Indole and skatole (3-methylindole, C₉H₉N) are common nitrogen-containing heterocyclic pollutants found in waste, wastewater treatment plants, and public restrooms and are the most notorious compounds in animal feces. Biodegradation was considered a feasible method for the removal of indole and skatole, but a comprehensive understanding of the metabolic pathways under both aerobic and anaerobic conditions was lacking, and the functional genes responsible for skatole biodegradation remained a mystery. Through metagenomic and gene cluster functional analysis, Acinetobacter piscicola p38 (NCBI: CP167896), genes 1650 (styrene monooxygenase: ACDW34_08180), and 1687 (styrene monooxygenase: ACDW34_08350) were identified as having the potential to degrade indole and skatole. The heterologous expression results demonstrate that the genes 1650 and 1651 (flavin reductase: ACDW34_08185), when combined, are capable of degrading indole, while the genes 1687 and 1688 (flavin reductase: ACDW34_08355), in combination, can degrade indole as well as skatole. These reactions necessitate the involvement of flavin reductase and NAD(P)H to catalyze the oxygenation process. This work aimed to provide new experimental evidence for the biodegradation of indole and skatole. This study offered new insights into our understanding of skatole degradation. The Acinetobacter_piscicola p38 strain provided an effective bacterial resource for the bioremediation of fecal indole and skatole.

Coated sodium selenite (CSS) is a rumen-protected selenium supplement that can improve selenium status and lactation performance in buffalo. This study investigated the effects of CSS supplementation on milk yield, rumen fermentation, digestibility, blood biochemical parameters, and antioxidant capacity in 28 dairy hybrid buffaloes (Murrah × local breed; milk yield = 5.96 ± 0.21 kg/d; parity = 2.96 ± 0.15, mean ± SD). The buffaloes were randomly allocated into four groups: control (basal diet), low CSS (LCSS, basal diet + 0.1 mg/kg CSS), medium CSS (MCSS, basal diet + 0.15 mg/kg CSS), and high CSS (HCSS, basal diet + 0.2 mg/kg CSS). The trial included a 7-day adaptation period followed by a 60-day experimental period. Compared with the control group, the LCSS group showed significant increases in rumen acetic acid, propionic acid, and total volatile fatty acid contents; milk yield, milk fat percentage, and 4% standard milk yield; neutral detergent fiber digestibility; and antioxidant capacity. These results demonstrate that supplementing 0.1 mg/kg CSS improves rumen fermentation efficiency and cellulose digestibility, thereby enhancing the antioxidant capacity and lactation performance of dairy buffaloes.