Effect of supplementing an α-amylase enzyme or a blend of essential oil components on the performance, nutrient digestibility, and nitrogen balance of dairy cows.

Autor:	Van den Bossche T; Flanders Research Institute for Agricultural, Fisheries and Food (ILVO), 9090 Melle, Belgium., Goossens K; Flanders Research Institute for Agricultural, Fisheries and Food (ILVO), 9090 Melle, Belgium., Ampe B; Flanders Research Institute for Agricultural, Fisheries and Food (ILVO), 9090 Melle, Belgium., Tamassia LFM; DSM Nutritional Products, 4303 Kaiseraugst, Switzerland., De Boever JL; Flanders Research Institute for Agricultural, Fisheries and Food (ILVO), 9090 Melle, Belgium., Vandaele L; Flanders Research Institute for Agricultural, Fisheries and Food (ILVO), 9090 Melle, Belgium. Electronic address: leen.vandaele@ilvo.vlaanderen.be.
Jazyk:	angličtina
Zdroj:	Journal of dairy science [J Dairy Sci] 2024 Jul; Vol. 107 (7), pp. 4509-4523. Date of Electronic Publication: 2024 Feb 17.
DOI:	10.3168/jds.2023-24073
Abstrakt:	Lowering dietary protein content is a promising strategy to reduce N excretions in cattle but it requires improved N utilization by the animal. Feed enzymes (e.g., exogenous α-amylase) and plant extracts (e.g., essential oils [EO]) are 2 additives that may enhance rumen function and possibly also microbial protein yield. This may increase fat- and protein-corrected milk yield (MY) and milk nitrogen efficiency and thus lower N losses from dairy cows. Both types of additives were studied in an experiment including 39 Holstein cows that had (average ± SD) 40.7 ± 7.95 kg/d MY, 89 ± 43 DIM, 2.7 ± 1.5 lactations, and 677 ± 68.6 kg of BW, consisting of a covariate (4 wk) and treatment period (5 wk). During the whole experiment cows were fed a typical Benelux diet (CTRL), supplemented with concentrates to meet individual requirements for energy and MP, which were fulfilled for 100% and 101%, respectively. The total diet was low in CP (15.5%) and relatively high in starch (22.6% and 6.6% rumen bypass starch). Cows were balanced for parity, DIM, MY, and roughage intake and randomly assigned to one of 3 groups, which received the following treatments in the treatment period: (1) CTRL (n = 13); (2) CTRL + 14 g/cow per day Ronozyme RumiStar α-amylase enzyme (AMEZ, n = 13; DSM); and (3) CTRL + 2.5 g/cow per day Crina Protect, a blend of EO components (ESOL, n = 13; DSM). Animal performance, ruminal pH, and enteric gas emissions were monitored throughout the experiment. During the last week of the covariate and treatment periods, nitrogen balances were conducted, total-tract nutrient digestibility was determined, and urinary allantoin and uric acid were determined as indicators for microbial N production. The statistical model applied to these variables contained group and DIM during treatment period as fixed effects and the values from the covariate period as covariate. Post hoc Dunnet-corrected comparisons between each treatment group and the control group were explored. The α-amylase enzyme tended to increase apparent total-tract starch digestibility and increased milk lactose concentration. The EO blend tended to increase MY and increased milk N output, milk nitrogen efficiency, and feed efficiency. Therefore, when feeding reduced dietary protein levels, EO have potential to improve the N-use efficiency in cattle, whereas the α-amylase enzyme might increase starch digestibility and milk lactose. However, additional research is necessary to substantiate our findings. (The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)
Databáze:	MEDLINE
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