Background and Aim: Antibiotics have been used as growth promoters in poultry. However, continuous and long-term antibiotics can cause resistance, suppress the immune system, and accumulate toxic residue. To overcome these problems, feed additives that are safe for livestock and health for humans are needed, including probiotics. Therefore, the study aimed to determine the effect of probiotics (Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus lactis, and Bifidobacterium spp.) and Moringa oleifera extract on performance (body weight gain, body weight, feed intake, feed efficiency, and feed conversion ratio [FCR]), carcass yield (carcass weight and percentage of carcass) and mortality of Peking duck.

Materials and Methods: This study used 48 Peking ducks, divided into four treatments and six replications. Each replication consisted of two ducks. The treatments were as follows: T0=control, T1=4 mL containing 1.2×10⁸ CFU/mL of probiotic in drinking water, T2=4 mL containing M. oleifera extract in drinking water, and T3=2 mL containing 1.2×10⁸ CFU/mL of probiotic in drinking water+2 mL containing M. oleifera extract in drinking water. The probiotics consist of L. acidophilus, L. casei, L. lactis, and Bifidobacterium spp. The data were statistically analyzed through analysis of variance. For the follow-up test, a multiple range test was conducted.

Results: There was no significant difference (p>0.05) between body weight, feed intake, and mortality treatments. By contrast, control and treatment showed a significant difference (p<0.05) on feed efficiency, FCR, body weight gain, carcass weight, and percentage of carcass weight. Results of body weight gain statistics showed no significant difference (p>0.05) between T0 and T1, but T0 and T1 showed a significant difference with T2 and T3. The results of the feed efficiency statistic showed no significant difference (p>0.05) between T0, T1, and T2, but there was a significant difference between T0, T1, and T3. Feed efficiency at T2 showed no significant difference with T3, T1, and T0. The results of the FCR statistic showed no significant difference (p>0.05) between T0, T1, and T2, but there was a significant difference between T0, T1, and T3. FCR at T2 showed no significant difference with T3, T1, and T0. The carcass weight statistic showed no significant difference (p>0.05) between T0, T1, and T3, but there was a significant difference between T0 and T2. T2 showed no significant difference with T1 and T3. The carcass percentage statistic showed no significant difference (p>0.05) between T0 and T1, but T0 and T1 showed a significant difference (p<0.05) with T2 and T3.

Conclusion: Based on the study results, it can be concluded that the use of a combination of probiotics (L. acidophilus, L. casei, L. lactis, and Bifidobacterium spp.) and M. oleifera extract can increase the production performance of Peking ducks and is safe for ducks' health.

Keywords: health, probiotic, Moringa oleifera, Peking duck.