title: Hydrolysable tannin-based diet rich in gallotannins has a minimal impact on pig performance but significantly reduces salivary and bulbourethral gland size.
abstract: Tannins have long been considered 'anti-nutritional' factors in monogastric nutrition, shown to reduce feed intake and palatability. However, recent studies revealed that compared with condensed tannins, hydrolysable tannins (HT) appear to have far less impact on growth performance, but may be inhibitory to the total activity of caecal bacteria. This in turn could reduce microbial synthesis of skatole and indole in the hindgut of entire male pigs (EM). Thus, the objective of this study was to determine the impact of a group of dietary HT on growth performance, carcass traits and boar taint compounds of group housed EM. For the study, 36 Swiss Large White boars were assigned within litter to three treatment groups. Boars were offered ad libitum one of three finisher diets supplemented with 0 (C), 15 (T15) or 30 g/kg (T30) of HT from day 105 to 165 of age. Growth performance, carcass characteristics, boar taint compounds in the adipose tissue and cytochrome P450 (CYP) isoenzymes CYP2E1, CYP1A2 and CYP2A19 gene expression in the liver was assessed. Compared with C, feed efficiency but not daily gain and daily feed intake was lower (P<0.05) in T15 and T30 boars. Except for the percentage carcass weight loss during cooling, which tended (P<0.10) to be greater in T30 than C and T15, carcass characteristics were not affected by the diets. In line with the numerically lower androstenone level, bulbourethral and salivary glands of T30 boars were lighter (P<0.05) than of T15 with intermediate values for C. Indole level was lower (P<0.05) in the adipose tissue of T30 than C pigs with intermediate levels in T15. Skatole levels tended (P<0.10) to be lower in T30 and C than T15 pigs. Hepatic gene expression of CYP isoenzymes did not differ between-treatment groups, but was negatively correlated (P<0.05) with androstenone (CYP2E1 and CYP1A2), skatole (CYP2E1, CYP2A) and indole (CYP2A) level. In line with the numerically highest androstenone and skatole concentrations, boar taint odour but not flavour was detected by the panellists in loins from T15 compared with loins from C and T30 boars. These results provide evidence that HT affected metabolism of indolic compounds and androstenone and that they affected the development of accessory sex glands. However, the effects were too small to be detected by sensory evaluation.
authors.affiliation: 1Agroscope Posieux,Tiolyere 4,1725 Posieux,Switzerland.
authors.forename: G
authors.initials: G
authors.lastname: Bee
authors.affiliation: 1Agroscope Posieux,Tiolyere 4,1725 Posieux,Switzerland.
authors.forename: P
authors.initials: P
authors.lastname: Silacci
authors.affiliation: 1Agroscope Posieux,Tiolyere 4,1725 Posieux,Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Ampuero-Kragten
authors.affiliation: 2Agricultural Institute of Slovenia,Hacquetova ulica 17,1000 Ljubljana,Slovenia.
authors.forename: M
authors.initials: M
authors.lastname: Čandek-Potokar
authors.affiliation: 1Agroscope Posieux,Tiolyere 4,1725 Posieux,Switzerland.
authors.forename: A L
authors.initials: AL
authors.lastname: Wealleans
authors.affiliation: 3Department of Agriculture,University of Reading,Reading RG6 6AR,UK.
authors.forename: J
authors.initials: J
authors.lastname: Litten-Brown
authors.affiliation: 4Department of Chemistry,University of Turku,20500 Turku,Finland.
authors.forename: J-P
authors.initials: JP
authors.lastname: Salminen
authors.affiliation: 3Department of Agriculture,University of Reading,Reading RG6 6AR,UK.
authors.forename: I
authors.initials: I
authors.lastname: Mueller-Harvey
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000736:Androstenes / Q000378:metabolism; D000818:Animals; D002030:Bulbourethral Glands / Q000187:drug effects / Q000254:growth & development*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004032:Diet / Q000662:veterinary; D047348:Hydrolyzable Tannins / Q000378:metabolism*; D007211:Indoles / Q000032:analysis; D008297:Male; D009812:Odorants / Q000032:analysis; D010641:Phenotype; D000069466:Red Meat / Q000032:analysis*; D012469:Salivary Glands / Q000187:drug effects / Q000254:growth & development*; D012862:Skatole / Q000378:metabolism; D013552:Swine / Q000254:growth & development / Q000502:physiology*
chemical_list: D000736:Androstenes; D047348:Hydrolyzable Tannins; D007211:Indoles; C000214:androst-16-en-3-one; C030374:indole; D003577:Cytochrome P-450 Enzyme System; D012862:Skatole
keywords: boar taint; growth performance; meat quality; pigs; tannins