The effect of immunization against somatostatin and β-agonist administration alone and in combination on growth and carcass composition in young steers

Abstract

The effect of active immunization against somatostatin and ^-agonist administration alone and in combination on growth, carcass composition and endocrine responses was investigated in young steers given a pelleted diet of dried grass and barley (0-7: 0-3) ad libitum for 16 weeks. Immunization alone increased growth rate by proportionately 0-10 but had no effect on plasma growth hormone (GH) or insulin-like growth factor-1 (IGF-1) concentrations (P > 0-10). Carcass protein content was unchanged but fat content tended to be increased. This was possibly associated with increased (P < 0-10) plasma insulin concentrations observed in these animals. Cimaterol administration significantly increased growth rate (P < 0-05) and carcass weight (P < 0-01). Carcass protein content was significantly (P < 0-01) increased and carcass fat was significantly (P < 0-001) reduced. Administration of cimaterol to immunized animals resulted in an enhancement of the repartitioning effect of the pagonist although growth rates were intermediate between the separate treatments. The mechanism by which this was achieved is unclear. Plasma IGF-1 concentrations tended (P < 0-10) to be lower in these animals compared with controls. Plasma insulin concentrations were also reduced (P < 0-05) in these animals. Both immunized animals and those given cimaterol alone showed an increased GH response to a single intravenous injection of growth hormone releasing factor (GRF) (P < 0-05). Animals given the combined treatment however showed a reduced response suggesting that the effects were not mediated through direct changes in GH secretion. The improved lean :fat ratio in the carcass was observed to be mediated through an enhancement of the lipolytic response to the /Jagonist with only small effects on protein accretion. It is suggested that immunoneutralization of somatostatin may increase the sensitivity of adipose tissue to lipolytic stimuli. This could occur through changes in the secretion of gastrointestinal or pancreatic hormones as a result of neutralization of the inhibitory influences of somatostatin. Further work is required to clarify these effects.

Dietary zilpaterol hydrochloride. II. Carcass composition and meat palatability of beef cattle

“…Additionally, Moloney et al (1990) showed an increase in lean and a decrease in fat due to treatment with the βAA L 644,969 . Typically, use of other βAA has not affected carcass ash percentage (Dawson et al, 1997;Schroeder et al, 2003b,c), which is similar to the effect of zilpaterol treatment in the present study. In addition, carcass percentage bone was shown to be decreased in heifers of the present study and by other βAA because of an increase in soft tissue mass (Fabry and Sommer, 1990;Moloney et al, 1990).…”

“…Use of other βAA has resulted in an increase in lean to bone ratio and decreases in lean to fat ratio (Moloney et al, 1990;Dawson et al, 1997). The present study data indicated that zilpaterol is a repartitioning agent, although not as strong as other β 2 -agonists.…”

“…Evidence of other βAA repartitioning capacity in cattle is well documented. An increase in carcass protein and moisture with a decrease in carcass fat percentage has been shown with clenbuterol (Ricks et al, 1984), cimaterol (Boucqué et al, 1994;Fiems et al, 1995;Dawson et al, 1997), and ractopamine (Parrott et al, 1990;Schroeder et al, 2003b,c). Additionally, Moloney et al (1990) showed an increase in lean and a decrease in fat due to treatment with the βAA L 644,969 .…”

Effect of Different Zilpaterol Hydrochloride Levels and Feeding Methods on the Growth Performance, Carcass Traits and Blood Parameters of Male Japanese Quails During Two Weeks of the Finishing Period

“…The percentage of moisture, protein, ash, and cholesterol in the breast and leg muscles were not affected (p≥0.10) by zilpaterol. Out results are consistent with those of Dawson et al (1997), who supplemented beef steers with other β-AA and did not find any effects on carcass ash percentage.…”

Oral and intranasal administration of somatostatin DNA vaccine mediated by attenuated Salmonella Enterica Serovar Typhimurium to promote growth of piglets

“…Many studies have shown that the use of immuno-neutralization against SS could enhance growth in animals (Spencer, 1986;Yun et al, 1996). Immunization against either a chemically synthetic or recombinant SS coupled to a carrier protein has been confirmed to promote the growth rates of immunized animals, including sheep, steers and chickens (Buonomo et al, 1987;Dawson et al, 1997;Shulkes et al, 1999).…”