Effect of betaine on growth hormone pulsatile secretion and serum metabolites in finishing pigs

An experiment was conducted to investigate the effect of dietary betaine (0%, 0.125%) on growth performance, growth hormone (GH) pulsatile secretion and serum metabolites in crossbred finishing pigs. Three replications of eight pigs (four barrows and four gilts) were used for each treatment, and blood samples for the determination of GH pulsatile secretion were collected every 15 min for 3 h. The results showed that betaine supplementation resulted in 5.45% (p < 0.05) increase in average daily gain, whereas average daily feed intake and feed to gain ratio were not affected. Serum basal GH level, mean GH level and GH pulse amplitude were elevated by 41.79% (p < 0.01), 48.98% (p < 0.01) and 35.05% (p < 0.05), respectively, with betaine treatment, but GH pulse frequency and pulse duration remained unchanged (p > 0.05). Serum urea nitrogen concentration in pigs fed betaine was 21.58% lower than that of controls (p < 0.01), whereas total protein level was significantly increased with betaine supplementation (p < 0.05). The study suggests that betaine could promote growth by enhancing GH secretion in finishing pigs.