In the context of global restrictions on the use of antibiotics, there has been increased research on natural plant-based ingredients as additives. It has been proved that many natural active ingredients contained in plants have positive effects on animal growth regulation. Artemisia argyi (A. argyi) is a traditional Chinese herbal medicine, and its extracts have been reported to have a variety of biological activities. Therefore, in order to explore the potential of the active extract of Artemisia argyi leaves (ALE) as a plant source additive, mice were fed with ALE at different concentrations for 60 days. Finally, the effects of ALE were evaluated by the growth indexes, blood indexes, and intestinal microflora changes of the mice. It was found that a medium concentration of ALE (150 mg/kg) could promote growth, and especially improved the feed efficiency of the mice. However, high concentrations of ALE (300 mg/kg) had some negative effects on the growth of mice, especially liver damage, which significantly increased AST and ALT levels in the blood. Therefore, the 150 mg/kg ALE treatment group was selected for 16S rDNA analysis. It was found that ALE could play a positive role by regulating the proportion of Bacteroidetes and Firmicutes in the intestinal tract. In particular, it can significantly up-regulate the quantities of Akkermansia and Bifidobacterium. These results suggest that ALE at appropriate concentrations can positively regulate animal growth.

Lipopolysaccharide (LPS) is an endotoxin that induces immune and inflammatory responses in the rumen epithelium of dairy cows. It is well-known that flavonoid phloretin (PT) exhibits anti-oxidative, anti-inflammatory and antibacterial activity. The aim of this research was to explore whether PT could decrease LPS-induced damage to bovine rumen epithelial cells (BRECs) and its molecular mechanisms of potential protective efficacy. BRECs were pretreated with PT for 2 h and then stimulated with LPS for the assessment of various response indicators. The results showed that 100 µM PT had no significant effect on the viability of 10 µg/mL LPS-induced BRECs, and this dose was used in follow-up studies. The results showed that PT pre-relieved the decline in LPS-induced antioxidant indicators (T-AOC and GSH-PX). PT pretreatment resulted in decreased interleukin-1β (IL-1β), IL-6, IL-8, tumor necrosis factor-α (TNF-α) and chemokines (CCL2, CCL5, CCL20) expression. The underlying mechanisms explored reveal that PT may contribute to inflammatory responses by regulating Toll-like receptor 4 (TLR4), nuclear transcription factor-κB p65 (NF-κB p65), and ERK1/2 (p42/44) signaling pathways. Moreover, further studies found that LPS-induced BRECs showed decreased expression of claudin-related genes (ZO-1, Occludin); these were attenuated by pretreatment with PT. These results suggest that PT enhances the antioxidant properties of BRECs during inflammation, reduces gene expression of pro-inflammatory cytokines and chemokines, and enhances barrier function. Overall, the results suggest that PT (at least in vitro) offers some protective effect against LPS-induced ruminal epithelial inflammation. Further in vivo studies should be conducted to identify strategies for the prevention and amelioration of short acute rumen acidosis (SARA) in dairy cows using PT.

Saccharomyces cerevisiae fermentation products (SCFP) can potentially promote gastrointestinal growth and immunity in young livestock. However, reports within the existing literature on the effects of SCFP supplements on calves have been inconsistent; therefore, we perform the following experiments to resolve the inconsistencies. A total of 22 Holstein calves [10 d after birth, BW = 48.93 ± 3.99 kg (mean ± SD)] were assigned randomly into two groups, namely the control group (CON) and SCFP group, each having 11 replicas. The calves in the CON were fed a basal diet, while the SCFP group was fed the basal diet supplemented with 5g/head/d SCFP (NutriTek, Diamond V, Cedar Rapids, IA52404, United States) incorporated into feed. All the calves were regularly fed thrice daily at 08:00, 14:30, and 21:00 and had free access to water. A 5-day adaptation phase was followed by a 45-day experimental period. The results showed that compared to the CON, at the end of the d-45 trial, the body weight was significantly greater in the SCFP group (p < 0.05), and during the 1-45 days, the ADG was higher (p < 0.05). The FCR in the 30-45 days SCFP group was higher (p < 0.05). Furthermore, the apparent digestibility of DM, CP, EE, ADF, Ca, and P were significantly increased in the SCFP group, except for NDF (p < 0.05). The concentration of GH and IGF-1 in serum showed a tremendous increase (p < 0.05) with SCFP supplementation on d 15 and d 45. On d 15, SCFP supplementation significantly increased the serum IgA contents (p < 0.05). Notably, on d 15 and d 45, the serum concentrations of IL-1β, IL-6, and TNF-α reduced (p < 0.001). Moreover, the Actinobacteriota in the SCFP group were significantly lower than those in the CON group (p = 0.034). SCFP significantly increased the abundance of Butyricimonas, Parabacteroides, and Ruminococcus. The differences among sob, Chao1, and PD-tree groups were statistically significant (p < 0.05). In conclusion, these results demonstrate that SCFP supplementation improved ADG, apparent digestibility and serum hormone, enhanced immunity, and regulated gut microbiota, thereby jointly promoting the growth of pre-weaning calves.