A meta-analysis was carried out to analyze the performance of post weaning piglets with addition of vegetal extract and synthetic antimicrobial in diets. Eleven publications with 48 treatments and 2,752 piglets were studied. The treatments were divided into two groups: synthetic antimicrobial (AS) and vegetal extracts (EV). The experimental variables and performance of the piglets were analyzed. No significant differences (P>0.05) were found among experimental variables, except for initial live weight. The average number of the piglets for each treatment was 57, the average experimental period was 35 days and average initial age was 25 days. The average initial weight (7.4kg) was 16% greater (P<0.05) for piglets that had consumed vegetal extracts. The average final weight was 25kg. The average nutritional values of diets (P>0.05) were: 3,345 kcal of EM kg-1, 0.39% of methionine, 1.42% of lysine and 21.8% of crude protein. No significant differences (P>0.05) were found among vegetal extracts and synthetic antimicrobials groups for average feed intake (818g d-1), average daily gain (480g d-1) and feed: gain (1.70). The use of synthetic antimicrobials or vegetal extracts in diets of weaning piglets did not show changes in feed intake, weight gain, feed conversion rate, metabolizable energy intake, crude protein, lysine, methionine, calcium, and phosphorus intake.
natural addictives; antibiotic; weaned; swine
