Dietary stimulation of the endogenous somatotropic axis in weaner and grower-finisher pigs using medium chain triglycerides and cysteamine hydrochloride.

David W Miller,Zoe Prosser,Bruce P Mullan,Christian F Hansen,Frank R Dunshea,John R Pluske,Edward Y W Chee

doi:10.1186/s40104-016-0121-9

David W Miller, Zoe Prosser + Show 5 more

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https://doi.org/10.1186/s40104-016-0121-9

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Abstract

BackgroundThree 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.ResultsIn 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.ConclusionsEvidence 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.

Highlights

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
For average daily weight gain (ADG) there was no effect of time or treatment, but there was a significant interaction of treatment and time (P < 0.05), and for feed conversion ratio (FCR) there was no effect of treatment or time, but there was a significant interaction of treatment and time (P < 0.05)
Evidence was provided in Experiment 1 showing that dietary MCT offers some promise as a means to bio-activate ghrelin, being the possible mechanism that led to the enhanced villous height observed

Summary

Introduction

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. The increase in GH secretion is due to the inhibitory effect of CSH on somatostatin release [5]. Dietary supplementations of CSH at 30 mg/kg and 50 mg/kg of feed resulted in significant increases in daily weight gain in finisher pigs, but had no effect on plasma concentrations of GH [7]. A dietary supplementation of CSH at 70 mg/kg of feed in finisher gilts caused an increase in daily weight gain, but GH levels were not measured in this study [8]

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