Interrelationships between porcine somatotropin and dietary lysine on growth performance and carcass characteristics of finishing swine2

Abstract

Seventy-two barrows (initial weight = 57.1 kg) were used to determine the interrelationship between porcine somatotropin (pST) and dietary lysine and their effects on growth performance and carcass characteristics. Pigs were injected daily in the extensor muscle of the neck with either 4 or 8 mg of pST and fed a pelleted corn-soybean meal-sesame meal diet (.8% lysine; 17.8% CP) or diets containing 1.0, 1.2, or 1.4% lysine provided by additions of L-lysine.HCl (2 x 4 factorial arrangement). Control pigs (placebo injection) received the .8% lysine diet. All diets were formulated to contain > or = 200% of current recommendations for other amino acids, vitamins, and minerals. A tendency for a pST x lysine interaction was observed for cumulative ADG (P < .15) and feed conversion (G/F; P < .05). Average daily gain and G/F were improved by increasing dietary lysine level in pigs injected with 4 mg/d of pST; however, pigs injected with 8 mg/d of pST had greater improvements in cumulative ADG and G/F with added lysine. Feed intake was reduced (quadratic, P < .10) as dietary lysine level and pST dosage increased. Increasing pST dosage and dietary lysine increased (linear, P < .05) longissimus muscle area and decreased backfat thickness. Trimmed ham and loin weights were increased (linear, P < .10) by pST dosage. Chemical composition of samples taken from the loin, ham, and belly indicated increased moisture and CP and decreased lipid content as pST dosage and dietary lysine level increased (quadratic, P < .05). Shear force values from loin and semimembranosus increased with increasing lysine level (quadratic, P < .01) and pST dosage (linear, P < .05); however, these differences were not detected by sensory analysis (P > .20). Plasma urea concentrations on d 28 decreased with increasing lysine level (quadratic, P < .05), and plasma lysine concentrations increased (linear, P < .01). Based on the pST x lysine interaction for ADG and G/F, these data suggest that the lysine level needed to maximize growth performance and carcass characteristics may be proportional to the pST dosage provided. Growth and carcass characteristics were maximized by dietary lysine intakes of 27 to 32 and > or = 36 g/d for pigs injected with 4 and 8 of mg/d of pST, respectively.

Influence of adiposity (genetic or hormonal) on the metabolism of amino acids and nutritional responses

“…These changes are thought to be the consequences of increased muscle proteolysis. Liver (Goodband et al, 1993), which is in accordance with the positive correlation between obesity and BCAA concentration in plasma found in rodents and humans. p-ST treatment also decreased uremia and increased plasma glucose (Goodband et al, 1993) whatever the dietary lysine concentration, and the adipose tissue of p-ST-treated pigs became resistant to insulin.…”

The effect of dietary protein supply on carcass composition, size of organs, muscle properties and meat quality of pigs

“…Several studies have reported lower carcass leanness and higher carcass fatness after a decrease in dietary protein supply (Karlsson et al, 1993;Essen-Gustavsson et al, 1994;Chiba et al, 2002) and/or lysine supply (Cromwell et al, 1993;Goodband et al, 1993;Castell et al, 1994;Kerr et al, 1995;Cisneros et al, 1996;Blanchard et al, 1999;Witte et al, 2000;Bidner et al, 2004). This was also evident in the present study.…”

The effect of porcine somatotropin (pST) and gender on production parameters and tissue yield of pigs slaughtered at 135 kg live weight

“…Feed intake, calculated cumulatively on a weekly basis, was not significantly influenced by pST or sex type in this study (Tables 2 and 3). This is in contrast with the findings of Goodband et al (1993) and Klindt et al (1995) who found a decrease in feed intake for animals treated with pST and fed diets with increased levels of lysine. Klindt et al (1995) also found a dose-dependent decrease in feed intake of boars and gilts slaughtered between 81.1 and 94.4 kg.…”