Effects of dietary supplementation of phytobiotics on growth performance and health status of growing-finishing 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 health status of growing-finishing pigs. Phytobiotics included encapsulated oregano essential oil. One hundred twenty pigs (60 barrows and 60 gilts at 27.9 ± 4.8 kg BW) were randomly allotted to 4 treatments (2 × 2 factorial arrangement) with 10 pens (3 pigs per pen) per treatment based on a randomized complete block design, and fed the experimental diets for 6 wk. Factors were antibiotic growth promoter (AGP: 0 or 0.5 g/kg) and phytobiotics (0 or 0.5 g/kg diet). All diets were formulated to meet or exceed the NRC nutrient requirements. Feed intake and body weight were measured weekly. At the end of 6 wk, blood samples to separate serum were obtained from 40 pigs representing a median BW of each pen. Serum samples were used to evaluate tumor necrosis factor-α (TNF-α) as an indicator of inflammatory status, immunoglobulin G (lgG) as an indicator of humoral immunity, and malnodialdehyde (MDA) and protein carbonyl (PC) as oxidative stress markers. Data were analyzed using the Mixed procedure in SAS with pen as the experimental unit with treatment and sex as fixed effects and initial BW as a random effect. There were AGP × phytobiotics interactions (P < 0.05) on BW, ADG, and ADFI. The G:F was increased (P < 0.05) by dietary AGP (0.464 to 0.478) and phytobiotics (0.465 to 0.477) in overall. The TNF-α was not affected by treatment factors. Dietary phytobiotics decreased (P < 0.05) concentration of IgG (10.40 to 8.76 mg/mL) and PC (5.33 to 4.07 nmol/mg protein). Collectively, both dietary AGP and phytobiotics enhanced feed efficiency only when they were used independently. Combinational use of AGP and phytobiotics had negative effects on growth performance. Dietary phytobiotics reduced systemic oxidative stress and humoral immune reaction whereas these were not affected by AGP.

Keywords: growth performance, oxidative stress, phytobiotics