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Maternal Nutrition Affects Nitrogen Isotopic Signature in Blood Plasma of Beef Cattle Dams and Their Offspring. Metabolites 2022; 12:metabo12121249. [PMID: 36557286 PMCID: PMC9781575 DOI: 10.3390/metabo12121249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/04/2022] [Accepted: 11/08/2022] [Indexed: 12/14/2022] Open
Abstract
This study evaluated the effects of gestational supplementation strategy on nitrogen isotopic signature in blood plasma of beef cows and their progeny. The study comprised 15 pregnant Nellore cows divided into three different supplementation protocols: NP) non-programmed group; PP) cows receiving protein−energy supplement in the last third of pregnancy; and FP) cows receiving protein−energy supplement throughout the gestational period. Blood plasma from cows was sampled at the beginning of gestation, in the prepartum, and postpartum periods as well as from their calves at 30 and 180 days of age, for the analysis of stable isotope ratios 15 N/14 N. At pre- and postpartum periods, cows fed PP and FP presented greater abundance of δ15 N compared to NP (p < 0.05) at pre- and postpartum. All three groups showed significant differences (p < 0.05) in the postpartum period. The δ15 N values of calves at 30 days of age differed between the NP group and PP and FP groups (p < 0.05), with no difference (p > 0.05) at 180 days of age. The different gestational supplementation strategies influenced isotopic fractionation of nutrients of cows and their calves after birth, indicating effects on nutritional metabolism and cumulative behavior on isotope abundance related to consumption during gestation.
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2
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Silva LFP, Hegarty RS, Meale SJ, Costa DAF, Fletcher MT. Using the natural abundance of nitrogen isotopes to identify cattle with greater efficiency in protein-limiting diets. Animal 2022; 16 Suppl 3:100551. [PMID: 35688653 DOI: 10.1016/j.animal.2022.100551] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 11/26/2022] Open
Abstract
The difficulty in selecting cattle for higher feed and nitrogen use efficiency (NUE) is an important factor contributing to poor growth and reproductive performance in dry-tropics rangelands. Therefore, the objectives were to examine the cattle variation in retaining nitrogen in a protein-deficient diet and the natural abundance of stable isotopes in body tissues as a practical alternative for the detection of more efficient cattle. In experiment 1, feed efficiency parameters were determined in 89 Brahman steers fed a protein-limiting diet for 70 days, followed by 7 days in metabolism crates for total collection of urine and faeces and calculation of nitrogen retention and NUE. The diet-animal fractionation of nitrogen isotopes (Δ15N) was quantified in tail hair and plasma proteins using isotope-ratio MS. There was a large variation in growth performance, feed efficiency and nitrogen losses among steers. Quantifying Δ15N in tail hair (Δ15Ntail hair) resulted in stronger correlations with feed efficiency and nitrogen metabolism parameters than when quantified in plasma proteins. Δ15Ntail hair was positively correlated with nitrogen losses in urine (r = 0.31, P < 0.01) and faeces (r = 0.25, P = 0.04), leading to a negative correlation with NUE (r = -0.40, P < 0.01). The group of steers with lower Δ15Ntail hair had greater feed efficiency, lower nitrogen losses, and greater NUE. In experiment 2, for evaluation of isotope fraction as a predictor of reproductive performance, 630 Brahman-crossed cows were classified for reproductive performance for 2 years. From this group, 25 cows with poor reproductive performance and 25 cows with good reproductive performance were selected. Tail hair representing 7 months of growth were segmented and analysed for carbon (δ13C) and nitrogen (δ15N) isotope enrichment. Reproductive performance was not associated with diet selection, as there was no difference in tail hair δ13C between groups. However, more productive cows had lower (P < 0.05) tail hair δ15N during the dry season, indicating differences in N metabolism and possibly lower N losses. In addition, cows with better reproductive performance and, therefore, greater nutrient demands, had similar body condition scores and a tendency (P = 0.09) for higher live weight at the end of the trial. In conclusion, the findings of the present study confirm that nitrogen isotope fractionation in tail hair can be used as a predictor of nitrogen losses, NUE, and reproductive performance of Brahman cattle on low-protein diets.
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Affiliation(s)
- L F P Silva
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Saint Lucia, Australia.
| | - R S Hegarty
- The University of New England, School of Environmental and Rural Science, Armidale, Australia
| | - S J Meale
- The University of Queensland, School of Agriculture and Food Sciences, Gatton, Australia
| | - D A F Costa
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Saint Lucia, Australia
| | - M T Fletcher
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Saint Lucia, Australia
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3
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Correa-Luna M, Johansen M, Noziere P, Chantelauze C, Nasrollahi SM, Lund P, Larsen M, Bayat AR, Crompton LA, Reynolds CK, Froidmont E, Edouard N, Dewhurst R, Bahloul L, Martin C, Cantalapiedra-Hijar G. Nitrogen isotopic discrimination as a biomarker of between-cow variation in the efficiency of nitrogen utilization for milk production: A meta-analysis. J Dairy Sci 2022; 105:5004-5023. [PMID: 35450714 DOI: 10.3168/jds.2021-21498] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 02/21/2022] [Indexed: 11/19/2022]
Abstract
Estimating the efficiency of N utilization for milk production (MNE) of individual cows at a large scale is difficult, particularly because of the cost of measuring feed intake. Nitrogen isotopic discrimination (Δ15N) between the animal (milk, plasma, or tissues) and its diet has been proposed as a biomarker of the efficiency of N utilization in a range of production systems and ruminant species. The aim of this study was to assess the ability of Δ15N to predict the between-animal variability in MNE in dairy cows using an extensive database. For this, 20 independent experiments conducted as either changeover (n = 14) or continuous (n = 6) trials were available and comprised an initial data set of 1,300 observations. Between-animal variability was defined as the variation observed among cows sharing the same contemporary group (CG; individuals from the same experimental site, sampling period, and dietary treatment). Milk N efficiency was calculated as the ratio between mean milk N (grams of N in milk per day) and mean N intake (grams of N intake per day) obtained from each sampling period, which lasted 9.0 ± 9.9 d (mean ± SD). Samples of milk (n = 604) or plasma (n = 696) and feeds (74 dietary treatments) were analyzed for natural 15N abundance (δ15N), and then the N isotopic discrimination between the animal and the dietary treatment was calculated (Δ15n = δ15Nanimal - δ15Ndiet). Data were analyzed through mixed-effect regression models considering the experiment, sampling period, and dietary treatment as random effects. In addition, repeatability estimates were calculated for each experiment to test the hypothesis of improved predictions when MNE and Δ15N measurements errors were lower. The considerable protein mobilization in early lactation artificially increased both MNE and Δ15N, leading to a positive rather than negative relationship, and this limited the implementation of this biomarker in early lactating cows. When the experimental errors of Δ15N and MNE decreased in a particular experiment (i.e., higher repeatability values), we observed a greater ability of Δ15N to predict MNE at the individual level. The predominant negative and significant correlation between Δ15N and MNE in mid- and late lactation demonstrated that on average Δ15N reflects MNE variations both across dietary treatments and between animals. The root mean squared prediction error as a percentage of average observed value was 6.8%, indicating that the model only allowed differentiation between 2 cows in terms of MNE within a CG if they differed by at least 0.112 g/g of MNE (95% confidence level), and this could represent a limitation in predicting MNE at the individual level. However, the one-way ANOVA performed to test the ability of Δ15N to differentiate within-CG the top 25% from the lowest 25% individuals in terms of MNE was significant, indicating that it is possible to distinguish extreme animals in terms of MNE from their N isotopic signature, which could be useful to group animals for precision feeding.
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Affiliation(s)
- M Correa-Luna
- Université Clermont Auvergne, INRAE, UMR Herbivores, F-63000 Clermont-Ferrand, France
| | - M Johansen
- Department of Animal Science, Aarhus University, AU Foulum, PO Box 50, DK-8830, Tjele, Denmark
| | - P Noziere
- Université Clermont Auvergne, INRAE, UMR Herbivores, F-63000 Clermont-Ferrand, France
| | - C Chantelauze
- Université Clermont Auvergne, INRAE, UMR Herbivores, F-63000 Clermont-Ferrand, France; Université Clermont Auvergne, INRAE, UNH, Plateforme d'Exploration du Métabolisme, MetaboHUB, Clermont, F-63000 Clermont-Ferrand, France
| | - S M Nasrollahi
- Université Clermont Auvergne, INRAE, UMR Herbivores, F-63000 Clermont-Ferrand, France
| | - P Lund
- Department of Animal Science, Aarhus University, AU Foulum, PO Box 50, DK-8830, Tjele, Denmark
| | - M Larsen
- Department of Animal Science, Aarhus University, AU Foulum, PO Box 50, DK-8830, Tjele, Denmark
| | - A R Bayat
- Milk Production Solutions, Production Systems, Natural Resources Institute Finland (Luke), FI 31600 Jokioinen, Finland
| | - L A Crompton
- Centre for Dairy Research, Department of Animal Sciences, School of Agriculture, Policy, and Development, University of Reading, Reading, RG6 6AH, United Kingdom
| | - C K Reynolds
- Centre for Dairy Research, Department of Animal Sciences, School of Agriculture, Policy, and Development, University of Reading, Reading, RG6 6AH, United Kingdom
| | - E Froidmont
- Walloon Agricultural Research Center (CRA-W), B-5030 Gembloux, Belgium
| | - N Edouard
- INRAE, Agrocampus-Ouest, PEGASE, 35590 Saint-Gilles, France
| | - R Dewhurst
- SRUC, West Mains Road, Edinburgh, EH9 3JG, United Kingdom
| | - L Bahloul
- Adisseo France S.A.S., 92160 Antony, France
| | - C Martin
- Université Clermont Auvergne, INRAE, UMR Herbivores, F-63000 Clermont-Ferrand, France
| | - G Cantalapiedra-Hijar
- Université Clermont Auvergne, INRAE, UMR Herbivores, F-63000 Clermont-Ferrand, France.
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Cheng L, Cantalapiedra-Hijar G, Meale SJ, Rugoho I, Jonker A, Khan MA, Al-Marashdeh O, Dewhurst RJ. Review: Markers and proxies to monitor ruminal function and feed efficiency in young ruminants. Animal 2021; 15:100337. [PMID: 34537442 DOI: 10.1016/j.animal.2021.100337] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/10/2021] [Accepted: 07/16/2021] [Indexed: 11/19/2022] Open
Abstract
Developing the rumen's capacity to utilise recalcitrant and low-value feed resources is important for ruminant production systems. Early-life nutrition and management practices have been shown to influence development of the rumen in young animals with long-term consequences on their performance. Therefore, there has been increasing interest to understand ruminal development and function in young ruminants to improve feed efficiency, health, welfare, and performance of both young and adult ruminants. However, due to the small size, rapid morphological changes and low initial microbial populations of the rumen, it is difficult to study ruminal function in young ruminants without major invasive approaches or slaughter studies. In this review, we discuss the usefulness of a range of proxies and markers to monitor ruminal function and nitrogen use efficiency (a major part of feed efficiency) in young ruminants. Breath sulphide and methane emissions showed the greatest potential as simple markers of a developing microbiota in young ruminants. However, there is only limited evidence for robust indicators of feed efficiency at this stage. The use of nitrogen isotopic discrimination based on plasma samples appeared to be the most promising proxy for feed efficiency in young ruminants. More research is needed to explore and refine potential proxies and markers to indicate ruminal function and feed efficiency in young ruminants, particularly for neonatal ruminants.
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Affiliation(s)
- L Cheng
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Dookie Campus, 3647 Victoria, Australia.
| | - G Cantalapiedra-Hijar
- Université Clermont Auvergne, INRAE, VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès-Champanelle, France
| | - S J Meale
- School of Agriculture and Food Sciences, Faculty of Science, University of Queensland, Gatton, 4343 Queensland, Australia
| | - I Rugoho
- Lely Australia Pty Ltd, 84 Agar Drive, Truganina 3029, Victoria, Australia
| | - A Jonker
- AgResearch Limited, Grasslands Research Centre, Private Bag 11008, Palmerston North 4410, New Zealand
| | - M A Khan
- AgResearch Limited, Grasslands Research Centre, Private Bag 11008, Palmerston North 4410, New Zealand
| | - O Al-Marashdeh
- Faculty of Agriculture and Life Sciences, Lincoln University, P.O. Box 85084, Lincoln, New Zealand
| | - R J Dewhurst
- Scotland's Rural College, King's Buildings, West Mains Road, Edinburgh EH9 3JG, United Kingdom
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Guarnido-Lopez P, Ortigues-Marty I, Taussat S, Fossaert C, Renand G, Cantalapiedra-Hijar G. Plasma proteins δ 15N vs plasma urea as candidate biomarkers of between-animal variations of feed efficiency in beef cattle: Phenotypic and genetic evaluation. Animal 2021; 15:100318. [PMID: 34311194 DOI: 10.1016/j.animal.2021.100318] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 06/21/2021] [Accepted: 06/21/2021] [Indexed: 10/20/2022] Open
Abstract
Identifying animals that are superior in terms of feed efficiency may improve the profitability and sustainability of the beef cattle sector. However, measuring feed efficiency is costly and time-consuming. Biomarkers should thus be explored and validated to predict between-animal variation of feed efficiency for both genetic selection and precision feeding. In this work, we aimed to assess and validate two previously identified biomarkers of nitrogen (N) use efficiency in ruminants, plasma urea concentrations and the 15N natural abundance in plasma proteins (plasma δ15N), to predict the between-animal variation in feed efficiency when animals were fed two contrasted diets (high-starch vs high-fibre diets). We used an experimental network design with a total of 588 young bulls tested for feed efficiency through two different traits (feed conversion efficiency [FCE] and residual feed intake [RFI]) during at least 6 months in 12 cohorts (farm × period combination). Animals reared in the same cohort, receiving the same diet and housed in the same pen, were considered as a contemporary group (CG). To analyse between-animal variations and explore relationships between biomarkers and feed efficiency, two statistical approaches, based either on mixed-effect models or regressions from residuals, were conducted to remove the between-CG variability. Between-animal variation of plasma δ15N was significantly correlated with feed efficiency measured through the two criteria traits and regardless of the statistical approach. Conversely, plasma urea was not correlated to FCE and showed only a weak, although significant, correlation with RFI. The response of plasma δ15N to FCE variations was higher when animals were fed a high-starch compared to a high-fibre diet. In addition, we identified two dietary factors, the metabolisable protein to net energy ratio and the rumen protein balance that influenced the relation between plasma δ15N and FCE variations. Concerning the genetic evaluation, and despite the moderate heritability of the two biomarkers (0.28), the size of our experimental setup was insufficient to detect significant genetic correlations between feed efficiency and the biomarkers. However, we validated the potential of plasma δ15N to phenotypically discriminate two animals reared in identical conditions in terms of feed efficiency as long as they differ by at least 0.049 g/g for FCE and 1.67 kg/d for RFI. Altogether, the study showed phenotypic, but non-genetic, relationships between plasma proteins δ15N and feed efficiency that varied according to the efficiency index and the diet utilised.
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Affiliation(s)
- P Guarnido-Lopez
- INRAE, VetAgro Sup, UMR Herbivores, Université Clermont Auvergne, F-63122 Saint-Genès-Champanelle, France
| | - I Ortigues-Marty
- INRAE, VetAgro Sup, UMR Herbivores, Université Clermont Auvergne, F-63122 Saint-Genès-Champanelle, France
| | - S Taussat
- Université Paris-Saclay, INRAE, AgroParisTech, UMR Génétique Animale et Biologie Intégrative, 78350 Jouy-en-Josas, France
| | - C Fossaert
- Institut de l'élevage, 75595 Paris, France
| | - G Renand
- Université Paris-Saclay, INRAE, AgroParisTech, UMR Génétique Animale et Biologie Intégrative, 78350 Jouy-en-Josas, France
| | - G Cantalapiedra-Hijar
- INRAE, VetAgro Sup, UMR Herbivores, Université Clermont Auvergne, F-63122 Saint-Genès-Champanelle, France.
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Chen Y, Vanderick S, Mota RR, Grelet C, Gengler N. Estimation of genetic parameters for predicted nitrogen use efficiency and losses in early lactation of Holstein cows. J Dairy Sci 2021; 104:4413-4423. [PMID: 33551153 DOI: 10.3168/jds.2020-18849] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 11/05/2020] [Indexed: 02/02/2023]
Abstract
The objective of this study was to estimate genetic parameters of predicted N use efficiency (PNUE) and N losses (PNL) as proxies of N use and loss for Holstein cows. Furthermore, we have assessed approximate genetic correlations between PNUE, PNL, and dairy production, health, longevity, and conformation traits. These traits are considered important in many countries and are currently evaluated by the International Bull Evaluation Service (Interbull). The values of PNUE and PNL were obtained by using the combined milk mid-infrared (MIR) spectrum, parity, and milk yield-based prediction equations on test-day MIR records with days in milk (DIM) between 5 and 50 d. After editing, the final data set comprised 46,163 records of 21,462 cows from 154 farms in 5 countries. Each trait was divided into primiparous and multiparous (including second to fifth parity) groups. Genetic parameters and breeding values were estimated by using a multitrait (2-trait, 2-parity classes) repeatability model. Herd-year-season of calving, DIM, age of calving, and parity were used as fixed effects. Random effects were defined as parity (within-parity permanent environment), nongenetic cow (across-parity permanent environment), additive genetic animal, and residual effects. The estimated heritability of PNUE and PNL in the first and later parity were 0.13, 0.12, 0.14, and 0.13, and the repeatability values were 0.49, 0.40, 0.55, and 0.43, respectively. The estimated approximate genetic correlations between PNUE and PNL were negative and high (from -0.89 to -0.53), whereas the phenotypic correlations were also negative but relatively low (from -0.45 to -0.11). At a level of reliability of more than 0.30 for all novel traits, a total of 504 bulls born after 1995 had also publishable Interbull multiple-trait across-country estimated breeding values (EBV). The approximate genetic correlations between PNUE and the other 30 traits of interest, estimated as corrected correlations between EBV of bulls, ranged from -0.46 (udder depth) to 0.47 (milk yield). Obtained results showed the complex genetic relationship between efficiency, production, and other traits: for instance, more efficient cows seem to give more milk, which is linked to deeper udders, but seem to have lower health, fertility, and longevity. Additionally, the approximate genetic correlations between PNL, lower values representing less loss of N, and the 30 other traits, were from -0.32 (angularity) to 0.57 (direct calving ease). Even if further research is needed, our results provided preliminary evidence that the PNUE and PNL traits used as proxies could be included in genetic improvement programs in Holstein cows and could help their management.
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Affiliation(s)
- Y Chen
- TERRA Teaching and Research Center, University of Liège, Gembloux Agro-Bio Tech (ULiège-GxABT), 5030 Gembloux, Belgium
| | - S Vanderick
- TERRA Teaching and Research Center, University of Liège, Gembloux Agro-Bio Tech (ULiège-GxABT), 5030 Gembloux, Belgium
| | - R R Mota
- TERRA Teaching and Research Center, University of Liège, Gembloux Agro-Bio Tech (ULiège-GxABT), 5030 Gembloux, Belgium
| | - C Grelet
- Walloon Agricultural Research Center (CRA-W), 5030 Gembloux, Belgium
| | | | - N Gengler
- TERRA Teaching and Research Center, University of Liège, Gembloux Agro-Bio Tech (ULiège-GxABT), 5030 Gembloux, Belgium.
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7
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Martinez-Fernandez G, Jiao J, Padmanabha J, Denman SE, McSweeney CS. Seasonal and Nutrient Supplement Responses in Rumen Microbiota Structure and Metabolites of Tropical Rangeland Cattle. Microorganisms 2020; 8:E1550. [PMID: 33049981 PMCID: PMC7600044 DOI: 10.3390/microorganisms8101550] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/29/2020] [Accepted: 10/05/2020] [Indexed: 01/31/2023] Open
Abstract
This study aimed to characterize the rumen microbiota structure of cattle grazing in tropical rangelands throughout seasons and their responses in rumen ecology and productivity to a N-based supplement during the dry season. Twenty pregnant heifers grazing during the dry season of northern Australia were allocated to either N-supplemented or un-supplemented diets and monitored through the seasons. Rumen fluid, blood, and feces were analyzed before supplementation (mid-dry season), after two months supplementation (late-dry season), and post supplementation (wet season). Supplementation increased average daily weight gain (ADWG), rumen NH3-N, branched fatty acids, butyrate and acetic:propionic ratio, and decreased plasma δ15N. The supplement promoted bacterial populations involved in hemicellulose and pectin degradation and ammonia assimilation: Bacteroidales BS11, Cyanobacteria, and Prevotella spp. During the dry season, fibrolytic populations were promoted: the bacteria Fibrobacter, Cyanobacteria and Kiritimatiellaeota groups; the fungi Cyllamyces; and the protozoa Ostracodinium. The wet season increased the abundances of rumen protozoa and fungi populations, with increases of bacterial families Lachnospiraceae, Ruminococcaceae, and Muribaculaceae; the protozoa Entodinium and Eudiplodinium; the fungi Pecoramyces; and the archaea Methanosphera. In conclusion, the rumen microbiota of cattle grazing in a tropical grassland is distinctive from published studies that mainly describe ruminants consuming better quality diets.
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Affiliation(s)
| | - Jinzhen Jiao
- CAS Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, The Chinese Academy of Sciences, Changsha 410125, China;
| | - Jagadish Padmanabha
- Agriculture and Food, CSIRO, St Lucia, QLD 4067, Australia; (G.M.-F.); (J.P.); (S.E.D.)
| | - Stuart E. Denman
- Agriculture and Food, CSIRO, St Lucia, QLD 4067, Australia; (G.M.-F.); (J.P.); (S.E.D.)
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8
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Cantalapiedra-Hijar G, Guarnido P, Schiphorst AM, Robins RJ, Renand G, Ortigues-Marty I. Natural 15N abundance in specific amino acids indicates associations between transamination rates and residual feed intake in beef cattle. J Anim Sci 2020; 98:5841057. [PMID: 32432323 PMCID: PMC7275638 DOI: 10.1093/jas/skaa171] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 05/14/2020] [Indexed: 11/29/2022] Open
Abstract
Improving the ability of animals to convert feed resources into food for humans is needed for more sustainable livestock systems. Genetic selection for animals eating less while maintaining their performance (i.e., low residual feed intake [RFI]) appears a smart strategy but its effectiveness relies on high-throughput animal phenotyping. Here, we explored plasma nitrogen (N) isotope ratios in an attempt to identify easily superior young bulls in terms of RFI. For this, 48 Charolais young bulls fed two contrasting diets (corn vs. grass silage diets) were selected from a larger population as extreme RFI animals (24 low-RFI vs. 24 high-RFI) and their plasma analyzed for natural 15N abundance (δ15N) in the whole protein (bulk protein) and in the individual protein-bound amino acids (PbAA). For the first time, we showed that the δ 15N in plasma bulk protein differed (P = 0.007) between efficient (low-RFI) and inefficient (high-RFI) cattle regardless of diet. Furthermore, most analyzed PbAA followed the same trend as the bulk protein, with lower (P < 0.05) δ 15N values in more efficient (low-RFI) compared with less efficient (high-RFI) cattle, again regardless of diet. The only three exceptions were Phe, Met, and Lys (P > 0.05) for which the first metabolic reaction before being catabolized does not involve transamination, a pathway known naturally to enrich AAs in 15N. The contrasted isotopic signatures across RFI groups only in those PbAA undergoing transamination are interpreted as differences in transamination rates and N-use efficiency between low- and high-RFI phenotypes. Natural isotopic N signatures in bulk proteins and specific PbAA can be proposed as biomarkers of RFI in growing beef cattle fed different diets. However, the current study cannot delineate whether this effect only occurs post-absorption or to some extent also in the rumen. Our data support the conclusion that most efficient cattle in terms of RFI upregulate N conservation mechanisms compared with less efficient cattle and justify future research on this topic.
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Affiliation(s)
| | - Pablo Guarnido
- INRAE, Université Clermont Auvergne, Vetagro Sup, UMRH, Saint-Genès-Champanelle, France
| | | | | | - Gilles Renand
- Université Paris-Saclay, INRAE, AgroParisTech, GABI, Jouy-en-Josas, France
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Nasrollahi SM, Meale SJ, Morgavi DP, Schiphorst AM, Robins RJ, Ortigues-Marty I, Cantalapiedra-Hijar G. The origin of N isotopic discrimination and its relationship with feed efficiency in fattening yearling bulls is diet-dependent. PLoS One 2020; 15:e0234344. [PMID: 32502191 PMCID: PMC7274422 DOI: 10.1371/journal.pone.0234344] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 05/23/2020] [Indexed: 11/19/2022] Open
Abstract
Nitrogen (N) isotopic discrimination (i.e. the difference in natural 15N abundance between the animal proteins and the diet; Δ15N) is known to correlate with N use efficiency (NUE) and feed conversion efficiency (FCE) in ruminants. However, results from the literature are not always consistent across studies, likely due to isotopic discrimination pathways that may differ with the nature of diets. The objective of the present study was to assess at which level, from rumen to tissues, Δ15N originates and becomes related to NUE and FCE in fattening yearling bulls when they are fed two contrasted diets. Twenty-four Charolais yearling bulls were randomly divided into two groups and fed during 8 months, from weaning to slaughter, either 1) a high starch diet based on corn silage supplying a balanced N to energy ratio at the rumen level (starch) or 2) a high fiber diet based on grass silage supplying an excess of rumen degradable N (fiber). All animals were slaughtered and samples of different digestive pools (ruminal, duodenal, ileal and fecal contents), animal tissues (duodenum, liver and muscle), blood and urine were collected for each animal. Ruminal content was further used to isolate liquid-associated bacteria (LAB), protozoa and free ammonia, while plasma proteins were obtained from blood. All samples along with feed were analyzed for their N isotopic composition. For both diets, the digestive contribution (i.e. the N isotopic discrimination occurring before absorption) to the Δ15N observed in animal tissues accounted for 65 ± 11%, leaving only one third to the contribution of post-absorptive metabolism. Concerning the Δ15N in digestive pools, the majority of these changes occurred in the rumen (av. Δ15N = 2.12 ± 0.66‰), with only minor 15N enrichments thereafter (av. Δ15N = 2.24 ± 0.41‰), highlighting the key role of the rumen on N isotopic discrimination. A strong, significant overall relationship (n = 24) between Δ15N and FCE or NUE was found when using any post-absorptive metabolic pool (duodenum, liver, or muscle tissues, or plasma proteins; 0.52 < r < 0.73; P ≤ 0.01), probably as these pools reflect both digestive and post-absorptive metabolic phenomena. Fiber diet compared to starch diet had a lower feed efficiency and promoted higher (P ≤ 0.05) Δ15N values across all post-absorptive metabolic pools and some digestive pools (ruminal, duodenal, and ileal contents). The within-diet relationship (n = 12) between Δ15N and feed efficiency was not as strong and consistent as the overall relationship, with contrasted responses between the two diets for specific pools (diet x pool interaction; P ≤ 0.01). Our results highlight the contrasted use of N at the rumen level between the two experimental diets and suggests the need for different equations to predict FCE or NUE from Δ15N according to the type of diet. In conclusion, rumen digestion and associated microbial activity can play an important role on N isotopic discrimination so rumen effect related to diet may interfere with the relationship between Δ15N and feed efficiency in fattening yearling bulls.
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Affiliation(s)
| | - Sarah Jade Meale
- School of Agriculture and Food Sciences, The University of Queensland, Gatton Campus, Gatton, Australia
| | - Diego P. Morgavi
- INRAE, Université Clermont Auvergne, Vetagro Sup, UMRH, Saint-Genès-Champanelle, France
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10
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Feed efficiency and nitrogen use rankings of Bos indicus steers differ on low and high protein diets. Anim Feed Sci Technol 2020. [DOI: 10.1016/j.anifeedsci.2020.114493] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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11
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Nitrogen partitioning and isotopic discrimination are affected by age and dietary protein content in growing lambs. Animal 2019; 14:942-951. [PMID: 31679553 DOI: 10.1017/s1751731119002647] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
It is difficult to separate an age-dependent fall in nitrogen use efficiency (NUE; N balance/N intake) in growing ruminants from a progressively decrease in animal protein requirements over time. This study examined the effect of dietary protein content on N partitioning, digestibility and N isotopic discrimination between the animal and its diet (Δ15Nanimal-diet) evaluated at two different fattening periods (early v. late). Twenty-four male Romane lambs (age: 19 ± 4.0 days; BW: 8.3 ± 1.39 kg) were equally allocated to three dietary CP treatments (15%, 17% and 20% CP on a DM basis). Lambs were reared with their mothers until weaning, thereafter housed in individual pens until slaughter (45 kg BW). During the post-weaning period, lambs were allocated twice (early fattening (30 days post-weaning) and late fattening (60 days post-weaning)) to metabolic cages for digestibility and N balance study. When diet CP content increased, the average daily gain of lambs increased (P < 0.05) while the age at slaughter decreased (P = 0.01), but no effect was observed on feed efficiency (P > 0.10). Diet CP content had limited effect on lamb carcass traits. Higher fibre digestibility was observed at the early v. late fattening period (P < 0.001). The N intake and the urinary N excretion increased when diet CP content increased (P < 0.001) and when shifting from early to late fattening period (P < 0.001). Faecal N excretion (P = 0.14) and N balance (P > 0.10) were not affected by diet CP content. Nitrogen digestibility increased (P < 0.001) as the diet CP content increased and on average it was greater at late v. early fattening period (P = 0.02). The NUE decreased (P = 0.001) as the diet CP content increased and as the lamb became older (P < 0.001). However, the age-dependent fall in NUE observed was lower at high v. low dietary CP content (CP × age interaction; P = 0.04). The Δ15Nanimal-diet was positively correlated (P < 0.05) with N intake (r = 0.59), excretion of faecal N (r = 0.41), urinary N (r = 0.69) and total manure N (r = 0.64), while negatively correlated with NUE (r = -0.57). Overall, the experiment showed NUE was lower in older lambs and when lambs were fed high diet CP content, and that Δ15Nanimal-diet was a useful indicator not only for NUE but also for urinary N excretion, which is a major environmental pollution factor on farm.
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Meale SJ, Auffret MD, Watson M, Morgavi DP, Cantalapiedra-Hijar G, Duthie CA, Roehe R, Dewhurst RJ. Fat accretion measurements strengthen the relationship between feed conversion efficiency and Nitrogen isotopic discrimination while rumen microbial genes contribute little. Sci Rep 2018; 8:3854. [PMID: 29497066 PMCID: PMC5832862 DOI: 10.1038/s41598-018-22103-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 02/16/2018] [Indexed: 01/20/2023] Open
Abstract
The use of biomarkers for feed conversion efficiency (FCE), such as Nitrogen isotopic discrimination (Δ15N), facilitates easier measurement and may be useful in breeding strategies. However, we need to better understand the relationship between FCE and Δ15N, particularly the effects of differences in the composition of liveweight gain and rumen N metabolism. Alongside measurements of FCE and Δ15N, we estimated changes in body composition and used dietary treatments with and without nitrates, and rumen metagenomics to explore these effects. Nitrate fed steers had reduced FCE and higher Δ15N in plasma compared to steers offered non-nitrate containing diets. The negative relationship between FCE and Δ15N was strengthened with the inclusion of fat depth change at the 3rd lumbar vertebrae, but not with average daily gain. We identified 1,700 microbial genes with a relative abundance >0.01% of which, 26 were associated with Δ15N. These genes explained 69% of variation in Δ15N and showed clustering in two distinct functional networks. However, there was no clear relationship between their relative abundances and Δ15N, suggesting that rumen microbial genes contribute little to Δ15N. Conversely, we show that changes in the composition of gain (fat accretion) provide additional strength to the relationship between FCE and Δ15N.
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Affiliation(s)
- Sarah J Meale
- Université Clermont Auvergne, INRA, VetAgro Sup, UMR Herbivores, F-63122, Saint-Genès-Champanelle, France
- School of Agriculture and Food Sciences, The University of Queensland, Gatton, QLD 4343, Australia
| | - Marc D Auffret
- SRUC, West Mains Road, Edinburgh, EH9 3JG, United Kingdom
| | - Mick Watson
- Division of Genetics and Genomics, The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, EH25 9RG, United Kingdom
- Edinburgh Genomics, The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, EH25 9RG, United Kingdom
| | - Diego P Morgavi
- Université Clermont Auvergne, INRA, VetAgro Sup, UMR Herbivores, F-63122, Saint-Genès-Champanelle, France
| | | | | | - Rainer Roehe
- SRUC, West Mains Road, Edinburgh, EH9 3JG, United Kingdom
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13
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Nitrogen isotopic fractionation as a biomarker for nitrogen use efficiency in ruminants: a meta-analysis. Animal 2018; 12:1827-1837. [DOI: 10.1017/s1751731117003391] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Surlis C, McNamara K, O'Hara E, Waters S, Beltman M, Cassidy J, Kenny D. Birth delivery method affects expression of immune genes in lung and jejunum tissue of neonatal beef calves. BMC Vet Res 2017; 13:391. [PMID: 29237479 PMCID: PMC5729508 DOI: 10.1186/s12917-017-1310-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 11/28/2017] [Indexed: 11/24/2022] Open
Abstract
Background Caesarean section is a routine veterinary obstetrical procedure employed to alleviate dystocia in cattle. However, CS, particularly before the onset of labour, is known to negatively affect neonatal respiration and metabolic adaptation in humans, though there is little published information for cattle. The aim of this study was to investigate the effect of elective caesarean section (ECS) or normal trans-vaginal (TV) delivery, on lung and jejunal gene expression profiles of neonatal calves. Results Paternal half-sib Angus calves (gestation length 278 + 1.8 d) were delivered either transvaginally (TV; n = 8) or by elective caesarean section (ECS; n = 9) and immediately euthanized. Lung and jejunum epithelial tissue was isolated and snap frozen. Total RNA was extracted using Trizol reagent and reverse transcribed to generate cDNA. For lung tissue, primers were designed to target genes involved in immunity, surfactant production, cellular detoxification, membrane transport and mucin production. Primers for jejunum tissue were chosen to target mucin production, immunoglobulin uptake, cortisol reaction and membrane trafficking. Quantitative real-time PCR reactions were performed and data were statistically analysed using mixed models ANOVA. In lung tissue the expression of five genes were affected (p < 0.05) by delivery method. Four of these genes were present at lower (LAP, CYP1A1, SCN11α and SCN11β) and one (MUC5AC) at higher abundance in ECS compared with TV calves. In jejunal tissue, expression of TNFα, Il-1β and 1 l-6 was higher in ECS compared with TV calves. Conclusions This novel study shows that ECS delivery affects the expression of key genes involved in the efficiency of the pulmonary liquid to air transition at birth, and may lead to an increased inflammatory response in jejunal tissue, which could compromise colostral immunoglobulin absorption. These findings are important to our understanding of the viability and management of neonatal calves born through ECS.
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Affiliation(s)
- Carla Surlis
- Animal and Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland.
| | - Keelan McNamara
- Animal and Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland
| | - Eoin O'Hara
- Animal and Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland
| | - Sinead Waters
- Animal and Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland
| | - Marijke Beltman
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - Joseph Cassidy
- School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - David Kenny
- Animal and Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland.
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Meale SJ, Morgavi DP, Cassar-Malek I, Andueza D, Ortigues-Marty I, Robins RJ, Schiphorst AM, Migné C, Pétéra M, Laverroux S, Graulet B, Boudra H, Cantalapiedra-Hijar G. Exploration of Biological Markers of Feed Efficiency in Young Bulls. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:9817-9827. [PMID: 29058420 DOI: 10.1021/acs.jafc.7b03503] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The efficiency with which ruminants convert feed to desirable products is difficult to measure under normal commercial settings. We explored the use of potential biological markers from easily obtainable samples, that is, blood, hair, and feces, to characterize potential causes of divergent efficiency when considered as residual feed intake (RFI) or feed conversion efficiency (FCE). A total of 54 Charolais bulls, 20 in period 1 and 34 in period 2, were examined for individual dry matter intake (DMI) and growth. Bulls were offered a diet of 70:30 wrapped grass silage to concentrate for 99 d. At the conclusion of the test period, blood samples were collected for the determination of vitamins B2 and B6, and plasma used for the determination of metabolites, natural isotopic 15N abundance (15N NIA, expressed as δ15N ‰) and fractionation (Δ15Nplasma proteins-diet and Δ13Cplasma proteins-diet) and near-infrared spectroscopy (NIRS). Feces were analyzed by NIRS. Bulls were slaughtered at 15-17 months of age and carcass characteristics determined. Bulls were ranked according to RFI with extremes (SD ± 0.5; n = 31) classified as either efficient (Neg-RFI) or inefficient (Pos-RFI). Extreme bulls were then classified for FCE (high vs low FCE), changing the groups. Pos-RFI bulls consumed 14% more feed than Neg-RFI bulls for the same level of weight gain. Low FCE bulls tended to eat more, but had lower weight gains than high FCE bulls. No differences were detected in carcass conformation, fat scores, hot carcass weight, or dressing percentage. Yet, heart and bladder weights were heavier in Pos-RFI, and rumen weight tended to be heavier in Pos-RFI bulls. RFI did not affect bulk 15N or 13C fractionation. A negative correlation was observed between FCE and Δ15Nplasma proteins-diet. Inefficient bulls (Pos-RFI) had higher δ15N in glycine compared to Neg-RFI bulls. Similarly, metabolomic analysis showed a tendency for concentrations of glycine and sarcosine to be elevated in Pos-RFI bulls, whereas aspartic acid and carnosine tended to be elevated, and serine tended to be lower in High FCE. Among vitamins, only flavin adenine dinucleotide concentration was higher in the blood of bulls with High FCE. These results suggest that the two feed efficiency metrics differ in the underlying mechanisms of metabolism, where RFI is driven by differences in the energetic requirements of visceral organs and the extent of AA catabolism.
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Affiliation(s)
- Sarah J Meale
- Université Clermont Auvergne, INRA , VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès-Champanelle, France
| | - Diego P Morgavi
- Université Clermont Auvergne, INRA , VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès-Champanelle, France
| | - Isabelle Cassar-Malek
- Université Clermont Auvergne, INRA , VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès-Champanelle, France
| | - Donato Andueza
- Université Clermont Auvergne, INRA , VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès-Champanelle, France
| | - Isabelle Ortigues-Marty
- Université Clermont Auvergne, INRA , VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès-Champanelle, France
| | - Richard J Robins
- Elucidation of Biosynthesis by Isotopic Spectrometry Group, CEISAM, CNRS-University of Nantes UMR6230 , B.P. 92208, F-44322 Nantes, France
| | - Anne-Marie Schiphorst
- Elucidation of Biosynthesis by Isotopic Spectrometry Group, CEISAM, CNRS-University of Nantes UMR6230 , B.P. 92208, F-44322 Nantes, France
| | | | | | - Sophie Laverroux
- Université Clermont Auvergne, INRA , VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès-Champanelle, France
| | - Benoit Graulet
- Université Clermont Auvergne, INRA , VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès-Champanelle, France
| | - Hamid Boudra
- Université Clermont Auvergne, INRA , VetAgro Sup, UMR Herbivores, F-63122 Saint-Genès-Champanelle, France
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16
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Ellies-Oury MP, Cantalapiedra-Hijar G, Durand D, Gruffat D, Listrat A, Micol D, Ortigues-Marty I, Hocquette JF, Chavent M, Saracco J, Picard B. An innovative approach combining Animal Performances, nutritional value and sensory quality of meat. Meat Sci 2016; 122:163-172. [DOI: 10.1016/j.meatsci.2016.08.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 08/05/2016] [Accepted: 08/06/2016] [Indexed: 10/21/2022]
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17
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Cantalapiedra-Hijar G, Ortigues-Marty I, Schiphorst AM, Robins RJ, Tea I, Prache S. Natural (15)N Abundance in Key Amino Acids from Lamb Muscle: Exploring a New Horizon in Diet Authentication and Assessment of Feed Efficiency in Ruminants. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:4058-4067. [PMID: 27148901 DOI: 10.1021/acs.jafc.6b00967] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Natural (15)N abundance (δ(15)N) varies between individual amino acids (AAs). We hypothesized that δ(15)N of nontransaminating and essential AAs ("source" AAs, such as phenylalanine) present in animal tissues could be used as a marker of dietary origin, whereas δ(15)N of transaminating AAs ("trophic" AAs, such as glutamic acid) could give more detailed insights into animal feed efficiency. Two diets based on dehydrated Lucerne pellets were tested in growing lambs, which promoted different feed efficiencies. No dietary effects were noted on δ(15)N of any AAs analyzed in lamb muscle. In addition, δ(15)N of phenylalanine was unexpectedly similar to that of glutamic acid, suggesting that δ(15)N of AAs is significantly derived from the metabolism of the rumen microbiota and, thus, are not suited for diet authentication in ruminants. In contrast, the δ(15)N of transaminating AAs facilitates an improved prediction of animal feed efficiency compared to the classical isotopic bulk N analysis.
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Affiliation(s)
- Gonzalo Cantalapiedra-Hijar
- UMR 1213 Herbivores, INRA , F-63122 Saint-Genès Champanelle, France
- VetAgro Sup, UMR 1213 Herbivores, Clermont Université , B.P. 10448, F-63000 Clermont-Ferrand, France
| | - Isabelle Ortigues-Marty
- UMR 1213 Herbivores, INRA , F-63122 Saint-Genès Champanelle, France
- VetAgro Sup, UMR 1213 Herbivores, Clermont Université , B.P. 10448, F-63000 Clermont-Ferrand, France
| | - Anne-Marie Schiphorst
- Elucidation of Biosynthesis by Isotopic Spectrometry Group, CEISAM, UMR6230, CNRS-University of Nantes , B.P. 92208, F-44322 Nantes, France
| | - Richard J Robins
- Elucidation of Biosynthesis by Isotopic Spectrometry Group, CEISAM, UMR6230, CNRS-University of Nantes , B.P. 92208, F-44322 Nantes, France
| | - Illa Tea
- Elucidation of Biosynthesis by Isotopic Spectrometry Group, CEISAM, UMR6230, CNRS-University of Nantes , B.P. 92208, F-44322 Nantes, France
| | - Sophie Prache
- UMR 1213 Herbivores, INRA , F-63122 Saint-Genès Champanelle, France
- VetAgro Sup, UMR 1213 Herbivores, Clermont Université , B.P. 10448, F-63000 Clermont-Ferrand, France
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Relationship between efficiency of nitrogen utilization and isotopic nitrogen fractionation in dairy cows: contribution of digestion v. metabolism? Animal 2016; 10:221-9. [DOI: 10.1017/s1751731115002025] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Cheng L, Logan CM, Dewhurst RJ, Hodge S, Zhou H, Edwards GR. Effects of feed intake and genetics on tissue nitrogen-15 enrichment and feed conversion efficiency in sheep. J Anim Sci 2015; 93:5849-55. [PMID: 26641195 DOI: 10.2527/jas.2015-9638] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study investigated the effects of sheep genetics and feed intake on nitrogen isotopic fractionation (ΔN) and feed conversion efficiency (FCE; live weight gain/DMI), using a 2 × 2 factorial design, with 2 levels of genetic merit for growth (high vs. low) and 2 levels of feed intake (110 vs. 170% of ME for maintenance [MEm]). No effect of genetic merit was detected for live weight gain ( = 0.64), FCE ( = 0.46), plasma urea nitrogen ( = 0.52), plasma glucose ( = 0.78), and ΔN of wool ( = 0.45), blood ( = 0.09), and plasma ( = 0.51). Sheep receiving 170% of MEm had 175% higher live weight gain ( < 0.001) and 77% higher FCE ( < 0.001) than sheep receiving 110% of MEm. There was no difference among treatments at the beginning of the study for either blood or plasma ∆N, but the treatment groups started to diverge in blood and plasma ∆N at 21 and 7 d, respectively. Blood, plasma, and wool samples were enriched in N compared with feed. There was a higher blood, plasma, and wool ∆N for the low feed intake group than the high feed intake group ( < 0.001 in all cases). Across the 4 treatment groups, higher FCE in sheep was associated with lower ∆N for plasma, blood, and wool. Overall, the results are consistent with the potential of ∆N as a rapid, low-cost biomarker of FCE in sheep, despite there being no effects of genetic treatment on FCE and ∆N.
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Diet-animal fractionation of nitrogen stable isotopes reflects the efficiency of nitrogen assimilation in ruminants. Br J Nutr 2015; 113:1158-69. [PMID: 25716533 DOI: 10.1017/s0007114514004449] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The natural abundance of ¹⁵N in animal proteins (δ¹⁵Nanimal) is greater than that in the diet consumed by the animals (δ¹⁵Ndiet), with a discrimination factor (Δ¹⁵N = δ¹⁵Nanimal - δ¹⁵Ndiet) that is known to vary according to nutritional conditions. The objectives of the present study were to test the hypothesis that Δ¹⁵N variations depend on the efficiency of nitrogen utilisation (ENU) in growing beef cattle, and to identify some of the physiological mechanisms responsible for this N isotopic fractionation in ruminants. Thus, we performed the regression of the Δ¹⁵N of plasma proteins obtained from thirty-five finishing beef cattle fed standard and non-conventional diets against different feed efficiency indices, including ENU. We also performed the regression of the Δ¹⁵N of different ruminant N pools (plasma and milk proteins, urine and faeces) against different splanchnic N fluxes obtained from multi-catheterised lactating dairy cows. The Δ¹⁵N of plasma proteins was negatively correlated with feed efficiency indices in beef cattle, especially ENU (body protein gain/N intake) and efficiency of metabolisable protein (MP) utilisation (body protein gain/MP intake). Although Δ¹⁵N obtained from different N pools in dairy cows were all negatively correlated with ENU, the highest correlation was found when Δ¹⁵N was calculated from plasma proteins. Δ¹⁵N showed no correlation with urea-N recycling or rumen NH₃ absorption, but exhibited a strong correlation with liver urea synthesis and splanchnic amino acid metabolism, which points to a dominant role of splanchnic tissues in the present N isotopic fractionation study.
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