Influence of porcine somatotropin on endocrine and histological variables in gilts.
Thirty-six crossbred gilts (71.7 +/- .9 kg and 140.1 +/- .9 d) were assigned to one of three doses (0, 35, or 70 micrograms.kg BW-1 x d-1) of recombinant porcine somatotropin (rpST). The doses of rpST were adjusted weekly, and i.m. injections continued until d 50. Gilts were pen fed (six gilts/pen) a 17% CP corn-soybean diet (1.2% lysine and 3.2 Mcal of ME/kg). At d 50, feed intake, feed:gain ratios (P = .02), and blood urea nitrogen were decreased (P < .001) by increasing rpST doses, whereas ADG was increased (P = .04) by increasing rpST doses. Injections of rpST did not affect (P > .05) conception rate, age, or weight at puberty. Numbers of blastocysts or corpora lutea observed at d 10.4 +/- 1.5 of gestation (42.2 d after final rpST injection) were unaffected (P > .05) by rpST treatment. Anterior and posterior pituitary weights were increased (P < or = .003) linearly with rpST dose. However, liver, adrenal, and heart weights were unaffected (P > .05) by rpST. After a withdrawal period of 42.2 +/- 2.0 d, rpST increased (P < or = .02) the estimated percentage of lean by 5.8% and longissimus muscle area by 10.4%. Eighteen hours before the initial rpST injection (d 0), 10 gilts per rpST dose were catheterized. Catheterizations were repeated on d 40. The rpST or diluent was given i.m. in the extensor muscle of the neck 1 h after initiation of blood collection. Adrenocorticotropic hormone (1.4 IU/kg BW) was administered through the catheter 3 h after initiation of blood collection.(ABSTRACT TRUNCATED AT 250 WORDS)
Andres
C J
CJ
Department of Animal Science, Purdue University, West Lafayette, IN 47907.
Green
M L
ML
Clapper
J A
JA
Cline
T R
TR
Diekman
M A
MA
Thomford
P J
PJ
D000273:Adipose Tissue / Q000187:drug effects / Q000254:growth & development; D000302:Adrenal Cortex / Q000187:drug effects / Q000254:growth & development; D000818:Animals; D004435:Eating / Q000187:drug effects; D005260:Female; D005306:Fertilization / Q000187:drug effects; D005640:Follicle Stimulating Hormone / Q000097:blood; D013006:Growth Hormone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D006854:Hydrocortisone / Q000097:blood; D007273:Injections, Intramuscular / Q000662:veterinary; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D024510:Muscle Development; D009132:Muscles / Q000187:drug effects; D009929:Organ Size / Q000187:drug effects; D010902:Pituitary Gland / Q000166:cytology / Q000187:drug effects / Q000254:growth & development; D011897:Random Allocation; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000494:pharmacology; D012741:Sexual Maturation / Q000187:drug effects; D013552:Swine / Q000097:blood / Q000254:growth & development* / Q000378:metabolism; D015430:Weight Gain / Q000187:drug effects
D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013006:Growth Hormone; D006854:Hydrocortisone