Effect of whole-body vibration in the vertical axis on cortisol and adrenocorticotropic hormone levels in piglets.

Vibration, being a consequence of motion during transport, may impair the welfare of pigs. Therefore, the primary objectives of this study were 1) to evaluate during transport simulation the use of ACTH and cortisol plasma levels, which are part of a basic adaptation mechanism of pigs and 2) to define comfort conditions for pigs related to the frequency and acceleration of vibration. Pigs with a body weight between 20 and 25 kg were vibrated in the vertical direction for 2 h at 2, 4, 8, and 18 Hz, in combination with root mean square acceleration magnitudes of 1 or 3 m/s2. Blood was sampled at regular intervals before, during, and after vibration as the pig's behaviors were recorded. Data on ACTH, cortisol, and behavior could be collected from 104 vibrated pigs and 21 controls. In addition, eight animals (3 controls, 5 vibrated) were treated with 0.1 mg of dexamethasone/kg BW, eight animals (3 controls, 8 vibrated) with 0.1 mg naloxone/kg BW, and six (2 controls, 4 vibrated) with a physiological salt solution. Blood samples were taken and products were administrated via an intravenous catheter. The pigs spent less time lying during both hours of vibration treatment than during control conditions. Compared with 2 and 4 Hz, time spent lying was 10 times shorter at 8 Hz and 18 times shorter at 18 Hz. At 1030, ACTH levels were significantly higher than basal levels in animals vibrated at 2 (P < 0.0001), 4 (P < 0.002), and 18 Hz (P < 0.0006). After 1 h, levels returned to basal values. Cortisol levels increased very rapidly after the beginning of vibration (P < 0.0001) and remained higher until 1 h after cessation of vibration (P < 0.003). An inferrence of the lines of equal responses for ACTH and cortisol indicated that, in the beginning of vibration exposure, pigs were extremely susceptible to vibrations at lower frequencies (2 and 4 Hz), whereas at the end of vibration exposure the responses were higher at 18 Hz. The application of dexamethasone and naloxone underpinned the emotional component of the response strategy of pigs to vibration. Hence, vibration during transport should be minimized in order to enhance the adaptive capacities of pigs.

Influence of vertical vibration on heart rate of pigs.

Pigs with a body weight between 15 and 20 kg were vibrated in the vertical direction for 1 h at 2, 8, and 18 Hz, in combination with root mean square (RMS) acceleration magnitudes of 1 or 3 m/s2. Welfare and stress were quantified by comparing heart rate characteristics during a control period (2200 to 0600) before vibration exposure and during vibration (1000 to 1100). The level of maximum heart rate and number of ventricular ectopic beats during vibration at 2 and 8 Hz in combination with a RMS acceleration of 3 m/s2 indicated a larger fear response than at 1 m/s2. Isocomfort contours based on mean heart rate during vibration showed the greatest specific sensitivity of the pigs to vibration at a frequency of 8 and 18 Hz, especially in combination with a RMS acceleration of 3 m/s2. During transport, RMS acceleration should be less than 3 m/s2 to protect pigs' welfare. Pigs were more sensitive to acceleration than to frequencies within the range of treatments in this investigation. Although the response of the pigs in this experiment fit within the model concept for adult humans and for domestic fowl, changes in heart rate are dependent on body weight.

An evaluation of ultrasound and nuclear magnetic resonance spectroscopy to measure in vivo intramuscular fat content of longissimus muscle of pigs.

Intramuscular fat content (IMF) of longissimus muscle of pigs growing from approximately 20 to 100 kg was measured in vivo using biopsies after complete or localized anaesthesia, ultrasound and 1H nuclear magnetic resonance (NMR) technology. Three lines of pigs, with 60 animals each, were available. Biopsies were taken from the same pigs at 20, 60, and 100 kg, and fat was extracted for gravimetric determination. At 20 kg, ultrasound images were collected, and in vivo 1H NMR spectroscopy was applied. A-mode ultrasound measurements were collected at 60 and 100 kg. The overall mean value of IMF was 1.60 +/- .56% at 20 kg, 1.53 +/- .50% at 60 kg, and 1.71 +/- .60% at 100 kg. Interactions between lines and body weight were observed. No statistically significant differences were found between methods at 20 kg. No significant correlations were found between the A-mode ultrasound measurements and the mean values of the gravimetric measurements. No visible pain or infections were observed in relation to the collection of a single biopsy. The ultrasound method in combination with image analysis is advantageous from the labor point of view and will also improve welfare of pigs in case of repeated sampling. However, further research is necessary to make the technology sufficiently reliable. A correlation between IMF and backfat thickness was not found.

Determination of phospholipid content of intramuscular fat by Fourier Transform Infrared spectroscopy.

A method has been developed to determine the phospholipid content in fat extract with FTIR (Fourier Transform Infrared). l-α-Phosphatidylcholine from egg yolk in hexane solution was used as a reference for band identification at different concentrations. Phosphate bands were determined at different wavenumbers as described in the literature. A dilution series was made from meat extract and from 1-α-phosphatidylcholine. A linear calibration curve was obtained between the FTIR-results and the Iatroscan results, which were used as a reference. The band between 1282 cm(-1) and 1020 cm(-1) can be used for determination of phospholipid content.