To investigate the effects of 5-hydroxymethylfurfural (5-HMF) on ruminal fermentation characteristics and bacterial community structure, 5-HMF was supplemented at the levels of 0, 7500, and 30,000 mg/kg DM under two dietary concentrate-to-roughage ratios (20:80, T1; 80:20, T2) in in vitro rumen incubation, mainly focusing on gas production, fermentation parameters, nutrient digestibility and bacterial community. The results showed that 24 h gas production (GP₂₄), 72 h gas production (GP₇₂), the gas production rate (c) and dry matter digestibility (DMD) in T2 were higher than those in T1 (p < 0.01). With increasing levels of 5-HMF supplementation, GP₇₂ and asymptotic gas production (B) increased linearly and quadratically (p < 0.05). T2 also had a higher butyrate concentration and a lower acetate/propionate (A/P) ratio than T1 (p < 0.05). With the increase in 5-HMF supplementation level, ruminal ammonia nitrogen (NH₃-N) concentration showed a quadratic response. In contrast, the concentrations of total volatile fatty acids (TVFAs), acetate and isobutyrate decreased linearly. Propionate concentration showed linear and quadratic decreasing trends, while the A/P ratio exhibited linear and quadratic increasing trends (p < 0.05). The supplementation of 5-HMF at 30,000 mg/kg DM reduced propionate and isobutyrate concentrations under both dietary conditions (p < 0.05). No differences were observed in the alpha diversity indices of the bacterial community among different 5-HMF levels or substrates (p > 0.05). PCoA and PERMANOVA revealed that community structure differed between the 7500 mg/kg DM group and the 0 mg/kg DM group in the T1 diet (p = 0.011), whereas no difference was detected among T2 treatments. LEfSe revealed that 6 and 13 differential bacterial taxa were identified in T1 and T2 at the 5-HMF level of 7500 mg/kg DM, respectively. Correlation analysis revealed that, in T1, GP₇₂ was positively correlated with Pseudomonadota, and the A/P ratio was positively correlated with fibrolytic taxa including Rikenellaceae_RC9_gut_group and Christensenellaceae_R-7_group. In T2, c was positively correlated with Fibrobacterota and Fibrobacter, while NH₃-N was positively correlated with Desulfovibrio, indicating diet-specific microbial associations with rumen fermentation (p < 0.05). In conclusion, the high-concentrate diet exhibited stronger rumen fermentation activity. 5-HMF exerted diet-specific effects: In the low-concentrate diet, 5-HMF at 7500 mg/kg DM enriched fibrolytic microbes and shifted fermentation toward an acetate-type pattern. In the high-concentrate diet, it modulated hydrogen-metabolizing bacteria while selectively enriching Pseudomonadota capable of participating in carbohydrate metabolism. The 30,000 mg/kg DM level inhibited rumen fermentation. The findings provide a theoretical reference for the application of 5-HMF in ruminant feeds. However, further in vivo trials are required to validate its effects, and future studies with refined dose gradients based on realistic 5-HMF concentrations in feedstuffs are needed to comprehensively evaluate its efficacy and safety.

This study optimized the cryopreservation protocol for cashmere goat semen by testing centrifugation speeds (750, 1000, 1250, 1500 rpm) for seminal plasma removal and L-proline concentrations (10, 30, 50 mmol/L) in a freezing extender. Semen from six 3-year-old breeding bucks of Inner Mongolia cashmere goats was evaluated post-thaw in terms of motility, membrane integrity, antioxidant capacity, and artificial insemination (AI) outcomes (n = 130 does). The results demonstrated that the group that underwent centrifugation at 1250 rpm saw significantly improved sperm motility (p < 0.05), curvilinear velocity (VCL, p < 0.05), and straight-line velocity (VSL, p < 0.05) compared to the other groups. The addition of 30 mmol/L L-proline further enhanced post-thaw sperm motility (p < 0.05), plasma membrane integrity (p < 0.05), and acrosome integrity (p < 0.05), while significantly reducing reactive oxygen species (ROS, p < 0.05) and malondialdehyde (MDA, p < 0.05) levels. This group also exhibited the highest antioxidant capacity, as indicated by elevated levels of total antioxidant capacity (T-AOC), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) (p < 0.05). AI trials revealed that semen treated with 1250 rpm centrifugation and 30 mmol/L L-proline achieved the highest kidding rate (56.82%), significantly outperforming the control group (37.21%, p < 0.05). Meanwhile, no significant differences were observed in prolificacy or offspring sex ratio (p > 0.05). In conclusion, this study demonstrates that combining 1250 rpm centrifugation for seminal plasma removal with the addition of 30 mmol/L L-proline to the freezing extender significantly improves the quality of cryopreserved cashmere goat semen and enhances AI outcomes.

This study examined the effects of purified lovastatin (LV) obtained from Monascus fermentation on ruminal fermentation, methane production, and microbial communities during a 48-h in vitro incubation. A fattening-sheep diet containing concentrate and roughage at 60:40 was treated with 0, 50, 100, or 150 mg LV/kg dry matter (DM). Samples from the control and 100 mg/kg DM treatments were selected for bacterial and archaeal 16S rRNA amplicon sequencing. Compared with the control, supplementation with 100 mg LV/kg DM significantly decreased methane production (mL/g DM) and methane content (%) by 22.1% and 12.7%, respectively, while increasing in vitro DM degradation by 4.9%. Cumulative gas production and total VFA concentration did not differ significantly among treatments. The molar proportion of propionate was higher at 150 mg/kg DM, while MCP concentration was higher at 100 mg/kg DM. Rikenellaceae RC9 gut group, Eubacterium, Succinivibrionaceae UCG-001, and Anaerovibrio were enriched in the LV treatment, whereas Methanococcus and Methanosphaera were enriched in the control. These results demonstrate the potential of lovastatin as a natural inhibitor of ruminal methanogenesis, with 100 mg/kg DM showing the greatest efficacy among the doses tested under the present in vitro conditions.

Goat meat is widely valued as a healthy option due to its lean nature, yet strategies to further optimize its intrinsic nutritional composition remain a key objective. This study examined the influence of melatonin on muscle development and visceral fat deposition in cashmere goats, focusing on its role in augmenting systemic antioxidant capacity and modifying gut microbiota. Thirty goat kids were randomly assigned to a control or a melatonin-treated (2 mg/kg body weight) group. Melatonin implantation induced a metabolic shift characterized by reduced visceral fat deposition (perirenal, omental, and mesenteric fat; p < 0.05) without impacting intramuscular fat. Concurrently, it promoted muscle accretion, as demonstrated by an increase in crude protein content and hypertrophy of muscle fibers in the Longissimus thoracis et lumborum, Gluteus medius, and Biceps femoris muscles (p < 0.05). These effects were underpinned by an enhanced systemic antioxidant capacity (elevated CAT, GSH-Px, T-AOC, and reduced MDA; p < 0.05), changes in gut microbiota, and a concomitant improvement in gastrointestinal morphology, evidenced by increased rumen papilla length and intestinal villus height. Melatonin enriched beneficial genera (e.g., Succiniclasticum, Butyrivibrio, Akkermansia), which were significantly correlated with reduced adiposity and improved protein deposition. These improvements resulted from the concerted actions of an enhanced systemic antioxidant defense system and a beneficially modulated gut microbial community. This trial observed no effect on intramuscular fat deposition, suggesting that improving intramuscular fat may require a systematic fattening regimen. This study provides a scientific foundation for employing melatonin as a nutritional strategy in goat production to improve meat quality.

Grain byproducts can serve as cost-effective alternatives to corn, but may lead to reduced production performance and increased greenhouse gas emissions. This study aimed to investigate the effects of replacing corn with the grain byproducts (wheat bran, sprayed corn bran) subjected to bacterial-enzymatic fermentation treatment or not in Hu sheep, mainly focusing on production performance, energy-nitrogen metabolism, rumen fermentation and greenhouse gas emissions. A total of fifty-four 6-month-old Hu sheep were divided into three groups, with 6 pens per group and 3 sheep per pen, and then randomly allocated to one of the three dietary groups for 60 days, i.e., a control group (CON), a group (RC) that corn was partially (~42%) replaced with grain byproducts, and a group (BF) that corn was partially replaced by fermented grain byproducts. Compared with the CON group, the RC group showed numerically lower rumen total volatile fatty acid (TVFA) concentration and its propionate proportion, nitrogen retention content (NR; −10.22%) and its retention ratio (NR/NI decreased by 4.27 percentage points, absolute reduction from 24.30% to 20.04%), corresponding to a relative decrease of 17.6%.) as well as a numerically reduced net profit (−2.18%) with a decreased feed price (−¥0.16/kg TMR). Meanwhile, the RC group showed a significant increase in the relative abundance of Methanobrevibacter (p < 0.05), accompanied by numerically higher daily methane emissions (+6.14%) and emission intensity (+4.08%), although these methane-related differences did not reach statistical significance (p > 0.05). Compared to the RC group, the BF group resulted in a numerical increase in feed price (+¥0.03/kg TMR), net profit (+27.93%), TVFA concentration, propionate proportion, NR (+28.17%), NR/NI (an increase of 5.38 percentage points), the relative abundance of Prevotella, Shuttleworthia and Succinivibrio as well as the decrease of fecal nitrogen (FN; −12.29%), daily methane emissions (−8.75%), emission intensity (−5.83%) and the relative abundance of Methanobrevibacter. In summary, replacing dietary corn by 42% with wheat bran and sprayed corn bran numerically reduced formula cost and nitrogen utilization, while increasing methane emissions and methanogens abundance, without significantly affecting growth performance. This combination led to no improvement in economic returns for fattening Hu sheep. Bacterial-enzymatic fermentation treatment of these byproducts could mitigate these drawbacks, being superior energy-nitrogen metabolism and lower greenhouse gas emissions intensity, presenting a potential strategy for cost reduction and efficiency enhancement. Further research with larger sample sizes is warranted to confirm these findings and support broader application.

Zearalenone-14-glucoside (Z14G) is a common modified mycotoxin attracting considerable attention due to its high occurrence in feed and food, and its potential to transform into the parent form zearalenone (ZEN) in vivo. However, the toxicokinetic data in ruminants remain scarce. In this study, male sheep (n = 5) were orally administered a single dose of Z14G at 2 mg·kg⁻¹ BW. Serum, rumen fluid, urine, and fecal samples were collected at designated time points, and tissue samples were obtained at slaughter 168 h post-dosing. Concentrations of Z14G, ZEN, α-zearalenol (α-ZOL), β-zearalenol (β-ZOL), α-zearalanol (α-ZAL), β-zearalanol (β-ZAL), zearalanone (ZAN), and zearalenone-14-sulfate (Z14S) in these samples were determined using liquid chromatography coupled with tandem quadrupole linear ion trap mass spectrometry (LC-Qtrap-MS/MS), so as to explore the absorption, distribution, biotransformation, excretion patterns, and tissue residue profiles of Z14G. The results showed that Z14G was rapidly hydrolyzed in the rumen, with multiple metabolites detected within 1 h. Among these, β-ZOL exhibited concentrations of 154.75 ± 55.66 ng·mL⁻¹, followed by ZEN 83.56 ± 33.36 ng·mL⁻¹. In serum, ZEN, β-ZOL, and Z14G all reached peak concentrations at 30 min, with values of 20.25 ± 2.55, 3.01 ± 0.59 and 2.15 ± 0.78 ng·mL⁻¹, respectively. The half-lives of all three analytes were less than 3 h, with Z14G eliminated the fastest (t_1/2 = 0.94 ± 0.31 h) and ZEN the slowest (t_1/2 = 2.91 ± 1.49 h). The total excretion of Z14G and its metabolites in feces and urine accounted for 0.90 ± 0.14% and 0.04 ± 0.01%, respectively. Z14G was not detected in any tissues, but ZEN was detected (1.38–3.61 ng·g⁻¹). As the first systematic toxicokinetic investigation of Z14G in ruminants, this study provides critical data for food safety risk assessment of Z14G, and offers a theoretical basis for controlling Z14G contamination in ruminant feed.