Porcine Somatotropin Affects the Dietary Lysine Requirement and Net Lysine Utilization for Growing Pigs

Abstract

This study was conducted to determine the effects of exogenous porcine somatotropin (pST) on the dietary lysine requirement and efficiency of absorbed lysine utilization for pigs during the 20- to 60-kg phase of growth. Seventy-two crossbred pigs (20 +/- 0.7 kg body wt) received daily intramuscular injections of either excipient (0 dose) or pST (150 micrograms/kg body wt) and were fed diets in which protein and lysine concentrations ranged from 6.4 to 23.5 g/100 g diet and from 0.40 to 1.48 g/100 g diet, respectively. Nutrient density was altered to compensate for reduced feed intake with pST, but diets were approximately isocaloric. Rate and efficiency of gain and whole-body protein accretion rate exhibited a dose-response improvement (P < 0.01) to increases in dietary protein for both excipient and pST-treated pigs. Pigs receiving pST grew more rapidly and more efficiently than control counterparts (P < 0.01). Treatment with pST improved the rate of protein accretion (P < 0.01) at all but the lowest level of dietary protein. The net lysine utilization for lysine accretion and maintenance was 0.46 for control pigs and 0.57 for pigs receiving pST, a 24% improvement in the efficiency. Thus, treatment with pST increased the maximum rate of protein accretion as well as the partial efficiency with which dietary lysine is used for protein accretion. Consequently, only a 9% increase in dietary lysine was required to maximize protein deposition in pST-treated pigs, because the metabolic efficiency of lysine utilization was improved.

Dietary lysine and threonine utilization by young pigs: Efficiency for carcass growth

“…Experiments in which graded levels of lysine (Batterham et al 1990), methionine (Chung and Baker 1992a), and protein (Campbell et al 1988) were fed to pigs, lysine and methionine concentrations of carcass and whole body protein were observed to increase while glycine concentration was reported to decrease as nuffient intake increased. The range of lysine concentration of carcass protein in the current studies of 6.06-6.79 g 100 g-r protein parallels values of 6.2-6.5 [Campbell et al (1988) in whole body protein], 6.4 [Batterham et al (1990) Baker (1992a) in whole body proteinl,7.0 fKyiazakis et al (1993) in whole body proteinl, 6.86 [Krick et al (1993) in carcass proteinl, and 6.5 [Bikker et al (1994) Krick et al (1993), and Bikker et al (1994 …”

“…Although not measured in the current experiments, these metabolic forms of lysine account for 10-15Eo of totaT lysine in body protein (Krick et al 1993;Kyrizakis et al 1993 …”

Exogenous porcine somatotropin administered to neonatal pigs at high doses can alter lifetime fat but not lean tissue deposition

“…Therefore, lysine intake from sows' milk normally limits lean tissue growth of pigs. It is well established that at low levels of dietary lysine there is very little effect of pST on lean tissue deposition in grower (Campbell et al 1990;Caperna et al 1990;Krick et al 1993) and finisher pigs (Campbell et al 1991;King et al 2000). Therefore, dietary lysine may have limited the lean tissue response to pST in the sucking pigs in both the present study and that of Dunshea et al (1999), whereas the neonatal pigs used in the study of Wester et al (1998) received a milk replacer containing adequate levels of lysine.…”

The Potential Impact of Animal Science Research on Global Maternal and Child Nutrition and Health: A Landscape Review

“…This same relation was illustrated with the use of adolescent pigs (20–60 kg) that consumed feed ad libitum in a lysine dose-response assay (75). The ratio of body protein (plus water) to lipid deposition improved 2-fold by increasing digestible lysine from 0.36% to 1.18% (as-fed basis).…”