OJHAS: Vol. 5, Issue
2: (2006 Apr-Jun)
Physiological Response Of Laying Birds To Neem (Azadirachta Indica) Leaf Meal-Based
Diets: Body Weight Organ Characteristics And Haematology
Department of Animal Science and Technology,
University of Technology, PMB 1526, Owerri, Nigeria
Address For Correspondence
Department of Animal Science and Technology,
University of Technology, PMB 1526, Owerri, Nigeria
Esonu BO, Opara MN, Okoli IC, Obikaonu HO, Udedibie C, Iheshiulor OOM.
Physiological Response Of Laying Birds To Neem (Azadirachta Indica) Leaf Meal-Based
Diets: Body Weight Organ Characteristics And Haematology Online J Health Allied Scs. 2006;2:4
Submitted: Mar 30,
2006; Accepted: Jul 14, 2006; Published:
Sep 11, 2006
A 12-weeks feeding trial was conducted
to evaluate the effects of Neem (Azadirachta indica) leafmeal (NLM) on
body weight gain, carcass and organ characteristics and haematological values of
laying hens. The leaves were harvested, chopped to facilitate drying in the sun
until they became crispy but still greenish in coloration. The Sun-dried leaves
were milled using a hammer mill to produce the leaf meal. Four layers diets were
formulated to contain the NLM at 0%,5%, 10% and 15% dietary levels respectively
and were used to feed 120 Shikka brown layers already 10 months in lay. The
birds were divided into 4 groups of 30 each and randomly assigned to the 4
treatment diets in a completely randomized design (CRD). NLM did not show any
appreciable difference in weight gain between the birds at 0% and those at 5%,
10% dietary levels. Carcass weight, dressed weight, liver, heart and gizzard
weights were significantly (P<0.05) increased at 5% dietary level of NLM.
There were no significant difference in Hb and PCV between birds on O% and 5%
treatment diets. However, these differed significantly (P<0.05%) from those
of birds on 10% and 15% treatment diets. There were variations in the
differential WB count , marked lymphocytopenia adversely affected the total
leucocyte counts in the birds on 5%, 10% and 15% treatment diets. The results of
this study suggest that laying birds could tolerate 5%- 15% dietary levels of
NLM without deleterious effects.
Laying birds, Neem
Nutrition is the most important
consideration in any livestock enterprise. Its survival is dependent on the
availability of feedstuffs, which are mainly components of human
The unavailability of grains and the
high cost of imported ingredients have made the price of commercial animal feed
to increase over 300%.1 These problems remain the most important
constraints to the expansion of commercial livestock production in Nigeria. The
need to exploit other available but neglected cheaper novel feed resources,
especially those indigenous to our environment and inedible to man is urgently
Neem (Azadirachta indica) is an
indigenous tropical plant predominant in Nigeria. It is known by names such as
“Ogwu-Iba” in Ibo land and “Dogonyaro” in Hausa. Azadirachta indica
is medicinal and it is used as insecticide and pesticide. The tree is relevant
in organic farming. The leaf meal has a proximate composition of 92.42 dry
matter; 7.58% moisture; 20.68% crude protein; 16.60% crude fibre; 4.13% Ether
extract; 7.10% Ash and 43.91% Nitrogen free extract. The nutritive value of Neem
leaf meal had earlier been reported.2 However, factors such as
nutrient inbalance, improper metabolism, presence of anti-nutritional factors
and toxic elements in such novel feed ingredient have been implicated in similar
products. Research has continued in our laboratory to identify the
anti-nutritional factors and toxic elements contained in Azadirachta
indica leaf. Again, understanding the haematological constituents of birds
feeding on some dietary inclusions of the leaf is important, since such
data indirectly reflect in the physiological responsiveness of the
animals3-11. The objective of the present study
therefore is to determine the effect of Neem leaf meal on the physiological
parameters such as weight gain, internal organ characteristics and haematology
of laying birds in a humid tropical environment.
The leaves of neem (Azadirachta
indica) were collected from and around the Federal University of Technology,
Owerri environs. The leaves were spread evenly and sun-dried for four days until
they become crispy while still retaining the greenish coloration. The
leaves thereafter were milled using a hammer mill to produce a leaf meal. Sample
of the leaf meal was then analyzed to determine the proximate
composition.12 Four experimental layers diets were formulated such
that they contained Neem leaf meal at 0.0%, 5.0%, 10.0% and 15.0% inclusion
One hundred and twenty (120) Shikka
brown layers already 10 months in lay were divided into 4 groups and randomly
assigned to the four treatment diets in a completely randomized design (CRD).
Each treatment was further divided into three replicates of 10 birds. Feed and
water were given ad-libitum. The birds were weighed at the beginning and end of
the trial. Feed intake was recorded daily. At the end of the 12th
week, 3 birds were randomly selected from each of the treatment groups, deprived
of feed but not water for 24 hours, slaughtered, eviscerated and the dressed
carcass weighed. In addition, 5mL of blood was collected from each of the
slaughtered birds and discarded into EDTA treated bottles for haematological
assay. Haematological measurements were determined.13,14 Data
collected were subjected to analysis of variance. 15 Where analysis
of variance (ANOVA) indicated significant treatment effect, the means were
compared using Duncans New Multiple Range Test
The result of the effect of different
inclusion levels of Neem leaf meal on the mean weight gain of laying hens after
12 weeks of treatment is shown in table 1. There was no difference in weight
gain between the birds in the control group and those fed diet containing 5%
inclusion level of Neem leaf meal. The layers placed on diet 10% inclusion of
Neem leaf meal had 4.6% mean weight gain. The ones fed diet containing 15% of
the test material gained 5.1% mean weight after the 12 weeks period of
Table 1: Effect of different inclusion levels of neem leaf meal (nml)
on weight gain of laying hens (after 12 weeks of treatment)
Group (% inclusion)
Post-treatment weight (g)
parenthesis are percentage weight gain
Table 2 shows the results of dietary
levels of Neem leaf meal on carcass and organ weights of laying hens. The
carcass weight of birds fed 10% inclusion level of Neem leaf meal was
significantly different from those on 15% level but similar to the carcass
weights of birds on 0% and 5% inclusion levels. Dressed percentages of the birds
fed 5% and 10% inclusion levels of Neem leaf meal were not
significantly different, but similar to those on the control (0.0%) diet.
However, the dressed percentages of these birds within the 5% and 10% treatment
levels differed significantly from those on 15% inclusion level of Neem leaf
meal. Liver weight of birds placed on diet with 5% inclusion levels of Neem leaf
meal increased significantly and differed from the 0% group but similar to the
livers of birds fed 10% and 15% levels of Neem leaf meal. The weight of the
hearts of birds on 0%, 5% and 10% treatment levels remained the same but
differed significantly from those of the birds in the 15% treatment group.
The weight of the gizzards of layers fed 5% inclusion level of Neem leaf meal is
significantly different from the gizzards of the birds fed 0% and 15% inclusion
level of Neem leaf meal.
Table 2 : The effect of dietary levels of neem
leaf meal on carcass and organ weights of laying hens
Live weight (g)
|Whole Carcass weight (%
|Dressed weight (% live wt)
|Liver weight (% live wt)
|Heart weight (% live)
Gizzard weight (% live wt)
abc: Means within the same row having different
superscripts are significantly different (P<0.05).
The data on the haematological
parameters of laying hens analyzed for the treatments are presented on Table 3.
Table 3: Effect of dietary levels of neem leaf meal on haematological values of laying hens, 12 weeks post treatment
Dietary Levels Of Neem
|Packed Cell Volume (%)
|Red blood Cell (x106/L)
|White Blood Cell
There were significant differences (P<0.05) in the hematological parameters
of birds fed 10% inclusion levels of Neem leaf meal, except for the
eosinophils and lymphocytes .Birds fed diet with 10% Neem leaf meal
recorded the highest haemoglobin value of 12.0g/100mL, but this is significantly
different from that of birds on the 15% diet (8.8g/100mL) but similar to
the control (10.2g/i00mL) and 5%(10.5g/100mL) inclusion levels. Again the packed
cell volume (PCV) of layers in the 10% treatment group differed significantly
from that of 15% treatment group, but similar to the PCV of the control (0%) and
5.0% treatment levels of Neem leaf meal. There was a significant difference in
the red blood cell (RBC) values of layers fed 0% and 10% inclusion levels of
Neem leaf meal and the RBC values of birds on 15% Neem leaf meal. There was a
significant difference in the total white blood cell counts (WBC) of laying hens
fed diets containing 5% inclusion level of Neem leaf meal, but the value is
similar to those in the 0% treatment group. The percentage heterophils of birds
on 10% and 15% diet levels were significantly different from that of O%
treatment group, but similar to the heterophil values of birds in the 5%
treatment group. The percentage of eosinophils increased significantly among the
birds fed ration with 15% inclusion level of Neem leaf meal, but similar to the
value in the birds belonging to the 0% treatment group. The lymphocyte values of
the 0% treatment group differed significantly but only similar to those of birds
in the 5% group. There was also a significantly difference in the monocyte
values of laying hens placed on 10% inclusion level of Neem leaf meal. This
difference was equally similar to the monocyte values of birds on 5% and 15%
The Mean corpuscular volumes (MCV) of
layers fed diets of Neem leaf meal at 5%, 10% and 15% differed significantly
from the MCV of birds on 0% inclusion levels of the test diet. Again these
laying birds had significantly higher but similar mean corpuscle haemoglobin
(MCV) values at 5% and 10% inclusion levels of Neem leaf meal than layers on 0%
and 15% treatment levels. The mean corpuscular haemoglobin concentrations (MCHC)
of layers on 0%, 5% and 10% inclusion levels of Neem leaf meal are significantly
higher than the MCHC of birds on 15% treatment group.
The result for the body weight gain across treatment
groups showed that higher dietary inclusion levels resulted in decreased weight
gain. This was probably due to the effects of incomplete elimination of toxic
factors.1,17 Other workers 18,19 have also
reported the effects of nutrient imbalance and poor metabolism20 on
monogastric animals fed high levels of unconventional feed ingredients.
There was a progressively slight increase in the
whole carcass weight, up to 10% inclusion level of NLM. This indicates that it
may be the optimal inclusion level of NLM that could result in increase in
carcass weight. The highest dressed percentage was obtained from layers
receiving 5% and 10% NLM diets,this shows that further increase in the quantity
of NLM depleted the energy in the muscle tissues which could have been utilized
for egg production.20,21 The percentage weights of the liver, heart
and gizzard obtained at 5% dietary levels of NLM indicate that it is at this
level that these organs gain their maximum weights. In addition, the decrease in
organ weights observed immediately above 5% NLM inclusion level indicates that
there may be certain toxic substances present in the test materials. This is in
agreement with earlier reports.18,22 Future research studies is
needed to identify the chemical compound responsible for the slight hepatomegaly
and changes in other organ weights observed in these laying hens fed diets
containing higher levels of NLM.
The haemoglobin values and packed cell
volume of the layers were significantly higher at 10% inclusion level of NLM
than other treatment groups However, the trend observed across these values was
a progressive increase with a later decrease among birds placed on diet
containing 15% NLM. With the exception of the 15% treatment group, the Hb values
at other levels of dietary inclusion of NLM were within the reported range of
9-13g/d.23 Also the PCV of birds across all the treatment levels were
within the normal range (30-40%)23. Although there were significant
differences in red blood cell counts of the laying hens placed on 0%, 5% and 10%
dietary levels of NLM, these values were much higher than the reported normal
count of 3.0 x100/L in temperate environment.23 The observed relative polycythaemia may be due to a reduction in the fluid component of the blood from
insufficient fluid intake23 or due to the slight
hepatomegaly24,25. Neem leaf meal has high fibre content which may
have resulted in dehydration due to inadequate water intake by the birds for egg
production and other normal physiological processes. Observations on the
haematological indices revealed that although the MCV of birds on diets
containing 5%, 10% and 15% inclusion levels of NML were significantly higher
than the control, all the values were below the reported range of 127(fl) for
chickens raised under temperate conditions.24 The MCHC which is an
indication of the average amount and concentration of haemoglobin in the red
blood cells is within reported normal range of 29gm%26, suggestive
of macrocytic normochromic red cells. Again, this may be as a result of the
slight hepatomegaly observed with the ingestion of different treatment diets of
There was a reduction in the
circulating white blood cells among birds placed on both control diet and
dietary levels of NLM. These values were below the reported range of 9-56 x
103/L23 The variations in the white blood cells of the
layers on different levels of diet in this experiment could therefore be
attributed to nutrient ambiance and /or poor nutrient utilization, thus
leading to leucopenia. Although the differential white blood cell counts
exhibited some levels of significance, the heterophils Eosinophils and monocytes
were within the reported ranges of 3-17,– 0-0.5 and 0 – 5 x 103/L
respectively for clinically healthy birds.23 The lymphocyte values on
the other hand were generally below reported range of
10-30x103/L23. This may have caused the observed
leucopenia, since lymphocyte numbers account for almost half of the WBC
population. The decreased lymphocyte numbers here suggest the effect of nutrient
imbalance and / ors nutrient utilization.
We conclude that though up to 15%
treatment diet of NLM may have increased both hen- day egg production and egg
yolk colour2, it did not improve many of the physiological and
haematological parameters measured. The relatively poor weight gain by laying
birds receiving increasing levels of NLM suggests nutrient imbalance and/or poor
nutrient utilization. Further detailed research on the pathophysiology of laying
birds fed ad libitum on the same dietary levels of NLM might be fruitful in
determining the actual differences in structural, functional and haematological
parameters of birds fed Neem leaf meal.
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