Impact of inoculating various lactic acid bacteria on vitamin A levels in total mixed ration silage

This study investigated the impact of different strains of lactic acid bacteria (LAB) on the vitamin A content in total mixed ration (TMR) silage. The TMRs were inoculated with Lactiplantibacillus plantarum (LP), Lacticaseibacillus casei (LC), Enterococcus faecium (EF) or left without LAB as control (CK) and subsequently ensiled under dark, anaerobic conditions for 56 days. Throughout the ensiling process, the fermentation quality, chemical composition, microbial community, and vitamin A content of the TMR silage were monitored. Additionally, the free radical scavenging ability, total antioxidant capacity (T-AOC), and activities of antioxidant enzymes (SOD, GSH-Px, CAT) in the three LAB strains were assessed. After 56 days of ensiling, the antioxidant enzyme activities of T-AOC, SOD, GSH-Px and CAT of TMR silage were also analyzed. The results indicated that LAB inoculation had a significant effect on both the fermentation quality and vitamin A content of TMR silage (p < 0.05). Among the LAB strains, LP and LC enhanced the fermentation quality of the TMR silage. Vitamin A loss rates in decreasing order were LC, CK, EF and LP groups. Notably, LAB strains with higher antioxidant properties were found to improve the antioxidant capacity of the TMR silage, thereby mitigating the degradation of vitamin A.