doi: 10.14202/vetworld.2014.257-261 How to cite this article: Das LK, Kundu SS, Kumar D and Datt C (2014) The evaluation of metabolizable protein content of some indigenous feedstuffs used in ruminant nutrition, Veterinary World 7(4): 257-261. Introduction estimates of available microbial and dietary escape protein [1, 2] and are potentially more accurate than the In ruminants, ration balancing based on CP CP systems are. content of feedstuffs has been considered as obsolete The CP degradability can be measured by in vivo due to the activities of ruminal microorganisms such as and in vitro methods. In vitro methods are quicker for degradation of feed protein, synthesis of microbial screening of large number of feeds but do not give protein and passage of both undegraded feed protein protein degradability in absolute terms. In situ method and microbial protein to lower intestine. Therefore of Agricultural Research Council (ARC) using nylon protein evaluation system in ruminants is now based on bag is widely accepted to measure the degradability, RDP and RUP. Mere classification of feed protein into which is analysed by a computer model developed by RDP and RUP also could not solve the purpose of Orskov and McDonald [3]. Several attempts were balancing ruminant diets for adequate protein as it did made to estimate the MP content of animal feeds by not provide any information regarding the protein various methods. Islam et al. [4] evaluated MP content available to the animals in the lower intestinal tract for of whole crop rice silage at different stages of harvest, productive purposes. In such a situation, the concept of which is usually not a common ruminant feed under MP content of ruminant feeds seems more logical and Indian conditions. Similarly MP content of Wolffia scientific as it represents the actual quantity of true meal was evaluated by Pooponpan et al. [5] in broilers. protein or amino acids that gets absorbed by the animal Rahbarpour et al. [6] used the nylon bag (in situ) [1]. MP systems define the animal's requirement using technique to determine the MP value of tomato pomace. However MP values of typical ruminants feeds are lacking. It is important to note that, MP content of feeds is a better indicator of animal performances, (particularly dairy animal production) than the corresponding CP Veterinary World, EISSN: 2231-0916 Available at www.veterinaryworld.org/Vol.7/April-2014/14.pdf The evaluation of metabolizable protein content of some indigenous feedstuffs used in ruminant nutrition 1 Lalatendu Keshary Das , S. S. Kundu , Dinesh Kumar and Chander Datt 1. Veterinary Dispensary, Kalampur, Kalahandi, Odisha, India; 2. Division of Dairy Cattle Nutrition, National Dairy Research Institute, Karnal, Haryana, India; 3. Division of Animal Nutrition, Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India. Corresponding author: Lalatendu Keshary Das, email: drlalatendu27@gmail.com Received: 01-02-2014, Revised: 20-03-2014, Accepted: 25-03-2014, Published online: 21-04-2014 2 3 2 Abstract Aim: To determine the metabolizable protein (MP) content of common indigenous feedstuffs used in ruminant nutrition using in situ method. Materials and Methods: Nine ruminant feeds such as maize grain (MG), groundnut cake (GNC), mustard oilcake (MOC), cottonseed cake (CSC), deoiled rice bran (DORB), wheat bran (WB), berseem fodder (BF), maize fodder (MF) and sorghum fodder (SF) were included in this study. Each test feed was dried, ground and chemically analysed for proximate principles (DM, CP, EE, OM, Total ash), fiber fractions (NDF, ADF, cellulose, hemicellulose, lignin), NDICP and ADICP. Two adult fistulated bulls were used for evaluating the protein degradation characteristics of each test feed using the nylon bag method. Metabolizable energy (ME) content of the test feeds were predicted from their chemical composition data using summative approach of NRC (2001) model. The equations of AFRC (1992) were used to predict the rumen degradable protein (RDP), digestible microbial protein (DMP), digestible undegraded feed protein (DUP) and MP content of test feeds. Results: The MP content of MG, GNC, MOC, CSC, DORB, WB, BF, MF and SF was found to be 95.26, 156.41, 135.21, 125.06, 101.68, 107.11, 136.81, 72.01 and 76.65 g/kg DM, respectively. The corresponding ME (MJ/kg DM) content of the test feeds was 13.66, 13.12, 13.65, 10.68, 9.08, 11.56, 9.64, 8.33 and 8.03, respectively. Among the test feeds, GNC contained the highest and MF contained the lowest MP per kg DM. Conclusion: It was concluded that the degradability of crude protein (CP) of the test feeds can be used in MP determination and diet formulation. Feed CP content is not available as such at intestinal level in ruminants as a definite part of it undergoes extensive microbial degradation in rumen. The pattern and extent of such degradation do influence the amount of protein presented to lower digestive tract (MP) for absorption and utilization in ruminants. It was also found that the MP content of a feed is not constant as that of its CP content as it entirely depends on the degradation characteristics in a given animal. Keywords: in situ method, metabolizable energy, metabolizable protein, microbial protein, ruminant nutrition. RESEARCH ARTI CLE Open Access Veterinary World, EISSN: 2231-0916 257 Copyright: The authors. 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