correlations were found between indole concentrations in the backfat and eating quality characteristics. However no effects of dietary NSP type or inclusion level on the eating quality characteristics of pig meat, with pigs given diets on the basis of equal energy and nutrient intakes, were detected.