Bacterial protein degradation by different rumen protozoal groups

Bacterial predation by protozoa has the most deleterious effect on the efficiency of N use within the rumen, but differences in activity among protozoal groups are not completely understood. Two in vitro experiments were conducted to identify the protozoal groups more closely related with rumen N metabolism. Rumen protozoa were harvested from cattle and 7 protozoal fractions were generated immediately after sampling by filtration through different nylon meshes at 39°C, under a CO2 atmosphere to maintain their activity. Protozoa were incubated with 14C-labeled bacteria to determine their bacterial breakdown capacity, according to the amount of acid-soluble radioactivity released. Epidinium tended to codistribute with Isotricha and Entodinium with Dasytricha; therefore, their activity was calculated together. This study demonstrated that big Diplodiniinae had the greatest activity per cell (100 ng bacterial CP per protozoa and hour), followed by Epidinium plus Isotricha (36.4), small Diplodiniinae (34.2), and Entodinium plus Dasytricha (14.8), respectively. However, the activity per unit of protozoal volume seemed to vary, depending on the protozoal taxonomy. Small Diplodiniinae had the greatest activity per volume (325 ng bacterial CP per protozoal mm3 and hour), followed by big Diplodiniinae (154), Entodinium plus Dasytricha (104), and Entodinium plus Dasytricha (25.6). A second experiment was conducted using rumen fluid from holotrich-monofaunated sheep. This showed that holotrich protozoa had a limited bacterial breakdown capacity per cell (Isotricha 9.44 and Dasytricha 5.81 ng bacterial CP per protozoa and hour) and per protozoal volume (5.97 and 76.9 ng bacterial CP per protozoal mm3 and hour, respectively). Therefore, our findings indicated that a typical protozoal population (106 total protozoa/mL composed by Entodinium sp. 88%, Epidinium sp. 7%, and other species 4%) is able to break down ∼17% of available rumen bacteria every hour. Entodinium sp. is responsible for most of this bacterial breakdown (70 to 75%), followed by Epidinium sp. (16 to 24%), big Diplodiniinae (4 to 6%), and small Diplodiniinae (2 to 6%), whereas holotrich protozoa have a negligible activity (Dasytricha sp. 0.6 to 1.2% and Isotricha sp. 0.2 to 0.5%). This in vitro information must be carefully interpreted, but it can be used to indicate which protozoal groups should be suppressed to improve microbial protein synthesis in vivo.This study was supported by the Framework 7 program from the EU “Innovative and practical management approaches to reduce nitrogen excretion by ruminants (Rednex)” and the Welsh government. We thank the Institute of Biological, Environmental and Rural Sciences staff for their assistance and collaboration

Determination of the absolute accuracy of UK chamber facilities used in measuring methane emissions from livestock

Respiration chambers are one of the primary sources of data on methane emissions from livestock. This paper describes the results from a coordinated set of chamber validation experiments which establishes the absolute accuracy of the methane emission rates measured by the chambers, and for the first time provides metrological traceability to international standards, assesses the impact of both analyser and chamber response times on measurement uncertainty and establishes direct comparability between measurements made across different facilities with a wide range of chamber designs. As a result of the validation exercise the estimated combined uncertainty associated with the overall capability across all facilities reduced from 25.7% (k = 2, 95% confidence) before the validation to 2.1% (k = 2, 95% confidence) when the validation results are applied to the facilities’ data

Efficiency of Nitrogen Use in Dairy Cows Grazing Ryegrass with Different Water Soluble Carbohydrate Concentrations

This experiment is one of a series designed to investigate the efficiency of nitrogen (N) use in Holstein-Friesian dairy cows grazing perennial ryegrass (Lolium perenne) which has been bred to express high water soluble carbohydrate (WSC) concentrations. Animals grazed either a High Sugar (HS) grass or a Control (C) variety chosen on the basis of heading date compatibility. Dry matter (DM) intakes were estimated using herbage mass. Milk yields, milk constituent concentrations and plasma concentrations of b-hydroxybutyrate, glucose, total protein, albumin and urea were also measured. Forage DM intakes were similar for the two grasses. However, because of differences in the nitrogen content of the varieties (128 vs 176 g crude protein (CP) kg-1 DM; s.e.d. 10.5; P \u3c 0.01) the animals consuming the C diet received ca. 35% more dietary N. Despite this, milk yields and outputs of milk fat, lactose and total protein were similar between treatments. These data indicate that the partition of dietary N for milk protein biosynthesis was much higher (P \u3c 0.01) in animals consuming the HS grass, which is reflected by the lower plasma urea concentrations in these animals. It is proposed that by providing grass varieties with a better match of readily available energy and protein, significant improvements in N use efficiency can be achieved

Upgrade of the MARI spectrometer at ISIS

The MARI direct geometry time-of-flight neutron spectrometer at ISIS has been upgraded with an $m=3$ supermirror guide and new detector electronics. This has resulted in a flux gain of ${\approx}6{\times}$ at $\lambda=1.8$ {\AA}, and improvements on discriminating electrical noise, allowing MARI to continue to deliver a high quality science program well into its fourth decade of life

Development of a dynamic energy-partitioning model for enteric methane emissions and milk production in goats using energy balance data from indirect calorimetry studies

[EN] The main objective of this study was to develop a dynamic energy balance model for dairy goats to describe and quantify energy partitioning between energy used for work (milk) and that lost to the environment. Increasing worldwide concerns regarding livestock contribution to global warming underscore the importance of improving energy efficiency utilization in dairy goats by reducing energy losses in feces, urine and methane (CH4). A dynamic model of CH(4)emissions from experimental energy balance data in goats is proposed and parameterized (n= 48 individual animal observations). The model includes DM intake, NDF and lipid content of the diet as explanatory variables for CH(4)emissions. An additional data set (n= 122 individual animals) from eight energy balance experiments was used to evaluate the model. The model adequately (root MS prediction error,RMSPE) represented energy in milk (E-milk;RMSPE = 5.6%), heat production (HP;RMSPE = 4.3%) and CH(4)emissions (E-CH4; RMSPE = 11.9%). Residual analysis indicated that most of the prediction errors were due to unexplained variations with small mean and slope bias. Some mean bias was detected for HP (1.12%) and E-CH4(1.27%) but was around zero for E-milk (0.14%). The slope bias was zero for HP (0.01%) and close to zero for E-milk (0.10%) and E-CH4(0.22%). Random bias was >98% for E-CH4, HP and E-milk, indicating non-systematic errors and that mechanisms in the model are properly represented. As predicted energy increased, the model tended to underpredict E-CH(4)and E-milk. The model is a first step toward a mechanistic description of nutrient use by goats and is useful as a research tool for investigating energy partitioning during lactation. The model described in this study could be used as a tool for making enteric CH(4)emission inventories for goats.This study was supported by LOW CARBON FEED Project reference LIFE2016/CCM/ES/000088.Fernández Martínez, CJ.; Hernando, I.; Moreno-Latorre, E.; Loor, J. (2020). Development of a dynamic energy-partitioning model for enteric methane emissions and milk production in goats using energy balance data from indirect calorimetry studies. Animal. 14:s382-s395. https://doi.org/10.1017/S1751731120001470Ss382s39514Agricultural and Food Research Council (AFRC) 1997. The nutrition of goats. Nutrition Abstract and Reviews (Series B) 67, 776–861.Aguilera, J. F., Prieto, C., & FonollÁ, J. (1990). Protein and energy metabolism of lactating Granadina goats. British Journal of Nutrition, 63(2), 165-175. doi:10.1079/bjn19900104Bannink, A., France, J., Lopez, S., Gerrits, W. J. J., Kebreab, E., Tamminga, S., & Dijkstra, J. (2008). 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KL Blaxter ), pp. 441–443. Academic Press, London, UK.Criscioni, P., Marti, J. V., Pérez-Baena, I., Palomares, J. L., Larsen, T., & Fernández, C. (2016). Replacement of alfalfa hay ( Medicago sativa ) with maralfalfa hay ( Pennisetum sp.) in diets of lactating dairy goats. Animal Feed Science and Technology, 219, 1-12. doi:10.1016/j.anifeedsci.2016.05.020Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of Methane Production from Dairy and Beef Cattle. Journal of Dairy Science, 90(7), 3456-3466. doi:10.3168/jds.2006-675Statistical data base Food and Agriculture Organization (FAOSTAT) 2018. FAO Statistical data base Food and Agriculture Organization of the United Nations, Rome, Italy. Retrieved on 25 June 2018 from http://faostat.fao.org/FERNÁNDEZ, C., LÓPEZ, M. C., & LACHICA, M. (2015). Low-cost mobile open-circuit hood system for measuring gas exchange in small ruminants: from manual to automatic recording. The Journal of Agricultural Science, 153(7), 1302-1309. doi:10.1017/s0021859615000416Fernández, C., Martí, J. V., Pérez-Baena, I., Palomares, J. L., Ibáñez, C., & Segarra, J. V. (2018). Effect of lemon leaves on energy and C–N balances, methane emission, and milk performance in Murciano-Granadina dairy goats. Journal of Animal Science, 96(4), 1508-1518. doi:10.1093/jas/sky028Fernández, C. (2018). Dynamic model development of enteric methane emission from goats based on energy balance measured in indirect open circuit respiration calorimeter. Global Ecology and Conservation, 15, e00439. doi:10.1016/j.gecco.2018.e00439Fernández, C., Pérez-Baena, I., Marti, J. V., Palomares, J. L., Jorro-Ripoll, J., & Segarra, J. V. (2019). Use of orange leaves as a replacement for alfalfa in energy and nitrogen partitioning, methane emissions and milk performance of murciano-granadina goats. Animal Feed Science and Technology, 247, 103-111. doi:10.1016/j.anifeedsci.2018.11.008Fernández, C., Gomis-Tena, J., Hernández, A., & Saiz, J. (2019). An Open-Circuit Indirect Calorimetry Head Hood System for Measuring Methane Emission and Energy Metabolism in Small Ruminants. Animals, 9(6), 380. doi:10.3390/ani9060380Grainger, C., & Beauchemin, K. A. (2011). Can enteric methane emissions from ruminants be lowered without lowering their production? Animal Feed Science and Technology, 166-167, 308-320. doi:10.1016/j.anifeedsci.2011.04.021Howarth, R. (2015). Methane emissions and climatic warming risk from hydraulic fracturing and shale gas development: implications for policy. Energy and Emission Control Technologies, 45. doi:10.2147/eect.s61539Hristov, A. N., Kebreab, E., Niu, M., Oh, J., Bannink, A., Bayat, A. R., … Yu, Z. (2018). Symposium review: Uncertainties in enteric methane inventories, measurement techniques, and prediction models. Journal of Dairy Science, 101(7), 6655-6674. doi:10.3168/jds.2017-13536Ibáñez, C., López, M. C., Criscioni, P., & Fernández, C. (2015). Effect of replacing dietary corn with beet pulp on energy partitioning, substrate oxidation and methane production in lactating dairy goats. Animal Production Science, 55(1), 56. doi:10.1071/an13119Institute Nationale Recherche Agronomique (INRA) 2017. Feeding system for ruminants. Wageningen Academic Publishers, Wageningen, the Netherlands.Jørgensen, S. E. (2015). New method to calculate the work energy of information and organisms. Ecological Modelling, 295, 18-20. doi:10.1016/j.ecolmodel.2014.09.001Kebreab, E., Johnson, K. A., Archibeque, S. L., Pape, D., & Wirth, T. (2008). Model for estimating enteric methane emissions from United States dairy and feedlot cattle1. Journal of Animal Science, 86(10), 2738-2748. doi:10.2527/jas.2008-0960Knapp, J. R., Laur, G. L., Vadas, P. A., Weiss, W. P., & Tricarico, J. M. (2014). Invited review: Enteric methane in dairy cattle production: Quantifying the opportunities and impact of reducing emissions. Journal of Dairy Science, 97(6), 3231-3261. doi:10.3168/jds.2013-7234Lin, L. I.-K. (1989). A Concordance Correlation Coefficient to Evaluate Reproducibility. Biometrics, 45(1), 255. doi:10.2307/2532051López, M. C., Estellés, F., Moya, V. J., & Fernández, C. (2014). Use of dry citrus pulp or soybean hulls as a replacement for corn grain in energy and nitrogen partitioning, methane emissions, and milk performance in lactating Murciano-Granadina goats. Journal of Dairy Science, 97(12), 7821-7832. doi:10.3168/jds.2014-8424López, M. C., & Fernández, C. (2013). Energy partitioning and substrate oxidation by Murciano-Granadina goats during mid lactation fed soy hulls and corn gluten feed blend as a replacement for corn grain. Journal of Dairy Science, 96(7), 4542-4552. doi:10.3168/jds.2012-6473Martí JV, Pérez-Baena I and Fernández C 2012. 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Characterisation of the microbiome along the gastrointestinal tract of growing turkeys

The turkey microbiome is largely understudied, despite its relationship with bird health and growth, and the prevalence of human pathogens such as Campylobacter spp. In this study we investigated the microbiome within the small intestine (SI), caeca (C), large intestine (LI) and cloaca (CL) of turkeys at 6, 10 and 16 weeks of age. Eight turkeys were dissected within each age category and the contents of the SI, C, LI and CL were harvested. 16S rDNA based QPCR was performed on all samples and samples for the 4 locations within 3 birds/age group were sequenced using ion torrent-based sequencing of the 16S rDNA. Sequencing data showed on a genus level, an abundance of Lactobacillus, Streptococcus and Clostridium XI (38.2, 28.1 and 13.0% respectively) irrespective of location and age. The caeca exhibited the greatest microbiome diversity throughout the development of the turkey. PICRUSt data predicted an array of bacterial function, with most differences being apparent in the caeca of the turkeys as they matured. QPCR revealed that the caeca within 10 week old birds, contained the most Campylobacter spp. Understanding the microbial ecology of the turkey gastrointestinal tract is essential in terms of understanding production efficiency and in order to develop novel strategies for targeting Campylobacter spppublishersversionPeer reviewe

Benefits of Leucaena diversifolia in grazing steer’s diet: performance, methane and fatty acids

Leucaena diversifolia (Ld) is a legume species that has received little attention in terms of its nutritive value, methane (CH4) emissions, and impact on meat quality. To address this gap, a study was conducted to compare the performance, CH4 emissions, and fatty acid content of steers grazing on a monoculture of tropical grass Urochloa hybrid cv. Cayman versus a combination of Cayman and Ld. Over a period of 15 months, 14 Angus crossbred steers weighing an average of 374±7.5 kg were used in the study, with half of them grazing only Cayman grass and the other half grazing on a combination of Cayman and Ld at a ratio of 74:26. Live weight gain was recorded and CH4 emissions were measured after the animal productivity test. Meat quality and fatty acid profiles were measured after the steers were slaughtered. The results showed that steers grazing on a combination of Cayman and Ld consumed more dry matter, crude protein, and energy per day than those grazing on grass alone, and this difference was still evident when digestibility was considered (P≤0.05). Moreover, animals grazing on a combination of Cayman and Ld weighed an average of 63 kg more at the end of the experiment compared to those grazing only Cayman (466 vs. 403 kg; P≤0.05). Interestingly, animals that consumed only Cayman grass emitted more CH4 than those that included Ld in their diet (168 vs. 144 g/d; P≥0.05). The total polyunsaturated, monounsaturated, and saturated fatty acid concentrations in the meat did not differ between the two groups (P≥0.05). In conclusion, incorporating Ld in the diet of grazing steers can increase nutrient intake (protein and energy) and animal productivity without affecting daily net CH4 emissions or fatty acid concentrations in the meat. This study sheds light on the potential benefits of legume inclusion in animal diets and highlights the need for further research in this area