Vet World   Vol.14   March-2021  Article-13

Effects of rumen-degradable-to-undegradable protein ratio in ruminant diet on in vitro digestibility, rumen fermentation, and microbial protein synthesis

Background and Aim: Feeding ruminants must notice the degradability of feed, especially protein. Microbial rumen requires ammonia from rumen degradable protein (RDP) beside that ruminant require bypass protein or rumen undegradable protein (RUP) and microbial crude protein. The aim of the study was to discover the best RDP:RUP ratio in beef cattle diets commonly used by Indonesian farmers using an in vitro methodology.

Materials and Methods: Samples of Pennisetum purpureum, Leucaena leucocephala, Indigofera zollingeriana, cassava, maize, palm kernel cake, rice bran, and tofu waste were formulated into dietary treatments (dry matter [DM] basis). All experiments were carried out using a 3×3×2 factorial, randomized block design with three replications. Treatments consisted of three protein levels (12%, 14%, and 16%), two energy levels (65% and 70%), and three RDP:RUP ratio levels (55:45, 60:40, and 65:35). The experimental diets were incubated in vitro using buffered rumen fluid for 48 h at 39°C. After incubation, the supernatants were analyzed to determine pH, ammonia concentration, total volatile fatty acid (VFA), and microbial protein synthesis. The residues were analyzed to determine DM, organic matter, protein, and RUP digestibility.

Results: Increased protein, energy, and RDP levels increased digestibility, ammonia concentrations, total VFAs, and microbial protein synthesis (p<0.05), while rations with 16% protein lowered these parameters (p<0.05).

Conclusion: Increased dietary protein (from 12% to 14% DM), energy (from 65% to 70% DM), and RDP (from 55% to 65% crude protein [CP]) levels increased nutrient digestibility, ammonia concentration, total VFA levels, and microbial protein synthesis. The diet containing 14% DM dietary protein and 70% DM energy, which contained 55%, 60%, or 65% CP RDP optimally increased nutrient digestibility, ammonia concentration, total VFA levels, and microbial protein synthesis. Thus, feed based on these RDP:RUP ratios can optimize ruminant productivity. Keywords: digestibility, microbial protein synthesis, protein, rumen characteristic, rumen degradable protein, rumen undegradable protein.

Keywords: digestibility, microbial protein synthesis, protein, rumen characteristic, rumen degradable protein, rumen undegradable protein.

How to cite this article: Putri EM, Zain M, Warly L, Hermon H (2021) Effects of rumen degradable-to-undegradable protein ratio in ruminant diet on in vitro digestibility, rumen fermentation, and microbial protein synthesis, Veterinary World, 14(3): 640-648.

Received: 17-10-2020  Accepted: 02-02-2021     Published online: 17-03-2021

Corresponding author: Mardiati Zain   E-mail: mardiati@ansci.unand.ac.id

DOI: 10.14202/vetworld.2021.640-648

Copyright: Putri, et al. This article is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.