PSXIII-5 Combination of Scutellaria baicalensis and Lonicera japonica herbal extracts enhance the growth performance and respiratory rate of grow-finishing by combating heat stress in summer.

Abstract The dietary inclusion of phytogenic feed additives to improve the performance and health status of pigs is safe, effective and environmentally friendly, thus gaining growing popularity among new strategies. Herein, we aimed to conduct a 10-week growth trial using three groups of 70 grow-finishing pigs [210 total pigs (Landrace × Yorkshire ♀ × (Duroc ♂) initial body weight (BW) 53.92 ± 2.38 kg] to assess the impact of herbal extract mixture (HEM, Scutellaria baicalensis and Lonicera japonica) on growth performance, nutrient digestibility, respiratory rate, rectal temperature, serum biochemical and hematology, and carcass quality. Pens of pigs (5 pigs/pen—3 gilts and 2 barrows) were randomly allocated into one of three dietary treatments in a completely randomized design with 14 replicates per treatment. The test diets were corn-soybean meal-based basal diets (CON) with the addition of none, 0.05%, and 0.10% of HEM. The diets were fed into two phases: Phase 1, from weeks 0–5, and Phase 2, from weeks 5–10. All data was analyzed using the GLM procedure of the SAS, and polynomial contrast was used to determine linear and quadratic effects on the graded level of HEM in pigs. P < 0.05 and at 0.05 > P ≤ 0.10 were considered as significant and tends, respectively. During Phase 1, pigs fed increasing HEM supplement had linearly decreased (P < 0.05) G:F compared to CON. However, during phase 2, the increasing level of HEM supplement had linearly increased (P < 0.05) BW, average daily gain (ADG), average daily feed intake (ADFI), and tendency to decrease (P < 0.10) gain to feed ratio (G: F) in pigs. Similarly, for the overall experimental period (i.e from weeks 0-10), pigs fed increasing HEM supplement had linearly (P < 0.05) increased their ADG and decreased G: F, and a tendency to increase ADFI. Moreover, HEM-treated groups showed linearly increased (P < 0.05) N digestibility. Furthermore, at the end of week 5, HEM-treated pigs showed linearly reduced (P < 0.05) respiratory rate and rectal heat. Correspondingly, serum cortisol, malondialdehyde (MDA), and heat stress protein 70 (HSP70) levels were linearly reduced in pigs receiving HEM supplement. Additionally, the biochemical variables such as glucose, insulin, lymphocytes, packed cell volume, superoxide dismutase (SOD), and glutathione peroxidase (GPx) were linearly (P < 0.05) increased in pigs fed increasing HEM supplementation with Nil effect on blood urea nitrogen, white blood cells, and nitric oxide. In summary, supplementing pigs with increasing levels of HEM, consisting of Scutellaria baicalensis and Lonicera japonica, could be a potential option to improve their growth performance, nutrient digestibility, and reduce heat stress without negative effects on carcass traits.