Fig. 1
Fig. 2
Fig. 3
HPLC gradient
| Time (min) | Flow (mL min−1) | Eluent A (%) | Eluent B (%) |
|---|---|---|---|
| 0.01 | 0.35 | 40 | 60 |
| 2.00 | 0.35 | 60 | 40 |
| 3.00 | 0.35 | 90 | 10 |
| 3.99 | 0.35 | 90 | 10 |
| 4.00 | 0.45 | 90 | 10 |
| 6.00 | 0.45 | 100 | 0 |
| 7.00 | 0.45 | 100 | 0 |
| 7.01 | 0.35 | 100 | 0 |
| 7.10 | 0.35 | 40 | 60 |
| 10.00 | 0.35 | 40 | 60 |
Results of studies on compounds responsible for boar taint in fat samples taken from gilts, surgically and immunologically castrated boars
| Gilts | Skatole | Indole | Androstenone |
|---|---|---|---|
| Number of samples tested (n) | 15 | 15 | 15 |
| Number of analyte-containing samples | 7 | 11 | 0 |
| C average (μg L−1) | 65.2 | 25.3 | |
| SD (μg L−1) | 8.0 | 40.9 | |
| C min-max (μg L−1) | 57.7–78.3 | 5.4–146.5 | |
| IMC boars | |||
| Number of samples tested (n) | 15 | 15 | 15 |
| Number of analyte-containing samples | 10 | 11 | 0 |
| C average (μg L−1) | 60.3 | 15.6 | |
| SD (μg L−1) | 5.8 | 8.8 | |
| C min-max (μg L−1) | 51.3–69.2 | 5.5–30.0 | |
| SC boars | |||
| Number of samples tested (n) | 15 | 15 | 15 |
| Number of analyte-containing samples | 7 | 9 | 0 |
| C average (μg L−1) | 60.3 | 18.4 | |
| SD (μg L−1) | 5.1 | 9.0 | |
| C min-max (μg L−1) | 54.0–67.5 | 5.2–35.2 | |
LC-MS/MS parameters (MRM) used for identification of indole, skatole and androstenone
| Analyte | Structure | MRM (mass-to-charge (m/z)) | Collision energy (eV) |
|---|---|---|---|
| Indole (2,3-benzopyrrole) | 118.0 > 91.1 | 23 | |
| 118.0 > 65.0 | 33 | ||
| 118.0 > 39.1 | 47 | ||
| Skatole (3-methylindole) | 132.5 > 117.1 | 22 | |
| 132.5 > 89.0 | 41 | ||
| 132.5 > 90.2 | 33 | ||
| 2-methylindole (IS) | 132.5 > 117.2 | 23 | |
| 132.5 > 89.1 | 41 | ||
| 132.5 > 90.0 | 34 | ||
| Androstenone | 273.5 > 255.3 | 13 | |
| 273.5 > 93.2 | 26 | ||
| 273.5 > 77.2 | 25 | ||
| Testosterone-d2 (IS) | 291.2 > 111.1 | 26 | |
| 291.2 > 99.2 | 24 | ||
| IS – internal standard | |||
LC-MS/MS method validation parameters for indole, skatole and androstenone in swine oral fluid and fat
| Parameter | Indole | Skatole | Androstenone | |
|---|---|---|---|---|
| Oral fluid | ||||
| Calibration curves | correlation coefficient | 0.9990 | 0.9988 | 0.9967 |
| Matrix calibration curves | correlation coefficient | 0.9980 | 0.9964 | 0.9859 |
| Limit of quantification | LOQ (μg L−1) | 5 | 50 | 50 |
| Repeatability | C.V. (%) | 28.20 | 30.0 | 24.4 |
| Recovery | (%) | 75.4 | 70.0 | 95.3 |
| Matrix effect | % | 10 | 11 | 30 |
| Fat | ||||
| Calibration curves | correlation coefficient | 0.9988 | 0.9989 | 0.9953 |
| Matrix calibration curves | correlation coefficient | 0.9968 | 0.9875 | 0.9840 |
| Limit of quantification | LOQ (μg L−1) | 5 | 50 | 100 |
| Repeatability | C.V. (%) | 5.0 | 32.9 | 26.3 |
| Recovery | (%) | 121.0 | 70.0 | 102.8 |
| Matrix effect | % | 75.6 | 82 | 27 |
Results of tests of pooled oral fluid samples taken from animals from four experimental groups each consisting of 14 animals
| Sampling time | Skatole | Indole | Androstenone |
|---|---|---|---|
| Gilts (control groups for IMC boars) | (μg L−1) | (μg L−1) | (μg L−1) |
| Before giving Improvac to the boars | - | - | - |
| Two weeks after the first boar immunisation with Improvac (pen 1) | - | - | - |
| Two weeks after the first boar immunisation with Improvac (pen 2) | - | - | - |
| Two weeks after the second immunisation with Improvac before slaughter | |||
| Pen 1 | 309.4 | - | - |
| Pen 2 | - | - | - |
| Pen 3 | 106.3 | - | - |
| Pen 4 | 136.4 | 38.6 | - |
| Immunologically castrated boars (IMC) | |||
| Before giving Improvac | 82.5 | - | - |
| Two weeks after the first immunisation with Improvac (pen 1) | - | - | - |
| Two weeks after the first immunisation with Improvac (pen 2) | - | - | - |
| Two weeks after the second immunisation with Improvac, before slaughter | - | - | - |
| Surgically castrated boars (SC) – samples taken before slaughter | |||
| Pen 1 | - | 23.8 | - |
| Pen 2 | 69.7 | 12.2 | - |
| Pen 3 | - | - | - |
| Pen 4 | - | 86.1 | - |
| Gilts and boars (SC), 50/50 – samples taken before slaughter | |||
| Pen 1 | 153.1 | 48.9 | - |
| Pen 2 | - | - | - |
| Pen 3 | - | 125.4 | - |
| Pen 4 | - | - | - |