Effects of exogenous porcine somatotropin (pST) administration on growth performance, carcass traits, and pork meat quality of Meishan, Pietrain, and crossbred gilts.
Seventeen to twenty-three females of lean (Pietrain, PI), fat (Meishan, MS), or intermediate genotype (PI x [3/4 Large White x 1/4 MS]), referred to as crossbred (CR), were injected between 60 and 100 kg live weight with 6 mg/d of porcine somatotropin (pST) and compared to similar numbers of control females receiving the vehicle only. Average daily gain increased similarly in the three genotypes (125 g/d). Feed conversion ratio tended to decrease to a higher extent in MS (-2.0 kg of feed/kg of gain) than in the other two genotypes (-1.1 and -.9 kg of feed/kg of gain for CR and PI, respectively). A significant genotype x treatment interaction was also observed for backfat thickness (BF) and fat, muscle, and bone development. Effects of pST in PI, CR, and MS pigs were, respectively, -6.2, -9.6, and -16.1 mm for BF and 3.0, 6.8, and 11.8% carcass muscle. The influence of pST on physical measurements of meat quality was rather low, although desirable effects (P less than .05) were obtained on the reflectance and water-holding capacity of PI and CR. Intramuscular fat content was reduced by approximately 1% in MS and CR but not in PI. The metatarsals of pST-treated animals had a higher water content (except in PI), a lower mineralization, and a lower breaking strength (except in MS). The existence of breed variations in the response to pST might result in changes of the relative merit of crossbreeding schemes.
Bidanel
J P
JP
Institut National de la Recherche Agronomique (INRA) Jouy-en-Josas, France.
Bonneau
M
M
Pointillart
A
A
Gruand
J
J
Mourot
J
J
Demade
I
I
D000273:Adipose Tissue / Q000187:drug effects / Q000254:growth & development; D000818:Animals; D001823:Body Composition / Q000187:drug effects; D001846:Bone Development / Q000187:drug effects; D001947:Breeding; D003433:Crosses, Genetic; D005260:Female; D005838:Genotype; D013006:Growth Hormone / Q000494:pharmacology*; D008460:Meat / Q000592:standards*; D024510:Muscle Development; D009132:Muscles / Q000187:drug effects; D011897:Random Allocation; D013552:Swine / Q000235:genetics / Q000254:growth & development*; D015430:Weight Gain / Q000187:drug effects
D013006:Growth Hormone