Effects of L-DOPA Supplementation on Concentrations of Brain Catechols, Dopamine Receptor Binding and the Incidence of Pale, Soft and Exudative Meat in Stress-Suspectible Pigs

Abstract

The purpose of this research was to determine if chronic dietary L-DOPA supplementation will alter differentially the brain catechol concentrations, dopamine receptor binding (KD and Bmax) and the incidence of pale, soft and exudative (PSE) meat in stress-susceptible (SS) and stress-resistant (SR) pigs. Stress-susceptible and SR pigs were assigned randomly to these four groups: SS pigs as controls, SR pigs as controls, SS pigs with L-DOPA supplementation and SR pigs with L-DOPA supplementation. The experiment began when pigs weighed 23 kg and terminated when pigs weighed 95 kg. Anatomical brain structures removed at slaughter included hypothalamus, thalamus, cortex, cerebellum, olfactory bulb, caudate nucleus, putamen and substantia nigra. Concentrations of norepinephrine and dopamine were greater in the hypothalami of SS than of SR control pigs. The L-DOPA supplementation eliminated the strain differences of brain catecholamine concentrations. Pigs fed L-DOPA had greater concentrations of dihydroxyphenylacetic acid in six of the eight brain regions analyzed than the controls. Dopamine receptor binding (Bmax and KD) of spiroperidol was similar in all four groups of pigs. Pale, soft and exudative pork developed to the same extent in SS pigs with or without L-DOPA treatment. The results suggest that L-DOPA supplementation eliminates strain differences in brain catecholamine concentrations but does not alter PSE meat development or striatal dopamine receptor binding.

The Effect of Acute Restraint Stress on Regional Brain Neurotransmitter Levels in Stress‐Susceptible Pietrain Pigs

“…In the hypothalamus, the concentrations of NA were lower in stress-susceptible Pietrain pigs than in stress-resistant Duroc pigs (Piekarzewska et al, 1999) or in Pietrain-Poland-China crosses (nn) which were also electrically stunned (Adeola et al, 1993). These results are at variance with those reported by Erlander et al (1985), where stress-susceptible Landrace-Large White crossbred pigs were killed by the same method and had a higher concentration of hypothalamic NA than did stress-tolerant Landrace-Large White crossbred pigs. The levels of NA and A of in the hypothalamus of Pietrain pigs were higher than those in the dog or rat.…”

“…Pigs are immobilized by taping all four feet to padded supports fixed to a metal frame. Our method of killing pigs was the same as that of Adeola et al (1993) and Erlander et al (1985), who also performed experiments on pigs.…”

Genetic differences in brain monoamines level in Pietrain and Duroc pigs exposed to acute restraint stress

“…On the contrary, they also include some physiological components such as muscle fatigue or positional cramping, which make them more complex. As it was stated before ( Piekarzewska et al 2000), we utilized the procedure of immobilization as well as the method of pig killing established by others ( Kvetnansky and Mikulaj 1970; Erlander et al 1985; Adeola et al 1993). Few studies have been made on changes in catecholamine and NE metabolite levels caused by acute stress in an extended number of brain regions.…”

Semi‐micro liquid chromatography of aromatic amino acid metabolites using isocratic elution and Column switching

“…This new system was tested for the analysis of catecholamine-related compounds in the pig brain, as pigs are a common animal model used for transgenic manipulation of neural genes (Erlander et al, 1985; Agarwal et al, 1993;Leshin et al, 1996;Danielsen et al, 2000;Cumming et al, 2001). Samples of 350 mg of fresh pig brain obtained from Tokyo Shibaura Zoki (Tokyo, Japan) were homogenized with 2.0 mL of 1.0 M HClO 4 .…”