Effects of different stocking density and phytogenic feed additives dosage levels on growth performance, nutrient digestibility, blood profile, and behavior change of growing-finishing pigs

This study was to investigate the effects of different phytogenic feed additives (PFA) dosage levels in grower finishing pigs with stressed by high stocking density. A total of 72 mix sexed 12-week growing pigs [(Landrace × Yorkshire) × Duroc] with initial body weight of 49.28 ± 4.58 kg were used for 8 weeks. There were 3 replicate pens in each treatment, with 3 pigs per pen. The dietary treatment consisted of basal diets in animal welfare density (NC, negative control), basal diet in high stocking density (PC, positive control), PC + essential oil (T1), PC + 0.08% essential oil (T2), PC + 0.10% bitter citrus extract and essential oil (T3), PC + 0.2% bitter citrus extract and essential oil (T4), PC + 0.05% grape pomace extract (T5), PC + 0.10% grape pomace extract (T6). The reduction of space allowance decreased (P < 0.05) growth performance such as average daily gain, feed efficiency and nutrient digestibility such as dry matter, crude protein, and gross energy. Also, the fecal score of PC groups increased (P< 0.05) compared with other treatments. 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 reducing growth performance, nutrient digestibility, some increasing stress indicators in blood and animal behavior. In conclusion, the supplementation of PFA improved the health of pigs with stress by high stocking density and low dosage of bitter citrus and essential oil (T3) is the most effective.

Key Words: pig, plant extract, dosage, stocking density, stress.

Published in the proceedings of the 10th Symposium on Gut Health in Production of Food Animals 2022, St. Louis, USA.