ABSTRACT
This study was carried out to investigate the in vitro gas
fermentation pattern using maize straw with cassava peels based supplement fed
to WAD goats. The goats were fed in six different treatments, with (treatment
1: maize straw +10%cassava peels concentrate without oil drench, treatment
2:maize straw +25%cassava peels concentrate with oil, treatment 3:maize straw +
50% cassava peels without oil, treatment 4:maize straw+25% cassava peels
concentrate without oil, treatment 5:maize straw+50%cassava peels concentrate
without oil and treatment 6:maize straw +10%cassava peels concentrate with
oil). Maize straw and cassava peels were later dried and milled for chemical
analysis and in vitro gas fermentation study. Chemical analysis of maize straw
and cassava peels show that cassava peels concentrate produced higher crude
protein content than maize straw. The NDF values for maize straw and cassava
peels was 55% and 33% while the ADF values were 31.5% and 16% respectively. In
vitro gas studies show that treatments with oil did not show significant
difference (P>0.05) to treatments without oil in terms of gas production as
shown in treatment 3 with oil and treatment 5 without oil. Gas volume was
significantly higher (P>0.05) in treatment 2 with oil compare to treatment 4
without oil. Value for methane production varied from 0.33ml to 4ml for
treatments with oil and 2ml to 4.33ml for treatment without oil.DMD was highest
in treatment 5 and lowest in treatment 6.This result show that oil had
significant effect (P<0.05) on gas production using maize straw supplemented
at low levels (0-25%) with cassava peels based concentrate as fed suggesting
that oil did significantly reduce the rate of methanogenesis in terms of
methane reduction at low level of supplementation with cassava peels.
TABLE OF CONTENTS
PAGE
Title Page——–ii
Abstract——–iii
Acknowledgement——-iv
Certification——–v
Dedication——–vi
Table of Contents——-vii
List of Tables——–ix
List of Plates——–x
CHAPTER ONE
INTRODUCTION——-1
1.1 Objective – ——3
CHAPTER TWO
LITERATURE REVIEW——4
2.1History of in vitro Gas production—-4
2.2Factors affecting Gas production —-6
2.2.1Effect of Venting Gas during the Incubation—6
2.2.2Effect of Changes in atmospheric pressure —6
2.2.3Effect of agitation of medium—- 7
2.2.4Effect of sample size and preparation —8
2.2.5Effect of inoculums——- 8
2.2.6Effect of inoculums concentration and sampling time -9
2.2.7Effect of inoculums preparation —10
2.2.8Use of blanks ——-10
2.2.9 Effect of medium composition—–11
2.2.10Effect of apparatus——12
2.3 Methanogenesis——-13
2.4Maize straw ——-13
2.5Cassava peel supplement —–14
CHAPTER THREE
MATERIALS AND METHODS —- -13
3.1The Experimental Site —–15
3.2Source of Feed Ingredients—–15
3.3Experimental Diets ——16
3.4Management of Experimental Animals—16
3.5Feeding procedure—— 17
3.5.1Composition of Supplement —- – 18
3.6Filling of bags into incubation bags —-18
3.6.1Collection of Rumen liquor—–18
3.6.2Preparation of inoculum—–19
3.6.3 Methane gas production —–21
3.7Chemical analysis ——21
3.7.1Moisture content determination —-22
3.7.2Ash Determination ——22
3.7.3Crude Protein Determination —-22
3.8Cell wall determination—-243.8.1 Neutral detergent fibre
determination —-24
3.8.2 Acid detergent fibre determination —– 25
3.9 Statistical analysis——25
CHAPTER FOUR
RESULTS——–26
4.1 Chemical composition of Maize straw and cassava peels
supplement 26
4.2 In vitro gas characteristics of maize straw and cassava
peels
Supplement with or without oil drench— 26
4.3 Post in vitro gas fermentation of maize straw and
cassava peels– 29
CHAPTER FIVE
DISCUSSION ——-31
5.1 Chemical Composition of maize straw and cassava peels-31
5.2 In vitro gas production at different hours of incubation
for maize
straw and cassava peels —–31
5.3 Post in vitro gas fermentation of maize straw and
cassava peels
Supplement——-32
CHAPTER SIX
CONCLUSION——-34
REFERENCES——-35
LIST OF TABLES
PAGE
Table 1: Composition of cassava peels supplement—18
Table 2: Chemical composition of Maize straw and cassava
peels
Supplement ——-26
Table 3: In vitro gas characteristics of maize straw and
cassava
peels supplement——28
Table 4: Post in vitro gas fermentation of maize straw and
cassava peels supplement——-29
LIST OF PLATES
Plate1: Collection of rumen liquor —–19
Plate 2: Preparation of inoculums—–20
Plate 3: Reading of methane production —-21
Plate 4: Weighing of chemical sample —-24
CHAPTER ONE
INTRODUCTION
The in vitro gas production technique has been frequently
used to assess biological values of feeds based on their pattern of accumulated
gas when incubated with rumen fluid under anaerobic conditions. The technique
was initially proposed by Menke et al., (1979) to assess digestibility and
metabolizable energy (ME) content f feeds commonly fed to ruminants. Empirical
equations using gas production and chemical components of the feeds were used
to predict ME (Menke and Steingass, 1988). Furthermore, it has been reported
that the feedstuffs in vitro is time consuming, laborious, expensive, requires
large quantities of feed and is unsuitable for large scale feed evaluation.
Methodology used to measure in vitro gas production is
reviewed to determine impacts of sources of variation on resultant gas
production profiles (GPP). Current methods include measurement of gas
production at constant pressure (e.g., use of gas tight syringes), a system
that is inexpensive, but may be less sensitive than others thereby affecting
its suitability in some situations. Automated systems that measure gas
production at constant volume allow pressure to accumulate in the bottle, which
is recorded at different times to produce a GPP, and may result in sufficiently
high pressure, that solubility of evolved gases in the medium is affected,
thereby resulting in a recorded volume of gas that is lower than that predicted
from stoichiometric calculations. Several other methods measure gas production
at constant pressure and volume with either pressure transducers or sensors,
and these may be manual, semi-automated or fully automated in operation. In
these systems, gas is released as pressure increases, and vented gas is
recorded. Agitating the medium does not consistently produce more gas with
automated systems, and little or no effect of agitation was observed with
manual systems.
The annual world production of cereal straws and stovers is
approximately 2 000 million tons, however, the energy contained in this vast
bulk of material is on the whole poorly utilized and its nitrogen incompletely
returned to the soil (Reddy et al.,2003). With the rising prices of both energy
and nitrogen fertilizer, interest is developing in more efficient ways of
utilizing straws, presently used mainly as livestock feed and as compost
material (small amounts are used for the manufacture of paper and fibreboards).
In the tropical and subtropical areas of the world almost all straw is fed to
livestock, the resulting dung being widely used as fuel. With straw feeding,
energy utilization is relatively efficient, except for the residual energy in
the indigestible matter which is wasted, but the introduction of dung
fermentation in place of dung burning increases the proportion of straw
nitrogen which is returned to the soil, thus improving the overall efficiency.
In developing countries like Nigeria where there is abundance of agricultural
wastes, the use of in vitro becomes relevant. The in vitro method of feed
evaluation is less expensive and less time consuming when compared with in vivo
methods (Akinfemi et al., 2010). The in vitro gas production system helps to
better quantity the nutrient utilization and its accuracy in describing
digestibility in animal has been validated numerous experiments (Rymer et
al.,1999). Although, gases produced during rumen fermentation are colossal
waste products and of no nutritive value to the ruminant, but gas production
test are used routinely in feed research as gas volumes are related to both the
extent and rate of substrate degradation.
1.1 Research Objective
The objective of this paper is to investigate the effect of
in vitro gas production using maize straw with cassava peels supplements as feeds
for ruminants. This will help to show;
The degradation of maize straw with cassava peels supplement
in terms of digestibility.
The effect of oil drench in defaunation of ruminants.
Effect of oil on methane gas production.