Xuezhao Sun

Objective: To evaluate the effects of four processing methods: intact corn (IT), ground corn (GD; ground to 2 mm), steam-flaked corn (SF; steamed at 85°C–100°C for 90 min and flaked to 2.5 mm thickness), and whole steamed corn (WS; steamed at 85°C–100°C for 90 min without flaking), on growth performance, digestibility, blood biochemistry, rumen microbiota, carcass traits, and meat quality in fattening lambs.Methods: Eighty-four male crossbred lambs (Small tailed Han×Northeastern Fine wool; 4.5 months; 34.2±3.5 kg) were blocked by stratifying body weight and then randomly assigned to four treatments (n = 21), each with 50% (as-fed) corn in the diet. In GD and WS treatments, corn was pelleted with other ingredients; in IT and SF treatments, corn was fed separately alongside non-corn pellets at a 1:1 (as-fed) ratio. After a 14 d adaptation period, lambs were fed for 60 d. Body weights were recorded on d 0, 30, and 60; blood samples were collected on d 31 and 60; and rumen fluid was sampled on d 35. Apparent total tract digestibility was determined by total fecal collection in a subset of lambs, and six lambs per treatment were slaughtered for carcass evaluation.Results: Lambs fed the WS diet showed the greatest average daily gain (ADG) at 319 g/d, improving 22%, 24%, and 7% over GD (261 g/d), SF (257 g/d), and IT (298 g/d) diets, respectively (p = 0.013). Dry matter intake did not differ significantly among treatments (p = 0.307), though WS, GD, and IT numerically exceeded SF by 6.7%–10.8%. Apparent total tract dry matter digestibility was greatest in SF (74.1%) and WS (72.1%), exceeding GD (69.3%) and IT (66.3%; p = 0.001) for the overall diet. Corn processing also altered rumen microbiota: WS tended to increase Erysipelotrichaceae_UCG 002 abundance sixfold over IT, SF enriched Actinobacteria, and IT uniquely harbored minor phyla such as Acidobacteriota. Hot carcass weight tended to be higher in WS (18.4% over GD; p = 0.078), while heart and kidney indices were greater in IT and SF (p<0.05). Meat quality parameters were not significantly affected by corn processing.Conclusion: Whole steamed corn enhanced growth performance, likely associated with improved starch utilization and modulation of the rumen microbiota, without compromising meat quality. Compared with grinding or flaking, steaming corn kernels provided a practical and energy-efficient approach, yielding 22%–24% higher ADG. Further research should refine steaming conditions and evaluate the economic viability of this method.

Reducing methane emissions from dairy goat production is essential for meeting sustainability targets and consumer expectations. Accurate quantification of enteric methane per unit of feed intake is a prerequisite for developing emission inventories and mitigation strategies. This pilot study developed and validated a methodology for measuring methane emissions from dairy goats using respiration chambers originally designed for cattle. Ten nonlactating Saanen dairy goats (mean ± standard deviation liveweight: 63 ± 9 kg) were group‐housed for 2 days and, then paired and housed in small pens for 9 days to adapt to the diet and environment. They were fed pasture silage ad libitum , supplemented with 200 g of maize grain daily. Four pairs were selected for methane measurements in cattle chambers following a 2‐day acclimation period. Methane emissions were recorded over 48 h at an airflow rate of 756 L/min. The mean methane yield was 22.9 ± 1.4 g/kg dry matter intake, consistent with values reported for sheep and cattle. Power analysis indicated that six pairs per treatment group are required to detect a 10% difference in methane yield with 80% power. These findings establish a validated protocol for using cattle respiration chambers to measure methane emissions from dairy goats.

Although high-protein diets are widespread, the fate of dietary protein, its fermentation by gut microbiota, and the resulting effects on intestinal health are not yet fully understood. This article provides a comprehensive overview of microbial protein fermentation and its impact on intestinal health. We focus on the bacterial anabolic and catabolic pathways involved in microbial protein metabolism and the generation of metabolites such as ammonia, biogenic amines (BAs), and short-chain fatty acids (SCFAs). This review also examines how excessive dietary protein affects intestinal health. Elevated protein levels may disrupt microbial homeostasis, promoting the proliferation of pathogenic bacteria while reducing beneficial microbiota. Furthermore, enhanced bacterial metabolic activity can lead to greater production of harmful compounds such as BAs. These alterations are associated with impaired intestinal barrier function, immune dysregulation, and elevated inflammatory responses. Further research is necessary to clarify the metabolism of high-protein diets and their consequences for intestinal health.

Bromoform, a bioactive compound in certain seaweeds, has gained attention for its methane-mitigating effects in ruminants. Research is underway to use synthetic bromoform as an alternative for providing consistent and predictable dosing of the bioactive compound, but its inherent volatility and liquid form limit its application. To address these challenges, an investigational feed additive (IFA) in the form of a powder containing synthetic bromoform has been developed by Rumin8 Pty Ltd., West Perth, WA, Australia. The objective of this study was to evaluate the effect of the Rumin8 IFA on methane emissions from cattle fed fresh pasture. Sixteen 18-month-old Hereford × Friesian heifers (427 ± 11 kg; mean ± SD) were stratified by weight and randomly allocated to control and treatment groups using a randomised block design. Treatments included IFA doses at 100, 300, or 500 mg/d of bromoform per heifer, plus a placebo control. The heifers were fed fresh pasture twice daily with a total feed allowance set at a level of 1.6 to 1.8 times their maintenance energy requirements with 800 g of dried distiller's grain pellets containing treatments or placebo before each meal. After 16 d, the heifers' methane emissions were measured in open-circuit respiration chambers for 48 h. The results showed that pasture-fed heifers produced less methane when treated with the bromoform-containing IFA at every dose level (P < 0.05). Reductions of up to 50% in methane emissions were observed in the first 4 h after feeding (P < 0.05). Methane yield declined linearly with bromoform dose (P = 0.001), showing 16% (300 mg) and 24% (500 mg) reductions vs. control (P < 0.05). No treatment effect on feed intake or bromoform accumulation in muscle or fat was observed. In summary, the IFA containing synthetic bromoform significantly reduced methane emissions in pasture-fed heifers, with a clear dose–response relationship, no adverse effect on feed intake, and no detectable residues in muscle or fat. These results have significant implications for reducing the environmental impact of cattle production, offering a practical solution to the challenge of methane emissions in pasture-fed systems where animals have access to supplements.

Introduction: Choline is an essential nutrient that plays a key role in lipid metabolism and growth performance in livestock. Methods: This study investigated the effects of rumen-protected choline (RPC) supplementation on serum metabolite profiles in fattening lambs. Twenty 3-month-old hybrid rams (Small-Tailed Han × Northeast Fine-Wool; initial body weight: 15.3 ± 1.8 kg) were randomly assigned to two groups ( n = 10 each): a control group (CON; 0 g RPC/kg dry matter [DM]) and an RPC group (5 g RPC/kg DM). Over a 122-day feeding period, lambs were provided ad libitum access to feed and water, with feedings at 08:00 and 15:00 daily. Serum samples were collected at the end of the trial and analyzed using untargeted metabolomics based on liquid chromatography–tandem mass spectrometry (LC-MS/MS). Results: A wide range of metabolites were identified, including benzenoids, lipids and lipid-like molecules, nucleosides and nucleotides, organic acids, and derivatives. Pathway analysis using the Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed involvement in lipid, amino acid, vitamin, and carbohydrate metabolism. Partial least squares-discriminant analysis (PLS-DA) showed clear separation between CON and RPC groups. Triacylglycerol, L-methionine, plasmenylcholine, taurocholate, 1-acyl-sn-glycero-3-phosphoethanolamine, and 1-acyl-sn-glycero-3-phosphocholine were identified as potential bio markers associated with increased hot carcass weight (HCW) and slaughter rate. Discussion: RPC supplementation significantly modulated the serum metabolome, enhancing HCW and slaughter rate, likely via lipid, amino acid, and energy metabolism pathways.

Bone development is essential for the growth, welfare, and long-term productivity of growing lambs. This study aimed to assess the effects of dietary oregano essential oil (OEO) supplementation on tibial morphology, mineralization, and mechanical properties in lambs. Twelve healthy, 3-month-old male lambs (Small-tailed Han × Black-boned cross, average liveweight 30.8 ± 0.4 kg) were randomly assigned to either a control group or a group receiving OEO at 0.5 g/kg of feed for 76 days. Tibiae were collected post-slaughter for morphometric and mechanical analysis. Tibiae were assessed for weight, length, bone mineral content (BMC), bone mineral density (BMD), bone area, bone volume, and breaking strength. Data were analyzed using independent sample t-tests, with significance set at P < 0.05. OEO supplementation significantly increased tibia weight (14.4%), BMC (19.7%), bone area (12.2%), and bone volume (19.6%) (P < 0.05). Tibia length, BMD, and breaking strength showed numerical increases but were not statistically significant. These findings suggest that bone mass and size may be more responsive to short-term dietary intervention than density or mechanical strength. This study provides original evidence that short-term OEO supplementation in lambs primarily promotes bone mass accretion and structural expansion rather than immediate improvements in density or mechanical strength. These findings expand the understanding of plant-derived feed additives in small ruminant bone health and suggest a potential strategy to enhance skeletal growth, warranting further research on long-term functional outcomes.

Coat colour formation in mammals is influenced by melanogenesis and pigmentation processes regulated by miRNAs, including miRNA-200a. Although miRNA-200a is differentially expressed in the skin of cashmere goats with varying coat colours, its regulatory mechanism remains unclear. In this study, miRNA-200a target genes were predicted using miRBase and TargetScan, identifying GNAI1 and PLCB4 as the target genes through GO and KEGG analyses. Dual-luciferase assays using wild-type and mutant plasmids confirmed a direct interaction between miRNA-200a and the 3’UTR regions of these genes. RT-qPCR and Western blot analyses demonstrated that the expression levels of miRNA-200a and its target genes differed significantly between black and white goat skin. In HaCaT cells, transfection with miRNA-200a mimics or inhibitors altered GNAI1 and PLCB4 expression at both mRNA and protein levels. To validate these findings in vivo, subcutaneous injection of antagomiR-200a into BALB/c mice significantly reduced melanin content (P < 0.01) and increased the expression of GNAI1 and PLCB4. These results indicate that miRNA-200a modulates skin pigmentation by suppressing GNAI1 and PLCB4, thereby influencing coat colour in cashmere goats. This study provides a foundational understanding for leveraging genetic regulation to enhance coat colour diversity and develop naturally pigmented breeds.

Introduction: Distiller’s dried grains with solubles (DDGS), a by-product of grain fermentation for ethanol production, are extensively used in livestock feed. Given their nutrient composition, DDGS could potentially influence methane (CH₄) emissions, a significant greenhouse gas concern in ruminant production systems. This study utilized a multilevel random-effects meta-analysis to assess the impact of DDGS inclusion in cattle diets on CH₄ production and yield.Methods: The literature search was conducted on 23 July 2024. Studies reporting CH₄ emissions and dry matter intake (DMI) in cattle fed DDGS-based diets were identified, and data extraction was performed. The meta-analysis calculated the mean difference (MD) for DMI and CH₄ yield and the relative mean difference (RMD) for CH₄ production across the selected studies.Results: A total of k = 25 effect sizes from 10 studies were included in the DMI meta-analysis. DDGS had no significant effect on DMI in dairy or beef cattle (p = 0.770, MD = 0.070, 95% confidence interval [CI] from −0.420 to 0.561). For CH₄ production, k = 24 effect sizes from 10 studies were analyzed, revealing no significant effect (p = 0.759, RMD = −1.045, 95% CI: from −8.025 to 5.935). Similarly, the meta-regression model indicated that the diet’s ether extract (EE) had no significant influence (p = 0.815, 95% CI from −1.121 to 1.409) on CH₄ production. For CH₄ yield, k = 23 effect sizes from 10 studies were included, with results showing no significant effect (p = 0.475, MD = −0.434 g/kg DMI, 95% CI: from −1.673 to 0.805). The regression model for the EE content of the diet also showed no significant impact on CH₄ yield (p = 0.311, 95% CI: from −0.366 to 0.122).Discussion: The findings suggest that the inclusion of DDGS does not significantly affect DMI, enteric CH₄ production, or CH₄ yield in cattle. Moreover, the EE content in DDGS-containing diets does not significantly influence CH₄ outcomes. These results indicate that DDGS can be incorporated into cattle diets without exacerbating CH₄ emissions, contributing to sustainable livestock feeding practices.

Chromium (Cr) has been reported to modulate blood biochemistry in dairy cows. However, there is a discrepancy in the literature regarding the effects of dietary Cr supplementation on various blood parameters. This meta-analysis aimed to evaluate the effects of Cr supplementation in dairy cows on blood glucose, insulin, glucagon, nonesterified fatty acid (NEFA), cortisol, and serum total protein (STP) concentrations. Following relevant literature data extraction, a 3-level meta-analytical random effect model was fitted to the data expressed as standardized mean difference (SMD) of outcome measures of control vs Cr-supplemented cows (i.e., difference in mean between control and treatment group / pooled standard deviation). The SMD can be categorized as having a small effect = 0.20, a moderate effect = 0.50, and a large effect = 0.80. The meta-regression identified the potential sources of heterogeneity, including the body weight (BW) of cows, experimental duration/duration of Cr supplementation, blood sampling time (3 weeks before parturition till 4 weeks after parturition categorized as the transition period, else as the non-transition period), and form of Cr complexes. Blood glucose did not differ significantly between control and Cr-supplemented cows with an estimated SMD of μ^ = 0.0071 [95% confidence interval (CI): -0.212 to 0.226]. The effect of Cr supplementation on blood insulin was also non-significant with an SMD of μ = 0.0007 (95% CI: -0.191 to 0.193). Cows receiving Cr supplements had significantly higher levels of glucagon than controls (95% CI: 0.116 to 0.489), with an estimated SMD = 0.303. Combined transition and non-transition data suggest Cr supplementation did not impact the concentration of NEFA. However, in transition cows, Cr supplementation significantly decreased blood NEFA levels as compared with controls (95% CI: -0.522 to -0.0039), with estimated SMD = -0.263. The estimated SMD was μ^ = -0.1983 (95% CI: -0.734 to 0.337) for cortisol and -0.0923 (95% CI: -0.316 to 0.131) for total protein. In summary, Cr supplementation in the transition cows decreased NEFA concentration. Blood glucose, insulin, cortisol, and STP concentrations were unaffected. However, Cr supplementation increased glucagon concentration.