Efficacy of non-nutritive sorbent materials as intestinal-binding agents for the control of boar taint

Abstract

In many countries, male pigs are castrated to prevent boar taint, but this practice raises concerns about animal welfare and reduces the production efficiency of pork. The objective of this study was to develop dietary manipulations to prevent boar taint. We evaluated the effectiveness of adding activated carbon (AC) or Tween-60 (Tween; polyoxyethylene sorbitan monostearate) to pig finishing diets to reduce levels of androstenone (AND) and skatole in plasma and fat of entire male pigs. Boars (159 6 2 days of age at the start of the experiment) were fed diets supplemented with either 5% AC or 5% Tween for 28 days followed by either 14 or 28 days of recovery. Plasma samples were collected at experimental days 0, 7, 14, 21, 28, 42 and 56, and backfat biopsies were taken at experimental days 0, 28, 42 and 56. Feeding AC significantly (P , 0.05) reduced the levels of AND in plasma by day 28 compared to day 0 and by day 42 in fat compared to day 0. AC treatment also decreased levels of oestrone sulphate (E 1 S) in plasma by day 7 compared to day 0. Treatment with Tween significantly decreased (P , 0.05) the levels of plasma AND by day 28 from levels at day 0. Tween treatment did not significantly affect levels of fat AND or plasma E 1 S compared to day 0; however, fat AND levels decreased between days 28 and 42 following treatment with Tween (P , 0.05). Levels of plasma E 1 S, plasma AND and fat AND for control boars remained constant throughout the experiment. Skatole plasma concentrations were very low and did not vary significantly (P . 0.05) from day 0 for any treatment, but fat skatole levels decreased by day 42 in the Tween treatment group. Importantly, there was no difference in growth rate between the control and experimental groups. We conclude that adding AC or Tween to finishing diets for boars can reduce the levels of plasma and fat AND, but further work is needed to confirm the effects of these treatments on reducing fat skatole levels.

Pork Production with Entire Males: Directions for Control of Boar Taint

“…Steroids can then be reabsorbed across the intestinal wall, which enables the recycling of these steroids in a process known as the enterohepatic circulation [36]. We have proposed interrupting the enterohepatic circulation as a potential approach to decreasing boar taint from androstenone [37].…”

“…The role of the enterohepatic circulation in regulating androstenone levels is not completely understood. Proof-of-concept studies have shown that adding activated charcoal to finishing diets can decrease androstenone levels [37], but the mechanism of the enterohepatic circulation of androstenone has not been described. There is also a need to find cost effective and selective adsorbents for androstenone that can be added to finishing diets of entire males.…”

“…They can then undergo subsequent deconjugation by the gut microflora and be reabsorbed back into the body via the enterohepatic circulation. We have proposed decreasing androstenone levels by adding non-nutritive sorbent materials to finishing diets, which can bind to androstenone in the gut and prevent its reuptake [37]. In a pilot study, activated charcoal supplemented in the feed effectively decreased fat androstenone concentrations to below threshold values for boar taint [37].…”

“…We have proposed decreasing androstenone levels by adding non-nutritive sorbent materials to finishing diets, which can bind to androstenone in the gut and prevent its reuptake [37]. In a pilot study, activated charcoal supplemented in the feed effectively decreased fat androstenone concentrations to below threshold values for boar taint [37]. This is a promising approach, but further detailed studies are needed to determine the mechanism and assess the efficacy of this technology under commercial production conditions.…”

Effect of Supplementing Hydrolysable Tannins to a Grower–Finisher Diet Containing Divergent PUFA Levels on Growth Performance, Boar Taint Levels in Back Fat and Intestinal Microbiota of Entire Males

“…Until recently, no evidence had suggested that A tissue concentration was affected by nutrition [7]. However, Jen and Squires [8] found that the EMs fed with activated carbon for 28 days in the finishing period had lower plasma as well as tissue A levels compared to a control group. The authors hypothesized that A, like oestadriol, undergoes enterohepatic circulation [9], and activated carbon could act as an absorbent, thereby diminishing A tissue levels.…”