|Myers, Michael - FDA|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 16, 1997
Publication Date: N/A
Interpretive Summary: Control pigs and those treated with porcine somatotropin (PST) from 20 to 60 kg body weight were i.v. injected with bacterially- derived lipopolysaccharide (LPS), an endotoxin, for 7 consecutive days to see how they would react to an induced septicemia, or induced disease state. During the seven days of LPS injections, daily liveweight gain and feed:gain did not differ between the treatment groups, although feed efficiency was impaired and quite variable. Rectal temperatures taken 3 hrs after LPS and PST treatments were progressively elevated with the LPS-treated group higher than the controls, and the LPS-PST combined treatment higher than those pigs treated with LPS alone. Fat stores were significantly reduced after LPS treatment in the PST-treated pigs. These results suggest that LPS induced a simulated septicemia whose effects were not negated by PST treatment.
Technical Abstract: Crossbred barrows were restrictively-fed starting at 20 kg. Treatments were: 1. daily i.m. buffer-injected controls; 2. daily i.m. injected with 100 g recombinant porcine somatotropin (PST)/kg BW, both groups treated until 55 kg; 3. i.v. saline- injected for seven consecutive days starting at 60 kg BW; 4. i.v. injected for seven days with 1 g bacterial lipopolysaccharide (LPS)/kg BW at 60 kg; and 5. the combined LPS + PST treatment. Pigs evaluated for LPS effects were fed to 60 kg anticipating a weight loss. Pigs were bled at 0800 and 1100 at 55 kg and on day seven of LPS treatment. Rectal temperatures were taken on day seven. Treatment with PST increased ADG by 13 to 20% and improved feed:gain by 17 to 23% prior to LPS treatment. During the seven days of LPS injections, ADG and feed:gain did not differ between the treatment groups, although feed efficiency was impaired and quite variable. Rectal temperatures at 1100 were progressively elevated: Cont < LPS < LPS-PST. Protein accretion was improved 27% by PST treatment while lipid accretion was decreased 45% prior to LPS. Lipid stores were significantly decreased after LPS treatment in the PST-treated pigs. LPS treatment and(or) lowered feed intake reduced the hyperinsulinemia and hyperglycemia associated with PST treatment. These results suggest that LPS induced a simulated septicemia whose effects were not negated by PST treatment.