Comparative toxicity of selenium from seleno-DL-methionine, sodium selenate, and Astragalus bisulcatus in pigs.
Selenium is an essential micronutrient, although ingestion in excess in pigs can cause disease conditions including neurological dysfunction and chronic skin and hoof lesions. Controlled feeding trials in growing swine, using the same Se content in feed sources, resulted in higher concentrations (p < or = 0.05) of Se in blood and organs of pigs fed seleno-DL-methionine compared with those receiving Astragalus bisulcatus or sodium selenate. Clinical signs of Se toxicity including neurological signs of paralysis were more severe and occurred sooner in the A. bisulcatus group than in the sodium selenate or seleno-DL-methionine groups. All five pigs fed A. bisulcatus developed neurological signs of paralysis, and in four the signs occurred within 5 days of the start of treatment. Four of five pigs fed sodium selenate also developed paralysis, but this occurred 4 to 21 days after treatment began. The fifth pig in the group developed signs of chronic selenosis. Two of five pigs fed seleno-DL-methionine developed paralysis on 9 and 24 days, respectively, and the remaining three developed chronic selenosis. Selenium fed to pigs in three forms [plant (A. bisulcatus), sodium selenate, or seleno-DL-methionine] resulted in neurological dysfunction and lesions of symmetrical poliomyelomalacia. These were most severe in the A. bisulcatus group, which also had polioencephalomalacia. Although seleno-DL-methionine caused the greater increase in tissue and blood Se concentrations, this did not correlate with severity of pathological changes, since animals fed A. bisulcatus developed more severe and disseminated lesions.
Panter
K E
KE
USDA-ARS Poisonous Plant Research Laboratory, Logan, Utah 84341, USA.
Hartley
W J
WJ
James
L F
LF
Mayland
H F
HF
Stegelmeier
B L
BL
Kechele
P O
PO
D000821:Animal Feed; D000818:Animals; D002493:Central Nervous System Diseases / Q000139:chemically induced; D005183:Failure to Thrive / Q000139:chemically induced; D010944:Plants / Q000737:chemistry*; D064586:Selenic Acid; D012643:Selenium / Q000097:blood / Q000633:toxicity*; D018036:Selenium Compounds / Q000633:toxicity*; D012645:Selenomethionine / Q000633:toxicity*; D013552:Swine
D018036:Selenium Compounds; D012645:Selenomethionine; D012643:Selenium; D064586:Selenic Acid