Effects of different stocking density and various phytogenic feed additives dosage levels on growing-finishing pigs

Hyun Ah Cho1, Min Ho Song2, Ji Hwan Lee3, Han Jin Oh1, Yong Ju Kim1, Jae Woo An1, Se Yeon Chang1, Young Bin Go1, Dong Cheol Song1, Seung Yeol Cho4, Dong Jun Kim4, Mi Suk Kim4, Hae Ryoung Park6, Hyeun Bum Kim5,*, Jin Ho Cho1,**
Author Information & Copyright
1Chungbuk National University, Cheongju-si 28644, Korea.
2Chungnam National University, Dajeon-si 16890, Korea.
3University of Georgia , Athens 30609, United States.
4Eugene-Bio, suwon-si 16675, Korea.
5Dankook University, cheonan -si 31116, Korea.
6Korea Agriculture Technology Promotion Agency, Iksan-si 54667, Korea.
**Corresponding Author: Hyeun Bum Kim, Dankook University, cheonan -si 31116, Korea, Republic of. E-mail: .
**Corresponding Author: Jin Ho Cho, Chungbuk National University, Cheongju-si 28644, Korea, Republic of. E-mail:

© Copyright 2023 Korean Society of Animal Science and Technology. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


This study was to investigate the effects of different phytogenic feed additives (PFA) dosage levels in growing- finishing pigs stressed by high stocking density. A total of 72 mix sexed 12 weeks growing pigs [(Landrace × Yorkshire) × Duroc] with initial body weight (BW) of 49.28 ± 4.58 kg were used for 8 weeks. There were 3 replicate pens in each treatment group, with 3 pigs per pen. The dietary treatment groups consisted of basal diets in animal welfare density (NC, negative control), basal diet in high stocking density (PC, positive control), PC + 0.04% essential oil (ES1), PC + 0.08% essential oil (ES2), PC + 0.10% bitter citrus extract & essential oil (CES1), PC + 0.20% bitter citrus extract & essential oil (CES2), PC + 0.05% grape pomace extract (GP1), PC + 0.10% grape pomace extract (GP2). The reduction of space allowance decreased (p < 0.05) average daily gain, feed efficiency and digestibility of dry matter, crude protein, and gross energy. Also, the fecal score of PC groups increased (p < 0.05) compared with other groups. Basic behaviors (feed intake, standing, lying) were inactive (p < 0.05) and singularity behavior (biting) was increased (p < 0.10) under high stocking density. There was no difference in blood profile. However, the supplementation of PFA alleviated the negative effects such as reduced growth performance, nutrient digestibility, some increasing stress indicators in blood (cortisol) and animal behavior (biting). In conclusion the negative effect of high stocking density was most effectively mitigated by normal dosage of mixture of bitter citrus extract and essential oil additive (CES1).

Keywords: pig; dosage; additive; stress; plant extract; stocking density