Zhiyong Hu

Background: Long-term high-fat diet (HFD) consumption induces hepatic lipid accumulation and metabolic dysregulation, but its integrated effects on the hepatic proteome and phosphoproteome remain incompletely understood. This study investigated HFD-induced hepatic molecular alterations using quantitative proteomics and phosphoproteomics. Methods: Eight-week-old male C57BL/6J mice were fed a control diet (CON) or HFD for 16 weeks, followed by phenotypic assessment, serum redox assays, and hepatic proteomic and phosphoproteomic analyses. Results: HFD-fed mice exhibited increased body weight, fat mass, liver weight, and marked hepatic lipid accumulation. Blood glucose levels and total pyruvate tolerance test area under the curve (AUC) were increased, whereas baseline-adjusted incremental AUC did not differ significantly. Serum malondialdehyde levels were elevated, whereas glutathione peroxidase activity was reduced, indicating impaired glucose homeostasis and redox balance. Proteomic analysis identified 15 differentially expressed proteins (4 upregulated and 11 downregulated), associated with lipid metabolism, biological oxidation, and xenobiotic metabolism. Gene set enrichment analysis identified significant positive enrichment of Class I peroxisomal membrane protein import and significant negative enrichment of cholesterol biosynthesis, gluconeogenesis, and xenobiotics. Phosphoproteomic analysis identified 8593 phosphoproteins and 28,180 phosphorylation sites, including 2045 differentially phosphorylated sites (1044 increased and 1001 decreased). Enrichment and exploratory network analyses implicated mitophagy, glucose metabolism, mTOR signaling, autophagy, oxidative phosphorylation, and cytoskeletal organization. Conclusions: Long-term HFD feeding induced obesity, glucose dysregulation, hepatic steatosis, and redox imbalance. Fatty acid oxidation and peroxisomal abundance patterns may reflect metabolic adaptation to lipid loading, while phosphosite abundance changes link nutrient sensing and autophagy regulation to the hepatic response.

Background: Branched-chain amino acid (BCAA) is involved in glucose and lipid metabolism and energy homeostasis, but whether its effects on maternal metabolism and offspring growth during lactation depend on dietary protein level remains unclear. Methods: C57BL/6J lactating dams were randomized after delivery to a normal-protein control group (CN, 20% protein), low-protein group (LP, 10% protein), CN + BCAA group (CNB), or LP + BCAA group (LPB) (n = 11/group). Maternal body composition, glucose and lipid metabolism, hepatic energy status, oxidative stress indices, and pup litter weight gain were assessed. Results: The LP diet reduced maternal body weight, pup litter weight gain, and glucose responses during the intraperitoneal pyruvate tolerance test (IPPTT), and increased hepatic lipid deposition and oxidative stress. BCAA supplementation increased pup litter weight gain under normal-protein conditions, but decreased maternal food intake and offspring growth under low-protein conditions. Metabolically, BCAA supplementation reduced the homeostasis model assessment of insulin resistance (HOMA-IR) and hepatic PEPCK1 activity under normal-protein conditions, while partially restoring IPPTT glucose responses and increasing hepatic PEPCK1 activity under low-protein conditions. In addition, BCAA supplementation reduced hepatic lipid deposition and ATP content at both protein levels. Notably, under low-protein conditions, BCAA supplementation increased serum β-hydroxybutyrate (β-HB), while alleviating hepatic oxidative stress. Conclusions: BCAA supplementation exerted opposite effects on offspring growth during lactation under different maternal dietary protein levels. These effects may be related to differential changes in maternal glucose and lipid metabolism and hepatic energy status, suggesting that BCAA supplementation during lactation should be evaluated according to maternal dietary protein level.

This preprint has been withdrawn at the request of the authors, as they have identified major flaws that cannot be adequately resolved by releasing an updated version.

Background: Dietary metabolizable energy (ME) and crude protein (CP) levels are important for lactation performance and metabolic responses in dairy ruminants. This study aimed to evaluate the effects of dietary ME and CP levels on lactation performance and postprandial metabolic responses in lactating dairy goats. Methods: Goats were randomly assigned to a 4 × 4 two-factor Latin square experiment consisting of four 14 d periods. The dietary treatments were high energy, high protein (HEHCP); high energy, low protein (HELCP); low energy, high protein (LEHCP); and low energy, low protein (LELCP). Serial postprandial arterial blood samples were collected at 17 daytime time points to characterize temporal changes in plasma amino acids, biochemical parameters and hormones. Results: Increasing CP supply elevated milk yield (+6%) and lactose yield (+5%) but decreased milk fat yield (−8%; p ≤ 0.04). Increasing ME supply tended to enhance milk yield and milk fat yield and increased milk lactose content only under the high CP condition (ME × CP interaction: p = 0.04), suggesting that the response to ME supply depended partly on dietary CP level. High CP increased plasma branched chain amino acid concentrations, whereas high ME reduced Leu and Val under the high CP condition. Most plasma amino acids exhibited marked postprandial dynamics, decreasing initially and then stabilizing, with CP × time interactions observed for Leu, Met, and Phe (p ≤ 0.05). High ME decreased plasma AST activity and tended to reduce urea N concentration and also reduced ALT activity and increased glucose concentration under the high CP diet. Following morning feeding, plasma urea N showed a progressive postprandial decline (p = 0.02), with glucagon decreasing and both prolactin and growth hormone increasing, despite no dietary effects on mean plasma hormone concentrations. Conclusions: Overall, dietary ME and CP levels affected lactation performance and selected plasma metabolic indicators in lactating dairy goats. Coordinated energy and protein supply should be considered when formulating diets for lactating dairy goats. Serial postprandial sampling further revealed temporal changes in plasma metabolites and hormones, providing useful information for refining precision nutrition strategies during lactation.

Heat stress, particularly during the prepartum period, compromises dairy cow health and has lasting effects on offspring. This study aimed to investigate the effects of maternal yeast culture (YC) supplementation during heat stress on the intestinal health of newborn calves, with a specific focus on elucidating the associated changes in jejunal morphology, microbial community, and metabolic profiles. Cows receiving YC had lower rectal temperatures, confirming mitigated heat stress. Their calves showed enhanced immune status (higher IgA, IgG) and reduced oxidative stress and metabolic markers. Jejunal structure and barrier integrity were improved. While microbial diversity was similar, specific bacterial abundances differed (e.g., Enterococcus spp. enriched in YC calves). Metabolomic analysis revealed modulated bile acid pathways and metabolites in YC calves, correlating with the microbial shifts. In conclusion, maternal YC supplementation during heat stress supports calf early-life gut health and development through maternal-offspring programming, optimizing gut microbiota, metabolism, and immunity.

Two-dimensional luminescent metal-organic frameworks (2D LMOFs), have garnered significant attention for their unique fluorescent properties and highly accessible active sites, yet designing these LMOFs with target-dependent fluorescence for sensing remains a challenging endeavor. Herein, a zinc tetra(4-carboxyphenyl)porphine (Zn-TCPP) LMOF was prepared and first applied to the fast and sensitive sensing of tetracycline hydrochloride (TCH). Upon TCH exposure, the signature red fluorescence of Zn-TCPP at 609 nm diminishes, accompanied by the emergence of a 520 nm peak, which were originated from photo-induced electron transfer (PET) of Zn-TCPP to TCH and inner filter effect (IFE) of TCH towards Zn-TCPP, and the triggers of Zn-TCPP on the instinct fluorescence of TCH, respectively. Notably, the I₅₂₀/I₆₀₉ fluorescence intensity ratio showed good linearity over a wide range of TCH concentrations (0.1-25 μmol/L), with a limit of detection (LOD) of 65.4 nmol/L. Additionally, the Zn-TCPP probe showed good TCH selectivity and anti-interference properties. The probe’s practicability was also validated by detecting TCH in spiked tap water, milk and chicken samples. Furthermore, test papers impregnated with the Zn-TCPP probe were prepared, allowing the visual detection of TCH with a smartphone. Results suggest the developed method is suitable for practical TCH detection.

This study evaluated the effects of supplementing rumen-protected methionine, threonine, isoleucine, and leucine to low-protein diets on lactating dairy cow performance. Sixty Holstein cows were assigned to one of four dietary treatments in a 9-week randomized complete block design: positive control (16% crude protein diet; 16% CP), negative control (12% CP), 12% CP plus the four essential amino acids (12% CP + EAA), and 14% CP supplemented with the four EAA (14% CP + EAA). The milk protein yield was significantly decreased in the 12% CP group compared to the 16% CP group but was restored to comparable levels with EAA supplementation of both the 12% and 14% CP diets. Dietary nitrogen intake and urinary nitrogen excretion both increased with higher dietary CP levels. Nitrogen utilization efficiency in milk was significantly improved by EAA supplementation, with the highest efficiency observed in the 12% CP + EAA treatment (39.0% vs. 33.3% in the 16% CP diet). Plasma urea levels increased with elevated dietary CP and EAA supplementation. Moreover, EAA supplementation significantly elevated venous methionine levels and showed a tendency to increase venous leucine levels. Additionally, compared to the negative control, EAA supplementation increased concentrations of glucagon and prolactin (p < 0.05). EAA supplementation of low-protein diets, particularly the 14% CP diet, improved the dietary protein efficiency of lactating cows without a concomitant decrease in milk protein yield.

The body condition of cows during the early perinatal period has a long-term impact on the health of their offspring calves; however, research on the mechanisms of liver metabolism in this context is limited. This study investigates the effects of pre-perinatal cow body condition score (BCS) on various blood biochemical, antioxidant and immune indices in offspring calves. The calves were categorized into two groups based on their mothers’ BCS: the high body condition group (OHBCS) and the low body condition group (OLBCS). The results indicate that the levels of insulin, non-esterified fatty acid, β-hydroxybutyrate, immunoglobulin G, glutathione peroxidase and superoxide dismutase in the blood of the OHBCS group were significantly higher than those in the OLBCS group (p < 0.05). In contrast, serum levels of tumor necrosis factor-α and interleukin-2 in the OHBCS group were significantly lower than those in the OLBCS group (p < 0.001 and p < 0.05, respectively). Additionally, integrating metabolomic and transcriptomic data revealed that levels of the tricarboxylic acid cycle, fatty acid β-oxidation and ornithine cycling were reduced in the OHBCS group, whereas the ketogenic pathway and triglyceride synthesis pathway were enhanced. These findings elucidate the mechanisms by which pre-perinatal cow BCS influences liver metabolism in offspring calves.

This study investigated the effects of Capsicum oleoresin (CAP) on the growth performance, nutrient digestibility and meat quality of fattening beef cattle. A total of 48 Simmental crossbred cattle, selected based on body weight (484.7 ± 48.4 kg), were randomly assigned to four treatment groups (each with 12 animals) in a randomized complete block design. In each group, the basal diet was supplemented with 0 g/d CAP (control), 4 g/d, 8 g/d and 12 g/d. The results showed that adding CAP linearly increased the dry matter intake (DMI; p = 0.023), led to a quadratic increase in the average daily gain (ADG; p = 0.035) and linearly decreased the feed-to-gain ratio (F/G; p = 0.018). The apparent digestibility of CP also linearly increased with increasing CAP dosage (p = 0.023), while the apparent digestibility of ADF showed a decreasing trend (p = 0.054). Additionally, the slaughter performance index and nutritional composition of beef were not affected by the amount of CAP added (p > 0.05), while the pH value of beef decreased linearly with increasing CAP addition (p = 0.016). Among all groups, the 8 g/d one exhibited the highest DMI, ADG, F/G, apparent digestibility of CP and water-holding capacity, as well as the lowest cooking loss. In conclusion, CAP can be used as a potential novel feed additive in the diet of beef cattle to improve growth performance and nutrient digestibility. Under the conditions applied in this study, a CAP amount of 8 g/d per cattle was found to be optimum for fattening beef cattle.

To investigate the effects of individual essential amino acids (EAA) on growth and the underlying mechanisms, EAA individually supplemented a low-protein (LP) diet fed to young rats in the present study. Treatments were an LP diet that contained 6% crude protein (CP), a high-protein (HP) diet that contained 18% CP, and 10 LP diets supplemented with individual EAA to achieve an EAA supply equal to that of the HP diet. The CP concentration of the LP diet was ascertained from the results of the first experiment, which examined the effects of dietary CP concentrations on growth rates, with CP ranging from 2% to 26%. Weight gain was increased with the supplementation of His, Ile, Lys, Thr, or Trp as compared to the LP diet (p < 0.05). Feed intake was greater for the His-, Lys-, and Thr-supplemented treatments as compared to the LP group (p < 0.05). Protein utilization efficiency was lower for the HP group than other groups (p < 0.01). The supplementation of Leu, Lys, and Val led to reduced protein utilization efficiency (p < 0.05), but the supplementation of Thr and Trp led to greater efficiency than the LP group (p < 0.05). Compared to the LP group, plasma urea concentrations were elevated with individual EAA supplementation, with the exception of the Thr addition. The added EAA resulted in increased concentrations of the corresponding EAA in plasma, except for Arg and Phe supplementation. The supplementation of Arg, His, Leu, Lys, and Met individually stimulated mTORC1 pathway activity (p < 0.05), and all EAA resulted in the decreased expression of ATF4 (p < 0.05). In summary, the supplementation of His, Ile, Lys, Thr, or Trp to an LP diet improved the growth performance of young rats. Responses to His and Lys additions were related to the activated mTORC1 pathway and feed intake increases. The improved growth performance resulting from the addition of a single EAA is not solely attributed to the increased plasma availability of EAA. Rather, it may be the consequence of a confluence of factors encompassing signaling pathways, the availability of amino acids, and other associated elements. The additivity of these factors results in independent responses to several EAA with no order of limitation, as is universally encoded in growth models for all production animal species.