The following research projects are being carried out at present in the
IFRU. Should you require further information please contact by email the
Project Leader as listed below each project title.
|
The potential use of diet composition markers in studies of
nutrition of free-ranging herbivores
Mr
Hafiz Ali, Sudan
Dr
B.L. Hector, Prof. E. R. Ørskov and
Dr R.W. Mayes(MLURI)
PhD Studentship funded by the Islamic Development
Bank Merit Scholarship Programme (commenced October 2000)
The study will be focused on free-ranging herbivores, their foraging
behaviour and the degree of selection of specific plant species,
factors which have great impact on their energy balance and plant
community dynamics and biodiversity. Since measurements of
plant species composition of the diet of free-ranging herbivores
are difficult under field condition and that existing methods have
considerable disadvantages, these measurements have been estimated
indirectly through marker substances that are quantified in faeces.
Alkanes of plant cuticular wax, for example, have been used to estimate
diet composition of free-ranging herbivores since it was found that
there were large and characteristic differences between plant species
in the patterns and concentrations of alkanes present.
Diet composition can be estimated from the knowledge of the alkane
profile (fingerprint) of a representative sample of diet (extrusa,
digesta or faeces) and the profiles of the individual components
of the diet. However the alkane marker technique has not been
completely validated in multi-component diets and it is expected
that the accuracy of estimations will decrease as the number of
dietary components increases. This project is investigating the
use of additional marker substances for the above mentioned purpose.
|
Optimising rumen environment
for better use of local feed resources in Mexico with emphasis on
sugar cane residues
Miss
Angeles Ortiz, Mexico
Prof
E.R. Ørskov and Dr B.L.Hector
PhD Studentship funded by National Autonomous
University of Mexico (commenced October 2000)
The developing countries, principally those
that are in the tropics, have more than 50% of the ruminants in
the world. The tropical zones have enough forage all year: sugar
cane, maize and grasses which have high levels of energy and low
levels of protein. However their use is not adequate. The principal
aim should therefore be to address improved feeding and nutrition,
in which the objective is maximum use of the available feed resources,
notably crop residues and low quality roughage, and also various
leguminous forages as supplements.
The supplementation provides deficient nutrients
in the form of fermentable N, energy and minerals, thereby enhancing
microbial growth in the rumen which in turn enables the ruminant
to consume more roughage. The primary aim of increasing the crude
protein intake in cattle grazing subtropical pastures is to increase
the availability of degradable or soluble N to meet the rumen microbial
requirement for N substrates. Feeding cattle with protected proteins
rather than those with soluble proteins or containing NPN may do
this task more efficiently. There are many factors involved in the
control of voluntary intake by the ruminant (fibre degradability,
rate of fermentation, rate of flow, microbial protein yield, N concentration),
which operate simultaneously, and interact, though on different
diets different individual factors may be dominant.
The search for efficiency needs to take cognisance
of the following interrelated issues:
- Knowledge of the totality of feeds (forages,
crop residues, agro-industrial by-products, and non-conventional
feeds).
- Appropriateness and efficiency of use within
production systems.
|
Anti-nutritive factors in
multi-purpose trees
Dr Simisola M. Odeyinka, Nigeria
Prof
E.R. Ørskov, Dr
B.L.Hector
Dr
J.C. Newbold - Rowett
Research Institute
Multi-purpose trees (MPT) have been identified to increase small
ruminant productivity in the tropics by providing high protein supplements
(Jones,1979, Odeyinka and Ademosun,1993). However, MPT contain secondary
compounds that may affect rumen microbes (D'Mello, 1992). It has
been reported that some MPT may have defaunating activity especially
on the protozoa population of the rumen. The high protein content
of the MPT combined with their defaunating activities can greatly
promote the growth of rumen bacteria which will result in greater
microbial protein flow into the small intestine thus providing the
host animal with more proteins. However, more work is needed on
the effect of the leaves of MPT on microbial distribution and physiology
of the rumen.
Therefore, the objectives of this research are to:
1. Acquire the necessary skills in the evaluation of nutritive value
of anti-nutrient contents of feedstuffs.
2. Study changes in the population of ruminal protozoa of sheep
and goats on diets supplemented with MPT and in-vitro.
3. Determine the digestibilty of the MPT using in vivo and in vitro
methods.
4.Investigate the possible use of MPT as by-pass proteins.
|
Benzoic acid as a marker of
lignocellulose digestion
Dr
Brenda L. Hector
Plant phenolic acids are released from lignin and metabolised in
the rumen of grazing animals. Metabolites are absorbed into
the blood and further metabolised by the animal before excretion
in the urine as benzoic acid and its conjugates. Aromatic
metabolites in ruminant urine could potentially be used as biological
markers of feeding responses. In particular, benzoic acid
might be used as a marker of lignocellulose digestion. There
is uncertainty associated with the metabolic pathways involving
benzoic acid and its precursors within the animal as researchers
have been unable to recover more than ~80% of benzoic acid precursors
infused into the rumen in the urine as benzoic acid and conjugates.
The aim of the current project is to increase the knowledge of the
metabolic pathway from the blood to the urine. The destination
of benzoic acid injected into the blood is being investigated using
radio-labelled tracer (14C-benzoic acid).
|
Estimation of botanical diet
composition of herbivores using Near Infrared Reflectance Spectrometry
(NIRS)
Dr
Brenda L. Hector
Dr
Ian Murray, Scottish Agricultural College
An investigation is being carried out to determine whether NIRS
can detect differences in urine as a result of consumption of different
plant species by goats. If differences can be detected, NIRS
has potential to be used as a tool to estimate the botanical composition
of herbivore diets.
|
Metabolism and Renal Excretion
of Allantoin and Uric Acid in Sheep and Cattle
Dr Pornrat Prasitkusol, Thailand
Prof E.R. Ørskov
PhD project funded by Thai Government under Rajabhat Institute Scheme
(completed December 2000)
Tracer technique was introduced to sheep and tropical cattle (Bos
indicus and Bos banteng) to study allantoin and uric
acid metabolism in those animals. This project aimed to study allantoin
kinetics in plasma, purine derivatives (PD) excretion in the urine,
urinary recovery of 14C allantoin and 15N
uric acid and the non-renal routes of PD excretion in different
species of ruminants. This work is currently being prepared
for publication
|
The potential use of urinary
metabolites of dietary plant compounds as markers for assessing
the composition of free-ranging ruminant diets
Dr
Brenda L. Hector, UK
Dr
R.W. Mayes and Prof
E.R.Ørskov
PhD project funded by Boyd Orr Research Centre
(Aberdeen Research Consortium) (completed July 2000)
The aim of this work was to develop a method by which a urine sample
can be analysed for metabolites and, from the compounds present,
an estimate can be made of the plant composition of the animals
diet. A 28 plant materials were screened for the production
of plant specific metabolites in the urine of goats. The screening
method used a simple feeding regime with urine collection.
Urine samples were analysed by HPLC and GC for aromatic acids and
organic compounds. A number of metabolites were detected in
urine samples arising as a consequence of ingestion of different
plant materials. The patterns ofmetabolites detected were
different for each of the 28 plant materials ingested. Attempts
were made to identify the metabolites using GC/MS. The plant
materials were also analysed by GC for monoterpene compounds which
were only detected in Pinus sylvestris (Scots pine).
Urine samples from goats consuming P. sylvestris were also
analysed for metabolites of monoterpenes by GC and identifiction
of metabolites was carried out using GC/MS. This work is currently
being prepared for publication. |
