Effect of Somatostatin and Chronic Cold Exposure on Hormonal and Metabolite Concentration, Metabolic Rate, Thermoregulation, and Gut Motility in Sheep

The effect of somatostatin-14 (SS-14) (6.7 ng min−1 kg−1 BW) on hormone and metabolite concentrations, gastrointestinal motility, thermoregulation, and heat production was studied in five ewe lambs (45.8 ± 2.8 kg BW) adapted to either thermoneutral (TN) (17.4 °C) or chronic cold (CC) (− 0.9 °C). Lambs received a barley:soybean diet at 25.6 g DM d−1 kg−1 BW. Environmental temperature and SS-14 infusion had no effect on the frequency or duration of components of the duodenal migrating myoelectric complex (MMC), although cold exposure increased (P < 0.05) total number of contractions within the MMC. CC increased (P < 0.05) heat production by 41%, while SS-14 decreased (P < 0.05) heat production by 4% in both environments. Plasma concentrations of free fatty acids (P < 0.05) were increased during cold exposure. In response to SS-14 infusion plasma free fatty acid levels increased (P < 0.05) in the TN environment, while their level declined in the cold environment. Growth hormone, glucagon, and insulin concentrations were not influenced by cold exposure or SS-14 infusion. CC increased plasma T3 concentration but this response was abolished by SS-14. Thus, in lambs fed a concentrate diet, somatostatin at low doses slightly reduces whole body metabolism, possibly by an influence on thyroid hormones.