In vitro assessment of the effect of free amino acids on ruminal fermentation and 15N enrichment of ruminal nitrogen pools
ABSTRACT: 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% C...
Saved in:
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-05-01
|
| Series: | Journal of Dairy Science |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S002203022500270X |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850281378322579456 |
|---|---|
| author | S.E. Räisänen C.V. Almeida X. Zhu L.F. Martins A. Richards D. Wasson A.N. Hristov |
| author_facet | S.E. Räisänen C.V. Almeida X. Zhu L.F. Martins A. Richards D. Wasson A.N. Hristov |
| author_sort | S.E. Räisänen |
| collection | DOAJ |
| description | ABSTRACT: 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 15N/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 15N 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 demonstrated that 9 EAA and 3 NEAA supplemented individually improved the incorporation of ammonia-N into bacterial-N, indicating that some AA can enhance N utilization in the rumen. |
| format | Article |
| id | doaj-art-aac602029b7043e7980a210c0ad2c229 |
| institution | OA Journals |
| issn | 0022-0302 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Dairy Science |
| spelling | doaj-art-aac602029b7043e7980a210c0ad2c2292025-08-20T01:48:20ZengElsevierJournal of Dairy Science0022-03022025-05-0110854963497410.3168/jds.2024-25947In vitro assessment of the effect of free amino acids on ruminal fermentation and 15N enrichment of ruminal nitrogen poolsS.E. Räisänen0C.V. Almeida1X. Zhu2L.F. Martins3A. Richards4D. Wasson5A.N. Hristov6Department of Animal Science, The Pennsylvania State University, University Park, PA 16802; Department of Agricultural Sciences, University of Helsinki, FI-00014 Helsinki, FinlandDepartment of Animal Science, The Pennsylvania State University, University Park, PA 16802Department of Animal Science, The Pennsylvania State University, University Park, PA 16802; Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China 0731Department of Animal Science, The Pennsylvania State University, University Park, PA 16802Department of Animal Science, The Pennsylvania State University, University Park, PA 16802Department of Animal Science, The Pennsylvania State University, University Park, PA 16802Department of Animal Science, The Pennsylvania State University, University Park, PA 16802; Corresponding authorABSTRACT: 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 15N/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 15N 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 demonstrated that 9 EAA and 3 NEAA supplemented individually improved the incorporation of ammonia-N into bacterial-N, indicating that some AA can enhance N utilization in the rumen.http://www.sciencedirect.com/science/article/pii/S002203022500270Xamino acidsin vitronitrogen utilizationrumen |
| spellingShingle | S.E. Räisänen C.V. Almeida X. Zhu L.F. Martins A. Richards D. Wasson A.N. Hristov In vitro assessment of the effect of free amino acids on ruminal fermentation and 15N enrichment of ruminal nitrogen pools Journal of Dairy Science amino acids in vitro nitrogen utilization rumen |
| title | In vitro assessment of the effect of free amino acids on ruminal fermentation and 15N enrichment of ruminal nitrogen pools |
| title_full | In vitro assessment of the effect of free amino acids on ruminal fermentation and 15N enrichment of ruminal nitrogen pools |
| title_fullStr | In vitro assessment of the effect of free amino acids on ruminal fermentation and 15N enrichment of ruminal nitrogen pools |
| title_full_unstemmed | In vitro assessment of the effect of free amino acids on ruminal fermentation and 15N enrichment of ruminal nitrogen pools |
| title_short | In vitro assessment of the effect of free amino acids on ruminal fermentation and 15N enrichment of ruminal nitrogen pools |
| title_sort | in vitro assessment of the effect of free amino acids on ruminal fermentation and 15n enrichment of ruminal nitrogen pools |
| topic | amino acids in vitro nitrogen utilization rumen |
| url | http://www.sciencedirect.com/science/article/pii/S002203022500270X |
| work_keys_str_mv | AT seraisanen invitroassessmentoftheeffectoffreeaminoacidsonruminalfermentationand15nenrichmentofruminalnitrogenpools AT cvalmeida invitroassessmentoftheeffectoffreeaminoacidsonruminalfermentationand15nenrichmentofruminalnitrogenpools AT xzhu invitroassessmentoftheeffectoffreeaminoacidsonruminalfermentationand15nenrichmentofruminalnitrogenpools AT lfmartins invitroassessmentoftheeffectoffreeaminoacidsonruminalfermentationand15nenrichmentofruminalnitrogenpools AT arichards invitroassessmentoftheeffectoffreeaminoacidsonruminalfermentationand15nenrichmentofruminalnitrogenpools AT dwasson invitroassessmentoftheeffectoffreeaminoacidsonruminalfermentationand15nenrichmentofruminalnitrogenpools AT anhristov invitroassessmentoftheeffectoffreeaminoacidsonruminalfermentationand15nenrichmentofruminalnitrogenpools |