|Seaman, Johnna - UNIV OF MISSOURI|
|Safranski, Tim - UNIV OF MISSOURI|
|Berg, Eric - UNIV OF MISSOURI|
Submitted to: Domestic Animal Endocrinology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 21, 2002
Publication Date: April 1, 2003
Citation: SEAMAN, J.S., CARROLL, J.A., SAFRANSKI, T.J., BERG, E.P. SHORT- AND LONG-TERM INFLUENCE OF PERINATAL DEXAMETHASONE TREATMENT ON SWINE GROWTH. DOMESTIC ANIMAL ENDOCRINOLOGY. 2003. v. 24. p. 193-208. Interpretive Summary: The overall objective of this research was to further evaluate the effects of a single dose of a potent synthetic glucocorticoid (i.e., dexamethasone) at birth on performance in pigs as well as to determine any potential dose-dependent effects on growth. Specific objectives were to evaluate the effects of dexamethasone on: 1) the growth axis and growth of pigs during the preweaning period, 2) the growth and performance through the grow/finish period, and 3) the carcass composition and meat quality at slaughter. For these experiments, we used crossbred piglets which were administered either dexamethasone (Dex; 1 mg/kg body weight) or sterile saline (control; equivalent volume) i.m. within 1 hr of birth. Serum concentration of insulin-like growth factor-1 (IGF-1) was increased by 17.3% in Dex pigs. IGF-1 is considered by most to be the predominant mediator of postnatal growth in domestic animals. The results indicated that Dex treatment increased growth from birth to market weight by 4.15% compared to controls without causing any detrimental or negative effects on the carcass or the meat quality. It is known that in swine, increased growth prior to weaning corresponds with greater overall growth and performance. The results of the present studies confirm our earlier reports that administering an exogenous glucocorticoid, such as Dex, during the perinatal period stimulates preweaning growth which is partially maintained until market weight. Increased growth rates decrease the time required to reach market weight, and this can lead to savings in feed and housing costs for swine producers. Given that this research has the potential to significantly impact the economics associated with swine production, it will be of interest to swine veterinarians and swine producers throughout the United States as well as other countries. This information will also be of interest to all individuals associated with swine production including scientists in academia, government, and industry.
Technical Abstract: The objective of the present studies was to evaluate the effects of perinatal treatment with dexamethasone, a potent synthetic glucocorticoid, on postnatal growth in pigs. Experiment 1: 42 crossbred piglets were assigned according to birth weight and sex to receive either dexamethasone (Dex; 1 mg/kg body weight; n = 11 males and 10 females) or sterile saline (control; equivalent volume; n = 12 males and 9 females) i.m. within 1 hr of birth. Body weights were recorded weekly and on d 18, when all pigs were sacrificed for blood and tissue collection. Birth weights (1.43 +/- 0.05 kg) did not differ between Dex and control pigs (P > 0.19). At 18 d of age, Dex pigs were heavier than control pigs (5.46 +/- 0.24 kg and 4.45 +/- 0.26 kg, respectively). Serum concentration of IGF-1 was influenced by treatment (P < 0.04) with Dex pigs having 17.3% more compared to controls. For serum concentration of GH, there was a treatment x sex interaction (P < 0.04). Growth hormone concentrations were 51% lower in Dex males compared to control males, while no effect was observed in females. Experiment 2: 71 crossbred pigs were assigned according to birth weight and sex to receive either Dex (2 mg/kg body weight; n = 18 males and 19 females) or sterile saline (control; equivalent volume; n = 16 males and 18 females) i.m. within 1 hour of birth. Body weights were recorded weekly until pigs were weaned at 21 d of age and then every 14 d until reaching market weight. Pigs were taken to a commercial packing plant for carcass and meat quality evaluation. Birth weights (1.53 +/- 0.03 kg) did not differ between Dex and control pigs (P > 0.35) or between males and females (P > 0.51). Dexamethasone treatment increased growth from birth to market weight by 4.15% compared to controls. The Dex males had a lower (P < 0.03) percent ham lean compared to the control males. Control pigs had a greater (P < 0.02) Hunter b* color value compared to Dex pigs but there was no difference (P > 0.05) in Hunter L* and a* values. Overall, Dex treatment at birth enhanced growth in pigs from birth to market weight with minimal effects on carcass and meat quality.