Dietary protein and chromium tripicolinate in Suffolk wether lambs: effects on production characteristics, metabolic and hormonal responses, and immune status.
Thirty-two Suffolk wether lambs were fed for 84 d in a 2 x 2 factorial experiment using two levels of dietary protein (9.0 to 12.1% CP, low protein, LP; or 12.8 to 14.4% CP, high protein, HP) and supplemental Cr (none, C; or 400 ppb Cr as chromium tripicolinate, Cr). At 14- to 21-d intervals, lambs were weighed, and jugular blood samples were collected. Mean ADG and carcass weight (P > .10) did not differ. In lambs fed HP, Cr reduced liver weight and increased kidney weight (P < .01). Lambs fed HP had elevated plasma urea N (PUN; P < .01) and albumin (P < .04). During an i.v. epinephrine challenge on d 43, plasma cortisol declined in lambs fed Cr (Cr x time, P < .03) and in lambs fed LP (CP x time, P < .001). An i.v. glucose tolerance test conducted 3 h later showed that supplemental Cr decreased glucose clearance rate in lambs fed HP (CP x Cr, P < .10) but not in lambs fed LP. On d 62, PUN was increased in lambs fed HP (P < .001) between 0 and 3 h postprandial, and there was a Cr x CP interaction (P < .04). Postprandial plasma NEFA declined with Cr vs C (Cr x time, P < .07) and with HP vs LP (CP x time, P < .10). By d 66, lambs fed Cr had an elevated (P < .03) blood platelet and fibrinogen content. Chromium increased erythrocyte count in lambs fed HP (Cr x CP, P < .08), and isolated peripheral lymphocytes had greater blastogenic response to 4 microg/mL of phytohemagglutinin (Cr x CP, P < .001). The lymphocyte response to pokeweed mitogen (.2 microg/mL) was reduced in lambs fed Cr (P < .10). In the present experiment, Cr supplementation had minimal and inconsistent effects on production and metabolic criteria of lambs.
Gentry
L R
LR
Department of Animal Science, Louisiana State University Agricultural Center, Louisiana Agricultural Experiment Station, Baton Rouge 70803-4210, USA.
Fernandez
J M
JM
Ward
T L
TL
White
T W
TW
Southern
L L
LL
Bidner
T D
TD
Thompson
D L
DL
Horohov
D W
DW
Chapa
A M
AM
Sahlu
T
T
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition / Q000187:drug effects; D001835:Body Weight; D002857:Chromium / Q000494:pharmacology*; D004044:Dietary Proteins / Q000494:pharmacology*; D019587:Dietary Supplements; D005230:Fatty Acids, Nonesterified / Q000097:blood; D010848:Picolinic Acids / Q000494:pharmacology*; D012756:Sheep / Q000254:growth & development* / Q000276:immunology / Q000378:metabolism
D001786:Blood Glucose; D004044:Dietary Proteins; D005230:Fatty Acids, Nonesterified; D010848:Picolinic Acids; D002857:Chromium; C079689:chromium tripicolinate