EFFECT OF DEHULLING RAPESEED ON FEED VALUE OF RAPESEED MEAL AND -CAKE FOR POULTRY

 

W. KRACHT, H. JEROCH, S. DAENICKE, W. MATZKE

 

*Institute of Animal Nutrition and Planned Crop Storage, Agricultural Faculty of Martin-Luther-University Halle-Wittenberg, Emil-Abderhalden-Str. 26, D-06108 Halle/Saale, Germany

 

ABSTRACT

 

Rapeseed meal (Rm) and -cake (Rc) from not dehulled (nd) and dehulled (d) rapeseed were evaluated in energy balance experiments with broiler chickens in the periods from day 16.-20. and

31.- 35.  of live. Rm was also examined in an energy-balance trial with laying hens during the 21. week of live. Beside it a feeding trial with broiler chickens was conducted between day 1.-35. of live to compare the influence of graded Rm levels (7%, 14%, 21%) from nd and d rapeseed on growth performance. The energy content of the diets was not equalized to show the effect of dehulling. The main ingredients of Rm and Rc are reported in this congress proceeding (Kracht et al. 1999ab). The following N corrected metabolizable energy (AMEN) contents in MJ/kg dry matter were determined: broiler (day 16.-20.of age). Rm nd 6.17, d 7.87; Rc nd 8.91, d 11.26; broiler (day 31.-35 of age) Rm nd 6.94, d 8.27; Rc nd 11.42, d 13.05; laying hens: Rm nd 8.08, d 9.91. The following weight gains (g) were observed in feeding trial at the different Rm substitution levels: 7% nd 1545, d 1595; 14% nd 1571, d 1605; 21% nd 1464, d 1540. In the average of the three levels the weight gain rose about 53 g (=3.5%). At a substitution level of 21% the growth decreased.

 

KEYWORDS:  AMEN, broiler chickens, laying hens, rapeseed dehulling.

 

INTRODUCTION

The proportion of hulls of the entire rapeseed amounts approximately 15-22% and is twice as high than that of soybean hulls, which is in the range between 6-8%. Therefore, the by-products of the rape-seed oil production contain twice as much fibre substances than the soybean products, remaining after soybean oil removal. The fibre substances and those, which are in intimate association with them, as for instance lignin, decrease the digestibility of crude nutrients and the absorption of amino acids. Beyond it, the availability of energy is depressed. In different countries investigations had been conducted to develop procedures for dehulling rapeseed (Schneider 1979, Jensen 1984, Bell 1993). In the following study a dehulling procedure was applied, which was developed by the Cimbria- Sket- GmbH, Magdeburg, (Germany) in connection with the University Essen (Germany). The by products, which remain after complete or incomplete oil withdrawal were evaluated in energy balance experiments with broiler chickens and laying hens and in a feeding trial with broiler chickens.

 

MATERIAL AND METHODS

 

A black seeded rapeseed, variety Express, was used to produce rapeseed meal (Rm) by removing the oil to a level of nearly 2% by means of prepress-solvent procedure or to obtain a rape- seed cake (Rc) with around 12% oil by pressing the rapeseed only. A description of the applied dehulling procedure will be given by Rasehorn (1999) on the occasion of this congress. The chemical composition of Rm and Rc will be reported by Kracht et al. (1999ab) in this congress proceeding.

In the balance experiments male broiler chickens of the Lohmann Meat- and laying hens of Lohmann-Braun-strain were used. The trials with broiler chickens were conducted between the day 16.-20. and 31.-35. of live. The laying hens were in the 21. week of live at the beginning of the laying period. During the experiments the animals were kept in single metabolic cages. Per feeding variant were assigned 7 broiler respectively 6 hens. The pre-and the collection periods comprised 5 days. The rape products (Rm and Rc) from not dehulled (nd) or dehulled (d) seed were substituted into the basal diets in a proportion of 40% in the trials with broiler chickens and of 30% in trial with hens. In order to show the effect of graded fibre levels, rape products from nd and d seed were mixed and used as substituts in the diets of the broiler groups 3 to 5. In these diets were included levels of 10, 20 and 30% Rm or Rc from d seed, which were substituted for equal parts of rape products from nd seed. The composition of the basal diets used in the experiments with broilers and laying hens were reported by Kracht et al.(1998).

The N-corrected apparent metabolizable energy (AMEN) content of the whole diets were calculated as difference between the gross energy input with feed and the energy output in feces, regarding the N-retention. Per g retained N were substracted 36.5 kJ. The AMEN contents of the Rm and Rc was estimated according the difference method by substracting the AMEN content of the basal diet from the AMEN content of the total diet considering the proportion of the basal diet of the total diet.

A feeding trial was conducted to examine the influence of dehulling rapeseed on the growth effect of Rm during the period between the 1.-35. day of live. The results of some groups will be reported here. In this trial feed mixtures were fed, which contained levels of 7%; 14% and 21% Rm, each from nd and d rapeseed, without adjustment of energy content of the diets. Per group 70 broiler chickens of the Lohmann-Meat strain were assigned.

The results of the experiments were subjected to statistical analysis using single element analysis of variance. Significant differences between mean values were detected by Newman-Keuls-Test.

All Statistics were conducted using the Statistica for the Windows TM operating system (Statsoft Inc., 1994).

 

RESULTS AND DISCUSSION

 

Results of balance experiments with broiler chickens

 

The feed intake was equalized for the 42 single kept broiler chickens, which were assigned to 6 groups in each of both experiments. Testing the energy content of Rm during the first period (16.-20. day) each broiler consumed in 5 days in total 175 g feed, while in the second period, which lasted from the 31.-35. day of live, the broiler chickens consumed 500 g per animal.

Examining the diets with shares of Rc in the first period (16-20 day) the feed intake achieved also a level of 175 g per animal, while during the 31.-35. day of live, in consequence of the higher energy content of the cake, only a lower level of 400 g feed intake was reached. The AMEN contents of Rm, which were established in two balance periods are shown in Table 1. In the first period from the 16.-20. day of live it was estimated a continuous increase of the AMEN content of the Rm substituts with rising proportions of Rm from dehulled seed. By full replacement of Rm nd with Rm d the AMEN content rose about 1.70 MJ that are about 27%. In the second period the ascent was not constant but at full replacement of Rm nd by Rm d there was a rise about 1.33 MJ, that are 19%. With increasing age of the birds the ability to utilize fibre substances is improved, by which the effect of dehulling decreased.   

 

 

 

 

Table 1.  AMEN contents of rapeseed meals (Rm) from not dehulled (nd) and dehulled (d)

                rapeseed as well as of their mixtures for broiler chickens (MJ/kg dry matter)

          

groups

      1

       2

       3

      4

      5        

      6

 

proportions of the rapeseed meal substituts in % of diets

Rm  not dehulled   

basal

    40

     30

     20

    10

      0

Rm  dehulled

diet

      0

     10     

     20

    30

     40

 

  AMEN MJ/kg dry matter of rapeseed meals

 

 

Rm nd

Rm nd+Rm d

Rm d

broiler 16.-20. day

    13.49

    6.17 a

    6.83 b

  7.22 c

    7.43 d

    7.87 e

broiler 31.-35. day

    13.90

    6.94 a

    6.72 a

   7.21 b

     7.55b

    8.27c 

P<0.05, Values within rows with no common superscripts are significantly different

 

The AMEN contents of rapeseed cakes, which are examined in two further balance periods, are reported in table 2. With increasing levels of cake from dehulled seed in both periods was established a constant increase of the AMEN values of Rc. By full replacement of Rc nd by Rc d in the first period there was an incease about 2.36 MJ/kg dry matter, that are around 27% and at the older animals a rise of 1.63 MJ, that are 14%. This extensively agrees with effect of dehulling established with Rm, although the AMEN content of Rc exceeds the corresponding values of Rm more than 40% at younger birds and around 60% at older broiler chickens.  

 

Table 2.  AMEN contents of rapeseed cakes (Rc) from not dehulled (nd) and dehulled (d) 

               rapeseed as well as of their mixtures for broiler chickens (MJ/kg dry matter

 

groups

      1

      2

      3

      4

      5

      6

 

proportions of the rapeseed cake substituts in % of diets  

Rc not dehulled

basal

    40

     30

      20

     10

      0

Rc  dehulled

diet

      0

     10

      20

     30        

     40

 

AMEN  MJ / kg dry matter of rapeseed cakes ( 12-13 % ether extract)

 

 

Rc nd

Rc nd + Rc d

 

broiler 16.-20. day

   13.83

    8.90 a

    9.52 b

     9.88 b

    10.77c

   11.26 d

broiler 31.-35. day

   12.86

   11.42a

   11.70 a

   12.24 b

    12.73c

   13.05 c

P<.05, Values with no common superscripts within rows are significantly different

 

Results of the balance experiment with laying hens

 

The results of the experiment with laying hens are reported in Table 3. The AMEN content of Rm was increased by dehulling the seed by approximately 1.83 MJ/kg dry matter(= 23%).

 

Table 3. Energy contents of rapeseed meals (Rm) from not dehulled and dehulled rapeseed    for laying hens in MJ / kg dry matter

variants

basal diet

rapeseed meal   not dehulled

rapeseed meal dehulled

gross energy  (GE)

     16.04

        19.40

       19.43

metabolizable energy, AME 

     13.09

          8.66

       10.50 

metabolizability of GE   %

       82

          45

         54

AMEN MJ

     12.52

          8.08 a

         9.91 b         

P<0.05, values with different superscripts are significantly different, within rows. 

 

Results of a feeding experiment with broiler chickens

 

The calculated AMEN  and the lysine contents of the diets rose by replacing Rm nd with Rm d, but the differences were slight. The crude protein contents of the mixtures were nearly equalized.  The methionine and cystine contents increased with increasing levels of Rm d in the diets because of the higher levels of these amino acids in dehulled Rm.   

 

Table 4. Some ingredients of feed mixtures and results of the feeding trial to compare the       effect of graded rapeseed meal (Rm) levels from not dehulled (nd) and dehulled

 (d) seed with broiler chickens

 

groups

 

       1

       2            

        3

        4

        5

       6

variants

7 % Rm  not  

 dehulled

7 % Rm dehulled

14 % Rm not         dehulled

14 % Rm dehulled

21 % Rm not          dehulled

21 % Rm dehulled

 

ingredients g/ kg feed

crude protein

    233

    232

    235

    230

     231

    233

ether extract

    102

    101

    107

    110

     110

    116

crude fibre

     36

      34

      39

      37

       44

      42

AMEN MJ

    13.23 

     13.32

     13.17

     13.36

     13.10

      13.39

L-lysine

    12.3

     12.5

     12.1

     12.5

     12.0

      12.5

met. + cys.

      8.8

       9.2

       9.0

       9.7

       9.1

       10.3 

 

results of the growth trial (1.-35. day of live) per animal

live weight gain  g

   1545 a

   1595 bc

   1571ab

    1605 c

    1464 d

    1540 a

feed intake/day   g

      67.2  

      68.9

      69.4

     67.7

     65.3

     66.5    

feed/gain           g/g

     1.52

     1.51

     1.55

     1.48

      1.56

      1.51

P<0.05, values with rows with unequal superscripts are significantly different

 

At each level of substituting Rm from dehulled seed for Rm from not dehulled seed the weight gains rose between 34 and 76 g. All differences are significant. The average increase amounted to 53 g, that are approximately 3.5%. The differences between the daily feed intakes and the feed/gain ratios were low.  

 

Conclusion

 

In energy balance experiments with broiler chickens and laying hens it was shown that the feed values of rapeseed meal and rapeseed cake are increased significantly by dehulling the seed before oil withdrawal. It is usefull to produce rape by-products from dehulled seed for the feeding of non-monogasric animals, while the products of non dehulled seed can be used for ruminants.

 

Acknowledgements

 

The authors are grateful to the Union zur Förderung von Oel- und Proteinpflanzen e V., Godesberger Allee 142-148, D-53175 Bonn for the financial support of the researches. We also thank     

the company Amandus Kahl Nachf., Reinbek, for treating the rapeseed and the oil mill PH.       Leman GmbH, Eystrup, for performing the oil extraction.

 

 

References

 

BELL, J., M., 1993: Factors affecting the nutritional value of canola meal: A review. Can. J. Anim. Sci. 73, 679 - 697

JENSEN, E.P.,1984: Fremstilling af skalfattige fraktioner af raps. Boiteknisk institut Kolding , Beretning Nr.118, pp 50

KRACHT, W., JEROCH, H. et al. 1998: Gesteigerter Futterwert durch Schälung von Rapssaat, UFOP- Schriften, Heft 10, Union zur Förderung von Oel-und Proteinpflanzen e V.  Godesberger Allee 142-148, D- 53175 Bonn

KRACHT, W., 1999: unpublished data

RASEHORN, H. J., 1999: unpublished data

SCHNEIDER, F. H., 1979: Schälung von Rapssaat durch definierte Verformung Teil II: Untersuchungen zum Schälverhalten. Fette- Seifen- Anstrichmittel 81, 2, 53 - 59

STATSOFT, INC., 1994: Statistica for the Windows TM operating system, Tulsa OK, USA