DefinePK

Abstract

Feed additives are commonly supplemented in poultry feed to improve the animal health status and performance. Previous in vitro studies about feed additives showed that coconut shell liquid smoke (CSLS), mangosteen peel extract (MP), and clove leaf extract (CL) had a similar antibacterial activity with the AGP. According to those insights, an in vivo study was designed to explore the effect of those combinations as feed additives on the slow-growth chickens’ performances. A total of 588-one-day-old unsexed chicks were distributed into 42 pens with 14 birds/pen and reared for 84 days. They were fed each of six different diets, The formulated diets are standard diet without feed additives as Negative Control (NC); NC + Virginiamycin as Positive Control (PC); NC + CSLS; NC + mixtures of CSLS + CL; NC + mixture of CSLS, CL, and MP in low-, medium-, and high- doses. Results showed no significant effects (P>0.05) of diets on body weight gain, feed consumption, and FCR during starter and whole periods. The treatments also showed no significant (P>0.05) effects on carcass yield, liver, spleen, and thymus weight. However, supplementation of a low-dose bioactive mixture produced a higher (P<0.05) abdominal fat, and supplementation of CSLS + CL or medium doses of CSLS + CL + MP mixtures produced a heavier (P<0.05) bursa weight than other treatments. In conclusion, the low-dose mixture of CSLS, CL, and MP was recommended based on a similar effectiveness trend to AGP in potentially improving the FCR.