Journal of Dairy Science最新文献

This study aimed to characterize the whey proteome of colostrum, transitional milk, and mature milk from Murciano-Granadina goats and to evaluate the use of transitional milk as a substitute for colostrum in feeding neonatal kids. Colostrum was collected at the first postpartum milking (within the first 12 h postkidding), transitional milk at the second postpartum milking (24 h after kidding), and mature milk at 3 to 4 mo postpartum. Proteomic analysis identified a total of 1,385 proteins, with 736 in colostrum, 668 in transitional milk, and 625 in mature milk. Colostrum and transitional milk displayed a high degree of similarity, particularly in proteins related to immune response and inflammation. In contrast, mature milk showed a shift toward proteins involved in metabolic and transport functions. To evaluate the practical application of transitional milk, newborn goat kids were fed either frozen colostrum (following standard farm protocol), freeze-dried colostrum, or freeze-dried transitional milk. All feeding strategies were well tolerated, with no adverse health effects, and resulted in similar growth performance. At 48 h of life, serum IgG concentrations were 13.95 mg/mL in kids fed frozen colostrum, 17.36 mg/mL in those fed freeze-dried colostrum, and 11.65 mg/mL in those fed freeze-dried transitional milk. Notably, kids fed freeze-dried transitional milk achieved satisfactory Ig levels, supporting its potential for passive immune transfer. These results highlight the biological value of transitional milk and support its use as a colostrum substitute in intensive farming systems, particularly when maternal colostrum is unavailable or insufficient. Furthermore, freeze-drying effectively preserved its functional properties, enabling convenient storage, handling, and administration. Overall, the successful use and preservation of transitional milk represent a sustainable approach to improving colostrum management, reducing waste, and increasing the efficiency of kid rearing in dairy goat production, in line with circular economy principles.

Heat waves are occurring more frequently around the world as global warming increases. Heat stress (HS) from hot and humid environments poses a significant threat to oocytes, including elevated levels of reactive oxygen species, mitochondrial dysfunction, spindle abilities, chromosomal mis-segregation, meiotic arrest, increased aneuploidy, and ultimately reduced developmental competence. Therefore, there is an urgent need to identify solutions to mitigate the negative effects of HS. In this study, HS markedly reduced the blastocyst formation rate in bovine embryos and arrested their development at the 8-cell stage. Consequently, transcriptome sequencing analysis of embryos at the 8-cell stage revealed a reduction in the expression of elongation of long-chain fatty acids very long-chain family member 2 (ELOVL2). This downregulation of ELOVL2 consequently led to a decrease in its major product, docosahexaenoic acid (DHA). Therefore, we supplemented DHA to examine whether it could mitigate HS-induced embryo development arrest. Supplementation with DHA during in vitro culture effectively counteracted the detrimental effects of HS on embryo development, including blastocyst formation rate, inner cell mass proportion, and apoptosis. Furthermore, compared with HS, DHA supplementation significantly re-established lipid metabolic homeostasis and prevented lipid peroxidation. In addition, our findings indicate that DHA prevents ferroptosis by activating the Nrf2 signaling pathway. The activation of Nrf2, in turn, restored the activity of the key antioxidant enzyme GPX4 and replenished cellular glutathione levels, thereby preventing lipid peroxidation and ferroptosis. In conclusion, HS induced bovine embryo arrest because of the deficiencies of DHA, which is regulated by ELOVL2. We found that DHA alleviates HS-induced ferroptosis by modulating the Keap1/Nrf2/GPX4 pathway, thereby improving the developmental competence of bovine embryos in vitro under HS conditions.

Yogurt consumption is a natural way of accessing bioactive metabolites such as peptides and short-chain fatty acids (SCFA). Proteolytic systems and metabolic pathways of lactic acid bacteria (LAB) and probiotics, which differ among the species, influence bioactive metabolite profiles in yogurt. This study determined the bioactive peptide and SCFA profiles in mixed-species yogurt incorporating Bifidobacterium bifidum ATCC 11863, Bifidobacterium breve ATCC 15700, Bifidobacterium animalis ssp. animalis ATCC 25527, and Lacticaseibacillus rhamnosus GG using ultra-performance liquid chromatography coupled to electrospray ionization quadrupole-time-of-flight MS and GC-MS, respectively. Significantly higher proteolytic activities were observed in yogurt incorporating either probiotic species of B. bifidum ATCC 11863 or L. rhamnosus GG. Yogurt incorporating B. bifidum ATCC 11863 contained more peptides with higher bioactivity. Bifidobacterium animalis ssp. animalis ATCC 25527 significantly enhanced the SCFA content (acetic acid) in yogurt. Whereas L. rhamnosus GG increased the production of both bioactive peptides and SCFA in yogurt when incorporated as a monoculture or coculture with B. bifidum ATCC 11863 and B. animalis ssp. animalis ATCC 25527, respectively. Novel short peptides (<10 AA) derived from minor milk serum proteins with potential antimicrobial properties were identified in the different probiotic yogurts. This study provides insights into the bioactive metabolite profiles of yogurt incorporating probiotics, L. rhamnosus and Bifidobacterium spp., and their role in developing yogurt with enhanced therapeutic benefits.

Edible films based on the dairy protein casein have been developed, but widespread adoption will require pasteurization, and nothing is known about the effects of pasteurization on properties of the film solutions or their resulting films. This study investigated alterations in calcium and sodium caseinate-based film solutions due to commonly used pasteurization techniques: low temperature, long time; HTST; and UHT. All pasteurization conditions resulted in films with most textural properties and water vapor permeabilities having no significant changes in comparison to those made from nonpasteurized solutions; the only exceptions were films made from the UHT-processed calcium caseinate and HTST-processed sodium caseinate solutions having increased tensile strength and decreased yield stress, respectively. The solutions themselves, however, changed dramatically after higher temperature pasteurization conditions, with reduced viscosity (resistance to flow), and a weakened storage and loss moduli. The pasteurized solutions would thus be easier to process, except more complications may arise during casting. The particle size distribution of the solution based on calcium caseinate, but not the sodium caseinate, changed with all pasteurization techniques to become more polydisperse. Whereas lower temperature processing did not change solution stability, UHT increased stability of the sodium caseinate film solution, but decreased the suspension stability of the calcium caseinate film solution. Processing with UHT was the only pasteurization technique that proved effective in reducing microbial counts to below the limit of detection (1 log₁₀ cfu∙mL^-1). Overall, we demonstrated that caseinate-based film solutions may be pasteurized without concern of obvious changes to properties of resulting films; however, considerable rheological changes to the film-forming solutions are likely to occur.

Heterofermentative lactic acid bacteria (LAB) have the ability to metabolize 6-carbon sugars, such as galactose, to produce carbon dioxide, which can cause late-stage gas formation defects in Cheddar cheese characterized by slits, cracks, and blown retail packaging. Slits and cracks make the cheese more difficult to shred and slice, and blown bags make the cheese less appealing to customers. Homofermentative LAB are often used as adjunct cultures to modify the flavor of Cheddar cheese and have the potential to act as bioprotective cultures and inhibit gas production by heterofermentative nonstarter LAB (NSLAB). Cheddar cheese was manufactured using 4 previously identified galactose-positive and lactose-negative LAB (Lacticaseibacillus rhamnosus 20DK04, Lacticaseibacillus paracasei 20DK06, Pediococcus acidilactici 23F, and Latilactobacillus curvatus WSU1) as adjunct cultures along with a starter culture consisting of Streptococcus thermophilus and Lactococcus species. The day after cheesemaking, cheese blocks were comminuted and inoculated with known gas-producing NSLAB (Levilactobacillus brevis 277-1, Limosilactobacillus fermentum 305-1, Lentilactobacillus parabuchneri CC01, and Paucilactobacillus wasatchensis WDCO4). The inoculated cheeses were then repressed into blocks, cut into smaller pieces, packaged, vacuum sealed, and stored at 14°C for 16 wk. Starter LAB, adjunct LAB, and gas-producing NSLAB were enumerated at 1, 8, and 16 wk using a modified Petrifilm method. Loosening of the cheese packages was used as a nondestructive measure of gas production every week. Extent of gas production was Lev. brevis 277-1 >Paucilactobacilluswasatchensis WDC04 >Lentilactobacillus parabuchneri CC01 >Limosilactobacillus fermentum 305-1. Using an adjunct LAB had varying effects and could either increase or reduce gas production depending on the NSLAB. Gas production was inhibited by Latilactobacillus curvatus WSU1 and Pediococcus acidilactici 23F when the NSLAB was Levilactobacillus brevis 277-1 but was stimulated when the NSLAB was Paucilactobacillus wasatchensis WDC04. In contrast, Lacticaseibacillus rhamnosus 20DK04 and Lacticaseibacillus paracasei 20DK06 had little effect on gas production by Lev. brevis 277-1 but inhibited gas production by Paucilactobacillus wasatchensis WDC04. Gas production by Lentilactobacillus parabuchneri CC01 was most inhibited by Pediococcus acidilactici 23F. Thus, when considering use of a bioprotective LAB to reduce unwanted gas production in Cheddar cheese, it is essential to know the NSLAB bacteria that is causing the gas defects.

Artificial reproduction technologies (ART) may exert long-term effects on offspring, which have not yet been addressed in dairy cattle. This longitudinal study examined reproductive outcomes and transgenerational effects of embryo recipients conceived by different ART, including artificial insemination (AI) and embryo transfer (ET) with fresh, frozen, and vitrified embryos. For this purpose, in vitro-produced (IVP) embryos were transferred to synchronized recipients (n = 298 ET from AI, and n = 84 ET from IVP-ET origin). Pregnancy on d 40 and 62, birth to term, and gestation length were recorded. From birth until adulthood, calf morphometry (weight, size, and chest perimeter) was monitored (n = 142 animals), and IGF2 methylation and expression were analyzed in peripheral blood lymphocytes (n = 113 samples). The plasma metabolome on d 0 (n = 179 samples) and d 7 (n = 176 samples) and metabolically regulated pathways were compared between estrus-synchronized recipients born by AI and ET. Data were analyzed with generalized mixed models (parametric) and Kruskal-Wallis test (nonparametric). Pregnancy and birth rates did not differ between AI and ET recipients. However, mothers from ET-born recipients were heavier at calving, and their calves showed transgenerational effects, including higher birth weight, size, gestation length, and daily weight gain compared with those from AI recipients. Only calves born from frozen embryos displayed transient IGF2 hypomethylation on d 30, which disappeared later on. In contrast, IGF2 expression decreased on d 0 and 30 in calves born from cryopreserved embryos, and increased in calves aged 2 to14 mo from vitrified embryos, but did not differ thereafter between any group. Among females >6 mo old, those from frozen embryos and AI were heavier and taller than females from vitrified and fresh embryos. Certain metabolite concentrations on d 0 and d 7 differed among recipient groups, mainly in essential amino acids and 1-carbon-generating units metabolites. Overall metabolic differences (Mahalanobis distance matrix) between females were higher in AI than in ET-cryopreserved females on d 0, and in AI versus ET-fresh females on d 7. These findings suggest that ART induces epigenetic and metabolic variations, potentially influencing nutritional efficiency.

General dairy herd management can be tailored to dilute enteric methane and total farm GHG emissions per kilogram of milk delivered and thereby serve as a mitigation strategy. However, there is limited information on the performance of different herd management strategies in dairy herds with varying productivity and the trade-offs between emission mitigation, farm economy, and dairy food production. Here, we simulated a set of herd management strategies in 10 high-yielding Danish conventional Holstein herds using herd simulation modeling and a cradle-to-farm gate partial life cycle assessment to estimate the effects on GHG emission, gross margin, and edible protein yield, and the trade-offs between these effects. These strategies included increased concentrate intake, improved reproduction, reduced risk of health problems, and extended lactation. The simulation was conducted by changing relevant parameters within certain targets according to Danish national figures for conventional Holstein herds. Results showed that the herd management strategies changed GHG emissions from a slight increase of 0.4% to a decrease of up to 3.2% on average across the 10 herds. These strategies also changed the gross margin from -2.2% to +5.0% across herds. The herds' edible protein yield increased except for a slight decrease in the strategies with improved reproduction or extended lactation. Overall, the effects of the strategies varied between herds. We did not detect any obvious trade-off between emission mitigation and gross margin. These findings revealed that tailored herd management can benefit emission mitigation and gross margin while generally maintaining edible protein production; however, the effects depend on the herds' initial management and productivity.

Hyperuricemia, driven by disrupted purine metabolism, predisposes individuals to hepatic and renal injury. To explore potential microbial interventions, 50 lactic acid bacterial (LAB) strains were isolated from Tibetan fermented foods, and 3 nucleoside-degrading candidates were identified, including Lactiplantibacillus plantarum 15-5, Lactiplantibacillus plantarum YL-2, and Lacticaseibacillus paracasei XS23. Strain 15-5 eliminated 99% of inosine and guanosine within 1 h, surpassing YL-2 and XS23. In hyperuricemic mice, L. plantarum 15-5 reduced serum uric acid by 42.91%, normalized hepatic xanthine oxidase activity by 22.57%, restored BUN and creatinine levels toward baseline, and markedly alleviated hepatic and renal tissue damage, while also suppressing proinflammatory cytokines IL-1β and TNF-α. The L. plantarum 15-5 increased fecal short-chain fatty acids, particularly propionate and butyrate (2- to 3-fold), and partially recovered gut microbial diversity and composition under hyperuricemia. Comparative genomics indicated that 15-5 possesses broader metabolic and ecological capacities than YL-2 or XS23, consistent with its superior functional performance. These results reveal a strain-specific framework linking nucleoside catabolism, microbiota-mediated fermentation, and host metabolic and inflammatory regulation, identifying L. plantarum 15-5 as a metabolically versatile candidate for intervention in hyperuricemia and associated hepatic and renal injury.

Early life killing of surplus dairy calves is widely recognized as a threat to the dairy industry's social license to operate. The aim of this study was to determine how different future scenarios influence the Australian public's perceptions of surplus calf management. A representative sample of the Australian public (n = 1,000) was recruited to an online survey. Participants were randomly presented 1 of 4 treatments comprising different combinations of 2 factors: (1) (a) presence or (b) absence of a dairy industry commitment to discontinue slaughtering calves in the first 2 wk of life; and (2) surplus calves are raised to 18 mo of age in either (a) a grazing system or (b) a feedlot system. Presence of pasture in the provided scenarios positively influenced participants' attitudes. However, presence of an industry commitment to ending early life slaughter did not. Our results provide insights into how different systems that address early life killing may affect public perceptions, indicating that even when early life killing of calves is addressed, the management of these animals may continue to present challenges.