Introduction
The current
scenario is very critical for poultry industry due to increasing the feed cost
in worldwide, generally 60-70% energy ingredients cost spent in broiler diet.
Therefore, numerous studies were conducted to reduce the production cost of
some energy ingredients, through improved feed efficiency in broiler chickens
by management of nutrient supply (Donohue and Cunningham 2009). While, plenty
of reports indicated that reduction of nutrient supply
could decrease the growth performance, FCR and leading to skeletal disorders
and also increases the fat accumulation in carcass (Thomas et al.
1978; Butzen et al. 2015; Mohammadigheisar et
al. 2018; Saleh et al. 2018; Boontiam et al. 2019; Saleh et
al. 2019). Therefore, poultry researchers and scientists feel immense
pressure to find the natural feed additives which may increases the growth
performance and optimize nutrient utilization. In addition, the impact of
certain mineral supplements on broiler performance, health status has been
attracting current research interest. In this regard combination of rare earth
elements (REE) and trace minerals are being actively researched for their
effects of growth performance, FCR and nutrient digestibility in broiler
chickens (He et al. 2010; Adu et al.
2011; Cai et al. 2014).
Azomite is considered a very useful natural mineral
product in Utah (USA) mined from volcanic eruption into a seabed and is a
distinction from any other mineral deposit in the world. It is the mixture of
animal, plants residues and minerals. It contains more than 70 trace minerals, especially rich in rare earth elements (REE).
The trace and REE are most important in diet because they play key role in
physiological process, proper growth, health status and bone development (Lei
and Liu 1997; Ladipo et al. 2015).
Interestingly, azomite is widely used as a natural mineral booster in aqua feed
industry as well as in livestock which improve the feed quality that can facilitates the utilization of nutrients which are not
available to the animals (Fodge et al. 2014). Azomite is certified by OMRI (Organic Material Review
Institute, USA) and AAFCO (Association of American Feed control Officials) as
kind of natural mineral booster that can be used in livestock, aquatic diet and
organic agriculture. In particular, several studies have been reported that
dietary azomite increases the weight gain and lower the FCR by improving the
digestibility of protein, enzymes activity and nutrient utilization in GMT
tilapia and white shrimp (Liu et al. 2011; Tan et al. 2014; Azam et
al. 2016), thereby reducing the amount of nutrient excreted in feces which
may also decreases the environmental pollution. Moreover, the beneficial effect
of azomite may be result of the improved dry matter, protein digestibility and
capacity for energy utilization (Fodge et al. 2014). Furthermore, Lumpkin et
al. (2014) and McNaugton (2011), documented that
addition of azomite in diet improved the growth performance and intestinal
morphology in broilers and pigs. These literatures
confirmed that azomite could improve the digestion and utilization of nutrients
by increasing digestive enzymes activity or other mechanism. Thus, there is
possibility to compensate for potential negative effect of low energy or low
other nutrient diet via the application of azomite. Broilers require high
dietary energy to meet their vigorous metabolism and rapid growth, thus energy
account for most of cost of diet. It is possible to lower dietary cost of
broilers by lowering dietary energy and meanwhile to alleviate negative effect
on growth performance by azomite addition.
Therefore, the main purpose of current study was to
examine the supplementation of azomite with low energy diet on growth
performance, nutrient digestibility, and bone development of broiler chickens,
and tried to lower feed cost of broilers.
Materials and Methods
Dietary treatments and bird’s management
All
experimental procedures, protocols and animal care for this study were approved
by Feed Research Institute, Graduate School of Chinese Academy of Agricultural
Sciences, Beijing China. A total number of 180 one-day
old male chicks were purchased from Beijing Huadu Broiler Company. Chicks were
weighed and randomly allocated into three treatments with six replicates of 10
chickens per replicate. The experiment was conducted in two phases, starter (1–21)
and finisher phase (22–42). The three dietary treatments for this experiment
consisted of control (CONT) containing 2950 kcal kg-1 starter phase
and 3050 kcal ME kg-1 finisher phase; low energy (LME) was
containing2850 kcal ME kg-1 starter phase and 2950 kcal ME kg-1
in finisher phase and LME with 0.25% Azomite Table 1: Ingredient composition and nutrient content for
basal diet
|
Ingredients |
Control |
LME |
||
|
|
Starter |
Finisher |
Starter |
Finisher |
|
Corn |
57.47 |
58.98 |
58.53 |
63.60 |
|
Soya bean Oil |
1.50 |
4.32 |
0 |
0.58 |
|
Soy Bean |
30.96 |
25.05 |
30.76 |
24.16 |
|
CSM |
5.00 |
7.00 |
5.00 |
7.00 |
|
Salt |
0.35 |
0.35 |
0.35 |
0.35 |
|
CaPo4 |
1.53 |
1.39 |
1.52 |
1.36 |
|
Lime stone |
1.54 |
1.40 |
2.18 |
1.42 |
|
Lys |
0.24 |
0.22 |
0.25 |
0.24 |
|
Meth |
0.14 |
0.15 |
0.14 |
0.15 |
|
Cyst |
0.07 |
0.04 |
0.07 |
0.04 |
|
Chol |
0.20 |
0 |
0.20 |
0.00 |
|
Premix |
0.50 |
0.10 |
0.50 |
0.10 |
|
Zeolite |
0.50 |
0.50 |
0.50 |
0.50 |
|
Total |
100 |
100 |
100 |
100 |
|
Calculated nutritional Levels |
||||
|
ME (kcal/kg) |
2950 |
3050 |
2850 |
2950 |
|
Protein (%) |
21.50 |
19.00 |
21.50 |
19.00 |
|
Lys (%) |
1.200 |
1.050 |
1.200 |
1.050 |
|
Meth (%) |
0.450 |
0.440 |
0.450 |
0.440 |
|
TSAA (%) |
0.900 |
0.800 |
0.900 |
0.800 |
|
Thr (%) |
0.866 |
0.724 |
0.866 |
0.724 |
|
Trypt (%) |
0.311 |
0.248 |
0.310 |
0.245 |
|
CF (%) |
3.471 |
3.027 |
3.485 |
3.054 |
|
EE (%) |
4.769 |
7.023 |
3.331 |
3.473 |
|
Ca (%) |
1.000 |
0.902 |
1.005 |
0.906 |
|
P (%) |
0.679 |
0.689 |
0.679 |
0.692 |
|
Avail P (%) |
0.450 |
0.552 |
0.450 |
0.555 |
The premix provided (for 1 kg of diets) VA 10000IU, VB1 1.8 mg, VB2 40 mg,
VB12 0.71 mg, VD3 2000 IU, VE 10 IU, VK3 2.5 mg, biotin 0.12 mg, folic acid 0.5
mg, D-pantothenic acid 11 mg, Cu (as copper sulfate) 8 mg, Fe (as ferrous
sulfate) 80 mg, Mn (as manganese sulfate) 60 mg, Zn
(as zinc sulfate) 40 mg, I (as potassium iodide) 0.35 mg and Se (as sodium
selenite) 0.15 mg
addition
(AZO-0.25). The ingredient composition and calculated nutrient analysis showed
in Table 1. The azomite sample was provided by Lytone Company, Taiwan.
Before arrival of broiler chicks, the house was cleaned
and disinfested. The experiment was conducted in stainless steel wired battery
cages, the house temperature maintained during 1st week at 32°C and
the gradually decrease 2°C each until it reached the 22°C at the last week.
Relative humidity was maintained at 55 to 65%, and lighting procedure of 23 h lighting:
1 h darkness was provided. The adlibitum access of feed and water
provided to the broilers.
Growth performance
and carcass traits
Live body
weight (LBW) and feed intake (FI) of broilers were recorded and the average
daily feed intake (ADFI), average daily gain (ADG) and feed conversion ratio
(FCR) were determined. ADG and FCR were calculated by using following formula.
ADG = Final body weight-Initial body weight / Age in days,
FCR= FI / ADG
Apparent digestibility of nutrients
Before the
one week of feces collection 0.4% titanium Oxide (TiO2) was added in
diets as indigestible marker to determine the digestibility of nutrients. Feces
were collected continuously three days from 39–41d from each replicate. After
dried at 65°C for 72 h, feces were ground and passed through 0.40 mm sieve.
Diet and feces were analyzed for dry matter and ash (AOAC 2000), crude protein
by Dumatherm (Gerhardt company, Germany), gross energy (GE) by calorimeter
(C2000, IKA, Germany), Ca by atomic absorption spectrometer (novAA 400P,
analytikjena, Germany) and phosphorus (P) by ammonium molybdate calorimetry.
The content of TiO2 in diets and feces were determined according to
(Sort et al. 1996).
The digestibility of nutrient was calculated according
to the indicator method. Following formula was used for calculation of nutrient
digestibility.
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Intestinal enzymes
activity
The digesta
was collected from jejunum and store in liquid nitrogen container. The enzymic
activity of lipase, amylase and trypsin were analyzed according to the
commercial kit’s instructions (Nanjing Jiancheng Bioengineering Institute,
Nanjing, China).
Morphology
of small Intestine
Whole small
intestine was dissected from the slaughtered birds carefully and cut into 3
segments. The duodenum was divided from gizzard to pancreo-biliary-duct, the
jejunum from pancreo-biliary-duct to Meckel’s diverticulum and ileum from
Meckel’s diverticulum to ileo-ceacal junction. The intestinal segments were
flushed with 10% formalin to remove the content and one centimeter long of each
segment were excised, then fixed in 10% formalin for minimum 48 h. The sections
5-µm thick were prepared and dyed in
hematoxylin-eosin solution. The structure of mucosa was observed at 40×
magnification using an Olympus BX 43 digital microscope (Olympus Tokyo, Japan)
and photographed using digital camera (eXcope T500). At least 10 intact well
oriented crypts and villi were measured per section and used to calculate
villus height (VH), crypt depth (CD).
Tibia bone
analysis
Tibia were dissected
from slaughtered birds at 42 days. The skin, muscle and other soft tissues were
removed carefully. After air-dried, the weight and length of tibia bones were
measured. The diameter was measured at the narrowest and widest points using
Vernier caliper, and then averaged. The bone breaking strength was determined
using texture analyzer. After measurement of bone breaking strength, the broken
bones were place in plastic bags for determining the content of ash, Ca and P.
All tibia bone samples defatted with ethanol and diethyl ether for 48 h. The
defatted samples were dried in oven at 100°C for 24 h, then weighed and ashed
in muffle furnace at 550°C for 16 h. Ash was weighted and then dissolved in 10
mL of HCl and 5 mL of HNO3. Digested samples were filtered and
diluted with deionized water to the required volume and analyzed for Ca by
atomic absorption spectrometer and P by ammonium molybdate calorimetry.
Statistical
analysis
The
differences among treatments were statistically analyzed by one-way ANOVA using
S.P.S.S. Statistics 19.0 Significant differences among means of treatments were
compared with Tukey’s test. The means and standard
error of means are presented. The significant level is set at 5%.
Results
Growth performance
The results of growth performance in broilers fed low
energy diet supplemented with AZO-0.25 are presented in Table 2. The LBW and
ADG significantly (P < 0.05)
higher in AZO-0.25 compare to CONT and LME treatment. Moreover, AZO-0.25 found
significantly lower (P < 0.05) FCR
than LME treatment, while lower ADFI recorded in CONT diet.
Nutrient digestibility
Table 3 shows that effect of supplementation of AZO-0.25
in low energy diets on digestibility of nutrients. Data revealed that
digestibility of DM, CP, ME, P and Ca was significantly (P < 0.05) higher in AZO-0.25 treatment compared to LME. However,
digestibility of ash (%) was showed non-significant (P > 0.05) difference among treatments.
Enzymes activity
The activity of intestinal
enzymes supplemented with AZO-0.25 diet with low protein is presented in Table
4. There were no significant (P > 0.05) difference were observed among all treatments on activity of lipase,
amylase and trypsin enzymes. However, activity of enzymes was numerical higher
in AZO-0.25 than that of birds fed with LME.
Intestinal morphology
As shown in Table 5, no significant (P > 0.05) difference observed on
villus height and crypt depth of intestine among all treatments. However,
villus height and crypt depth were numerically higher in AZO-0.25 treatment. No
significant difference observed on VH/CD ratio among all treatments.
The results
presented in Table 6 noted that TL and TBS were significantly (P < 0.05) higher in birds fed
AZO-0.25 compare LME diet, while TWT and TD found no significant difference
among all treatments. Birds fed the AZO-0.25 diet had higher (P < 0.05) percentage of Ash, P and Ca
compare to those fed the LME diet.
Table 2: Effect of azomite
supplementation to low energy diet on growth performance in broiler chickens
|
Parameters |
Control |
LME |
AZO-0.25 |
P. Value |
|
LBW (g) |
2705 ± 0.08b |
2641 ± 0.07b |
2894 ± 0.08a |
P < 0.05 |
|
ADG (g) |
64.4 ± 1.95b |
62.9 ± 1.90b |
67.8 ± 1.38a |
P < 0.05 |
|
ADFI (g) |
97.8 ± 3.66b |
103.1 ± 2.21a |
103.9 ± 2.44a |
P < 0.05 |
|
FCR |
1.54 ± 0.02b |
1.63 ± 0.06a |
1.52 ± 0.03b |
P < 0.05 |
abc Means in same row with no common superscript differ
significantly (P < 0.05).
CONT=Control; LME= Low
energy; AZO-025= LME+ 0.25% Azomite. LBW= live body
weight; ADG= average daily gain; ADFI= average daily feed intake; FCR; feed
conversion ratio
Table 3: Effect of Azomite
supplementation to low energy diet on nutrient digestibility in broiler
chickens
|
Parameter |
Control |
LME |
AZO - 0.25 |
P. Value |
|
DM% |
72.91 ± 0.23ab |
71.42 ± 0.09b |
74.40 ± 0.12a |
P < 0.05 |
|
CP% |
66.66 ± 0.14ab |
64.86 ± 0.06b |
67.60 ± 0.14a |
P < 0.05 |
|
ME% |
76.98 ± 0.20ab |
75.21 ± 0.11b |
78.25 ± 0.07a |
P < 0.05 |
|
Ash% |
65.20 ± 0.04a |
62.40 ± 0.03a |
64.14 ± 0.03a |
P > 0.05 |
|
P% |
45.55 ± 0.39a |
41.17 ± 0.25b |
49.75 ± 0.06a |
P < 0.05 |
|
Ca% |
51.49 ± 0.39a |
47.78 ± 0.17b |
55.21 ± 0.05a |
P < 0.05 |
a,b,c Means in same row with no common superscript differ
significantly (P < 0.05). CONT=
Control; LME= Low energy; AZO-025= LME+ 0.25% Azomite.
DM= dry matter; CP= crude protein; ME= metabolizable
energy; P= phosphorus; Ca= calcium
Table 4:
Effect of Azomite on
digestive enzymes activity in jejunum of broiler
|
Parameter |
Control |
LME |
AZO-0.25 |
P. Value |
|
Lipase
U/mg |
267.66 ± 63.92a |
213.03 ± 6.33a |
246.05 ± 61.44a |
P > 0.05 |
|
Amylase
U/mg |
3.28 ± 1.19a |
3.27 ± 0.68a |
3.66 ± 0.22a |
P > 0.05 |
|
Trypsin
U/mg |
168.38 ± 41.99a |
133.11 ± 27.96a |
175.13 ± 18.68a |
P > 0.05 |
abc Means in same row with no common superscript differ
significantly (P < 0.05). CONT=Control; LME= Low energy; AZO-025= LME+
0.25% Azomite
Table 5:
Effect of Azomite on
intestinal morphology of broiler
|
Parameter |
Control |
LME |
AZO - 0.25 |
P. Value |
|
Villus Height µm (VH) |
||||
|
Duodenum |
1594.4
± 260.5a |
1557 ± 171.4a |
1682 ± 275.0a |
P > 0.05 |
|
Jejunum |
1423.0
± 230.3a |
1250 ± 250a |
1288 ± 86.9a |
P > 0.05 |
|
Ileum |
1033 ± 125.3a |
999 ± 181.0a |
1092 ± 69.3a |
P > 0.05 |
|
Crypt Depth µm (CD) |
||||
|
Duodenum |
217 ± 18.7a |
201 ± 23.8a |
216 ± 23.3a |
P > 0.05 |
|
Jejunum |
186 ± 12.3a |
157 ± 15.0a |
176 ± 21.0a |
P > 0.05 |
|
Ileum |
173 ± 26.8a |
149 ± 29.2a |
167 ± 18.9a |
P > 0.05 |
|
Villus Height :Crypt Depth µm |
||||
|
Duodenum |
7.86 ± 0.28a |
7.58 ± 0.79a |
7.32 ± 0.53a |
P > 0.05 |
|
Jejunum |
7.911 ± 1.15a |
7.63 ± 0.32a |
7.82 ± 0.85a |
P > 0.05 |
|
Ileum |
6.20 ± 1.05a |
6.05 ± 0.58a |
6.30 ± 0.72a |
P > 0.05 |
a,b,cMeans in same row with no common superscript differ
significantly (P < 0.05).
CONT=Control; LME= Low energy; AZO-025= LME+ 0.25% Azomite.
Table 6:
Effect of Azomite on bone
mineralization of broiler
|
Parameter |
CONT |
LME |
AZO-0.25 |
P. Value |
|
TWT
(g) |
7.19 ± 0.82a |
6.73 ± 0.64a |
7.48 ± 0.71a |
P > 0.05 |
|
TL
(cm) |
8.53 ± 1.02ab |
7.52 ± 0.37b |
8.83 ± 0.64a |
P < 0.05 |
|
TD
(cm) |
0.84 ± 0.42a |
0.78 ± 0.03a |
0.84 ± 0.05a |
P > 0.05 |
|
TBS
(kg) |
22.35 ± 32ab |
19.41 ± 2.7b |
25.94 ± 4.45a |
P < 0.05 |
|
Ash % |
48.5 ± 0.01a |
45.26 ± 0.01b |
49.21 ± 0.01a |
P < 0.05 |
|
P % |
7.64 ± 03a |
6.82 ± 0.2b |
8.23 ± 0.7a |
P < 0.05 |
|
Ca % |
16.8 ± 1.24ab |
14.62 ± 1.13b |
18.5 ± 3.15a |
P < 0.05 |
a,b,c Means in same row with no common superscript differ
significantly (P < 0.05).
CONT=Control; LME= Low energy; AZO-025= LME+ 0.25% Azomite.
TWT=tibia weight; TL=tibia length; TD=tibia diameter; TBS=tibia breaking
strength; Ca=calcium; P=phosphorus
Discussion
The current
study was designed to examine the dietary azomite added into low energy diet
improves the growth performance of broiler chickens. To the best of our
knowledge limited literature is currently available on the use of azomite in
aqua culture species. However, only few academic reports are available on
broiler chickens. The research findings of present study demonstrated that
reduction of energy in broiler diet decreased the LBW, ADG and increased the
FCR. However, supplementation of azomite with low energy in broiler diet
enhanced LBW, ADG and lowered FCR, indicating the efficient utilization of
feed. Batool et al. (2018) reported that supplementation of azomite in
catfish diet increases the ADG and lower the FCR significantly. Similarly, Azam
et al. (2016) found that significant improvement in BWG, ADG and FCR was
reported when tilapia was fed a diet supplemented with azomite. Tan et al.
(2014) also suggested that effect of the supplementing 0.2% azomite to the diet
have great impact on growth performance and FCR in white shrimp due to the
improvement in nutrient digestibility. These findings are agreed with results
of current study. It has been suggested that azomite can improve the
digestibility and nutrient utilization which can elevate the growth performance
with low energy diets in broiler chickens. It seems that azomite might exert
their action locally within the gastrointestinal tract, including effect on
enterocyte, bacterial microflora as well as nutrient
uptake, absorption and utilization, which may alleviate the negative effect of
low energy on broiler growth performance Like growth performance, the better
improvement in nutrient digestibility of DM, CP, ME, P and Ca was observed in
broiler fed diets with azomite. Our research findings are well recognized in
aquatic species. Fodge et al. (2011) reported that a supplementation
level of azomite 0.25% significantly improved the digestibility of DM, and CP
of tilapia fish. Remarkably, the positive impact of azomite on improvement in
DM, CP, AME, P and Ca digestibility of nutrients in broiler chickens could be
speculated by the improved activity of digestive enzymes. Azam et al.
(2016) reported that supplementation of Azomite in tilapia fish improved the
digestives enzymes activity. Tan et al. (2014) also revealed that
supplementation of azomite improved the enzymes activities in stomach protease.
The better absorption of nutrients depends upon the better morphology of
intestine. Similarly, intestinal barrier integrity may improve the digestion
and absorption ability in animals (Schmidt et
al. 2007). Lumpkin et al. (2014) reported that Azomite supplementation
in diet improves the villus height of broilers. Improving the VH may give
verification for improvement in gut health and absorption of nutrients.
Unfortunately, our study witnessed only numerical increase of VH and CD in
birds fed with azomite supplementation.
The bone indices such as, bone weight, length, diameter,
bone strength and ash content analyze the mineralization of bone in chickens
(Onyango et al. 2003). Furthermore, the bone mineralization makes bone
stronger which empowers the skeleton to withstand the gravity, addition loading
and avert the leg abnormalities in broiler chickens (Shim et al. 2012).
However, no study of azomite on bone parameters reported yet. The research
findings of current study show that the supplementation of azomite with low
energy to the broiler diet improved the tibia length, strength, ash, P and Ca percentage in broilers. Subsequently, azomite
increased the utilization of minerals such as P and Ca which might led improving in tibia breaking strength and bone mineralization.
From the above research findings, it is verified that azomite enhance the bone
strength and mineralization. It linked obviously with significant increasing of
availability of P and Ca by azomite addition.
Interestingly, the outcomes of present study showed that
azomite with low energy diet have unique
characteristics in terms of improving the growth performance in broilers and
decreases the cost of feed. In general, improvement in growth performance and
bone mineralization by enhancing the nutrient digestibility in GI tract of
broiler chickens induced by dietary supplementation of azomite in a comparison
with more or same beneficial effect of control diet. Azomite also numerical
enhances the activity of enzymes without adverse effect on intestinal morphology
in broiler chickens. Azomite had a positive effect on strength and
mineralization of tibia bone was attributed to increase the retention of Ca and
P in the tibia bones.
Conclusion
The low
energy diet can negatively effect on growth performance, carcass, nutrient
digestibility and bone development in broiler chickens, while supplemental
azomite 0.25% with low energy diet had remarkably positive effect on growth
performance and nutrient digestibility in broiler chickens. Inclusions of azomite with low energy diet improved the bone indicators
in broilers. Therefore, azomite could be an effective supplement to reduce the
energy level in broiler diet and the feed cost.
Acknowledgments
We are
thankful to the National key R&D Program of China (2018YFD0501401) for
funding of this Study. We are also grateful to the staff of the laboratory of
Feed Biotechnology of Agricultural Ministry, Feed Research Institute, GSCAAS,
Beijing, for the technical assistance.
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