Effects of phytogenic feed additives in growing and finishing pigs under different stocking density

This study was to investigate effects of different phytogenic feed additives (PFA) in grower finishing pigs with stressed by high stocking density. A total of 84 growing pigs ([Landrace × Yorkshire] × Duroc) with initial body weight (BW) of 28.23 ± 0.21 kg were used for 10 weeks (4 replicate pens with 3 pigs per pen). The dietary treatment consisted of basal diets in animal welfare density (positive control [PC]), basal diet in high stocking density (negative control [NC]), NC + 0.04% bitter citrus extract (PT1), NC + 0.01% microencapsulated blend of thymol & carvacrol (PT2), NC + 0.10% mixture of 40% bitter citrus extract and 10% microencapsulated blend of thymol and carvacrol (PT3), NC + 0.04% premixture of grape seed and grape marc extract, green tea and hops (PT4), and NC + 0.10% fenugreek seed powder (PT5). The reduction of space allowance significantly decreased (p < 0.05) growth performance (average daily gain, average daily feed intake, feed efficiency) and nutrient digestibility (dry matter, crude protein). Also, the fecal score of NC group increased (p < 0.05) compared with other groups. In blood profiles, lymphocyte decreased (p < 0.05), and neutrophil, cortisol, TNF-α increased (p < 0.05) when pigs were in high stocking density. Basic behaviors (feed intake, standing, lying) were inactive (p < 0.05) and singularity behavior (biting) were increased (p < 0.05) under high stocking density. However, PFA groups alleviated the negative effects such as reducing growth performance, nutrient digestibility, increasing stress indicators in blood and animal behavior. In conclusion, PFA groups improved the health of pigs with stressed by high stocking density and PT3 is the most effective.