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RELATIONSHIP BETWEEN BY PASS CRUDE PROTEIN AND N-ADF IN SOME GROUPS OF FEEDS FOR RUMINANTS. C hrenková M., Č erešňáková Z., Weisbjerg M.R.,* P oláčiková M., F ormelová Z. , F ľak P. Animal Production Research Centre Nitra, Slovak Republi c
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RELATIONSHIP BETWEEN BY PASS CRUDE PROTEIN AND N-ADF IN SOME GROUPS OF FEEDS FOR RUMINANTS Chrenková M., Čerešňáková Z., Weisbjerg M.R.,* Poláčiková M., Formelová Z., Fľak P. Animal Production Research Centre Nitra, Slovak Republic * Faculty of Agricultural Sciences, Aarhus University, Denmark Kostinbrod, November 2010
The challenges of REDNEX are • Growing demand for • safer, healthier, higher quality food • sustainable use and production of renewable bio-resources • Threats to sustainability and security of agricultural, aquaculture and fisheries production Since dairying is becoming more intensive and more specialised it is necessary To move to management practices beyond“usual good-farming practice”
The goal of REDNEX is Reduce N input on dairy farms without reduction in N output via consumable proteins(specific objectives within this project) One of the way is Standardised, rapid tools for feed evaluation
Systems of feeds evaluation There are many systems for feeds avaluation in Europe and other countries: • PDI – French protein evalaution system • DVE/OEB – Duch protein evaluation system • Nor-ForTM – Nordic feeds evaluation system • Danish feeds evaluation system • German feeds evaluation system • CNCPS – The Cornel Net Carbohydrate and Protein System (USA) and other countries used some of thouse systems modificated The basic principles of all those systems are very similar
New knowledges help to increase precision of the informations about quality of nutrients and nutritive quality of feeds for ruminants The Cornel Net Carbohydrate and Protein System assumes that feed protein is subdivided by chemical composition, physical charcteristics, ruminal degradation, and postruminal digestibility characteristics
In CNCPS • crude protein (N*6.25) ispartitioned into 5 fractions, A, B1, B2, B3, C and • every fractionhas different degradation characteristics.
Protein fractions • Fraction A – protein soluble in buffer • Fraction B1 – protein soluble in buffer and precipitable by TA • Fraction B2 – protein insoluble in buffer but soluble in neutral and acid detergent solutions • Fraction B3 – protein insoluble in buffer and neutral detergent solution but soluble in acid detergent solution • Fraction C is the protein that is insoluble in acid detergent
Fraction C • Is protein assotiated with the cell wall mainly with lignin (ADIP) • Contains protein - tannin complexes, and Maillard products • They are highly resistant to breakdown by microbial and mammalian enzymes • Is assumed to be unavailable for the animals Also common feedstuffs may contain significant amount of the Fraction C
The aim of the present experiment • was to estimate indigestible protein fraction (C), • bypass crude protein and/or undegradable crude protein, • intestinal digestibility of bypass crude protein in selected feedstuffs • to find out the relationship between fraction C and by pass CP.
Material and method • In the experiment were used 39 samples of different feedstuffs - 11 samples of cereals, - 5 samples of legumes, - 3 samples of oilseed cake, - 4 samples of oilseed meal, - 3 samples of oilseed, - 4 samples of DDGS) - 2 samples of maize silage, - 7 samples of lucerne, - 3 samples of mixed silages • Chemical composition of feeds was determined according to the Decree of the Ministry of Agriculture of the Slovak Republic No. v1497/4/1997-100. • Method for acid-insoluble nitrogen (ADIN and/or N-ADF) determination is described in Licitra et al. (1996) • By pass of CP (N) was determined using standardised in sacco method (100 – ruminaly undegraded CP after 16 h incubation) • Intestinal digestibility was determined using standardised mobile bag technique
Chemical composition of examined samples of cereals and legumes
Results • ADF concentration is similar in all kinds of cereal samples • are differences among them in N-ADF content • the differences among share of N-ADF from total CP content are greater • legumes have higher ADF content than cereals • lignin is in the range from 2.3 g.kg-1DM for field beans to 40.7 g.kg-1DM for lupine • fraction C is the highest in lupine but as percentage of the total CP it is 11.1 % and in pea 12.9 % • field beans with the lowest content of lignin (2.3 g.kg-1DM) have also the lowest N-ADF content (14.2 g.kg-1DM) as other kind of legumes
Chemical composition of examined samples of oilseed feeds, DDGS and silages
Results • There was not a large differences in N-ADF content of oilseed feed samples except linseed and linseed cake (11.0 and 18.9 g.kg-1DM). • All kinds of these feeds have high concentration of lignin. • From the feedstuffs samples, the highest content of acid detergent insoluble nitrogen was determined in DDGS from corn (49.0±8.67 g.kg-1DM), it means 16 % of total CP. • in feeds like distillers grains Maillard reactions have increased the natural content of N-ADF. • Like the group the lowest and similar N-ADF concentration was estimated in silages. • in N-ADF of total N was found considerable variation among the silage samples
Content (g·kg -1 DM) of acid detergent insoluble nitrogen (N-ADF) in % of total N and bypass N (%) of feed groups
Results • The large variability in N-ADF and its percentage of total N was found for cereals. • Bypass CP was estimated very variable in the group of cereals and in the group of oilseeds. • Since fraction C is resistent to bacterialattackwehave used regression analysis to find relationship between by pass CP and N-ADF content, but • The best linear correlation but not very high was found between by pass N and fraction C (% of total N) for all samples together • There is significance (P<0.058) of linear relationship between bypass N and N-ADF (% of total N) : by pass N=10.729+0.503N-ADF for all tested feedstuffs • Regression analysis shows different feed types of unsatisfactory correlation between them. Correlation is significant only for cereals (p<0.005)
Intestinal CP digestibility of ruminally undegraded residues
Conclusion Our results show • the variation of acid detergent insoluble N content among feedstuffs. • With respect to a low correlation between N-ADF content and by-pass CP, fraction C is not a satisfactory indicator to predict the amount of undegraded crude protein of feeds in the rumen. • It is necessary to examine more samples of every kind of feeds to obtain more data to put them into the correlation
AcknowledgementThe work has been carried out with financial support from the Commission of the European Communities, FP7, KBB-2007-1.