Mycotoxin contamination is a major food safety issue worldwide, posing a serious threat to animal production performance and human health. Lactic acid bacteria are generally regarded as safe fermentation potential probiotics. They have the advantages of low toxicity, small pollution, strong specificity and high safety, and can reduce the contamination of microorganisms and mycotoxins. In this study, we compared the mycotoxin degradation capacity of 15 lactic acid bacteria strains from the rumen of Qinghai yak, through comprehensive analysis, we finally identified the strains as potential probiotics because they have a fast growth speed, strong acid production capacity (pH < 4.5), and they can grow normally in an environment with a pH of 3.5, bile salt concentration of 0.1%, and good self-agglutination and hydrophobicity. It was found that the fermentation group (Pediococcus acidilactici C2, Pediococcus acidilactici E28, Pediococcus pentosaceus A16 and Enterococcus lactis C16) could significantly reduce mycotoxin content, and both the nutritional and fermentation quality of the feed improved after 7 days of fermentation, meaning that the fermentation group can be used as a functional feed additive.

To develop green feed additives suitable for antibiotic-free livestock farming on the Qinghai–Tibet Plateau, this study used Lactobacillus salivarius TB2.1, isolated from Tibetan black pigs, and Lactobacillus agilis CW13.2, isolated from wild boars in the Changbai Mountains, to prepare fermented feed. The study investigated the effects of these additives on the growth performance, slaughter performance, meat quality, immune and antioxidant functions, and gut microbiota composition of Duroc × Landrace × Large White crossbred finishing pigs (DLY finishing pigs). The experiment included 72 finishing pigs with an average body weight of 54.07 ± 1.02 kg, which were randomly divided into three groups, each with four replicates of 6 pigs. The control group (CK) was fed a basal diet, one treatment group (TB) was fed a diet consisting of 50% basal diet plus 50% Lactobacillus salivarius TB2.1-fermented feed, and the other treatment group (CW) was fed a diet consisting of 50% basal diet plus 50% Lactobacillus agilis CW13.2-fermented feed. The pre-feeding period lasted 3 days, and the experimental period lasted 57 days. The results showed that, compared with the CK group, (1) the CW and TB groups had significantly higher levels of crude protein, lactic acid, acetic acid, and propionic acid in the feed (p < 0.05), and significantly lower levels of crude fiber, neutral detergent fiber, acid detergent fiber, ammonium nitrogen, and pH (p < 0.05); (2) in the CW and TB groups, final body weight, average daily weight gain, and average daily feed intake were significantly higher (p < 0.001), while the feed-to-gain ratio was significantly lower (p < 0.01), with the CW group performing better than the TB group; (3) in both the CW and TB groups, carcass weight, eye muscle area, and meat redness significantly increased (p < 0.001), while backfat thickness and shear force significantly decreased (p < 0.001); (4) in both the CW and TB groups, serum immunoglobulin G, interleukin-2, and superoxide dismutase levels significantly increased (p < 0.05), malondialdehyde levels were significantly reduced in the CW group (p < 0.05), and catalase activity was significantly increased in the TB group (p < 0.05); (5) the relative abundance of Escherichia spp. in the cecum was significantly reduced in both the CW and TB groups (p < 0.05), while beneficial bacteria such as Lactobacillus spp. were significantly enriched (p < 0.05). In summary, feed fermented with Lactobacillus salivarius TB2.1 and Lactobacillus agilis CW13.2 can effectively improve the production performance of finishing pigs, enhance meat quality, strengthen immune and antioxidant capacities, and optimize the gut microbiota structure. Among these, CW13.2 was more effective in promoting weight gain, while TB2.1 was more effective in regulating protein and lipid metabolism. Fermented feed produced with both strains shows promising application prospects and can provide high-quality microbial strains and technical support for antibiotic-free swine farming on the Qinghai–Tibet Plateau.

This study aimed to evaluate the nutritional composition and fermentation quality of feed fermented by Bacillus amyloliquefaciens and Bacillus licheniformis as well as their effects on growth performance, meat quality, blood parameters, and gut microbiota in fattening pigs. A total of 72 healthy Duroc × Landrace × Large White crossbred barrows (68.78 ± 1.41 kg, p > 0.05 for initial body weight among groups) were randomly assigned to three dietary treatments, with four replicates pens per treatment and six pigs per pen. The pigs were fed one of three diets: (1) CK: 100% basal diet; (2) YR1: 50% basal diet + 50% feed fermented with Bacillus amyloliquefaciens YR3.2; and (3) YR2: 50% basal diet + 50% feed fermented with Bacillus licheniformis YR3.1. The experiment consisted of a 7-day adaptation period and a 50-day treatment period. The results showed that the crude protein, starch, lactic acid, acetic acid, and propionic acid contents were significantly higher in the treatment groups than in the control group (p < 0.05). The final body weight of fattening pigs, serum superoxide dismutase activity, and redness value of the longissimus dorsi muscle were significantly higher in the treatment groups than in the control group (p < 0.05). The carcass weight of the YR1 group was significantly higher than that of the other groups (p < 0.05). Moreover, the shear force of pork was significantly lower in the treatment groups than in the control group (p < 0.05). Microbial analysis showed that Firmicutes dominated the jejunum and cecum in all groups (>80%). In the YR1 group, the abundance of Clostridium increased in the jejunum, whereas the abundance of Terrisporobacter decreased. In the YR2 group, the abundances of both Clostridium and Terrisporobacter increased in the jejunum and cecum. In conclusion, fermented feed prepared with Bacillus amyloliquefaciens and Bacillus licheniformis has a positive effect on the growth performance of fattening pigs, but fermented feed prepared by Bacillus amyloliquefaciens YR3.2 has a more significant effect on improving growth performance, feed conversion efficiency and some meat quality indicators.