80 Biochar as a broadly applicable dietary treatment for the prevention of boar taint.

Abstract Boar taint is a meat quality issue of off-odour and flavour in heated pork products from intact male pigs, due to the accumulation of androstenone and skatole in the fat. There are many physiological pathways that contribute to boar taint development, depending on the age, genetics and environment of the animal. Maturity status may also influence boar taint development and is assessed through plasma estrone sulfate (E1S) levels. Our previous work showed that a 5% inclusion of biochar in the diet will prevent boar taint in a subset of slaughter weight boars, but it is unclear if this treatment is broadly applicable across genetic lines. Therefore, the objective was to compare the success of biochar treatment in two genetic lines of boars and assess if treatment response relates to maturity status. This was done using (n=17) Alliance Genetics Canada (AGC) boars and (n=52) Pig Improvement Company (PIC) boars, all of which were 3-way [(Yorkshire x Landrace) x Duroc] cross boars at a starting weight of 73.20 ± 1.19 kg. All animals were fed a 5% biochar diet for a 4-week treatment period, followed by a 2-week recovery period on a standard finisher diet. Plasma samples were collected weekly to assess maturity status through an E1S radioimmunoassay. Backfat biopsies were performed bi-weekly and used to quantify fat androstenone using an androstenone-specific enzyme-linked immunosorbent assay. Repeated-measures 2-way ANOVAs were performed using SAS to evaluate changes in androstenone levels and maturity status over the trial and to compare results between the two genetic lines. We identified three distinct boar taint phenotypes, low boar taint animals that do not require treatment, high boar taint boars that respond positively to treatment, and high boar taint boars that do not respond to treatment. 47% of AGC boars had low boar taint, compared to 71% in the PIC line. In high boar taint animals treated with biochar, 90% of AGC boars and 67% of PIC boars responded to treatment. In positive responders, the concentration of fat androstenone was similar between both genetic lines at all time points during the trial (p >0.05). Maturity status within the three boar taint phenotypes was examined in both genetic lines (Figure 1). Early maturing boars were identified in all three boar taint phenotypes, while late maturing boars either had low boar taint or responded positively to biochar treatment. These findings suggest that biochar treatment is a broadly applicable treatment for boar taint, as it is similarly effective in two genetic lines. Additionally, the response to biochar treatment is affected by maturity status, which may help to identify animals that respond favourably to biochar treatment and allow for the administration of biochar treatment in a targeted manner.