Effect of Fresh Forage
Canola on Production Performance and Egg Quality of Laying Hens
Yixiao Ma1,
Qiaohua Wang1,2*, Bo Wang3,4*, Jie Kuai3,4, Guangsheng Zhou3,4 and Tingdong Fu3,4
1College of Engineering, Huazhong Agricultural University,
Wuhan, P. R. China
2Key Laboratory of Agricultural Equipment in
Mid-lower Yangtze River, Ministry of Agriculture and rural affairs; Wuhan, P. R. China
3College of Plant Science and Technology, Huazhong
Agricultural University, Wuhan, P. R. China
4MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle
Reaches of the Yangtze River, Wuhan, P. R. China
*For correspondence: wqh@mail.hzau.edu.cn
Received 30 November 2020; Accepted 12 January 2021; Published 16 April
2021
Abstract
Feed shortage had become a major
factor constraining the development of animal husbandry. Forage canola has been
found to be a potential feed crop due to its high yield and good quality.
Therefore, this study mixed different proportions of forage canola to the diet
of laying hens and all eggs were collected for analysis. Laying hens were divided
into four groups according to the feeding amount of canola: 0 kg, 3 kg, 6 kg, 9
kg, with 30 laying hens in each group. In the feeding trial, there was no
negative effect on hen body weight, egg production, or overall egg quality. The
results showed that Group B, C and D complete feed consumption is less than
Group A. From the spectrum analysis, the trend of the Group A was different
from that of the other three groups. After 35 days of rearing, the laying rate
of the Group B and the Group C increased about 30% compared to 1 to 7 day. The
weight of the Group B and Group C increased about 5% compared with the initial
period, while the Group A increased 0.6% and the Group D increased by 3%. The
eggshell strength of the Group B and Group C also increased significantly. The
contents of phosphorus and potassium in the Group B and C were higher than
those in the Group A and Group D. The effects of canola to poultry diets is therefore of practical interest. This study will provide
us a potential forage substance in laying hens production performance. © 2021 Friends Science Publishers
Keywords: Egg; Egg Production Rate; Egg Quality; Forage canola; Laying hens
Introduction
With the rapid development of animal husbandry,
feed shortage has become one of the main factors limiting its sustainable
development (Kerorsa 2019). With the rapid progress of rapeseed breeding, most
of the cultivars used in the rapeseed production were with low content of
erucic acid and glucosinolate in China, which guarantee the forage safety in
animal husbandry (Shi et al. 2011).
In the context of such challenges, many scholars
are interested in studying the development of new forages. Currently, canola
meal (CM) has been proposed as an alternative source of protein (Min et al. 2011; Wickramasuriya et al. 2015). There have been trials evaluating the use of CM as a substitute for soybean
meal in broiler diets, but an appropriate number of enzymes must be added to
improve feed digestion in chicken industry (Irani et al. 2012; Conradie et al.
2018). Canola had great potential as an alternative replacement to soybean meal in broiler diets and could be helpful in designing low-cost feed formulations that
would improve growth performance and health status in poultry farming systems
in the future (Disetlhe et al. 2018).
With the improvement of rapeseed breeding, it was found that the content of
crude protein was significantly increased. Canola also contains certain
cellulose, crude fat, minerals, such as Ca, Fe, P, Mn, Se and Mg and various vitamins (Sinclair et al. 2012; Karlsson et al.
2016; Gidlund et al. 2017). Due to
the characteristics of being easily planted, high yield and beneficial to the
protection of cultivated land, it was regarded as high quality
forage in China now (Zhang et al. 2019). The effects of canola to
poultry diets is therefore of practical interest. This
may be expected to reduce feed stress and this possibility has been confirmed
in several researches in China (Jeroch et
al. 2001; Yi et al. 2017).
However, up to date, there are few reports on directly feeding leaves or stalks
of fresh canola or the comparison of feeding effects in terms of egg yield and
quality by adding different proportions of canola stalks to common diets.
To illuminate this uncharted area, we mixed
different proportions of forage canola to the diet of laying hens and analyzed
the total egg yield and egg quality using sensory evaluation (Panaite et al. 2019), physicochemical methods
(Lokaewmanee et al. 2010) and
infrared spectroscopy (Nicolas et al. 2011).
The objective of this study was to study the effects of forage canola on the
production efficiency and egg quality of laying hen, which will provide us a
potential forage substance in laying hens’ production performance.
Materials and Methods
The experiment was approved by the Institutional
Animal Care and Use Committee at Huazhong Agricultural University, Wuhan, China
(HZAUCH-2017-011) and it was conducted in accordance with the National
Institute of Health guidelines for the care and use of experimental animals.
Animals, Treatments and Sample Collection
The laying hens are Jingyang Chicken raised in
Enshi, Hubei, China. All feeding trials took place at the poultry unit of
Badong Experimental Farm. One hundred and twenty laying hens were divided into
four groups randomly. Ten hens were caged individually as a replicate and each
group has 3 replicates. Each group is provided with sufficient complete feed.
The Group A was the control, which were fed the complete feed without fresh
canola. The Group B, C and D were fed with complete feed by adding 3 kg, 6 kg
and 9 kg fresh canola respectively.
During the test period, the hens were fed twice a
day, freely drinking water, and the number of eggs laid, egg weight, feed
intake, and growth of laying hens were recorded daily. The trial period was
from August 1 to September 4 for a total of 35 days. Data was analyzed every
week. All eggs laid in each period are tested.
The main component of the complete feed is show in
Table 1. The added forage canola was Brassica
napus L. cv. Huayouza 62 (Table 2), which was bred by Huazhong Agricultural
University. Fresh leaves and/or stalks from the seedling stage to the initial flowering
stage cultivated in the experimental field at Jingyang were used, which were
mechanically pulverized into leaves and/or stalks with a length of 0.5 to 1.0
cm for digestion before feeding.
Data collection
Method for determination of visible near-infrared:
Eggs were decontaminated with
distilled water, dried naturally, and grouped by visible near-infrared
spectroscopy (USB2000+, Ocean Optics). The fiber optic spectrometer was
preheated for 30 min, and each egg sample was repeatedly scanned five times to
obtain an average spectral curve. In this experiment, Spec suite was used as
the spectrum acquisition software. To avoid distortion of the collected
spectral data, the integration time is set to 60 Ms. Each egg was spectrum
scanned three times, with the smooth width at 3. Visible near-infrared
spectroscopy was performed on all samples, and it was performed to obtain
differences between the groups of eggs from the spectral characteristics.
Table 1: Main ingredients and nutrient levels of complete feed
composition |
% |
Nutritional
level |
% |
corn |
60 |
Crude
protein |
18.45 |
Cardamom |
10 |
ether
extract |
3.46 |
Wheat
bran |
8 |
Ash |
6.42 |
shell |
7 |
Crude
fiber |
3.16 |
Pine
needle |
5 |
Ca |
1.36 |
Fish meal |
10 |
P |
0.52 |
Table 2: Canola Huaza 62 nutrition index
in different periods
Period |
CP |
EE |
Ash |
NDF |
ADF |
Ca |
p |
Seedling
stage |
16.32c |
4.91c |
8.06a |
42.43c |
29.76c |
1.76b |
0.44c |
Grey moss
period |
17.46b |
5.87b |
7.89a |
48.65b |
36.16b |
2.13a |
0.68b |
Florescence |
18.17a |
8.30a |
8.32a |
51.98a |
39.62a |
2.49a |
0.83a |
Note:
Different letters within each column indicate a significant difference (P < 0.05)
Determination of egg quality parameters
An electronic balance was used to measure egg
weight. The eggshell strength tester (FGV-10XY, Israel Oka Food Technology Co.,
Ltd.) measured the maximum pressure the eggshell could withstand per square
centimeter. Egg Quality Analyzer (EA-01, Israel Oka Food Technology Co., Ltd.)
was used to obtain the yolk color grade.
Biochemical analysis
The egg white yolk mixture was weighed and then
nitric acid, perchloric acid, and sulfuric acid were added on a tunable
electric furnace (120–180°C) until the mixture was digested to a white smoke
and was colorless, transparent or slightly yellow. A standard curve of
phosphorus standard solution in the cuvette was made at a wavelength of 660 nm.
The phosphorus content of the liquid samples was determined and compared with
the standard series to obtain the phosphorus concentration in the measurement
liquid. The content of the phosphorus element was calculated according to the
formula (1):
(1)
Where X is phosphorus content in the sample / (mg/100
g); m1: the mass of phosphorus in the sample solution for
measurement/(μg); m0:
mass of phosphorus in the blank solution for measurement/(μg); V1: digested liquid sample volumetric
volume/(mL); m: sample volume or transfer volume/(g); V2: volume of
sample digestive solution / (mL); 100, 1000: conversion factor.
The content of potassium and calcium in the egg
samples were determined. Samples were digested using the microwave digestion
method. Under the same experimental conditions for measuring the standard curve
working solution, the blank solution and the measuring solution were injected
into an atomic absorption spectrometer, and the potassium and calcium
absorbance was measured. The concentration of potassium and calcium in the
liquid to be tested was obtained according to a standard curve. The potassium
and calcium content were calculated according to the formula (2):
(2)
Where X is content of the measured element in the
sample / (mg/100 g); ρ: mass concentration of the element in the
measuring solution / (mg/L); ρ0: determination of the
mass concentration of the element in the blank test solution / (mg/L); v:
sample volume / (mL); m: mass of the sample / (g); f: dilution factor of
the sample; 100, 1000: conversion factor.
Results
Dosage for each group
Sufficient
complete feed and different proportions of feed canola were provided to each
group in the experiment. According to Fig. 1, the feed intake of complete feed
in the Group A was between 0.120 kg and 0.140 kg per day. Table 3: Feed intake of
each group of hens after adding different proportions of feed rapeseed in the
diet (kg)
Composition |
Group A (control) |
Group B (add 3 kg) |
Group C (add 6 kg) |
Group D (add 9 kg) |
Complete
feed |
0.131 |
0.100 |
0.096 |
0.083 |
canola |
/ |
0.100 |
0.178 |
0.181 |
Total
amount |
0.130 |
0.200 |
0.274 |
0.264 |
Fig. 1: Changes in feed intake of laying hens after adding
different proportions of canola to diets
This
figure mainly describes the daily consumption of each chicken in the four
groups A, B, C and D. A-fodder represents the amount of complete feed consumed by Group A.
B-fodder represents the amount of
complete feed consumed by Group B. C-fodder represents the amount of complete feed consumed by Group C.
D-fodder represents the amount of
complete feed consumed by Group D. B-canola represents the amount of canola consumed by Group B. C-canola
represents the amount of canola consumed by Group C. D-canola represents the
amount of canola consumed by Group D
Fig. 2: Spectral changes of different
groups after adding different proportions of feed canola to the diet
The red line in the figure indicates the spectral
transmittance of Group A eggs. The spectral transmittance of eggs in the three
Group B, Group C, and Group D is consistent, and they are all represented by
black lines. The vertical dotted line indicates where the second trough appears
The feed intake of complete feed in the
experimental group was about 0.10 kg. The feed intake of complete feed
gradually decreased with the passage of time. In terms of food consumption, the
Group A consumed 0.130 kg; the Group B consumed 0.200 kg. And the Group C
showed the largest consumption at 0.274 kg, while the Group D consumed 0.264 kg
(Table 3).
It is generally agreed that the huff unit is an
important standard of egg freshness (Jones and Musgrove 2005). The eggs were
all AA evaluated by Huff value. None of the results below will be biased by egg
freshness.
Analysis of visible near-infrared spectral
characteristics
It is interesting to note that, the eggs all
showed the first wave trough at a wavelength of 625 nm. The second wave trough
appeared in the Group B, C and D at a wavelength of 675 nm, while the Group A
did not show a wave trough (Fig. 2). From the spectrum analysis, the trend of
the Group A was different from that of the other three groups, and the trend of
the waveforms of the three groups using canola was similar.
Canola influence egg laying rate
Fig. 3: Changes in egg production rate of laying hens after
adding different proportions of canola to diet
Group A: feeding with no canola.
Group B: feeding with 3 kg canola. Group C: feeding with 6 kg canola. Group D:
feeding with 9 kg canola (the same as follows)
Fig. 4: Changes in whole egg weight after adding different proportions of canola
to the diet
Fig. 5: Changes of eggshell strength after adding different proportions of canola
to the diet
The change in the laying rate of hens after adding
different proportions of canola to the diets of each group (Fig. 3), which
showed that the laying rate of each group was about 30% at the 1-to-7-day stage
from the start of the experiment, and there was no significantly difference
between each group. From day 29th to 35th, the laying
rate of the Group A and the Group D was about 30%, with no obvious increase
between the laying rates of 1 to 7 day. The laying rate of the Group B and the
Group C was about 30% higher than that of 1 to 7 day.
In addition, the whole egg weight of different
groups showed no difference in 1 to 7 days (Fig. 4). By the end of the
experiment, i.e., 29 to 35 days of
feeding, the whole egg weight of each group showed an upward trend. Among the
groups, the weight of the Group B and Group C increased by about 5% compared
with the initial period, the Group A increased by 0.6%, and the Group D
increased by 3%.
Comparison of eggshell intensity with feeding
different amounts of canola
Eggshell strength is one of the most important
factors in egg quality. The eggshell strength (Fig. 5) did not show any
difference between groups at the first week (P > 0.05). At the later stage of the experiment, i.e., 29 to 35 days, the results showed
that the eggshell strength of the Group B and Group C increased, but the Group
D and the Group A did not change significantly, which indicated that adding an
appropriate amount of canola could enhance the eggshell strength of laying
hens.
Comparison of egg yolk color with feeding
different amounts of canola
Eggshell color was significantly affected by feed (Kanda et al. 2009). Non-phytate phosphorus levels have an extremely
significant interaction effect on egg yolk color (Nie et
al. 2014). The color change of egg yolk after adding different
proportions of canola to the diet (Fig. 6) was not
significant (P > 0.05) after the
preliminary experiment. The egg yolk color of the experimental group added with
canola had changed compared with that of the Group A. With an increased time of
feeding, there was no obvious change in the egg yolk color of Group A, whereas
the egg yolk color of the test group gradually deepened with feeding time. By
the end of the experiment, i.e., 29
to 35 days, the index color of the Group D was as dark as 12 and the color was
positively correlated with the proportion of canola added to the basal diet.
Comparison of trace element in eggs of hens fed
canola
In the first 1 to 7 days of the experiment, there
was a significant difference in the phosphorus content between the Group D and
the other three groups. During the test period, the content of phosphorus in
the eggs of each group fluctuated, and the Group C was higher than the other
groups. During 8 to 28 days, the Group C and the other three groups showed
significant differences; at the end of the trial, i.e., 29 to 35 days, there was no significant difference in each
group (Fig. 7).
The content of potassium in the diets was
increased after adding different proportions of canola to the diet. The
potassium content of the eggs in the Group B, C and D was higher than that in
the Group A during the 15 to 35 days after feeding (Fig. 8).
In the first 1 to 7 days of the experiment, the
content of calcium in the eggs of the Group A was significantly higher than
that of the experimental group; there was no significant difference between the
groups in the 8 to 14 days of the experiment. In the 15 to 21 days of the
experiment, the calcium content in the Group C and D increased, which was
significantly higher than the Group A and B. On the 22 to the 35 days, the
content of calcium in eggs in the Group C and D showed a downward trend,
slightly higher than the Group A and Group B, and on the 29 to the 35 day, it
was significantly lower than in the Group A and B (Fig. 9).
Fig. 6: Color change of egg yolk after adding different
proportions of canola to grain
Fig. 7: Changes of phosphorus content in eggs after adding
different proportions of canola to diet
Fig. 8: Changes of calcium content in eggs after adding different proportions of
canola to the diet
After feeding canola for 15 to 35 days, the
contents of phosphorus and potassium in the Group B and C were higher than
those in the Group A and Group D, indicating that the proper amount of feed
canola can promote the accumulation of these nutrients in the eggs and improve
the nutritional quality of the eggs.
Discussion
Feed intake is one of the most important indexes
in this study because it is the basis to measure whether canola can be used as
feed in laying hens. The high fiber content in canola reduces feed intake
(Thacker and Widyaratne 2012).
Thus, complete feed consumption in the Group B, C and D is less than Group A,
which can reduce farming costs.
There was no obvious difference in the spectra of
the Group B, C and D. The trend of the Group A was different at the 675 nm,
which showed that the difference in eggs was mainly caused by canola. By
scanning the near-infrared spectrum of the sample, the characteristic
information of the hydrogen-containing groups in the organic molecules in the
sample can be obtained.
Laying hens in the canola experiment group (the
Group B, C and D), consumed a large amount of food (Fig. 2), because the feed
consumption of laying hens was closely related to the dietary energy and
decreased with the increase of dietary energy (Ivy and Gleaves 1976). The energy content of
canola of the same quality is lower than that of the complete feed, but the
energy provided to laying hens is almost the same. Therefore, the amount
consumed has little influence on the performance of the laying hens. Thus, the
composition and structure of the eggs changed after the canola was digested and
absorbed by laying hens.
There was a negative correlation between egg weight
and egg number, so the two traits should be considered when comparing the
effects of canola on the performance of production (Wu et al. 2009). The results showed that the laying rate could be
increased by adding a proper amount of canola to the basic diet, while it could
be decreased by adding too much canola. Overall, the Group B and the Group C
not only increased the weight of eggs but also increased the number of laying
hens, thus, the production efficiency of laying hens was improved
significantly.
The eggshell strength of the Group B and the Group
C was greater than that of the Group A (control), but the eggshell strength of
the Group D was not significantly different from that of the control group.
Compared with feeding only complete feed, adding canola to the diet increased
the phosphorus content in the egg and the increase of phosphorus content
increased the eggshell strength (Taylor 1965).
However, when the phosphorus content is too high, the eggshell strength will
decrease. It may be that the high level of phosphorus will hinder the
reabsorption of bone calcium and interfere with calcium escaping from bone into
the blood, thus affecting the formation of eggshells, which is more serious
than the consequences caused by the lack of phosphorus (Wang 2010). In this
study, the Group B of laying hens ate more canola than the Group A, but less
available phosphorus was obtained compared with the Group C and D. However, the
eggshell strength of the Group B was significantly higher than that of the
other three groups, which indicated that the feeding level of the Group B was
optimum in eggshell strength traits.
The results showed that the addition of canola
might have some influence on the carotene in egg yolk. With the increase of
canola dosage, egg yolk color gradually deepened, which showed that the
absorption of rich nutrients is promoted in the eggs of laying hens fed canola.
Mohammad et
al. (2018) found that there was no significant difference in trace elements
in the egg to produce contents of the feed-fed laying hens with large
differences. It can be seen from Fig. 7 and 8 that there are large changes in
phosphorus and calcium in the four groups of eggs in different period, but the
difference between the four groups is not significant. In Fig. 9, there is a
significant difference in 21 to 28 days, but the difference is not significant
in the 28-to-35-day period and there are some changes in the waveform in this
period in Fig. 7 and 8, which may due to the high temperature in this cycle
caused stress response of laying hens.
Conclusion
This aspect of the research suggested that feeding
laying hens with the proper amount of forage canola has no toxic side effects,
and its growth and development have no harmful effects. The study found that
when each laying hen was fed with 0.10 kg of canola and 0.10 kg of complete feed, the egg yield, storage quality and nutritional
quality were the optimum. Collectively, forage canola can provide the necessary
nutrients for the egg production of laying hens. This may be considered a
promising aspect of feed substitutes.
Future research should consider the potential
effects of the digestive system of laying hens more carefully. And we do not
know that feed canola can be used as fodder for other poultry or not, such as
ducks. This is an issue for future research to explore.
Acknowledgements
This study was supported by National Natural
Science Foundation of China (31871863), Technical Innovation Project in Hubei
Province (2017ABA064) and the Fundamental Research Funds for the Central
Universities (2662017JC005).
Author Contributions
Wang Qiaohua and Wang Bo
designed the experiment and revise the manuscript. Ma Yixiao collected and
analyzed the data and prepared the manuscript. Fu Tingdong helped designing the
experiment. Kuai Jie and Zhou Guangsheng helped interpret the results. All authors
read and approved the final manuscript.
Conflict of Interest
The authors declare that the research was conducted in the
absence of any commercial or financial relationships that could be construed as
a potential conflict of interest.
Data Availability
All datasets presented in this study will
be available on a fair request to the corresponding authors
Ehics
Approval
The
approved protocol of the Institutional Animal Care and Use was applied in all
animal handling procedures.
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