This study aims to investigate the effects of probiotics and Chinese medicine polysaccharides (CMPs) on growth performance, blood indices, rumen fermentation, and bacteria composition in lambs. Forty female lambs were randomly divided into four groups as follows: control, probiotics, CMP, and compound (probiotics + CMP) groups. The results showed that probiotics treatment increased the concentrations of blood glucose (GLU) and immunoglobulin G (IgG) and enhanced rumen microbial protein contents but declined the value of pH in rumen fluid compared with the control (P < 0.05). Furthermore, supplementation with CMP enhanced the average daily gain (ADG) and the contents of IgA, IgG, and IgM in the serum but decreased the F:G ratio compared with the control (P < 0.05). Besides, both CMP and compound (probiotics + CMP) treatments decreased the ratio of acetic acid and propionic acid compared with the control (P < 0.05). High-throughput sequencing data showed that at the genus level, the relative abundance of Veillonellaceae_UCG-001 in the probiotics group was increased, the relative abundance of Succiniclasticum and norank_f__Muribaculaceae in the CMP group were enhanced, and the relative abundance of Ruminococcaceae_UCG-002 in the compound group was raised compared with the control (P < 0.05). In summary, supplementation with probiotics can promote rumen protein fermentation but decrease the diversity of bacteria in rumen fluid; however, CMP treatment increased the relative abundance of Fibrobacteria, changed rumen microbial fermentation mode, increased the immune function, and ultimately improved the growth performance.

To investigate the effect of Puerarin on intramuscular fat deposition in heat-stressed beef cattle and its underlying mechanism. Thirty-two healthy Jinjiang bulls were randomly divided into four groups and dietary with 0 (Control), 200 (Pue200), 400 (Pue400), and 800 (Pue800) mg/kg Puerarin in the feed concentrate. The results showed that Puerarin treatment enhanced the concentration of crude fat, fatty acid (C14:1 and C17:1), and the activity of fatty acid synthase in Longissimus thoracis (LT), but decreased the levels of blood leptin (P < 0.05). High-throughput sequencing of mRNA technology (RNA-Seq) was used and the analysis showed that 492 genes were down-regulated and 341 genes were up-regulated in LT, and these genes were significantly enriched to the pathways related to lipid metabolism. These results indicated that dietary supplemental with Puerarin enhanced intramuscular fat deposition by regulating lipid metabolism of heat-stressed beef cattle.

The experiment was conducted to investigate the effects of dietary supplementation with Puerarin on meat quality, muscle antioxidant ability, and muscle fiber characteristics of beef cattle under a hot environment in summer. Thirty-two 15 ± 1.5-month-old Jinjiang bulls (291.65 ± 8.84 kg) were randomly divided into four groups with dietary Puerarin at 0 (control), 200 (Pue200), 400 (Pue400), and 800 (Pue800) mg/kg in the feed concentrate (n = 8). The feeding trial lasted for 60 days after a 10-day adaptation period (July 1–September 8); the average values of temperature, relative humidity and temperature, and humidity index were 30.68°C, 68.05%, and 81.81, respectively. The growth performance on day 40 of the experiment period was calculated. After 60 days' experimental period, four Jinjiang cattle per treatment from the control group, Pue400 group, and Pue800 group were slaughtered. Compared with the control group, the Pue400 and Pue800 groups improved the growth performance of beef cattle; the Pue800 group elevated the activities of superoxide dismutase, total antioxidant capacity, and glutathione peroxidase in the M. longissimus thoracis (LT) muscle. In the control group, the cell membrane was incomplete, and most of the mitochondria were elongated and in a fission state, while in the Pue400 and Pue800 groups, the cell membrane was clear and complete, and the mitochondria presented with round and oval shapes. Compared with the control group, the Pue400 and Pue800 groups reduced the shear force of the LT muscle, and the Pue400 group decreased the muscle fiber diameter and the myosin heavy-chain (MyHC)-IIb gene expression. Furthermore, the Pue400 and Pue800 groups decreased the ratio of AMP/ATP, the Pue800 group reduced the AMP-activated protein kinase α2 mRNA expression, and the Pue400 group improved the nuclear respiratory factor 1 mRNA expression. These results indicated that dietary supplementation with Puerarin might be beneficial to the meat quality of heat-stressed beef cattle by improving muscle antioxidant ability and reducing the MyHC-IIb muscle fiber composition. Based on the results of this study, we recommended 400 mg/kg Puerarin in the feed concentrate of beef cattle (~300 kg) for mitigation of heat stress.

This study was carried out to investigate the effects of probiotics and Chinese medicine polysaccharides (CMP) on carcase characteristics, meat quality, muscle fibre type and intramuscular fat deposition in lambs. Forty female lambs with 4-5 months old and 21.69 ± 0.46 kg were randomly divided into four groups as follows: control, probiotics, CMP and probiotics + CMP groups. The results showed that supplemental probiotics increased carcase yield, the percentage of abdominal fat and perirenal fat of lambs, the levels of moisture and intramuscular fat in Longissimus thoracis (LT) muscle and the mRNA expression of MyHC I but decreased the value of shear force, lightness (L*) and yellowness (b*) and the percentage of heneicosanoic acid (C21:0) in LT muscle compared with the control group (p < .05). Supplemental CMP declined the value of b*, the percentage of C21:0 and mRNA expression of MyHC I but enhanced the percentage of arachidonic acid (C20:4N6) and the content of moisture in LT muscle compared with the control group (p < .05). The percentage of abdominal fat and perirenal fat, the value of meat redness (a*) and the mRNA expression of MyHC IIx were higher, while pH_24 h value was lower in lambs fed probiotics + CMP diets than those fed control diets (p < .05). All groups increased muscle fibres density of lambs compared with the control group (p < .05). Current results suggested that supplemental probiotics can affect muscle fibre characteristics, increase intramuscular fat deposition and improve meat quality. Probiotics should be a promising feed additive for production of high-quality lamb meat.

Pogostemon cablin essential oil (PEO), extracted from P. cablin, has anti-oxidant, anti-inflammatory, and anti-stress properties, as well as the ability to improve gastrointestinal digestion. This study aims to evaluate the effects of PEO on the performance, rumen epithelial morphology, and barrier function in heat-stressed beef cattle. Thirty-six male Jingjiang cattle at 18 months old were randomly assigned into four groups and fed a diet containing PEO at 0 (control), 50, 100, or 150 mg/kg in the feed concentrate (n = 9). All experimental cattle were fed under high temperature and humidity in summer for 60 days. The results indicated that 50 mg/kg of PEO treatment enhanced the average daily gain of beef cattle compared with the control group (P = 0.032). All PEO treatments reduced the diamine oxidase activity (P = 0.004) and malondialdehyde content (P = 0.008) in serum. In addition, the content of 70 kDa heat shock protein in the 100 mg/kg group was increased, and the activity of glutathione peroxidase and total antioxidant capacity in both 100 mg/kg and 150 mg/kg groups were enhanced compared to the control group (P < 0.05). More importantly, PEO treatment with 50 mg/kg enhanced the mRNA relative expressions of occludin in ruminal epithelia but decreased the mRNA relative expressions of c-Jun N-terminal kinase, P38 mitogen-activated protein kinases, caspase-3, Beclin1 (P < 0.05), and extremely significant declined the mRNA relative expressions of extracellular regulated protein kinases and ubiquitin-binding protein in contrast to the control group (P < 0.01). These findings indicated that dietary PEO supplementation might be favorable to improve growth performance and repairing damaged rumen epithelium of heat-stressed cattle by down-regulating the mitogen-activated protein kinase signaling pathway.