Use of low-cost, non-nutritive adsorbents as intestinal binding agents to sequester the boar taint compound androstenone

Abstract Text: Boar taint is an unpleasant odor and taste detected from pork of some intact males when cooked, caused by high accumulation of the testicular steroid androstenone and the indole skatole. Currently available research exploring dietary approaches to control androstenone is scarce. The objective of this study was to evaluate for the efficacy of binding agents in vivo against androstenone and its impacts on performance in intact male pigs, following up on previous works in vitro. The study aims to capitalize on a hormone-recycling phenomenon which takes place in the gastrointestinal tract of animals, called enterohepatic circulation. Four adsorbents have been assessed for their binding effectiveness against androstenone in our laboratory; these were previously used in studies which successfully mitigated negative effects associated with mycotoxin ingestion in production animals. All additives bound androstenone in high efficacies in vitro, which warranted evaluation of the effectiveness of these binders in swine diets to reduce its levels in plasma and fat. Ninety (n = 90) purebred Duroc boars (123 ± 6 days of age at start of experiment) were equally allocated (n = 18) and fed 1 of 4 diets added with 2% bentonite (BNT), 3.5% diatomaceous earth (DE), 15% spent filter aid (SFA), or 0.7% hydrated sodium-calcium aluminosilicate (HSCAS) for at least 28 days followed by 14 days of recovery. All groups were compared with a control entire male group (n = 18) fed a typical corn-soybean meal finisher diet. Plasma samples and backfat biopsies were collected at days 0, 14, 28, 42, and 56 of trial. Pigs were weighed weekly and calculated for growth performance parameters. Estrone-1-sulfate in plasma was analyzed as a positive control for enterohepatic circulation. Analysis of trends during the treatment period were performed using the PROC MIXED repeated measures procedure in SAS (SAS Institute, Cary, NC, USA). There were no differences in ADG, ADFI, or FCR across diets (P > 0.05) throughout the treatment period. In addition, there were no significant decreases in backfat or plasma androstenone and estrone-1-sulfate across pigs fed treatment diets by day 28 (P > 0.05). However, there was a wide variation in plasma and fat androstenone concentration, which may result from the process of transporting the pigs into a novel environment and mixing. Further research using of crossbred pigs that will not be mixed and/or transported into unfamiliar groups is needed to conclusively evaluate the efficacy of these treatments.

Keywords: boar taint