Effect of maternal administration of salbutamol to sows on post-natal growth and carcass characteristics in the progeny

Abstract

The effects of salbutamol administration to pregnant sows on post-natal growth and carcass characteristics of the progeny were investigated. Salbutamol (4 mg/kg diet) was fed to sows during the first (0 to 38 days, TI), second (39 to 78 days, T2) or third (79 days to term, T3) trimester of pregnancy. At birth, maternal administration of salbutamol had no effect on body weight, dressing percentage or weights of liver, heart, semimembranosus and semitendinosus muscle in proportion to body weight in the progeny. No significant effects of maternal treatment with salbutamol on body weight, dressing percentage, semitendinosus muscle weight in proportion to body weight and loin eye area were observed in the progeny at 21 days. P2 fat depth at 21 days was greater (P < 0-05) in TI than in controls. The percentage of type I fibres in the deep portion of semitendinosus muscle was higher (P < 0.05) in treatment groups as compared with controls: 27.4, 42.8, 36.9 and 36.0% in control, TI, T2 and T3 respectively. At slaughter (90 kg), carcass and meat parameters including length, P2 fat depth, meat colour and drip loss were not affected by maternal administration of salbutamol. However, loin eye areas were larger in T1 than in controls. Larger loin eye areas, coupled with numerically (but not statistically) significant heavier carcasses and lower backfats, resulted in greater estimates of carcass protein mass in TI pigs as compared with controls (P = 0.06).

The effects of in utero exposure of lambs to a beta-adrenergic agonist on prenatal and postnatal muscle growth, carcass cutability, and meat tenderness.

“…Whereas it has been reported that in utero exposure to a b-adrenergic agonist decreased hindlimb muscle weights in rats (Maltin et al, 1990) and increased longissimus area in pigs (Kim et al, 1994), in utero exposure to L 644,969 did not affect weights of lamb carcass components or individual muscles in the present experiment (Table 4).…”

“…Maltin et al (1990) demonstrated that in utero exposure to a BAA decreased postnatal muscle growth in rats. Kim et al (1994) reported that treatment of sows with a BAA during either of the first two-thirds of pregnancy resulted in increased longissimus area in the carcasses of the progeny. The mechanisms by which prenatal BAA treatment alters muscle growth have not yet been fully explored.…”

Responses to maternal GH or ractopamine during early–mid pregnancy are similar in primiparous and multiparous pregnant pigs

“…This is the first report of fetal growth responses to maternal b 2 -agonists in the pig. Similar to effects of maternal pGH, previous studies of maternal b 2 -adrenergic agonist administration in early-mid pregnancy in the pig have reported changes in progeny postnatal development without changes in birth weight (Kim et al 1994, Hoshi et al 2005a. In utero exposure to the b 2 -adrenergic agonist L 644,969 from day 25 to 95 of pregnancy in sheep (w0 .…”

“…Mixed effects of in utero exposure to b-agonists have been reported previously in the pig, with no change in total fiber numbers or muscle cross-sectional areas reported in progeny of sows treated with ractopamine (Hoshi et al 2005a), but increased muscle size and the proportion of type 1 muscle fibers in progeny of sows treated with salbutamol (Kim et al 1994). In lambs, in utero exposure to the b 2 -adrenergic agonist L 644,969 from day 25 to 95 of pregnancy also did not alter fiber type proportion or size in young adult offspring (Shackelford et al 1995).…”

“…Progeny growth rates and carcass weight, but not birth weight, muscle size nor muscle fiber numbers, were increased in sows fed with the b 2 -adrenergic agonist ractopamine from day 25 to 50 of pregnancy (Hoshi et al 2005a,b). Feeding sows the b 2 -adrenergic agonist salbutamol in the first third of pregnancy increased muscle size and altered muscle fiber types of progeny (Kim et al 1994). Whether these changes in progeny muscle development are preceded by increased fetal and placental growth is not known, and parity differences in responses to b-adrenergic agonists have also not been explored.…”