Effects of dietary betaine supplementation on back fat thickness and serum IGF-1 in late finishing pigs

This study was performed in finishing pigs to investigate the effects of betaine HCl on carcass fat deposition and lipid metabolism in relation to growth hormone (GH) and insulin-like growth factor 1 (IGF-1) alterations. Sixty cross-bred finishing pigs (30 gilts and 30 barrows) with an average initial body weight of 74.0 +/- 1.8 kg were randomly allocated into two groups, each with six replicate pens. Each group was fed either 0% or 0.125% betaine HC1 supplementation for 41 days. Results showed that the betaine HC1 supplementation had no effect on growth performance (P>0.05). In the betaine-supplemented group, Lenden-speck-quotient index, average back fat thickness, serum triglycerides concentrations and fatty acid synthase (FAS) activities were lower than those in the untreated control group (P<0.05, P<0.01, P<0.05 and P<0.05, respectively). The betaine supplementation did not alter serum GH concentrations (P>0.05), but serum IGF-1 concentrations were higher in the betaine group (P<0.01). In conclusion, betaine reduced lipogenesis by reducing the FAS activity and increased serum IGF-1, leading to improvement in carcass characteristics.