title: Dietary stimulation of the endogenous somatotropic axis in weaner and grower-finisher pigs using medium chain triglycerides and cysteamine hydrochloride.
abstract: BACKGROUND
  Three experiments were conducted to examine the overall hypothesis that addition of medium chain triglycerides (MCT) and cysteamine hydrochloride (CSH) into the diets of young and growing pigs would stimulate the endogenous somatotropic axis to improve growth and performance.
  
  
  RESULTS
  In Experiment 1, weaner pigs were given either a 5 d dietary supplement of 5 % MCT (n= 8) or a control diet (n= 8). MCT increased the plasma concentration of growth hormone (GH;P< 0.05) and the GH secretagogue, ghrelin (P< 0.05). Additionally, the MCT treatment reduced scouring (P< 0.05), maintained villous height in the small intestine (P< 0.05) and stabilised daily weight gain (P< 0.05), compared to the controls. Experiment 2 compared the effects of 4 levels (0, 1, 3 and 6 % v/v) of MCT supplementation in grower-finisher male pigs, of approximately 35 kg live weight (n= 15 per treatment). Blood samples taken after 7 wk of treatment showed that the MCT supplementation increased circulating ghrelin (P< 0.001), GH (P< 0.01) and insulin (P< 0.05) concentrations in a dose-dependent manner. Daily weight gain, feed intake and feed conversion ratio were not affected by the MCT diets. In Experiment 3, 64 female pigs of approximately 60 kg live weight were allocated to one of three dietary treatments: control (n= 20); 6 % MCT (n= 21); and 70 mg/kg CSH (n= 21). After 3 wk of supplementation, the MCT treated pigs had a higher plasma concentration of ghrelin compared to the control and CSH pigs (P< 0.05). Plasma concentrations of GH and weight were not affected by any of the dietary treatments.
  
  
  CONCLUSIONS
  Evidence is provided in Experiment 1 to support the use of dietary MCT supplements, perhaps acting via stimulation of somatotropic endocrine pathways, to minimise weaning-associated disorders such as slowing of growth and diarrhoea. In Experiments 2 and 3, although there was no effect on weight gain or feed conversion ratio in either experiment, MCT and CSH increased endocrine components of the somatotropic axis.
authors: School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150 Australia.
authors: David W
authors: DW
authors: Miller
authors: School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150 Australia.
authors: Zoe
authors: Z
authors: Prosser
authors: School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150 Australia.
authors: Edward Y W
authors: EY
authors: Chee
authors: Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Groennegaardsvej 2, 1870 Frederiksberg C, Denmark.
authors: Christian F
authors: CF
authors: Hansen
authors: Melbourne School of Land and Environment, University of Melbourne, Parkville, VIC 3051 Australia.
authors: Frank R
authors: FR
authors: Dunshea
authors: Department of Agriculture and Food Western Australia, Bentley Delivery Center, Locked Bag 4, Bentley, WA 6983 Australia.
authors: Bruce P
authors: BP
authors: Mullan
authors: School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150 Australia.
authors: John R
authors: JR
authors: Pluske
keywords: Ghrelin; Growth; Pig; Somatotropin