Gastrointestinal motility and plasma hormone and metabolite responses to acute cold stress and somatostatin-14 in sheep

Abstract

Effects of intrajugular infusions of somatostatin-14 (SS-14) (8.9, 18.4, and 37.3 ng min−1 kg−1 BW) or saline were studied in three acutely (2 h) cold-stressed (0 °C) ewe lambs (39.8 ± 1.8 kg BW) fed a barley soybean meal diet at 25.6 g DM d−1 kg−1 BW. Acute cold exposure transiently increased (P < 0.001) and rewarming decreased (P < 0.001) recticular contraction frequency, with no effect of SS-14. The duration of duodenal irregular spiking activity was decreased (P < 0.05) by SS-14 at doses of 18.3 and 37.3 ng min−1 kg−1 and was not affected by cold exposure. This resulted in a decrease (P < 0.05) in the average duration of the individual migrating myoelectric complex. Cold exposure increased (P < 0.01) plasma concentration of free fatty acids (FFA). Orthogonal contrasts of the changes during somatostatin infusion indicated linear increases in glucose and linear and cubic increases in FFA concentrations in plasma (P < 0.05). Infusion of somatostatin had no effect on basal concentrations of growth hormone, insulin, or glucagon but produced linear reductions in plasma insulin and glucagon responses during cold exposure (P < 0.05). Somatostatin modestly influenced hormone and metabolite concentration during acute cold exposure without apparent effect on body temperature. Key words: Cold, somatostatin, sheep, gastrointestinal motility, glucagon, insulin