چكيده لاتين :
استفاده از روش
in situ
براي مقايسه ضراي
ب تبديل پروتيين خام به پروتيين قابل
متابوليسم در پودر ضايعات كشتارگاهي، دانه سو
ياي تفت داده
شده و
...
31
In situ method
to compare conversion coefficients of crude protein to
metabolisable protein in poultry by
-
product
meal, roasted soybean and fish
meal
M Kazemi
-
Bonchenari
1
, M Zohrevand
2
, A Alizadeh
3
and S Afshar
4
*
Received:
April 14, 2015
Accepted
:
February
25
,
2017
1
Assistant
Professor, Department of Animal Science, Faculty of Agriculture
and Natural Resources
,
Arak University, Arak,
Iran
2
MSc Graduated Student, Department of Animal Sciences, Saveh Branch, Islamic Azad University,
Saveh, Iran
3
Assistant
Profess
or, Department of Embryology, Reproductive Biomedicine Research Center, Royan
Institute for Reproductive Biomedicine, ACECR, Tehran, Iran
4
Expert,
Institute of
Technical & Vocational
Higher Education
& Skill Training
of Agriculture Jihad
,
Agricultural Res
earch, Education
&
Exten
s
ion Organization, Tehran, Iran
*
Corresponding Author;
Email:
salmanafshar
2007
@gmail.com
Introduction
:
The
amount of nitrogen obtainable from the slaughterhouse wastes was 22.36
kg
per
1,000
head which could be an excellent biological source of nitrogen (protein) in animal nutrition.
The
poultry by
-
product meal
(PBM)
is one of the most important rendering by
-
product with a high
protein content for use to feed ruminants
.
It has been r
eported previously that i
ncluding
PBM
as
protein substitute for soybean meal (SBM) could decrease feed costs in growing hair lambs.
However, a better understanding of the chemical composition and protein degradation patterns of
PBM
would be very useful in
improving the accuracy of formulation of animal diet
. Among the
chemical analysis clearing the protein quality, the evaluation of metabolisable protein of feedstuffs
could help in more precise ration formulation especially in protein
-
rich by
-
products. Soyb
ean as
well as fish meal are two commonly used protein sources in ruminant nutrition. Evaluation and
comparison of MP for different protein sources in ruminant nutrition bring this opportunity for
replacement the feedstuffs instead of each other. There
are
different methods to identify the
coefficient of crude protein convert in to metabolisable protein.
Each method have robustness and
weakness as well.
This study
was carried out
to estimate and compare the crude protein to
metabolisable protein (MP) conver
sion coefficients of poultry by
-
product meal, roasted s
oybean
(RSB) and fish meal (FM) by
in situ method
.
Materials and methods
:
The
experiment was conducted on three male rumen cannulated Ghezel
sheep which allocated in Latin Square change over design.
T
he sheep were fed two times daily on
0800 and 1400 h. The basal diet was consisted of 50, 35 and 15% of alfalfa hay, barley and a
composition of three experimental feedstuffs (PBM, SB, and FM), respectively. The in situ
experiment was done with incubation
times on 4, 8, 16, 24, 36 and 48 h. The crude protein for all
incubation times were measured. The slow degradable and fast degradable fractions of protein
contents were estima
ted based on in situ experiment. T
he fractionating of protein based on
Cornell
ne
t carbohydrate and protein system (CNCPS)
was carried out as well.
Phosphate buffer soluble
nitrogen was measured using phosphate buffer. Neutral detergent insoluble nitrogen and acid
detergent insoluble nitrogen (ADIN) were
determined as nitrogen
content
of residual after neutral
and acid detergent procedures, respectively. B2 fraction calculated by difference and results were
presented as percentage of CP.
The degradation profiles were calculated by the nonlinear model
described by Ørskov and McDonald (19
79). The effective degradability (ED) in the rumen was
calculated, ED = a + [(b × c)/ (c + k)], using NEWAY software; where "a" is the water
-
soluble
fraction, "b" the potentially degradable fraction, "c" degradation rate of parameter "b", and "k" the
passa
ge rate of the digesta out of the rumen.
Then metabolisable protein estimation as well as rumen degradable and undegradable contents of the protein in different experimental feedstuffs
were calculated based on in situ data.
Results and
d
iscussion
:
The chem
ical analysis of the experimental feedstuffs results show that the
greatest protein content was for fish meal. The protein content of PBM was obtained 561 g/kg. The
protein content of PBM was similar as previous reports. The ether extract of the PBM was ho
wever
the greatest value among treatments. Because most of the ether extract refusal was included in
PBM, so this fraction was greater than that of those observed for FM and RSB. The CNCPS
fractionation of different PBM sources clear that except than that
of “A” fraction all the fractions
were differed among samples. This shows the huge difference for different sub
-
samples of this by
-
product. This suggests to do the chemical abalysis for PBM before using as feedstuff in animal
nutrition. Regarding the degra
dability trail results suggest that t
he parameter
(
a+b
)
was 76.6, 98.2
and 79.2% for PBM, RSB and FM, respectively (P < 0.05).
The slow degradation fraction of the
protein was the greatest for fish meal as well as the greatest value for effective rumen deg
radable
protein. However the greatest value for undegradable protein was obtained for PBM. This clear that
this feedstuff has potential to have valuable by
-
pass protein. However the lower digestibility of by
-
passed protein from PBM suggest that this feedst
uff protein needs to be processed to have more
biological value.
The estimated MP contents were 25.59, 23.97 and 48.53%, and CP to MP
conversion coefficients were 0.45, 0.63 and 0.70 for PBM, RSB and FM, respectively. The results
clarified that despite hig
h CP content of PBM, CP to MP conversion coefficient was less than 0.5
indicating the low protein efficiency for this product.
Different processing may be used to improve
the protein quality of PBM. The present study clear that in addition to high quantity
of protein in
PBM, higher quality of its protein may use it as a by
-
product which is rich in protein in ruminant
nutrition. More work is need to evaluating the replacement of processed PBM instead of commonly
used protein sources in animal nutrition.
Con
clusion
:
The results of this study indicated that,
lowering the content of ADIN from poultry by
-
products through the different forms of processing may improve protein efficiency and
consequently cause improvement in CP to MP conversion coefficient.
Improvi
ng the protein quality
of PBM may make it a suitable replacement feeding instead of commonly used protein sources in
ruminant nutrition.
