Influence of supplemental magnesium, tryptophan, vitamin C, and vitamin E on stress responses of pigs to vibration1

Abstract

Our objectives were to investigate and compare the effects of supplemental Mg, Trp, vitamin E (vit E), and vitamin C (vit C) on stress responses of pigs undergoing transport simulation. In this study, 126 pigs (25.1 +/- 4.4 kg BW) were allocated to one of the six following treatments: 1) negative control (no supplementation); 2) positive control (i.m. injection with 0.5 mg of carazolol/20 kg BW 12 h before vibration, beta-blocker); 3) Trp (additional amount of 6 g/kg of feed for 5 d, as-fed basis); 4) Mg (3 g/L drinking water for 2 d); 5) vit E (additional amount of 150 mg/kg of feed for 21 d, as-fed basis); 6) or vit C (additional amount of 300 mg/kg of feed for 21 d, as-fed basis). Pigs were treated in groups of three, and each treatment was replicated seven times. Feed and water intake were not different among treatments. Heart rate variables (mean, peak, and minimum heart rate, ventricular ectopic beats, and ST elevation of Channels A and B) and heart rate variability were registered from the night before vibration. Pigs were subjected to vibration in a transport simulator (8 Hz, 3 m/s) for 2 h and allowed to recover for 2 h. Generally, the positive control pigs had the lowest heart rate values (mean, peak, minimum heart rate, ST elevation of Channel A; P < 0.05), whereas Mg and Trp decreased ventricular ectopic beats and ST elevation of Channel B, respectively. The effect of vit C and E as vagal stimulators was clearly visible, whereas carazolol and Mg clearly blocked the sympathetic pathways of the autonomic nervous system. During vibration, the negative control pigs lay the least, and Mg pigs the most (P < 0.05). Salivary cortisol concentrations (taken before and after vibration and after recovery) showed that vit E pigs produced the least cortisol during stress periods. Intermediary metabolites (glucose, lactate, creatine kinase, and NEFA) were analyzed in plasma from blood taken before and after vibration. At the two sampling points, the vit E and Mg pigs had the lowest NEFA concentrations (P < 0.05), and the vit E pigs also had the lowest lactate concentrations before vibration. Urine samples were collected before and after vibration to determine catecholamine concentrations; only negative control pigs had an increase (P = 0.04) in epinephrine concentration, despite large individual variation. In general, these results indicate that the supplementation of Trp, Mg, vit E, or vit C improved coping ability of pigs during vibration comparison with the negative control treatment. A muscular injection of carazolol influenced only the heart rate variables.

Effects of water supplementation with tryptophan and vitamin B6 or feeding hydrogenated fat on reducing hunger-induced drinking pre-slaughter in pigs

“…While these findings disagree with two studies in which supplemental Trp increased lying behaviour (Peeters et al 2004;Li et al 2006), they are consistent with other studies which have found no influence of Trp supplementation in feed on pig behaviour (Koopmans et al 2005;Peeters et al 2005;Panella-Riera et al 2009). …”

“…This result was explained by the fact that Trp and NEFA share the same carrier, i.e., albumin (Davis et al 2000). However, in other studies, Peeters et al (2004Peeters et al ( , 2005 reported that Trp supplementation had no effect on blood NEFA levels as in the present study. Nevertheless, NEFA content tended to be lower by over 20% (P 00.09) in HF pigs when compared with CONT; this may reflect a lower utilization of body reserves during fasting in these pigs and higher resistance to fasting.…”

The influence of a magnesium-rich marine extract on behaviour, salivary cortisol levels and skin lesions in growing pigs

“…Conversely, supplementation with ractopamine, which increases activity in pigs, is associated with increased oral-nasal behaviour and aggression (Poletto et al, 2010b). A limited number of studies demonstrate welfare benefits probably arising from a reduction in negative behaviours associated with supplementing pig diets with magnesium (Mg) because of what appears to be its 'calming' effect (Kuhn et al, 1981;Peeters et al, 2005 and. Thus, there is the potential for Mg supplementation to also help reduce the performance of negative behaviours.…”

“…Thus, there is the potential for Mg supplementation to also help reduce the performance of negative behaviours. Peeters et al (2005) suggested that Mg supplementation improved the pigs' ability to cope with the stress of vibration by blocking the sympathetic pathways of the autonomic nervous system. Meanwhile, Kietzmann and Jablonski (1985) reported lower plasma corticosteroids, plasma catecholamines and neuromuscular stimulation in pigs supplemented with Mg.…”

Magnesium in the Central Nervous System

“…Notably, exposure to long--term road traffic noise in both children and adults leads to elevated night time secretion of noradrenaline and cortisol when compared to controls (Ising and Braun, 2000). Mg administration is effective in diminishing ototoxicity (Abaamrane et al, 2009;Ehrenberger and Felix, 1995) as well as in alleviating transportation stress (Tang et al, 2008;Peeters et al, 2005). Cold stress also induces a decrease in Mg levels in CSF and raises the incidence of clinical manifestations (Matsui, 2007).…”