Effects of dietary supplementation of phytobiotics on intestinal health and growth performance of nursery pigs

Abstract Text: This study was to determine the effects of dietary supplementation of phytobiotics (By-O-reg, Advanced Ag Products, Hudson, SD) on growth efficiency and intestinal development of nursery pigs. Phytobiotics included encapsulated oregano essential oil. Forty pigs (20 barrows and 20 gilts at 6.4 ± 0.3 kg BW) were randomly allotted to 4 treatments (2 × 2 factorial arrangement) with 10 pens (1 pig per pen) per treatment based on a randomized complete block design, and fed the experimental diets for 3 wk. Two factors were antibiotic growth promoter (AGP: 0 or 0.5 g/kg) and phytobiotics (0 or 0.5 g/kg diet), respectively. All diets were formulated to meet or exceed the NRC nutrient requirements. Feed intake and body weight were measured weekly. Blood samples were taken on d 20 to measure tumor necrosis factor-alpha (TNF-α), immunoglobulin G (IgG), IgA, and protein carbonyl (PC). On d 21, all pigs were euthanized to obtain the duodenal and jejunal mucosa and tissue. The mucosa samples were used to measure TNF-α, IgG, IgA, and PC. The tissues were used to measure morphology. Data were analyzed using the Mixed procedure in SAS with factors, interaction between factors, and sex as fixed effects and initial BW as a random effect.  Interaction between factors were again analyzed using PDIFF to evaluate a different effect of each treatment. Overall, there were AGP × phytobiotics interactions (P < 0.05) on ADG and G:F. Among these interactions, both dietary AGP (P = 0.071; 627 g/d) and phytobiotic (P = 0.057; 624 g/d) tended to increase ADG compared with basal diet (543 g/d) at wk 3. Dietary phytobiotics increased (P < 0.05) jejunal villus height (443 to 471 μm). Dietary phytobiotics decreased (P < 0.05) concentration of TNF-α (4.41 to 3.82 ng/g protein) and IgG (1.42 to 1.19 μg/mg protein) in jejunum and PC (4.2 to 2.9 nmol/mg protein) in plasma. Dietary AGP tended to decrease (P= 0.063) jejunal IgA levels (1.60 to 1.14 μg/mg protein) in jejunum. Collectively, both dietary AGP and phytobiotics enhanced ADG only when they were used independently. A combinational use of AGP and phytobiotics had negative effects on growth performance. Dietary phytobiotics improved jejunal development by reducing inflammatory and humoral immune reaction.

Keywords: antibiotic growth promotor, growth performance, intestinal health, nursery pigs, phytobiotics