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

Abstract

Growing pigs can display undesirable behaviours, reflecting or causing poor welfare. Addition of magnesium (Mg) to the diet could reduce these, as Mg supplementation has been associated with improved coping ability in response to stress. This study examined the effect of supplementation with a Mg-rich marine extract-based product (Supplement) on the behaviour, skin and tail lesion scores and salivary cortisol concentrations of growing pigs. At weaning (28 days), 448 piglets were assigned to either Control or Supplement (0.05%) diets in single-sex groups of 14. Four weeks later (c. 17 kg), pigs were blocked according to weight and back test scores. Seven piglets from each pen were mixed with seven from another pen of the same sex and dietary treatment to yield the following groups: control male, Supplement male, control female and Supplement female (n 5 4 of each). This marked the start of the 9-week experimental period. Instances of the following behaviours were recorded in each pen for 8 3 2 min periods 1 day/week: aggression (fight, head-knock and bite); harmful (tail-in-mouth, ear-chewing and belly-nosing); and sexual/ mounting behaviour. Four focal pigs were selected from each pen, and their behaviour was continuously recorded for 2 3 5 min periods on the same day. Saliva was collected once per week at 1000 h by allowing pigs to chew on a cotton bud for c. 1 min. Salivary cortisol was analysed in duplicate by an enzyme immunoassay. Skin and tail lesions were scored according to severity 1 day/week. There were fewer aggressive incidents in Supplement pens ( P , 0.01), and mounting behaviour (performed only by males) was almost three times lower in Supplement than in control pens ( P , 0.01). However, there was no effect of Supplement on the incidence of each of the harmful behaviours. Behaviour of the focal pigs showed no treatment effect on the duration or incidence of aggressive behaviour. However, Supplement pigs spent less time performing harmful behaviours compared with control pigs ( P , 0.001). Supplement had no effect on the occurrence or severity of tail-biting outbreaks or on tail lesion scores. However, Supplement females had lower skin lesion scores, in particular in the ears and shoulders ( P , 0.01). Finally, Supplement pigs had lower salivary cortisol concentrations ( P , 0.01). Mounting is a major welfare concern in uncastrated pigs, and therefore this represents an important welfare benefit of Supplement. Reduced salivary cortisol, in conjunction with reduced skin lesion scores in supplemented females, suggests that addition of a Mg-rich marine extract improved pig welfare in this system.

Effects of tail docking and/or teeth clipping on behavior, lesions, and physiological indicators of sows and their piglets

“…Previous studies have shown that skin lesion scores were related to the aggressive behavior in pigs (O'Driscoll et al, ). Aggressive behavior reduced gradually after the teat order had been established (Skok & Skorjanc, ).…”

“…Welfare of pigs can be assessed by physiological and behavioral indicators, such as heart rate (von Borell et al, ), body temperature (Soerensen & Pedersen, ), serum immunoglobulin and cytokine (Torrey et al, ), lesions on the body and tail of pigs (O'Driscoll, O'Gorman, Taylor, & Boyle, ; Teixeira & Boyle, ), lesions on the teats of sows (Gallois, Cozler, & Prunier, ), and positive and negative social behaviors (Welfare Quality, ).…”

Analysis of serum magnesium ions in dogs exposed to external stress: A pilot study

“…Further experiments with more dogs must take place; however, the variation of serum Mg 2+ levels of dogs may become one of biomarkers that reflect physical status of dogs. Previous research has shown that pigs became healthier after administration of the Mg 2+ supplement (O'Driscoll et al, 2013). Supplementation of Mg 2+ in healthy dogs with vigorous exercise or training regimes must be discussed for animal welfare.…”

Pituitary-Gonadal, Pituitary-Adrenocortical Hormones and IL-6 Levels Following Long-Term Magnesium Supplementation in Male Students

“…On the other hand, subchronic supplementation with Mg in elderly subjects reduced cortisol concentration without a change in ACTH level (21). Furthermore, in the study on pigs where a Mg-rich marine extract-based supplement was added for four weeks, O'Driscoll et al (22) showed that supplemented pigs had significantly lower salivary cortisol accompanied with reduction in aggressive behavior. On the contrary, Cinar et al (23) showed an increase in ACTH after one-month-long supplementation with magnesium.…”