Effects of dietary nucleotide supplementation on growth performance and hormonal and immune responses of piglets

The effects of dietary nucleotide supplementation from 9 days of age until the end of post-weaning on piglets hormonal and immune responses and on growth performance were investigated. During lactation (days 9 to 21) and post-weaning (days 22 to 55) 10 [HBI Fomeva11*(Large White*Landrace)] litters (n.108 piglets) had ad libitum access to two standard diets, both supplemented with 0% (T0 group) or 0.1% (T1 group) of yeast extract nucleotides. BW of piglets at days 21 ( P<0.10), 35 and 55 ( P<0.05) was greater in T1 compared with T0. Feed intake was not different between groups (P>0.05). Cortisol content was lower in T1 than in T0 at days 28 and 35 (P<0.05), whereas growth hormone was lower at day 35 ( P<0.05). Levels of IGF-1 were similar across groups ( P>0.05). Nucleotide-supplemented diets increased lymphocyte subpopulation CD4-CD8+high at days 21 and 35 (P<0.05), whereas CD4+CD8- cells were higher in T1 than in T0 at day 21 (P<0.05). Peripheral blood mononuclear cells cytokine expression was influenced by dietary nucleotide supplementation. At weaning, interleukin (IL)-6 and IL-1-beta expression was lower ( P<0.05) in T1 compared with T0, whereas the expression of interferon (IFN)-gamma and IL-10 was higher (P<0.05). At day 28, piglets in T1 showed higher values of tumor necrosis factor (TNF)-alfa expression than T0 and lower values of IL-10 expression (P<0.05). Dietary nucleotide supplementation had a suppressive effect on IL-6 and IL-10 expression (P<0.05) at day 35. On the contrary, the expression of IFN-gamma, TNF-alfa and IL-1-beta was enhanced (P<0.05). In conclusion, these results suggest that starting a dietary nucleotide supplementation before weaning can improve the adaptive capabilities of weaned piglets to the stressors, enhancing the growth performance.