| Abstrakt: |
Stress can disturb the ecological balance of the microbiota residing in the GI tract of piglets leading to dysbiosis. This unhealthy imbalance causes the piglets to be more vulnerable to deleterious effects induced by opportunistic pathogens. Antibiotics and increased zinc levels have often been used as dietary supplements to help minimize these stressors in pigs. Emerged evidence suggests that phytochemicals can promote growth by boosting nutrient digestibility, immune cell activity, and possessing bactericidal characteristics. We evaluated two phytochemicals formulations as safer and more environmentally friendly dietary alternatives for postweaning pigs. We used a total of 240 weaned piglets [average body weight (BW): 6.26 ± 0.36 kg] which were blocked (n = 8) by BW and then randomly assigned to 1 of 5 dietary treatments. Treatments were negative control (NC), Mecadox 10 (Phibro Animal Health Corp., Teaneck, NJ) + ZnO positive control (PC), Mecadox + phytochemical 1 (Lippia origanoides; Phyt1+AB), phytochemical 1 alone (Phyt1), and phytochemical 2 (Lippia origanoides + Rosmarinus officinalis + Sodium humates; Phyt2). The pigs were fed a 7-phase feeding regime: Nursery phase (NP) 1, 2, and 3, Grower phase 1 and 2 (Grower), and Finisher phase 1 and 2 (Finisher). The antibiotic and ZnO were withdrawn at the end of NP3, while Phyt1 and Phyt2 remained in feed throughout the entire study period. Data were analyzed using Mixed procedure of SAS (Cary, NC) with treatments as the main effect and BW blocks as the random effect. Pen was the experimental unit. Supplemental phytochemicals (Phyt1+AB, Phyt1, Phyt2) had greater average daily gain (ADG) and gain to feed ratio (G:F) during NP1 when compared with the pigs fed NC, but were still less than pigs fed PC (P< 0.0001). Pigs fed PC maintained a greater ADG during nursery overall than NC, Phyt1, and Phyt2 with pigs fed Phyt1+AB as intermediate (P< 0.0001). Phyt1 exerted an adverse effect (Phyt1+AB and Phyt1) on ADG during relatively mild stress in Grower phase (Grower, P= 0.0146), and resulted in the lighter BW at the end of Grower than pigs fed PC (P= 0.031). Notably, the pigs experienced summer heat stress during the Finisher phase, of which, the presence of phytochemicals minimized. Pigs fed Phyt2 had a greater ADG during Finisher than pigs fed NC with pigs fed PC, Phyt1+AB, and Phyt1 as intermediates (Finisher, P= 0.0419), while pigs fed Phyt1+AB and Phyt2 had greater G:F when compared with pigs fed PC and NC with pigs fed Phyt1 as intermediate (Finisher, P= 0.0032). Collectively, we demonstrated that phytochemical 2 can be a safer medication diet replacement to help pigs sustain weaning and heat stress. The mode of action and the optimum concentrations of these phytochemicals to achieve maximum benefits need further investigation. |
