In vitro degradability of feed proteins in the rumen: use of non-rumen proteases
M. Aslam Mirza A C and E. L. Miller BA Institute of Animal Nutrition and Feed Technology, University of Agriculture, Faisalabad, Pakistan.
B Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, United Kingdom CB3 OES.
C Corresponding author. Email: mmirza@nsac.ns.ca
Australian Journal of Agricultural Research 56(8) 797-801 https://doi.org/10.1071/AR04111
Submitted: 17 May 2004 Accepted: 14 June 2005 Published: 25 August 2005
Abstract
Various feed proteins were incubated independently with bacterial protease from Streptomyces griseus (SGP), papain (Corica papaya), and ficin (Ficus glabrata) in a simple laboratory assay to predict ruminal protein degradability. The estimates obtained from in vitro assays were compared with those obtained from an in situ analysis using synthetic fibre bags. The rate and extent of degradation in vitro using proteases from non-rumen sources differed among substrates used. A high correlation coefficient (r2 = 0.99) was observed between N-degradability from the in vitro method using SGP and in situ estimates when soybean meal was the substrate. Soybean meal nitrogen (N) was almost completely hydrolysed (0.99) in vitro. The correlation coefficients were low and variable with assays using other enzymes. The correlation coefficient was also high (r2 = 0.77–0.84) with in vitro methods using either SGP, papain, or ficin when incubated with fish meal. The N disappearance from barley in vitro was slow to moderate. The ‘b’ estimate of barley obtained with the in vitro assay was significantly (P < 0.01) lower than that observed in situ. Slower proteolysis observed in barley may possibly be linked to poor accessibility of structural proteins rather than the degradability of N per se. None of the enzymes could rank barley in the same order as the in situ method.
Additional keywords: protein degradation, bacterial protease, papain, ficin.
Acknowledgments
This study was sponsored by the Cambridge Commonwealth Trust in the form of a scholarship provided to the first author. The assistance of Dr Alan Fredeen, Haley Institute of Animal Science and Aquaculture, NSAC, Truro, NS, in reading the manuscript and giving useful suggestions is gratefully acknowledged.
AOAC (1990).
ARC (1980).
Barret, AJ ,
and
Salvesen, G (1986).
Chamberlain DG, Thomas PC
(1979) Prospective laboratory methods for estimating the susceptibility of feed proteins to microbial breakdown in the rumen. The Proceedings of the Nutrition Society 38, 138A.
| PubMed |
Clark JH, Klusmeyer TH
(1989) Dairy production: optimising microbial protein. Feed International Sept., 47–52.
Coblentz WK,
Abdelgadir IEO,
Cochran RC,
Fritz JO,
Fick WH,
Olson KC, Turner JE
(1999) Degradability of forage proteins by in situ and in vitro enzymatic methods. Journal of Dairy Science 83, 343–354.
Cottrill BR, Evan PJ
(1984) Estimation of protein degradability. Interdepartmental Protein Working Party, ARC Technical Review.
Miller EL
(1978) Evaluating the protein contribution of feedstuffs for ruminants. Technical Bulletin, International Association of Fish Meal Manufacturers, Hertfordshire, UK.
Nocek JE
(1988)
In situ and other methods to estimate ruminal protein and energy digestibility; a review. Journal of Dairy Science 71, 2051–2069.
Ørskov ER, McDonald I
(1979) The estimate of protein degradability in the rumen from incubation measurements weighted according to rate of passage. Journal of Agricultural Science (Cambridge) 92, 499–503.
Pichard G, Van Soest PJ
(1977) Protein solubility of ruminant feeds. ‘Proceedings of Cornell Nutrition Conference for Feed Manufacturers’. (Cornell University: Ithaca, NY)
Pion R, Genest C, Bayle G, Thivend P
(1983) Assessment of protein degradability in concentrates using an enzymatic method. ‘6th International Symposium on Protein Metabolism and Nutrition’. (INRA Publ. (Les Colloques de I’INRA, No. 16): Clermont-Ferrand, France)
Poos-Floyd M,
Klopfenstein T, Britton RA
(1985) Evaluation of laboratory techniques for predicting ruminal protein degradation. Journal of Dairy Science 68, 829–839.
Roe MB,
Chase LE, Sniffen CJ
(1991) Comparison of in vitro techniques to the in situ technique for estimation of ruminal degradation of protein. Journal of Dairy Science 74, 1632–1640.
| PubMed |
Siddons RC, Paradine J
(1983) Protein degradation in the rumen of sheep and cattle. Journal of the Science of Food and Agriculture 34, 701–708.
| PubMed |
Siddons RC,
Paradine J,
Gale DL, Evans RT
(1985) Estimation of the degradability of dietary protein in the sheep rumen by in vivo and in vitro procedure. Journal of Nutrition 54, 545–561.
| Crossref | GoogleScholarGoogle Scholar |
Tecator (1981).