Here, we investigated the roles and mechanisms of flavonoids from mulberry leaves (FML) on lipid metabolism in high fat diet (HFD)-fed mice. ICR mice were fed either a control diet (Con) or HFD with or without FML (240 mg/kg/day) by oral gavage for six weeks. FML administration improved lipid accumulation, alleviated liver steatosis and the whitening of brown adipose tissue, and improved gut microbiota composition in HFD-fed mice. Microbiota transplantation from FML-treated mice alleviated HFD-induced lipid metabolic disorders. Moreover, FML administration restored the production of acetic acid in HFD-fed mice. Correlation analysis identified a significant correlation between the relative abundances of Bacteroidetes and the production of acetic acid, and between the production of acetic acid and the weight of selected adipose tissues. Overall, our results demonstrated that in HFD-fed mice, the lipid metabolism improvement induced by FML administration might be mediated by gut microbiota, especially Bacteroidetes-triggered acetic acid production.

Chlorogenic acid (CGA), as one of the richest polyphenol compounds in nature, has broad applications in many fields due to its various biological properties. However, initial data on the effects of dietary CGA on protein synthesis and related basal metabolic activity has rarely been reported. The current study is aimed at (1) determining whether dietary CGA supplementation improves the growth performance and carcass traits, (2) assessing whether dietary CGA alters the free amino acid profile, and (3) verifying whether dietary CGA promotes muscle protein synthesis in finishing pigs. Thirty-two (Large × White × Landrace) finishing barrows with an average initial body weight of 71.89 ± 0.92  kg were randomly allotted to 4 groups and fed diets supplemented with 0, 0.02%, 0.04%, and 0.08% CGA, respectively. The results indicated that, compared with the control group, dietary supplementation with 0.04% CGA slightly stimulated the growth performance of pigs, whereas no significant correlation was noted between the dietary CGA levels and animal growth ( P > 0.05 ). Furthermore, the carcass traits of pigs were improved by 0.04% dietary CGA ( P < 0.01 ). In addition, dietary CGA significantly improved the serum free amino acid profiles of pigs ( P < 0.01 ), while 0.04% dietary CGA promoted more amino acids to translocate to skeletal muscles ( P < 0.05 ). The relative mRNA expression levels of SNAT2 in both longissimus dorsi (LD) and biceps femoris (BF) muscles were augmented in the 0.02% and 0.04% groups ( P < 0.05 ), and the LAT1 mRNA expression in the BF muscle was elevated in the 0.02% group ( P < 0.05 ). We also found that dietary CGA supplementation at the levels of 0.04% or 0.08% promoted the expression of p-Akt and activated the mTOR-S6K1-4EBP1 axis in the LD muscle ( P < 0.05 ). Besides, the MAFbx mRNA abundance in the 0.02% and 0.04% groups was significantly lower ( P < 0.05 ). Our results revealed that dietary supplementation with CGA of 0.04% improved the free amino acid profile and enhanced muscle protein biosynthesis in the LD muscle in finishing pigs.

This study aimed to investigate the effects of dietary beta-hydroxy beta-methyl butyrate (HMB) supplementation on muscular lipid metabolism in Bama Xiang mini-pigs. Thirty-two piglets (8.58 ± 0.40 kg, barrow) were selected and fed a basal diet supplemented either with 0 (control), 0.13%, 0.64%, or 1.28% HMB for 60 days. Throughout the experiments, they had free access to clean drinking water and diets. Data of this study were analyzed by one-way ANOVA using the SAS 8.2 software package, followed by a Tukey’s studentized range test to explore treatment effects. The results showed that compared to the control, 0.13% HMB decreased the intramuscular fat (IMF) content and increased polyunsaturated fatty acids (PUFAs) in Longissimus thoracis muscle (LTM), and increased the n3 PUFAs in soleus muscles (SM, p < 0.05). Moreover, HMB supplementation led to alterations in the mRNA expression of genes related to lipid metabolism. Serum metabolome profiling showed that in both LTM and SM of Bama Xiang mini-pigs, N-Methyl-l-glutamate was positively correlated with SFA and nummularine A was negatively correlated with C18:3n3 PUFA (p < 0.05). Therefore, N-Methyl-l-glutamate and nummularine A might be potential biomarkers of the HMB-supplemented group. These results suggested that dietary HMB supplementation could decrease the IMF content and increase n3 PUFAs as well as regulate the related metabolites (N-Methyl-l-glutamate and nummularine A) in the serum of pigs.

This study examined the effects of dietary leucine supplements on antioxidant capacity and meat quality in growing-finishing pigs. A total of 24 crossbred (Duroc × Landrace × Yorkshire) pigs with an average initial weight of 68.33 ± 0.97 kg were randomly allotted to three treatment groups. All pigs were exposed to constant heat stress. Each group of pigs was fed a basal diet, or a diet supplemented with increasing levels of leucine (0.25% or 0.50%). The results showed that leucine intake could improve average daily gain and reduce feed/gain of finishing pigs under heat stress (p < 0.05). The supplementation of leucine could improve the carcass slant length (p = 0.09), and dramatically increased loin-eye area of the finishing pigs (p < 0.05) but had no significant effect on other carcass traits. Compared with the control group, 0.50% leucine markedly reduced drip loss and shear force of longissimus dorsi muscle, and increased pH value at 24 h after slaughter (p < 0.05). Dietary supplementation of 0.25% leucine increased the contents of inosine monophosphate and intramuscular fat in biceps femoris muscle (p < 0.05). Supplementation of 0.25% or 0.50% leucine significantly stimulated the activities of antioxidant enzymes while reduced the level of MDA in serum, liver and longissimus dorsi muscle (p < 0.05). Compared with the control group, 0.50% leucine supplementation markedly modulated the relative mRNA expression levels of genes related to muscle fiber type and mitochondrial function in longissimus dorsi muscle and the gene relative antioxidant in the liver (p < 0.05). In conclusion, dietary leucine supplementation could improve the growth performance and meat quality of the finishing pigs under heat stress, and the pathway of Keap1-NRF2 and PGC-1α-TFAM might be involved.

Iron is a trace element necessary for cell growth, development, and cellular homeostasis, but insufficient or excessive level of iron is toxic. Intracellularly, sufficient amounts of iron are required for mitochondria (the center of iron utilization) to maintain their normal physiologic function. Iron deficiency impairs mitochondrial metabolism and respiratory activity, while mitochondrial iron overload promotes ROS production during mitochondrial electron transport, thus promoting potential disease development. This review provides an overview of iron homeostasis, mitochondrial iron metabolism, and how mitochondrial iron imbalances-induced mitochondrial dysfunction contribute to diseases.

Branched-chain amino acids (BCAAs) have key physiological roles in the regulation of protein synthesis, metabolism, food intake and aging. This study aimed to investigate the protective effect of balanced BCAAs...

Background: It has been demonstrated that low-protein diets can improve the meat quality of pork. This study aimed to investigate the effects of long-term protein restriction from piglets to finishing pigs for 24 weeks on meat quality and muscle metabolites of Shaziling pigs. Results: Compared to the control group, reducing dietary protein levels by 20% reduced the L* value (p < 0.05), increased the a* value (p < 0.01), and tended to decrease pressing loss (p = 0.06) of longissimus thoracis muscle (LTM). Furthermore, compared to the control group, the −20% group had significantly lower levels of muscular danazol, N,N-dimethyl-Safingol, and cer(d18:0/14:0) (p < 0.05), all of which were positively associated with the L* value and negatively associated with the a* value (p < 0.05). Therefore, danazol, N,N-dimethyl-Safingol, and cer(d18:0/14:0) might be potential biomarkers for meat color. Conclusions: These results indicated that reducing dietary crude protein by 20% for 24 weeks could improve meat quality and alter muscular metabolites of Shaziling pigs, and the improvement in meat quality might be ascribable to decreased danazol, N,N-dimethyl-Safingol and cer(d18:0/14:0).

This study aimed to explore the effects of the incremental injection of lipopolysaccharide (LPS) on liver histopathology, inflammation, oxidative status, and mitochondrial function in piglets. Forty healthy Duroc × Landrace × Yorkshire castrated boars (21 ± 2 days old, weight 6.84 ± 0.11 kg) were randomly assigned to five groups (n = 8) and then slaughtered on days 0 (group 0, without LPS injection), 1 (group 1), 5 (group 5), 9 (group 9), and 15 (group 15) of LPS injection, respectively. The results showed that, compared to the piglets without LPS injection, LPS injection caused liver injury in the early phase, as manifested by the increased activities of serum liver injury-related parameters (aspartate amino transferase, alanine aminotransferase, alkaline phosphatase, cholinesterase, and total bile acid) on day 1, and impaired liver morphology (disordered hepatic cell cord arrangement, dissolved and vacuolized hepatocytes, karyopycnosis, and inflammatory cell infiltration and congestion) on days 1 and 5. Meanwhile, LPS injection caused liver inflammation, oxidative stress, and mitochondrial dysfunction on days 1 and 5, as reflected by the upregulated mRNA expression of TNF-α, IL-6, IL-1β, TLR4, MyD88, and NF-κB; increased MPO and MDA content; and impaired mitochondrial morphology. However, these parameters were ameliorated in the later phase (days 9~15). Taken together, our data indicate that the incremental injection of the LPS-induced liver injury of piglets could be self-repaired.