Journal of Dairy Science最新文献

{"title":"Global, regional, and national burden of disease attributable to a diet low in milk, 1990–2021: An updated analysis of the Global Burden of Disease study 2021","authors":"Meihui Tao ,&nbsp;Po Zhang ,&nbsp;Weifeng Yang ,&nbsp;Yanping Wang ,&nbsp;Junfa Chen ,&nbsp;Xiu Shi ,&nbsp;Erfang Dai ,&nbsp;Wei Yan ,&nbsp;Yu Fu","doi":"10.3168/jds.2024-26131","DOIUrl":"10.3168/jds.2024-26131","url":null,"abstract":"<div><div>Diet low in milk has been linked to various chronic diseases and cancer. To better understand the global health effect of a diet low in milk, this study analyzed the latest data from the Global Burden of Disease study 2021. Our findings revealed that the number of deaths and disability-adjusted life years (DALY) of colon and rectum cancer (CRC) attributable to a diet low in milk increased from 1990 to 2021. The age-standardized mortality rates (ASMR) and age-standardized DALY rates (ASDR) for CRC due to low milk intake declined slightly over this period, with a faster decline observed among females. Predictive analysis shows similar tendency, even higher ASMR and ASDR in CRC associated with a diet low in milk in males than in females by 2050. In contrast, the rate of prostate cancer attributable to a diet low in milk remained relatively stable. Regionally, southern Latin America exhibited the highest ASMR and ASDR for CRC associated with a diet low in milk in 2021, whereas western sub-Saharan Africa had the most notable changes in these rates for prostate cancer. The largest decrease in ASMR and ASDR of CRC due to a diet low in milk was observed in the high socio-demographic index (SDI) region. In addition, the low SDI region exhibited the highest change rates for prostate cancer attributable to a diet low in milk. In summary, our study provides valuable insights into trends for the global burden of CRC and prostate cancer attributable to a diet low in milk, emphasizing the importance of considering gender, age, regional, and national differences in dietary habits and disease risk when formulating public health policies and dietary recommendations.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 4558-4572"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143727237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Invited review: Mastitis Escherichia coli strains—Mastitis-associated or mammo-pathogenic?","authors":"Pierre Germon ,&nbsp;Gilles Foucras ,&nbsp;David G.E. Smith ,&nbsp;Pascal Rainard","doi":"10.3168/jds.2024-26109","DOIUrl":"10.3168/jds.2024-26109","url":null,"abstract":"<div><div>Bovine mastitis remains a major concern for dairy farmers, mainly because of its effect on the economy of their activity and on animal welfare. Because <em>Escherichia coli</em> is considered a major mastitis pathogen, the diversity of <em>E. coli</em> strains isolated from mastitis cases has been studied for decades, with the aim to discover new ways to fight this infection. With the recent advances in whole-genome sequencing, a detailed view of the peculiarities of mastitis <em>E. coli</em> strains has emerged. This review aims to bring together the knowledge garnered over the years with the more recent results of whole-genome analyses. Whereas the concept of a mammary pathogenic <em>E. coli</em> has been proposed, because a common set of virulence genes cannot be identified among mastitis <em>E. coli</em> strains, we prefer the use of mastitis-associated <em>E. coli</em> (MAEC), with MAEC being more an “ecotype” rather than a “pathotype.” Indeed, data available so far suggest that a common feature of MAEC would rather be an enrichment in fitness capabilities that makes them well-suited for survival and rapid adaptation to changing biotopes in the mammary gland, which we qualify as intramammary ecotopes.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 4485-4507"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143727247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of milk feeding levels and starter feed crude protein and fat contents on growth performance, rumen fermentation, and purine derivative excretion in urine of dairy calves","authors":"M. Yazdanyar ,&nbsp;M. Kazemi-Bonchenari ,&nbsp;M. Eghbali ,&nbsp;A. Sadeghisharif ,&nbsp;A. Jafari ,&nbsp;M. Molaei ,&nbsp;M. Kornasi ,&nbsp;H. Khalilvandi-Behroozyar ,&nbsp;M.H. Ghaffari","doi":"10.3168/jds.2024-25957","DOIUrl":"10.3168/jds.2024-25957","url":null,"abstract":"<div><div>The study investigated how different milk feeding levels and the composition of the starter feed interact to influence growth performance, rumen fermentation, certain blood parameters, and the excretion of purine derivatives in the urine of dairy calves. A total of 72 female Holstein dairy calves (mean BW = 40.6 ± 1.9 kg) were assigned to a completely randomized design with a 2 × 3 factorial arrangement. The starter diets differed in CP (20% vs. 24%, DM basis) and total crude fat (CF, ether extract; 3.0% vs. 5.5%, DM basis). The 6 treatment groups were as follows: moderate milk with 20% CP and 3% CF (MM-CON), moderate milk with 24% CP and 3% CF (MM-HCP), moderate milk with 20% CP and 5.5% CF (MM-HCF), high milk with 20% CP and 3% CF (HM-CON), high milk with 24% CP and 3% CF (HM-HCP), and high milk with 20% CP and 5.5% CF (HM-HCF). Calves had free access to a starter feed and water and were weaned on d 53 but remained in the study until d 73. Calves fed the HM-HCF diet had the lowest starter feed intake both pre- and postweaning, and calves fed the HM-HCP and HM-CON diets had the greatest preweaning ADG. Feed efficiency and protein intake were also lowest in HM-HCF calves before weaning, whereas fat intake was consistently greater in calves fed HCF diets. Calves fed the HM-HCP diet had the largest body size, heart girth, and withers height at weaning and at the end of the study, whereas the HM-HCF calves had the smallest. Rumen fermentation profiles showed that total VFA concentrations were lowest in HM-HCF calves, along with an increased acetate-to-propionate ratio. In contrast, HM-HCP calves had a greater molar proportion of propionate preweaning and butyrate postweaning, along with a greater proportion of branched-chain VFA in high-CP diets, indicating more efficient microbial activity in the rumen. Urinary analyses were consistent with these results, as HM-HCF calves had the greatest creatinine levels and lowest urine volumes, whereas HM-HCP calves showed the greatest excretion of the microbial protein synthesis markers allantoin and uric acid. Blood metabolite analysis showed that glucose levels were greater in HM-fed calves preweaning, whereas BHB levels were lowest in HM-HCF calves. Overall, diets with high milk allowance, high CP (24% of DM), and moderate fat (3% of DM) may promote growth, rumen function, and metabolic efficiency, whereas high-fat starter diets (5.5% of DM) may limit feed intake and growth of dairy calves.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 5000-5015"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of canola meal or soybean meal on duodenal flow of nitrogen fractions in dairy cows","authors":"F. Nadon ,&nbsp;É. Charbonneau ,&nbsp;H. Lapierre ,&nbsp;S. Binggeli ,&nbsp;D.R. Ouellet","doi":"10.3168/jds.2024-25773","DOIUrl":"10.3168/jds.2024-25773","url":null,"abstract":"<div><div>Canola meal (CM) is a protein supplement increasingly used in dairy cow diets. Substituting soybean meal (SBM) with CM has been shown to have a positive effect on milk and milk protein yields. This positive response on milk production occurs even though the NRC predicted a reduction in MP supply when CM replaces SBM in dairy rations. The objective of this project was to evaluate the ¹⁵N kinetics in 5 N fractions from duodenal samples after a ruminal bolus ¹⁵N-labeled CM or SBM to determine the effects on MP supply. The ¹⁵N fractions were as follows: total duodenal, small particles, fluid phase, particle-associated bacteria (PAB), and fluid-associated bacteria (FAB). Four cows fitted with a ruminal and a duodenal cannula were used in a crossover design with diets including CM or SBM. On d 18 or 19 of each period, a ruminal bolus of ¹⁵N-labeled CM or SMB was administered and duodenal digesta samples were collected regularly for 72 h. The proportion of FAB in the duodenal digesta was higher when cows were fed CM than SBM. The areas under the curve of the enrichment of ¹⁵N as a function of time after the ruminal bolus were greater for CM for the fraction associated with small particles, the PAB, and the FAB. These results indicate that the N lost from nylon bags during ruminal incubation of CM contribute to the duodenal N flow. Canola meal probably contains a substantial amount of small particles that leave the bags during ruminal incubation but, contrary to what is now assumed, they are not degraded in the rumen and contribute directly to the MP supply and would contribute to the positive response to CM.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 4895-4905"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143565596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sociopsychological factors influencing Brazilian farmers' intention to regularize their cheese production","authors":"A.C.V. Plefh,&nbsp;F.I. Bánkuti,&nbsp;J.C. Damasceno,&nbsp;G.T. dos Santos","doi":"10.3168/jds.2024-25672","DOIUrl":"10.3168/jds.2024-25672","url":null,"abstract":"<div><div>Milk and cheese products serve an important economic and social function in Brazil, as most of the production is carried out on small-scale family farms. Farmers who fail to meet institutional and market requirements related to production scale and milk quality often abandon the activity or turn to selling raw milk or unlicensed cheese. In this research, we adopted the theory of planned behavior (TPB) as a theoretical framework to investigate unlicensed farmers' intention to regularize cheese production. Interviews were conducted on site with 286 cheese producers in Paraná and Minas Gerais States, Brazil. The data were analyzed using descriptive statistics, regression analysis, and structural equation modeling—the procedures recommended in the TPB. The results were discussed based on the TPB and Brazilian institutional and market characteristics. Farmers' intention to regularize cheese production was positively correlated with social characteristics (farmer's age and experience in dairy farming) and farm characteristics (milk or cheese production area and milk volume). The construct perceived behavioral control (PBC) was the most important in determining cheese producers' intention to regularize cheese production, followed by the construct subjective norms (SN). The high importance of the PBC construct suggests that farmers believe they have sufficient capacities to regularize cheese production. The importance of the SN construct suggests that people close to farmers would support the regularization of cheese production. The attitude (ATT) construct was not significant in determining farmers' intention. The lack of significance of the ATT construct on farmers' intention indicates an absence of perceived incentive for licensing. The model defined by SN and PBC explained 24.9% of farmers' intention to regularize cheese production.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 5016-5026"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143565627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A dual enhancement strategy for ultrasensitive detection of norovirus based on catalytic hairpin assembly–assisted CRISPR/Cas12a sensing system","authors":"Yao Shuo ,&nbsp;Xuehui Feng ,&nbsp;Chao Zhao ,&nbsp;Jing Zhang ,&nbsp;Ying Wang ,&nbsp;Jingran Wang ,&nbsp;Yukun Ding ,&nbsp;Xuening Shi ,&nbsp;Juan Li ,&nbsp;Xiuling Song ,&nbsp;Juan Wang","doi":"10.3168/jds.2024-26150","DOIUrl":"10.3168/jds.2024-26150","url":null,"abstract":"<div><div>Noroviruses are a leading cause of food-borne illnesses, responsible for over 50% of global gastroenteritis outbreaks. Whereas reverse transcriptase PCR (RT-PCR) and other nucleic acid amplification methods are crucial for norovirus detection, their reliance on specialized equipment highlights the urgent need for more accessible detection methods. Herein, we propose an isothermal cascade signal amplification assay that integrates catalytic hairpin assembly (CHA) and cluster regularly interspaced short palindromic repeats (CRISPR)/Cas12a for rapid and accurate detection of norovirus in food samples. By incorporating the advantages of CHA and CRISPR/Cas12a, the dual signal enhancement sensing strategy can achieve high sensitivity low to 14 f<em>M</em> within 70 min, and good specificity in adenovirus, human enterovirus, rotavirus, and other interfering agents. The proposed dual enhancement strategy for norovirus detection has satisfactory accuracy and acceptable recoveries in milk samples compared with RT-PCR assay, and holds promise for improving food safety monitoring, particularly in dairy products.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 4726-4733"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143727107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Invited review: Antimicrobial resistance genes in milk—A 10-year systematic review and critical comment","authors":"Theresa Sievers,&nbsp;Julia A. Blumenberg,&nbsp;Christina S. Hölzel","doi":"10.3168/jds.2024-25528","DOIUrl":"10.3168/jds.2024-25528","url":null,"abstract":"<div><div>The occurrence of antibiotic resistance genes (ARG) in milk is eagerly discussed as a public health risk, and frequently investigated. Here, we perform a systematic review on the abundance of antimicrobial resistance genes in milk from primary production over a 10-year period. We aim to provide a comprehensive dataset on known and emerging antimicrobial resistance genes in major mastitis pathogens, occurring worldwide in milk at primary production, and to critically discuss the relevance and constraints of these findings. We searched PubMed for peer-reviewed studies published between 2012 and 2022 that fit fixed combinations of key words and did not meet exclusion criteria such as “mixed with other sources.” For synthesis, data on occurrence was extracted from studies and supplements. To address plausibility issues, we performed an National Center of Biotechnology Information Basic Local Alignment Search Tool (BLAST) search. Our search revealed 2,222 publications in total. Of them, 500 studies were eligible for full-text reads and 306 publications were included in data compilation. An overwhelming majority of studies dealt with <em>mec</em>A in <em>Staphylococcus aureus</em>, followed by extended-spectrum β-lactamase-encoding genes such as <em>bla</em>CTXM in <em>Escherichia coli</em>, while other mastitis pathogens, such as <em>Streptococcus</em> spp., were scarcely investigated. In most cases, &lt;5% of milk samples were positive for major pathogens bearing the antimicrobial resistance gene of interest. However, huge study-to-study differences were found between regions, but also on a national level. For instance, the estimate prevalence of <em>Escherichia coli</em>-borne <em>bla</em>CTXM in mastitis milk samples ranged from 0.0% to 55%, with a median value of 7.3%, but in healthy individuals and bulk milk, the prevalence ranged from 0.0% to 20.0%, with a median value of 0.8%. Several studies reported antimicrobial resistance genes for the very first time in a species, but did not stand up to scrutiny. As an example, frequent detection of <em>bla</em>TEM-genes in streptococci is most likely attributed to contamination of molecular reagents, as reported elsewhere. Despite the large amount of data, there is a need for more quality control, more representative sampling of milk, more quantitative research, and deeper insights into bacterial genomics, to identify relevant or emerging antimicrobial resistance genes in milk. Considering a low percentage of contaminated milk samples, unknown ARG concentrations, and an unproven role in human disease, the risk attributed to ARG in milk seems to be exaggerated by far. However, the risk of ARG selection on farm, resulting in low treatment success in cattle, is a real one and should be met by prudent use of antibiotics.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 4508-4543"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142794262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of maturity at harvest of small-grain grasses on the nutritional composition of forage and ration formulation","authors":"G. Ferreira ,&nbsp;C.L. Teets ,&nbsp;H. Galyon ,&nbsp;A.L. Cappellina ,&nbsp;M.E. Schultz ,&nbsp;K.M. Payne ,&nbsp;S. Stewart ,&nbsp;W.E. Thomason","doi":"10.3168/jds.2024-26020","DOIUrl":"10.3168/jds.2024-26020","url":null,"abstract":"<div><div>We hypothesized that, relative to harvesting small-grain grasses at the soft dough stage (SFT) of maturity, harvesting small-grain grasses at the boot stage (BT) of maturity would result in less expensive dairy rations when commodity prices are high but not when commodity prices are low. Small plots of small-grain grasses were planted during the fall of 2020 and 2021 in Blacksburg, Blackstone, and Orange, Virginia. In each year and location, 2 varieties of barley, 2 varieties of rye, and 4 varieties of triticale were planted in plots replicated 6 times, yielding 288 plots. Within each year and location, we harvested half of the plots at BT and the other half at SFT. For each of the 6 small-grain grasses, we formulated 8 rations according to 8 different scenarios using the least-cost optimizer. The scenarios included high and low commodity prices, high and low dietary forage (60% and 40% forage, respectively), and the inclusion of small-grain grasses harvested at BT or SFT. Harvesting at SFT yielded 107% to 205% more DM than harvesting at BT. Relative to BT, small-grain grasses harvested at SFT had greater concentrations of OM, NDF, ADF, ADL, and starch but lower concentrations of CP. Relative to BT, small-grain grasses harvested at SFT also had a greater concentration of undegraded NDF (NDF basis). Species had minimal influence on the nutritional quality of small-grain grasses for silage. Under a low-price scenario, the ration formulation system ignored all 6 small-grain grass silages and included corn silage as the only forage source when we did not limit its inclusion. Under a high-price scenario, the ration formulation system included all 6 small-grain grass silages when formulating low-forage diets with unlimited corn silage. However, a preference between BT and SFT stages did not exist, with the optimizer not consistently selecting a specific maturity stage. After evaluating the yields, the chemical composition, and the effects on ration formulation in this study, future studies should aim to evaluate the influence of maturity at harvest of small-grain grasses on cow performance and environmental impacts.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 4934-4945"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143727160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Manufacture of high-solids milk protein concentrate retentate using plate-and-frame membrane filtration system at low and high temperatures","authors":"Achyut Mishra ,&nbsp;Prafulla Salunke ,&nbsp;Venkateswarlu Sunkesula ,&nbsp;Lloyd E. Metzger","doi":"10.3168/jds.2024-25472","DOIUrl":"10.3168/jds.2024-25472","url":null,"abstract":"<div><div>In the typical milk protein concentrate (MPC) manufacturing process, skim milk is ultrafiltered using a spiral-wound membrane to produce MPC80 with ∼20% total solids (TS) and 80% total protein on a DM basis. However, improving the production efficiency by achieving higher solids in the retentate has been a challenge when using spiral-wound membranes due to the limitation of operating pressure. We attempted flat-sheet UF membrane in a plate-and-frame (PF) module to concentrate the MPC further and achieve better production efficiency. Three replicates of ultrafiltered skim milk (feed) from spiral-wound UF membrane were concentrated in 3 different PF settings, including PF at 22°C (PF22), PF at 50°C for medium solids (PF50MS), and PF at 50°C for high solids (PF50HS). Hence, there were total 4 treatments: feed, PF22, PF50MS, and PF50HS. Filtration was carried out until the pressure drop reached 900 kPa for PF22 and PF50HS. For the PF50MS, the filtration was stopped when the TS achieved close to 30%. The average permeate flux and final TS were significantly higher for the treatments conducted at 50°C compared with 22°C with permeate fluxes of 8.76, 10.50, and 11.18 Lm⁻²h⁻¹ and TS of 26.83, 29.92, and 34.24%, respectively, for the PF22, PF50MS, and PF50HS treatments. The apparent viscosity of the final retentates was 577; 1,513; and 12,805 cP at a constant shear rate of 100 s⁻¹ for the PF22, PF50MS, and PF50HS treatments, respectively. Standard plate count increased in the high-temperature PF retentates; however, the level was below the acceptable limit as described in the USDA standards for fluid milk. This study determined that PF temperature is an important parameter for improving the filtration performance of MPC. The study establishes guidelines for increasing TS and protein levels in dairy foods production.</div></div>","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 4785-4795"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143727205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In vitro assessment of the effect of free amino acids on ruminal fermentation and 15N enrichment of ruminal nitrogen pools","authors":"S.E. Räisänen ,&nbsp;C.V. Almeida ,&nbsp;X. Zhu ,&nbsp;L.F. Martins ,&nbsp;A. Richards ,&nbsp;D. Wasson ,&nbsp;A.N. Hristov","doi":"10.3168/jds.2024-25947","DOIUrl":"10.3168/jds.2024-25947","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The objective of this study was to evaluate the effects of individual AA on ruminal fermentation and N utilization in vitro. Four, 24-h batch-culture incubations were conducted with rumen fluid from 3 (2 per incubation run) donor lactating dairy cows as inoculum and a standard TMR (16.5% CP, 30.9% NDF, and 25.5% starch of DM) as the basal substrate. Nitrogen-15 labeled ammonium sulfate (165 mg/L; 15 mg &lt;sup&gt;15&lt;/sup&gt;N/L) was used as a tracer to determine microbial ammonia-N incorporation in all treatments. Amino acids were supplemented individually (at 155 mg/L) as follows: His, Leu, Lys, Met, Phe, Trp, Val (EAA1; incubations 1 and 2), and Arg, Asp, Asn, Cys, Glu, Gln, Gly, Ile, Pro, Ser, Thr, and Tyr (EAA2 and NEAA; incubations 3 and 4). Each incubation included treatments with ammonium sulfate (AS; 101 mg/L) as a negative control and hydrolyzed CN (Amicase; 177 mg/L) as a positive control. Incubation medium samples were collected at 24 h and analyzed for VFA and ammonia-N concentrations, as well as NDF degradability. A subset of samples was processed for determination of &lt;sup&gt;15&lt;/sup&gt;N enrichment (i.e., atom percent excess) of 3 rumen N pools: solids, bacterial, and ammonia pools, respectively. For statistical analysis, the individual AA treatments were grouped and analyzed by set of incubations: EAA1 (incubations 1 and 2), EAA2 and NEAA (incubations 3 and 4) versus Amicase and AS. Additionally, responses to Amicase and individual AA treatments were compared expressed as the percent difference from AS (negative control). In incubations 3 and 4, compared with AS and EAA2 treatment groups, Amicase and NEAA had a greater total gas production. Total VFA was greatest for Amicase, while the molar proportion of acetate and acetate-to-propionate ratio were lowest and isovalerate was greatest for the EAA1 group. On an individual AA basis and relative to AS (negative control) acetate-to-propionate ratio decreased for Cys, Asp, Tyr, Gln, Met, Asn, Ile, and Thr by 4.5% to 12.5%. Furthermore, the isobutyrate molar proportion increased by 98.2% with Val, whereas Pro increased valerate by 84.1%, and Ile and Leu increased isovalerate by 71.1% and 61.1%, respectively. Nitrogen-15 enrichment of the bacterial-N pool in incubations 1 and 2 was greater for the EAA1 group compared with AS and Amicase, and the incorporation of ammonia-N into bacterial-N was greater for the EAA1 group, and tended to be greater for Amicase, versus AS. Incorporation of ammonia-N into bacterial-N was greater for Leu, Tyr, Met, Ile, Val, Trp, Gly, Phe, His, Pro, Cys, and Arg, ranging from 9.9% to 23%, relative to AS, but the proportion of bacterial-N in solids-N (i.e., a proxy for microbial protein synthesis) was not affected. Overall, supplemental AA (supplied at a dose of 155 mg/L) had minor effects on in vitro fermentation variables and fiber degradability, but supplementation of branched-chain AA and Pro increased molar proportions of their respective branched-chain VFA. Data","PeriodicalId":354,"journal":{"name":"Journal of Dairy Science","volume":"108 5","pages":"Pages 4963-4974"},"PeriodicalIF":3.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}