Phytogenic feed additives in piglets challenged with Salmonella Typhimurium

The effects of phytogenic feed additives on piglet performance and fecal score (FDD), as well as on lipid oxidation of pork meat were evaluated. One hundred and twenty crossbred weaned piglets were randomly assigned to six treatments according to a 2 × 3 factorial design with five replicates per treatment. Factors were: challenge with Salmonella Typhimurium at 35 days of age or no challenge, and three different additives (control (CTR), basal diet; phytogenic feed additives (PHY), basal diet plus 2000 ppm of phytogenic feed additives - Rosmarinus officinalis, Mentha piperita, Lippia sidoides and Porophyllum ruderale; and antimicrobial agent (ATB), basal diet plus 100 ppm of tylosin, 2000 ppm of zinc and colistin sulfate, 30 ppm in the pre-starter basal diet, 10 ppm in the starter basal diet I and II, and 5 ppm in growth and finishing basal diet). Body weight (BW) of the piglets of ATB was greater throughout the experimental period, without any differences detected between CTR and PHY. Nevertheless, from 96 to 106 days of age, the BW of the CTR group was greater than PHY. From 21 to 34 days of age, feed conversion of ATB was lower than CTR; however, PHY showed an intermediate result, which did not differ from either ATB or CTR. Challenged animals reduced feed intake from day 35 to 48 compared with unchallenged animals. Piglet performance and fecal score from 21 to 48 days of age were lower in piglets that received ATB compared with the other treatments. However, from 35 to 48 days of age, the FDD of PHY was lower than CTR. Lipid oxidation was not reduced in treated animals. Antimicrobial agent improved the growth performance of piglets until 63 days of age, and no difference was observed between the treatments from 64 to 131 days of age. Antimicrobial agent reduced FDD; the FDD of PHY was similar to that of ATB after 48 days. None of the treatments affected lipid oxidation of pork meat