Stocking density stress is one of the most common management stressors in the poultry industry. The present study was designed to investigate the effect of dietary Sophora koreensis (SK; 0 and 20 mg/kg diet) and stocking density (SD; 14 and 16 chickens/m²) on the antioxidant status, meat quality, and growth performance of native Korean chickens. There was a lower concentration of malondialdehyde (MDA) and a higher concentration of catalase, superoxide dismutase (SOD), and total antioxidant capacity in the serum and leg muscle with the supplementation of SK. The concentration of MDA was increased and concentrations of SOD were decreased in the leg muscle of chickens in low SD treatments. The SK-supplemented treatments showed an increased 3-ethylbenzothiazoline-6-sulfonate-reducing activity of leg muscles. The higher water holding capacity of breast muscle and a lower cooking loss and pH were shown in the SK-supplemented treatments. The addition of dietary SK resulted in a greater body weight gain and greater spleen and bursa Fabricius weight, as well as lower feed intake and abdominal fat. The low SD and supplementation of SK increased the concentrations of cholesterol. The concentration of glucose was increased in the low SD treatment. Corticosterone level was decreased in the SK-supplemented and low SD treatments. In conclusion, SK supplementation reduced the oxidative stress and increased meat quality and antioxidant status of chickens apart from the SD stress.

Sophora koreensis is an endemic species of Gangwon-do, Korea, that has a variety of applications for foods and for folk remedies. Here this research analyzed and compared compounds present in leaves, stems, and roots of S. koreensis collected from three different habitats in Chuncheon, Inje and Yanggu in South Korea. This research also analyzed soil microorganisms present in the three habitats to determine the correlation between the compound and microorganisms. N-methylcytisine was the most common compound in all three habitats, but the amounts varied with Chuncheon having the highest amount (509 mg/L), followed by Yanggu and Inje(102 mg/L and 39 mg/L, respectively). The composition of microorganisms also varied by habitat. Yanggu, Inje, and Chuncheon had 1013, 973, and 814 taxa, respectively. According to the phylogenetic relations, the composition of the soil microorganisms in Chuncheon was significantly different from the other two. It contained more PAC000121_g (Solibacteres), major taxa in all three habitats (14% in Chuncheon). In contrast less Opitutus minor taxa was found than Yannggu and Inje. The correlation between the soil microorganism N-methylcytisine was analyzed. Among these microorganisms, Paraburkholderia had a positive correlation with N-methylcytisine. Meanwhile, Rhizomicrobium, CP011215_f (Paceibacter), KB906767_g (Solibacteres) and Opitutus negatively correlated with N-methylcytisine. The results suggested that soil microorganisms in the habitats influenced the variations of the N-methylcytisine.

Sophora koreensis Nakai, listed as endangered on the IUCN Red List, is a species native to Korea, specifically found in parts of Gangwon-do. Recent research highlights its potential in hangover relief and as an antioxidant source, sparking interest in enhancing its components through mutation for commercial purposes. Given its limited distribution, micropropagation of S. koreensis is essential for its economic exploitation. This study focuses on in vitro culture to develop an elongation system for micropropagation. The hormonal combination of 6-benzylaminopurine (2 μM), thidiazuron (2 μM), and indole-3-butyric acid (0.5 μM) produced the highest number of shoots (14) with an average length of 0.7 cm compared to the control. Additionally, adjusting photoperiod conditions under specific culture media further increased shoot length to 0.6 cm, which was also higher than that of the corresponding control group under standard light conditions. However, survival rates were generally low across all treatments during subculture. Isolating and individually culturing induced explants resulted in shorter shoots and lower survival rates. Improvements were noted when explants with 10 shoots were subcultured, achieving an 83% survival rate, with an average of 4.93 shoots at 0.95 cm in length. Rooting was most successful with 10 μM IBA, also showing the highest root number, indicating a potential pathway for enhancing micropropagation efficiency.