Feed value of dried and ensiled paulownia (Paulownia spp.) leaves and their relationship to rumen fermentation, in vitro digestibility, and gas production characteristics

Abstract

ABSTRACT The study aimed to evaluate the potential use of dried or ensiled paulownia (Paulownia spp.) leaves as roughage source for ruminants. Paulownia tree leaves were collected from one-year-old hybrid (C-125, CAR, and TF-33 clones) trees. Dried paulownia leaves of the clones were different in dry matter (DM), crude ash (CA), crude protein (CP), ether extract (EE), crude fiber (CF), and nitrogen-free extract (NfE) and similar in neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL); however, these values (except EE and ADL) of ensiled leaves were significantly different among the clones. Mean CP, CA, and condensed tannin contents in dried leaves were 15.36, 9.21, and 1.75%, respectively; NDF, ADF, and ADL contents were 38.35, 35.49, and 12.08%, respectively. Mean total volatile fatty acids, in vitro organic matter digestibility (IVOMD), and metabolizable energy (ME) value in dried leaves were 95.26 mmol/L, 76.34%, and 10.77 MJ/kg, respectively, whereas, CO2 and CH4 production were 54.66 and 29.78 mmol/L, respectively. Buffering capacity and water-soluble carbohydrates varied among the pre-ensiled paulownia leaves, although their means were 395.66 mEq/kg DM and 86.63 g/kg DM, respectively. In ensiled leaves, the pH, lactic acid ratio, and acetic acid ratio were 4.98, 11.23, and 2.56%, respectively, and butyric acid was not detected in any of the silages. Mean values of IVOMD and ME in ensiled leaves were 72.30% and 9.93 MJ/kg, respectively. Dried paulownia leaves are a high-quality alternative forage and the ensiled form is of medium quality. Therefore, paulownia leaves could be used as an alternative roughage source for ruminants.

Full text

Brazilian Journal of Animal Science
e-ISSN 1806-9290
www.rbz.org.br
R. Bras. Zootec., 50:e20210057, 2021
https://doi.org/10.37496/rbz5020210057
Forage crops
Full-length research article
Feed value of dried and ensiled
paulownia (Paulownia spp.) leaves
and their relationship to rumen
fermentation, in vitro digestibility,
and gas production characteristics
ABSTRACT - The study aimed to evaluate the potential use of dried or ensiled
paulownia (Paulownia spp.) leaves as roughage source for ruminants. Paulownia tree
leaves were collected from one-year-old hybrid (C-125, CAR, and TF-33 clones) trees.
Dried paulownia leaves of the clones were different in dry matter (DM), crude ash


detergent lignin (ADL); however, these values (except EE and ADL) of ensiled leaves
           
contents in dried leaves were 15.36, 9.21, and 1.75%, respectively; NDF, ADF, and ADL
contents were 38.35, 35.49, and 12.08%, respectively. Mean total volatile fatty acids,
in vitro organic matter digestibility (IVOMD), and metabolizable energy (ME) value in
dried leaves were 95.26 mmol/L, 76.34%, and 10.77 MJ/kg, respectively, whereas, CO2
and CH4 production were 54.66 and 29.78 mmol/L, respectively. Buffering capacity and
water-soluble carbohydrates varied among the pre-ensiled paulownia leaves, although
their means were 395.66 mEq/kg DM and 86.63 g/kg DM, respectively. In ensiled leaves,
the pH, lactic acid ratio, and acetic acid ratio were 4.98, 11.23, and 2.56%, respectively,
and butyric acid was not detected in any of the silages. Mean values of IVOMD and ME
in ensiled leaves were 72.30% and 9.93 MJ/kg, respectively. Dried paulownia leaves are
a high-quality alternative forage and the ensiled form is of medium quality. Therefore,
paulownia leaves could be used as an alternative roughage source for ruminants.
Keywords: alternative roughage, nutritive value, Paulownia tree leaf
Hülya Özelçam12*, Sema Özüretmen1,
Önder Canbolat3
1 Ege 
2 
3 Bursa 
Tu rkey.
*Corresponding author:
huseyinipcak@gmail.com
Received: March 28, 2021
Accepted: July 5, 2021
How to cite:
Özüretmen, S. and Canbolat, Ö. 2021. Feed value
of dried and ensiled paulownia (Paulownia
spp.) leaves and their relationship to rumen
fermentation, in vitro digestibility, and gas
production characteristics. Revista Brasileira de
Zootecnia 50:e20210057.
https://doi.org/10.37496/rbz5020210057
Copyright: This is an open access article
distributed under the terms of the
Creative Commons Attribution License
(http://creativecommons.org/licenses/by/4.0/),
which permits unrestricted use, distribution,
and reproduction in any medium, provided the
original work is properly cited.
1. Introduction
As the increasing world population also increases the demand for food of animal origin, it also increases
              
therefore, within the agricultural sector, the aim must be to improve the nutritional value of a product,
create a sustainable and green agriculture, and reap more diverse products with a higher quality per
unit area. For this, land management systems (i.e., agroforestry) (De Baets et al., 2007) is considered
where agriculture, livestock, or agriculture + livestock are combined with planting various trees and
where more than one product is obtained concurrently. Within these systems, the objective is to
utilize the same land in multiple ways, obtain food and feed products simultaneously or consecutively,
increase the yield from the land, improve the socioeconomic conditions, control illegal logging, and
reduce erosion (Turna et al., 2014). These systems are applied as agrisilviculture (agriculture +

R. Bras. Zootec., 50:e20210057, 2021
Feed value of dried and ensiled paulownia (Paulownia spp.) leaves and their relationship to rumen...
Özelçam et al.
2
forestry), silvopastoral (forestry + livestock), agrosilvopastoral (agrisilviculture + silvopastoral), and
the production of multipurpose trees (King, 1979; Jensen, 2016). Among these, the leaves of these
multipurpose trees are used as fresh and green grass for ruminants during seasonal transitions and

In Turkey, especially with silvopastoral systems, which are agroforestry systems with high-application
potential, trees are planted for growing fodder leaves (Filiz and Tolunay, 2003). It has been reported
that the leaves of 11 species of multipurpose trees (Acacia spp., Albizzia procera, Calliandra
calothyrsus, Dalbergia sissoo, Eucalyptus hybrida, Gmelina arborea, Leucaena leucocephala, Morus
alba, Paulownia spp., Samanea saman, and Sesbania sesban) can be used as a source of nutrition,
especially for small ruminants, in terms of protein content (11-30%), organic matter digestion
(49-51%), and metabolizable energy (ME; 6-7 MJ/kg) values (Dzowela et al., 1995; Datt et al., 2008;
Woods, 2008; Vu et al., 2011).
The paulownia (Paulownia spp.) tree is an agroforestry tree used in silvorable or silvopastoral
systems (Sonja, 2018). Its leaves are used as roughage in many countries, especially in China, South
American countries, Japan, and Australia. The cultivation of this tree, which has the ability to grow
   
(AFBI, 2008; Cheema et al., 2011). This tree is preferred because it grows between the rows of plants



In Turkey, paulownia trees have been used in landscaping for several years; however, by cultivation,
attempts have been made to produce multipurpose trees to obtain more products per unit of land within

leaves. Considering that 100 trees could be placed per hectare and one tree produces an average of
100 kg/year of leaves, it is possible to obtain 10 t/ha/year of fresh forage from leaves (Briggs, 2012).
Hence, it can be suggested that they may have a high potential as an alternative roughage source.
This study aimed to determine the nutritional value and in vitro digestibility of paulownia tree
leaves and demonstrate their potential as alternative source of roughage for ruminants.
2. Material and Methods
2.1. Feed materials
The paulownia leaves used in the study were taken from a special plantation area in 
(38°15'14.4" N, 27°8'2.4" E) at the end of October 2018. The leaves were collected from one-year-old
hybrid trees created by crossing different paulownia species—Paulownia tomentosa, P. elongata,
and P. fortunei. These trees comprised C-125 (P. elongata × P. elongata), Caroline/CAR (P. elongata ×
P. fortunei), and TF-33 (P. tomentosa × P. fortunei) clones obtained from tissue cultures. Green leaves
and their petiole were collected randomly from plants of the exact clone (10 trees per clone and
approximately 1000 g of leaves of each tree) by hand. The samples were taken from the upper, middle,
and lower branches of the tree [the average leave length (petiole not included) was 52.75 cm for
C-125, 42.83 cm for TF-33, and 37.5 cm for CAR]. Samples collected from each tree were pooled and
dried. Thus, the leaves of each tree were homogeneously used in chemical analysis. The chemical
compositions of the paulownia leaves before ensiling are shown in Table 1.
2.2. Preparation of feed samples
The leaves brought to the laboratory were separated into use as dried and ensiled. Leaves (leaf + its

leaves that were used for ensiled material were cut into 2- to 3-cm pieces using scissors and left to
× 70 cm airtight vacuum bags; the air inside the bags
was vacuumed out, and the bags were wrapped tightly with duct tape. The ensiling period was 60 d.

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Feed value of dried and ensiled paulownia (Paulownia spp.) leaves and their relationship to rumen...
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2.3. Chemical composition of paulownia leaves
The nutrient contents of the paulownia leaves [dry matter (DM), crude ash (CA), HCl insoluble ash
           
(Luff Scroll), and starch) were determined using the Weende analysis method (Menke and Huss,


and P contents of leaves were calculated according to the permanganometric and spectrophotometric
(Ultraspec 2100 pro, USA) methods, respectively. The contents of the cell walls of the leaves [neutral






water-soluble carbohydrate content (WSC) in spectrophotometer by an antron-thiourea method, and
the Playne and McDonald (1966) method was used for determining the buffer capacity (BC). The pH of
ensiled leaves was measured using the Hanna HI2211 digital pH meter, and organic acids [lactic (LA),
acetic (AA), and butyric (BA)] were created by distillation (DLG, 1987; Naumann und Bassler, 1993;

4
then 48% H2SO4 
20 and the next 10 min) are recorded as D1 and D2. The D3 distillation is also obtained after adding
chromic acid and pure water. The distillates are titrated in a 0.05 N NaOH solution and organic acids
(lactic, acetic, and butyric) are calculated based on values obtained in titration.
2.4. In vitro rumen fermentation of paulownia leaves
The gas production technique was used to determine the in vitro values of leaf organic matter
digestibility (OMD) and ME (Menke and Steingass, 1988). Using this method, the net gas production
Table 1 - Nutrient composition of fresh paulownia leaves (% DM)
Component Clone Mean
C-125 CAR TF-33
DM 27.06 29.18 26.97 27.74
CA 8.55 9.00 10.50 9.35
HCl-insol. 1.06 1.02 1.02 1.03
CP 13.07 15.45 18.70 15.74
EE 4.38 4.41 3.12 3.97
CF 18.07 18.00 22.87 19.65
NfE 55.70 53.11 44.82 51.21
NDF 37.85 36.61 40.60 38.35
ADF 34.44 35.46 36.59 35.50
ADL 12.47 12.84 10.93 12.08
HEM 3.42 1.16 4.01 2.86
CEL 21.97 22.62 25.65 23.41
WSC (g/kg DM) 87.89 96.98 75.02 86.63
BC (mEq/kg DM) 391.72 383.83 411.43 395.66
C-125: P. elongata × P. elongata; CAR (Caroline): P. elongata × P. fortunei; TF-33: P. tomentosa × P. Fortunei.
DM     
       
carbohydrates; BC - buffer capacity.

R. Bras. Zootec., 50:e20210057, 2021
Feed value of dried and ensiled paulownia (Paulownia spp.) leaves and their relationship to rumen...
Özelçam et al.
4
(GP) of the feed was taken over 3, 6, 12, 24, 48, 72, and 96 h as a basis, and the in vitro organic matter
digestibility (IVOMD) and ME values were calculated as follows:
× GP + 0.0595 × CP + 0.0675 × CA
× GP + 0.0057 × CP + 0.0002859 × EE2,


In the present study, the rumen content used was taken from healthy cows with unknown dietary
at a slaughterhouse to replace cannulated animals in a trial evaluating feedstuffs (Lutakome et al.,





isovaleric (IVA), and isobutyric (IBA) acids] (Wiedmeier et al., 1987). Carbon dioxide (CO2) and
methane (CH4) gases that were produced in vitro by fermentation were calculated using the following
           
Blümmel et al., 1999). The nitrogen content of ammonia (NH3
according to the recommendations of Blümmel et al. (1997).
CO2 (mmol L× BA)
CH4 (mmol L×2
2.5. Statistical analyses
Statistical analyses of the obtained data were conducted using SPSS version 22.0 (IBM Corp., Armonk,
NY, USA). Data were checked for normality, using the Kolmogorov-Smirnov or Shapiro-Wilk tests,
and for homogeneity of variances, using Levene’s test. One-way analysis of variance (ANOVA) was
applied to determine the difference between the mean values of groups. The post-hoc Duncan test

The mathematical model of the trial plan was:
Yiji + eij,
in which i
eij
3. Results
3.1. Nutritional compositions of dried and ensiled paulownia leaves

                

was detected in TF-33, and that of P was in CAR. The CT values of clones also differed from 1.36 to
2.02%, with the lowest CT found in TF-33 and the highest in C-125. On the other hand, there was no
difference in the cell wall components of the clones, which ranged from 37.85 to 40.60% of DM for
NDF, 34.44 to 36.59% of DM for ADF, and 10.93 to 12.84% of DM for ADL (P>0.05).
The DM content in the ensiled leaves was between 23.76 and 27.81% and was lower than that in the
pre-ensiled leaves (Table 3). Although the greatest DM loss was in the TF-33 clones, the highest CA
             
The EE values in leaves ranged from 3.25 to 3.52% of DM with no differences among them (P>0.05);
however, the CF values ranged from 20.48 to 26.08% of DM in the clones, with the highest value found

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Feed value of dried and ensiled paulownia (Paulownia spp.) leaves and their relationship to rumen...
Özelçam et al.
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Table 3 - Nutrient composition and fermentation characteristics of ensiled paulownia leaves (% DM)
Component Clone Mean SEM P-value
C-125 CAR TF-33
Crude nutrients
DM 27.81a 27.20a 23.76b 26.26 0.428 
CA 9.88b 10.02b 10.81a 10.21 0.108 
CP 10.78b 15.98a 14.65a 13.49 0.570 
EE 3.52 3.41 3.25 3.39 0.126 0.694
CF 26.08a 20.48b 22.66b 22.83 0.633 
NfE 42.66a 42.22a 35.66b 40.18 0.877 
Cell-wall contents
NDF 41.64a 36.50b 40.18a 39.22 0.649 
ADF 39.17a 34.80b 35.87b 36.92 0.586 
ADL 13.89a 14.13a 11.33b 13.09 0.474 0.020
HEM 2.22b 1.71b 4.09a 2.56 0.357 0.019
CEL 25.41 20.94 22.89 23.51 0.751 0.050
CT 1.86a 1.65b 1.26c 1.59 0.088 
pH 5.02 4.84 5.07 4.98 0.050 0.128
LA 9.24b 11.45a 12.99a 11.23 0.517 0.004
AA 1.68b 1.89b 4.10a 2.56 0.292 
BA 0.00 0.02 0.00 0.01 0.007 0.452
WSC (g/kg DM) 53.85 56.94 50.69 53.83 2.008 0.414
DM 

BA - butyric acid; WSC - water-soluble carbohydrates; SEM - standard error of the mean.
Values 
Table 2 - Nutrient composition of dried paulownia leaves (% DM)
Component Clone Mean SEM P-value
C-125 CAR TF-33
Crude nutrients
DM 92.05b 92.24a 92.29a 92.18 0.037 0.019
CA 8.55b 9.00b 10.50a 9.21 0.342 
CP 13.07c 15.45b 18.71a 15.36 0.898 
EE 4.38a 4.41a 3.12b 3.97 0.270 
CF 18.07b 18.00b 22.87a 19.64 1.060 0.021
NfE 55.70a 53.11a 44.82b 51.21 2.111 0.006
Sugar 4.41c 5.47b 6.49a 5.46 0.380 
Cell-wall contents
NDF 37.85 36.61 40.60 38.35 0.838 0.096
ADF 34.44 35.46 36.59 35.49 0.696 0.563
ADL 12.47 12.84 10.93 12.08 0.483 0.268
HEM 3.42 1.16 4.01 2.86 1.046 0.613
CEL 21.97 22.62 25.65 23.41 0.778 0.058
Minerals
Ca 1.32c 1.88b 2.02a 1.74 0.107 
P 0.22c 0.87a 0.37b 0.49 0.125 
CT 2.02a 1.85b 1.36c 1.75 0.100 
DM  

error of the mean.
Values 

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Feed value of dried and ensiled paulownia (Paulownia spp.) leaves and their relationship to rumen...
Özelçam et al.
6




ADL in TF-33 (11.33% of DM) and the highest value of ADF in C-125 (39.17% of DM); however, there
was no difference between the HEM and CEL values in the clones.
On the other hand, there was no difference in pH among the clones (P>0.05), which ranged between
     

 
                
determined in any sample (P>0.05); however, the WSC values in the ensiled leaves were similar
(P>0.05) and ranged between 50.69 and 56.94 g/kg DM.
3.2. Rumen fermentation of dried and ensiled paulownia leaves
   
The highest TVFA and highest PA were found in TF-33 (95.18 and 20.99 mmol/L, respectively),
although there was no difference in AA and BA among the clones (P>0.05). pH values ranged between
3-N values in the dried
leaves were found in C-125 (35.29%) and TF-33 (36.20%) and the lowest in CAR (33.29%); however,
we observed that these values were lower in the ensiled leaves and there was no difference among
the clones in any of these parameters, with the exception of PA and VA (P>0.05).
The effect of clones on in vitro gas production, IVOMD, and ME values in the dried and ensiled
             
ensiled leaves increased with the incubation period and varied on average within the range of 17.12 to
Table 4 - Rumen fermentation from dried and ensiled paulownia leaves
Clone Mean SEM P-value
C-125 CAR TF-33
Dried
TVFA 91.15b 90.43b 95.18a 95.26 0.910 0.040
Acetic 54.18 53.26 54.88 54.11 0.497 0.466
Propionic 18.78b 18.48b 20.99a 19.42 0.435 0.005
Volatile fatty acids (mmol/L) Butyric 14.84 15.04 15.61 15.16 0.175 0.189
Isobutyric 0.64b 0.69ab 0.78a 0.70 0.025 0.039
Valeric 0.89 0.93 0.96 0.92 0.024 0.527
Isovaleric 1.82b 2.04a 1.96ab 1.94 0.039 0.040
pH 6.72a 6.64b 6.57b 6.65 0.023 0.006
NH3-N (%) 35.29a 33.29b 36.20a 34.93 0.485 0.010
Ensiled
TVFA 84.94 84.29 86.72 85.32 0.691 0.379
Acetic 51.06 51.24 52.27 51.52 0.400 0.475
Propionic 16.73ab 15.73b 17.45a 16.64 0.297 0.026
Volatile fatty acids (mmol/L) Butyric 14.01 14.03 13.77 13.94 0.169 0.834
Isobutyric 0.63 0.65 0.69 0.66 0.020 0.536
Valeric 0.79b 0.89a 0.89a 0.86 0.019 0.031
Isovaleric 1.72 1.74 1.65 1.70 0.034 0.586
pH 6.79 6.77 6.68 6.75 0.023 0.084
NH3-N (%) 30.27 30.22 31.12 30.53 0.341 0.544
TVFA - total volatile fatty acids; SEM: standard error of the mean.
Values 

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
except from 3 to 6 h for the dried leaves and 3 h for the ensiled leaves. The lowest and highest IVOMD
values were found in C-125 for both the ensiled and dried leaves (69.47 and 72.53%, respectively) and
TF-33 for ensiled and dried leaves (74.35 and 81.02%, respectively). Similarly, the highest ME value
was found in TF-33 for dried (11.05 MJ/kg DM) and ensiled (10.24 MJ/kg DM) leaves; the lowest value
was determined in C-125 for both dried (10.47 MJ/kg DM) and ensiled leaves (9.70 MJ/kg DM).
The effect of clones on in vitro CO2 and CH4 production in dried and ensiled paulownia leaves was not
  2 production was between 53.81 and 56.10 mmol/L in
dried leaves and 50.60 and 51.16 mmol/L in ensiled leaves. In addition, CH4 was detected in both the
dried and ensiled leaves at between 29.53 and 30.00 and 28.35 and 28.70 mmol/L, respectively.
Table 5 - In vitro gas production (mL/200 mg DM), IVOMD (%), and ME values (MJ/kg DM) of dried and ensiled
paulownia leaves
Clone Mean SEM P-value
C-125 CAR TF-33
Dried
3 h 17.93 16.83 16.60 17.12 0.287 0.116
6 h 25.33b 27.57a 29.07a 27.29 0.639 0.013
12 h 36.93c 41.83b 43.80a 40.86 1.039 
Gas production (mL/200 mg DM) 24 h 50.20b 51.50b 54.30a 52.00 0.637 
48 h 59.87b 60.87b 64.10a 61.61 0.664 
72 h 67.77ab 66.50b 69.40a 67.89 0.485 0.016
96 h 68.93b 68.33b 72.77a 70.01 0.734 0.001
IVOMD 72.53c 75.47b 81.02a 76.34 1.256 
ME 10.47c 10.78b 11.05a 10.77 0.088 0.001
Ensiled
3 h 15.17 15.77 14.97 15.30 0.241 0.424
6 h 22.00b 26.33a 24.60a 24.31 0.679 0.003
12 h 34.10b 38.33a 36.67a 36.37 0.671 0.004
Gas production (mL/200 mg DM) 24 h 47.40b 46.33b 50.03a 47.92 0.664 0.031
48 h 58.67a 55.17c 57.10b 56.98 0.537 0.001
72 h 64.33a 61.50b 63.23ab 63.02 0.497 0.031
96h 66.80a 63.33b 65.47a 65.20 0.545 0.003
IVOMD 69.47c 72.09b 74.35a 72.30 0.906 0.002
ME 9.70b 9.85b 10.24a 9.93 0.095 0.022
IVOMD - in vitro organic matter digestibility; ME - metabolizable energy; SEM - standard error of the mean.
Values 
Table 6 - Carbon dioxide and CH4 gas production (mmol/L) from dried and ensiled paulownia leaves
Clone Mean SEM P-value
C-125 CAR TF-33
Dried
CO254.05 53.81 56.10 54.66 0.469 0.064
CH429.82 29.53 30.00 29.78 0.212 0.722
Ensiled
CO250.72 50.60 51.16 50.83 0.397 0.871
CH428.35 28.70 28.66 28.57 0.209 0.803
SEM 

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4. Discussion
4.1. Nutritional compositions of dried and ensiled paulownia leaves
In the study, the chemical composition in terms of CA, CP, CF, and Ca in dried paulownia leaves differed
among clones, and TF-33 had the highest values. Compared with previous studies about Paulownia spp.
leaves, the CP content of dried leaves in our study was higher than that in Varlyakov et al. (2013) and
Gutiérrez et al. (2015), but lower than that in Mueller et al. (2001). The differences in nutrients can
be attributed to species, age, and climatic conditions. The chemical composition of foliage belonging
to this clone is similar to that found in some of the studies made using acacia leaf (Abdulrazak et al.,
2000a,b; Mokoboki et al., 2005) and are compatible with the results of several studies on different tree

Canbolat, 2012; Güven, 2012; Akçil and Denek, 2013; Kurt and Öztürk, 2018). On the other hand, the Ca
and P contents in leaves (excluding the CAR clone) exceeded the desired ratio of 2:1, but this problem
could be easily corrected using cautious mineral supplementation. However, the CT in the dried leaves
differed among clones, and C-125 had the highest value, whereas TF-33 had the lowest. This value in
some tree leaves has been reported to vary between 0.1 and 16% (Abdulrazak et al., 2000a,b; Mokoboki
          

effect because it decreases protein degradation in the rumen (Barry, 1987; Canbolat, 2012), a high
level (>5%) negatively affects protein digestion and microbial and enzymatic activities (Kumar and
Singh, 1984); therefore, it can be reported that the CT values of all clone leaves are suitable for rumen
fermentation.
In ensiled leaves, the clone was important in DM, CA, CP, CF, and NfE. Clones C-125 and CAR had the
highest value for DM, whereas CAR and TF-33 had the highest value for CP. The CP value of leaves
belonging to these clones was higher than that in corn silage and lower than that in meadow grass
silage (DLG, 1991; NRC, 2001). In our study, it was observed that ensiling suppressed the CT value of
leaves belonging to all clones. The lowest and highest CT contents were respectively found in TF-33
        
nutrients, especially for small ruminants, and could be an alternative roughage source.
Furthermore, there was no difference among clones for NDF, ADF, and ADL in dried form. The
          
the lowest in CAR and TF-33. The NDF and ADF contents obtained for dried paulownia leaves were

than the values of P. elongata leaves found in Gutiérrez et al. (2015). However, dried leaves of all clones
were lower in those ratios than that found in the leaves of acacia and oak species (Mokoboki et al.,
2005; Elahi, 2010) and similar to that found in Chitra and Balasubramania (2016). Our results are
also consistent with those of many studies on the leaves of different tree species (e.g., oak, mulberry,
 
2018). This can be attributed to species, age, and climatic conditions. In the present study, the HEM
ratio in leaves belonging to both forms, in particular, was quite low because the NDF and ADF ratios
in the leaves were very similar. This was attributed to the fact that the paulownia tree used was a
hybrid plant that grew very fast in the early years. Indeed, Jung and Allen (1995) reported that the
biotechnological processes applied to plants can cause differences in their cell wall biosynthesis and

present study, the average cell wall component was lower in dried leaves than in silages, because the
leaves deteriorated into botanical fractions in the silage compared with that before being ensiled.
Indeed, the CP content was lower in the ensiled than in the dried leaves, which was the result of leaf
damage during fermentation such that, when the silage was opened, the leaf:stem ratio shifted toward
the stem. In addition, cell wall results showed that the paulownia leaf silage had low NDF but high ADF
contents compared with corn silage, but low NDF and ADF contents compared with meadow grass

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
terms of their cell wall contents and that drying or ensiling does not affect these parameters.
There was a difference among clones for LA and AA, whereas pH, BA, and WSC were similar. According to
the data on silage fermentation, the pH value was slightly higher than desired (3.5-4.5) in good-quality
     
and the ratio of this acid should constitute 65-70% of the total silo acids for a successful fermentation
       
were 85, 86, and 76%, respectively. However, the difference among clones for AA was quite high, and
the highest value was in TF-33. A high AA ratio in the silages has been associated with the converting
carbohydrates or lactate in the environment to PA or AA or the development of heterofermentative
lactic acid bacteria that produces AA (Ray and Daeschel, 1992; Filya and Sucu, 2005; Kung Jr., 2014).
On the other hand, it was reported that there was a close relationship between AA and aerobic stability
in some studies, because AA could play a critical role in inhibiting harmful microorganisms in the
silage (Danner et al., 2003; Kung Jr., 2018). Therefore, the greatest aerobic stability between ensiled
paulownia clones can be expected in TF-33.
Water-soluble carbohydrate rate was decreased in all ensiled leaves in proportion to fresh material.
Nevertheless, the highest decrease was in CAR, C-125, and TF-33, and the WSC contents of all clones
were found similar in ensiled form even if it was not the same initially. Baghdadi et al. (2016) reported
that WSC helped to drop pH rapidly in silage in their study. Low buffer capacity also plays a critical
role in the drop of pH (McDonald et al., 2010), explaining why C-125 had a lower pH than others, even
if there is no difference between groups.
4.2. Rumen fermentation of dried and ensiled paulownia leaves
In our study, the rate of total VFA was the highest in TF-33 in dried form, whereas the values were
similar in ensiled form. Total volatile fatty acids are the main products after microbial fermentation
in the rumen (Castillo-González et al., 2014) and are evaluated in energy metabolism in ruminants
(Wang et al., 2020). In the present research, TF-33 in dried form had the highest sugar content, and
this value increased the TVFA rate by inducing fermentation in the rumen. However, there was no
difference for TVFA in ensiled form, because sugar was used during silage fermentation. On the other
hand, in dried and ensiled leaves, TF-33 had the highest value for propionic acid, while there was no
     
highest propionic acid in silage form may be because it has the highest LA value as a fermentation
characteristic, because propionic acid, one of the major TVFA, is also one of the major volatile acid
produced by carbohydrates or LA fermentation (Wang et al., 2020). Therefore, it can be thought that the
LA ratio of the silage changes the propionic acid value in the rumen. On the other hand, the type of clone
used altered the value of rumen pH and rate of NH3-N in dried leaves, whereas it was not important in
ensiled form. When the present research was compared with previous studies on the effects of various
tree leaves (Azadirachta indica, Newbouldia laevis, Populus L., Quercus L, Robinia pseudocacia L.,
Fagos adsidue, Spondias mombin) on the rumen characteristics, it was observed that the presence of
 
important for optimum fermentation due to the use of rumen microorganism N as a source of protein

values of dried and ensiled leaves. Gutiérrez et al. (2015) reported lower IVOMD of P. elongata than
that found in the present study for the dried leaves. The difference in these values between the two
studies might have been a result of species. Moreover, some studies have reported that IVOMD values in
different tree leaves were lower than the leaves of tree clones used in the present study (Kamalak et al.,

values of leaves change according to chemical composition and secondary metabolite content of tree
except for type. Abdulrazak et al. (2000a,b) reported that phenolic compounds have a negative effect
on IVOMD. Indeed, in the present study, we observed that IVOMD increased with decreasing CT in


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paulownia leaves. According to data, the greatest rate of these parameters was detected in TF-33. It was
also higher than the values that Gutiérrez et al. (2015) reported in their studies. However, the ME value

et al., 2010a,b; Canbolat, 2012; Güven, 2012; Akçil and Denek, 2013). When the ME value in dried
leaves was compared with dry roughages, it was detected that it was higher than that in alfalfa hay,
immature grass-legume hay, and grass hay. The ME value in ensiled leaves was also higher than in the
ensiled triticale, grass, and corn (NRC, 2001).
In contrast, the clones show no effect on CO2 and CH4 gas production in both dried and ensiled form.
Sallam et al. (2010) stated that plants rich in condensed tannins alter methanogenesis by reducing

that CH4 production decreases with silage nutrition compared with nutrition in dry roughages, which
was attributed to the formation of less AA during ruminal fermentation of silage feed (Morgavi et al.,
2011; Meral and Biricik, 2013). This report supports the low AA ratio in the rumen of ensiled leaves
compared with that in dried paulownia leaves. On the other hand, Hindrichsen et al. (2004) reported
that feeds high in lignin suppress CH4 production, and less AA is formed from the lack of lignin
digestion in the rumen. It has also been reported that ADL is the carbohydrate form that suppresses
CH4 production the most, and as the amount of ADL in the ratio increases, the IVOMD value and CH4
production decrease. This report was consistent with the high ADL content, low IVOMD, and low CH4
values in ensiled leaves compared with those in dried paulownia leaves.
5. Conclusions
Ensiled and dried forms of paulownia (especially TF-33) leaves could be used as an alternative
roughage source in ruminant feeding in nutrient composition, in vitro organic matter digestibility,
metabolizable energy value, and rumen fermentation characteristics.


Author Contributions
  Ö. Canbolat. Data curation: H. Özelçam,
 Ö 
Ö
ÖÖ.

ÖÖ. Canbolat.
Ö
S. Özüretmen and Ö       Ö. Canbolat.
Ö. Canbolat. Writing-review & editing:
Ö. Canbolat.

This study was supported by the  (project number
118O461). Researchers extend their special thanks to  (Türkiye Bilimsel ve Teknolojik
) and Salih Ertan for their assistance in obtaining the paulownia leaves.
References
Abdulrazak, S. A.; Fujihara, T.; Ondiek, J. K. and Ørskov, E. R. 2000a. Nutritive evaluation of some Acacia tree leaves from
Kenya. Animal Feed Science and Technology 85:89-98. https://doi.org/10.1016/S0377-8401(00)00133-4

R. Bras. Zootec., 50:e20210057, 2021
Feed value of dried and ensiled paulownia (Paulownia spp.) leaves and their relationship to rumen...
Özelçam et al.
11
Abdulrazak, S. A.; Orden, E. A.; Ichinone, T. and Fujihara, T. 2000b. Chemical composition, phenolic concentration and
in vitro gas production characteristics of selected Acacia fruits and leaves. Asian-Australasian Journal of Animal Sciences
13:935-940. https://doi.org/10.5713/ajas.2000.934
Adelusi, O. O.; Isah, O. A.; Onwuka, C. F. I.; Afolabi, R. O.; Aderinboye, R. Y. and Idowu, O. J. 2016. Effect of tree leaves on
rumen fermentation, microbial count and blood urea nitrogen of west african dwarf goats. Malaysian Journal of Animal
Science 19:19-30.
AFBI - Agri-Food and Bioscience Institute. 2008. Paulownia as a novel biomass crop for Nortehrn Ireland? Available at:

Eucalyptus camaldulensis
in vitro
Anonymus. 1986. The analysis of agricultural materials: a manual of the analytical methods used by the agricultural

Pinus pinaster,
Prunus amygdalus and Ulmus glabra. Hayvansal Üretim 51:1-7.

kermes oak (Quercus coccifera) leaves. Livestock Research for Rural Development 22(2).
Baghdadi, R.; Halim, R. A.; Radziah, O.; Martini, M. Y. and Ebrahimi, M. 2016. Fermentation characteristics and nutritive
value of corn silage intercropped with soybean under different crop combination ratios. The Journal of Animal & Plant
Sciences 26:1710-1717.
Barry, T. N. 1987. Secondary compounds of forages. p.91-120. In: The nutrition of herbivores. Hacker, J. B. and Ternouth, J. H.,
eds. Academic Press, Sydney.
Blümmel, M.; Aiple, K. P.; Steingaß, H. and Becker, K. 1999. A note on the stoichiometrical relationship of short chain
fatty acid production and gas evolution in vitro Journal of Animal Physiology and
Animal Nutrition 81:157-167. https://doi.org/10.1046/j.1439-0396.1999.813205.x
Blümmel, M.; Makkar, H. P. S. and Becker, K. 1997. In vitro gas production: a technique revisited. Journal of Animal
Physiology and Animal Nutrition 77:24-34. https://doi.org/10.1111/j.1439-0396.1997.tb00734.x
              
Report, United of Kingdom. 82p.
Canbolat, Ö. 2012. Determination of potential nutritive value of exotic tree leaves in Turkey. 
Fakültesi Dergisi 18:419-423.
Castillo-González, A. R.; Burrola-Barraza, M. E.; Domínguez-Viveros, J. and Chávez-Martínez, A. 2014. Rumen microorganisms
and fermentation. Archivos de Medicina Veterinaria 46:349-361. https://doi.org/10.4067/S0301-732X2014000300003
Cheema, U. B.; Younas, M.; Sultan, J. I.; Virk, M. R.; Tariq, M. and Waheed, A. 2011. Fodder tree leaves: an alternative source
of livestock feeding. Advances in Agricultural Biotechnology 2:22-33.
Chitra, P. and Balasubramanian, A. 2016. A study on chemical composition and nutritive value of albizia tree leaves as
a livestock feed. International Journal of Science, Environment and Technology 5:4638-4642.
Danner, H.; Holzer, M.; Mayrhuber, E. and Braun, R. 2003. Acetic acid increases stability of silage under aerobic conditions.
Applied and Environmental Microbiology 69:562-567. https://doi.org/10.1128/AEM.69.1.562-567.2003
Datt, C.; Datta, M. and Singh, N. P. 2008. Assessment of fodder quality of leaves of multipurpose trees in subtropical
humid climate of India. Journal of Forestry Research 19:209-214. https://doi.org/10.1007/s11676-008-0035-2
De Baets, N.; Gariépy, S. and Vézina, A. 2007. Portrait of agroforestry in Quebec. Executive summary. Agriculture and
Agri-Food Canada. 16p.
DLG - Deutsche Landwirtschafts-Gesellschaft. 1987. Bewertung von grünfutter, silage und heu. Merkblatt No: 224.
DLG - Deutsche Landwirtschafts-Gesellschaft. 1991. Futterwerttabellen für wiederkauer. DLG-Verlag, Frankfurt am Main.
Dzowela, B. H.; Hove, L.; Topps, J. H. and Mafongoya, P. L. 1995. Nutritional and anti-nutritional characters and rumen
degradability of dry matter and nitrogen for some multipurpose tree species with potential for agroforestry in
Zimbabwe. Animal Feed Science and Technology 55:207-214. https://doi.org/10.1016/0377-8401(95)00803-U
Elahi, M. Y. 2010. Nutritive value of oak leaves in sheep. Pakistan Journal of Nutrition 9:141-145. https://doi.org/10.3923/
pjn.2010.141.145
Filiz, S. and Tolunay, A. 2003. Agroforestry practices and useful plant species in agroforestry practices for Isparta
province. Süleyman Demirel Üniversitesi Orman Fakültesi Dergisi A(2):149-160.

           
stabilite ve in situ rumen parçalanabilirlik özellikleri üzerine etkisi. Tarim Bilimleri Dergisi 11:51-56.

R. Bras. Zootec., 50:e20210057, 2021
Feed value of dried and ensiled paulownia (Paulownia spp.) leaves and their relationship to rumen...
Özelçam et al.
12

Agriculture Handbook, No. 379. USDA, Washington D.C., USA.
Gutié            Caracterización nutricional de las hojas de
Paulownia elongata en el periodo previo a su caída. Revista Iberoamericana de Ciencias 2:103-112.
         
18:865-869.
Hindrichsen, I. K.; Wettstein, H. R.; Machmüller, A.; Soliva, C. R.; Bach Knudsen, K. E.; Madsen, J. and Kreuzer, M. 2004.
Effects of feed carbohydrates with contrasting properties on rumen fermentation and methane release in vitro.
Canadian Journal of Agricultural Science 84:265-276. https://doi.org/10.4141/A03-095
 Paulownia elongata x fortunei plantation in Izmir, Turkey.

Jensen, J. B. 2016. An investigation into the suitability of Paulownia as an agroforestry species for UK & NW European
farming systems. Thesis (M.Sc.). Department of Agriculture & Business Management, Scotland`s Rural College.
Jung, H. G. and Allen, M. S. 1995. Characteristics of plant cell walls affecting intake and digestibility of forages by
ruminants. Journal of Animal Science 73:2774-2790. https://doi.org/10.2527/1995.7392774x
Kamalak, A.; Canbolat, Ö.; Gürbüz, Y.; Özay, O. and Özköse, E. 2005. Chemical composition and its relationship to in vitro
gas production of several tannin containing trees and shrub leaves. Asian-Australasian Journal of Animal Sciences
18:203-208. https://doi.org/10.5713/ajas.2005.203

King, K. F. S. 1979. Concepts of agroforestry. International Council for Research in Agroforestry, Nairobi.
Kumar, R. and Singh, M. 1984. Tannins: Their adverse role in ruminant nutrition. Journal of Agricultural and Food
Chemistry 32:447-453. https://doi.org/10.1021/jf00123a006
Kung Jr., L. 2010. Understanding the biology of silage preservation to maximize quality and protect the environment.
In: Proceedings, 2010 California Alfalfa & Forage Symposium and Corn/Cereal Silage Conference, Visalia, CA. University
of California, Davis, CA.
Kung Jr., L. 2014. A review on silage additives and enymes. Department of Animal and Food Sciences, University of
Delaware, Newark, DE.
Kung Jr., L.; Shaver, R. D.; Grant, R. J. and Schmidt, R. J. 2018. Silage review: Interpretation of chemical, microbial, and
organoleptic components of silages. Journal of Dairy Science 101:4020-4033. https://doi.org/10.3168/jds.2017-13909
Kurt, Ö. and Öztürk, D. 2018. Determination of nutritive value of some legume tree fruits. Black Sea Journal of Agriculture
1:60-65.
Lutakome, P.; Kabi, F.; Tibayungwa, F.; Laswai, G. H.; Kimambo, A. and Ebong, C. 2017. Rumen liquor from slaughtered
cattle as inoculum for feed evaluation. Animal Nutrition 3:300-308. https://doi.org/10.1016/j.aninu.2017.06.010
Makkar, H. P. S.; Blümmel, M. and Becker, K. 1995. Formation of complexes between polyvinyl pyrrolidones or
polyethylene glycols and tannins, and their implication in gas production and true digestibility in in vitro techniques.
British Journal of Nutrition 73:897-913. https://doi.org/10.1079/BJN19950095
McDonald, P.; Edwards, R. A.; Greenhalgh, J. F. D.; Morgan, C. A.; Sinclair, L. A. and Wilkinson, R. G. 2010. Animal nutrition.
7th ed. Pearson, Harlow.
Menke, K. H. and Huss, W. 1975. Tierernährung und futtermittelkunde. Verlag Eugen Ulmer, Stuttgart. p.74-79.
Menke, K. H. and Steingass, H. 1988. Estimation of the energetic feed value obtained from chemical analysis and in vitro

Meral, Y. and Biricik, H. 2013. Ruminantlarda metan emisyonunu azaltmak için kullanilan besleme yöntemleri. p.310-316.

Mokoboki, H. K.; Ndlovu, L. R.; Ng´ambi, J. W.; Malatje, M. M. and Nikolova, R. V. 2005. Nutritive value of Acacia tree
foliages growing in the Limpopo Province of South Africa. South African Journal of Animal Science 35:221-228.
https://doi.org/10.4314/sajas.v35i4.3963
Morgavi, D. P.; Eugène, M.; Martin, C. and Doreau, M. 2011. Reducing methane emission in ruminants: is it an achievable
goal? p.65-73. In: Ranilla, M. J.; Carro, M. D.; Ben Salem, H. and Morand-Fehr, P., eds. Challenging strategies to promote
the sheep and goat sector in the current global context. CIHEAM/CSIC/Universidad de Leon/FAO, Zaragoza. (Options
Méditerranéennes: Série A. Séminaires Méditerranéens, n. 99).
Mueller, J. P.; Luginbuhl, J. M. and Bergmann, B. A. 2001. Establishment and early growth characteristics of six Paulownia
genotypes for goat browse in Raleigh NC, USA. Agroforesty Systems 52:63-72. https://doi.org/10.1023/A:1010641602384
Naumann, C. and Bassler, R. 1993. Die chemische untersuchung von futtermitteln, Methodenbuch. Band III. VDLUFA-
Verlag, Frankfurt.

R. Bras. Zootec., 50:e20210057, 2021
Feed value of dried and ensiled paulownia (Paulownia spp.) leaves and their relationship to rumen...
Özelçam et al.
13
NRC - National Research Council. 2001. Nutrient requirements of domestic animals. 7th rev. ed. National Research Council,
Washington, DC, USA.
Özdemir, Ö. and Kaya, A. 2020.    in vitro     
 
Playne, M. J. and McDonald, P. 1966. The buffering constituents of herbage and of silage. Journal of the Science of Food
and Agriculture 17:264-268. https://doi.org/10.1002/jsfa.2740170609
Ray, B. and Daeschel, M. 1992. Food biopreservatives of microbial origin. CRC Press, Boca Raton.
Sallam, S. M. A.; Bueno, I. C. S.; Nasser, M. E. A. and Abdalla, A. L. 2010. Effect of eucalyptus (Eucalyptus citriodora) fresh or
residue leaves on methane emission in vitro. Italian Journal of Animal Science 9:e58.
Sonja, K. 2018. Assessment of ecosystem services provided by agroforestry systems at the landscape scale. University of
Zurich, Faculty of Science, Zuric. https://doi.org/10.5167/uzh-158640
Sultan, J. I.; Rahim, I. U.; Nawaz, H.; Yaqoob, M. and Javed, I. 2008. Nutritional evaluation of fodder tree leaves of Northern
grasslands of Pakistan. Pakistan Journal of Botany 40:2503-2512.
  

Varlyakov, I.; Radev, V.; Slavov, T. and Ganchev, G. 2013. Blood parameters in yearling sheep fed Paulownia (Paulownia spp.)
leaves. Agricultural Science & Technology 5:405-409.
Vu, C. C.; Verstegen, M. W. A.; Hendriks, W. H. and Pham, K. C. 2011. The nutritive value of mulberry leaves (Morus alba)
and partial replacement of cotton seed in rations on the performance of growing Vietnamese cattle. Asian-Australasian
Journal of Animal Sciences 24:1233-1242. https://doi.org/10.5713/ajas.2011.90328
Wang, L.; Zhang, G.; Li, Y. and Zhang, Y. 2020. Effects of high forage/concentrate diet on volatile fatty acid production and
the microorganisms involved in VFA production in cow rumen. Animals 10:223. https://doi.org/10.3390/ani10020223

and nutrient digestibility in cattle. Journal of Dairy Science 70:284-289. https://doi.org/10.3168/jds.S0022-
0302(87)80009-7
Woods, V. B. 2008. Paulownia as a novel biomass crop for Northern Ireland? Agri-Food and Biosciences Institute, AFBI
Hillsborough, Northern Ireland. Occasional Publication, No. 7. 47p.
Zhu, Z. H.; Chao, C. J.; Lu, X. Y. and Xing, Y. G. 1986. Paulownia in China: cultivation and utilization. CAF, Beijing, China.
p.46-49.