Application of biotechnology to nutrition of animals in developing countries
FAO ANIMAL PRODUCTION AND HEALTH PAPER 90
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Application of biotechnology to nutrition of animals in developing countries |
by
R.A. Leng
Professor of Nutritional Biochemistry
Director of the Institute of Biotechnology
University of New England
Armidale, NSW
Australia
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M-23
ISBN 92-5-103035-9
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1.2 Definition of Biotechnology or High Technology
1.3 The Promise of the New Biotechnology
2.1 Conditions of Ruminants in Third World Countries
2.2 Productivity of Livestock in Developing Countries
2.3 The Implication of Low Productivity
2.4 Feed Resources Available to Ruminants
2.5 Chemical Composition of Low Quality Forages
3.1 The Rumen and its Micro-organisms
3.2 Fermentative Efficiency in the Rumen
3.3 Meeting the Requirements for Efficient Microbial Growth in the Rumen
3.4 Consequences of the Ruminant Mode of Digestion
3.5 Quantitative Aspects of Fermentative Digestion in the Rumen
3.5.1 A Model of Fermentation in the Rumen
3.6 Protein Utilisation by Ruminants
3.6.1 Ensuring a Balanced Nutrition For Ruminants on Forage Based Diets
3.7 Optimising Microbial Growth in the Rumen
3.7.1 Mineral Requirements of Rumen Microbes
3.7.2 Requirements for Ammonia
3.7.3 Timing of Urea Supplements and the Ratio of Sugars and Starches to Fibre in a Diet
3.7.4 Requirements for Amino Acids/ Peptides by Rumen Organisms
3.7.5 Amino Acid Requirements of Microbes Digesting Fibre
3.7.6 The Roles of Small Amounts of Fresh Forage in Straw Based Diets
3.7.7 Elimination of Rumen Protozoa and Preservation of the Fauna-Free State
3.8 Factors Influencing Efficiency of Feed Utilisation
3.9 Climate, Supplementation and Intake of “Low Quality Forages”
3.10 Feeding Standards and Feed Evaluation
3.10.1 Implications of low Productivity of Ruminants in the Tropics
3.11 Some Basic Explanations for the Inefficiency of Ruminants on Forage Diets
3.11.1 Inefficiency of Acetate Utilisation
3.11.2 Requirements for Glucose by Ruminants.
3.11.3 Balancing Nutrition for Reproduction/ Pregnancy and Lactation
3.12 Implication of Parasite/ Disease and Nutrition
3.13 Implications of an Increased Nutrient Requirements for Work
3.14.1 Implications for Areas of Research
5 Present Knowledge and Priority Research Areas
5.1 Adjusting P/E Ratio in the Nutrients Absorbed by Ruminants with Protein Supplements
5.1.2 Bypass Protein Supplements
5.2 Adjusting P/E Ratio by Manipulation of the Rumen
5.2.1 Supplementation of the Rumen Microbial Ecosystem
5.2.2 Chemical Manipulation of Rumen Fermentative Efficiency
5.2.3 Other Manipulations of Rumen Ecosystems
5.2.4 Alteration of Protein and Amino Acid Composition of Rumen Microbes—Recombinant DNA Technology
5.3 Adjusting P/E Ratios from the Rumen by Manipulating the Feed Base
5.3.1 Feed Technology and Development of Supplements
5.3.2 Supplementation with “Naturally” Protected Protein: A Case Study in Strategic Supplements
5.3.3 Providing Bypass Protein in Areas Without Protein Resources
5.4 Maximising Digestibility of Fibrous Feeds
5.4.2 Improving the Enzymatic Ability of Rumen Microbes to Degrade Fibre
5.4.3 Potential Targets for Improving Fibre Digestion
5.4.4 State of the Art in Bioengineering of Rumen Organisms
5.4.5 Selection of Anaerobic Fungi for Better Fibre Degradation in the Rumen
5.4.6 Selection of Bacteria for Fibrolytic Activity
5.4.7 Solubilisation of Lignin
5.4.8 Detoxification of Anti-microbial, Toxic and Anti-quality Factors in Plants
5.5 Developing Detoxification Mechanisms in Rumen Organisms
5.6 Treatment to Increase Digestibility
5.6.1 Improving the Digestibility of Crop Residues by Chemical Treatments
5.6.2 Microbial Treatment of Straw and Other Crop Residues to Improve Digestibility
5.7 Altering the Partitioning of Nutrients Within the Animal
5.7.4 Injected Growth Promotants versus Supplementation to Balance Nutrition
5.8 Cross Breeding to Improve Partitioning of Nutrients into Milk
5.9 Transgenesis and Embryo Manipulation
6 Biotechnology and Monogastric Nutrition
6.2 Potential Areas for Biotechnology in Pig Nutrition
6.2.1 Overcoming Feed Intake Problems on High Fibre Protein Supplements
6.2.2 Possibility of Modifying the Digestive Function Through Development of Transgenic Animals
6.2.3 Porcine Growth Hormone (PSt.)
6.2.4 Transgenic Pigs—Porcine Growth Hormone
7 Biotechnology and Environment
8 Some Practical Problems for Biotechnology Research in Developing Countries
8.1 Present Research Priorities and Change
8.2 Real World Problems of Capitalising on Modern Biotechnology in Developing Countries
8.2.1 Secrecy in Industrialised Countries
8.2.2 The Need for Expertise in Developing Countries to Capitalise on Various Developments
9 Conclusions and Recommendations
9.2.1 The Vision of the New Biotechnology
A Methods Involved in Modifying Rumen Bacteria
B Some Comments on Use of Protein Meals for Use as Supplement for Ruminants Fed Forages
1.1 Food consumption/percentage of diet for meat, wheat and rice, and coarse grains
3.1 Energetics of rumen fermentation (Leng, 1982)
3.4 Intake of low digestibility forages by cattle
3.6 Temperature humidity index (THI) of climates in temperate countries.
5.1 Growth response to different levels of protein meal
5.2 Sites of action of chemicals that, when added to straw, improve its digestibility.
7.2 Trends in emissions of CO2 (Source: World Resources Institute).
7.3 Trends in atmospheric methane accumulation (Khalil & Rasmussen, 1986)
7.5 Improving rumen fermentative activity and the production of methane/kg gain
7.6 Flow diagram showing the potential recycling of feed and faeces biomass from crop residues
7.7 An example of an integrated farming system
2.1 Average meat production (kg) per animal of total population of cattle/buffaloes in Europe
2.2 Average carcass weight (kg) per animal slaughtered (Jasiorowski, 1988) (1986 statistics)
2.3 The change in the average milk yield per cow in industrialised and third world countries
5.1 Summarised data on growth and milk production responses
5.2 The effects on P/E ratio in the nutrients absorbed of supplementation with a bypass protein
7.1 Estimates of methane emissions from animals (adapted from Crutzen et al., 1986)
Improving animal production in developing countries through the application of biotechnology in nutrition is first discussed in relation to the feed resources available and the climatic and environmental constraints. This report targets ruminant animals, because of their enormous contribution to the welfare of people in developing countries. These ruminants, in general are fed on poor quality forages, crop residues and pastures produced on relatively infertile lands and they do not compete with humans for staple food.
The outcomes from ruminant systems are either single or multi-purpose and include milk, meat, draught-power and a variety of other minor products.
There are at a minimum five target sub-objectives which could allow substantial increases in production. These include:—
Manipulation of the feed base
Elimination or amelioration of disease/parasitism
Manipulation of the metabolism and digestive physiology of the animal
Manipulation of the use of feed for production (partitioning of nutrients)
Manipulation of the digestibility of feed prior to consumption.
Amelioration of parasite/disease is an area that has some considerable prospects for application of modern biotechnology but is not part of the brief.
Biotechnology is defined here in two ways—broadly as the application of biological organisms/systems and chemical processes to the production of animal products. In the broad sense there is considerable scope for application of biotechnology to increasing animal production. The other definition of biotechnology which will be termed modern biotechnology is the application of recombinant DNA technology to improvement of nutrition, it also includes the integration of microbiology, biochemistry and chemical and process engineering. In the discussion of priorities modern biotechnology is de-emphasised, largely because of the long-lead time to application which it is suggested has been considerably underestimated in the past and the potential of the broader approach to biotechnology resulting in 2–5 fold increases in present levels of production from ruminants in developing countries. Further reasons for de-emphasising modern biotechnology as applied to nutrition of animals is the need to invest considerable funds in basic research at the present time and the probable inability of a developing country to capitalise on any potential wealth generating invention.
The development of the broad-biotechnology approach is aimed largely at local research to find ways and means of applying recent developments in ruminant nutrition that emphasise balanced nutrition.
The research in ruminant nutrition that are most applicable to the animals husbanded by small farmers in developing countries have until now been scattered through the scientific literature. They have been drawn together in the book by Preston, T.R. & Leng, R.A. (1987) Matching ruminant production Systems with available Resources in the Tropics and Sub-tropics. Since that publication, a new synthesis that emphasises the nutrition of animals fed poor quality forages in the tropics has revealed important ways forward for improving productivity of ruminants which have been tested and applied on a wide scale in India.
The Indian experience in application of the concepts of balanced nutrition to large ruminants owned by village farmers has given feed-back which provided the information which has since allowed the concepts to develop further. As these new concepts, which, when applied, have the potential to increase animal productivity 2 to 5 fold and increase efficiency of feed utilisation conservatively by 10 fold are not generally understood, a major section of the report deals with the development of the concepts.
The scientific discussion leads to the following conclusions:—
The primary constraint to ruminant production on fibrous feeds is the low efficiency of feed utilisation and not its energy density.
Efficiency is determined by the products of the digestion of the feed meeting the quantities and balance of nutrients needed to meet production needs.
In practice improving the ratio of protein (amino acids) absorbed relative to energy nutrients (largely volatile fatty acids arising in fermentative digestion) is the primary factor that effects efficiency of product formation by ruminants.
Energy density of a feed (often meaning only digestibility) only becomes a constraint after the nutrient balances of the animal have been corrected.
Altering the protein to energy ratio in nutrients absorbed in general improves only efficiency (except where feed intake is depressed by heat stress in which case it will increase feed intake also) but this could result in a 2–5 fold increase in production.
Improving the digestibility of a poor quality forage allows increased intake. This increased intake can only be capitalised upon by the animal when the protein to energy ratio is appropriate. In which case a further doubling of productivity will result for every 5 units increase in digestibility (see Figure 5.1).
The priorities for nutritional research must therefore be:—
To optimise P/E ratio in the nutrients absorbed by ruminants from poor quality forage based diets (Priority 1).
To optimise digestibility of the basal feed resource (Priority 2).
To partition nutrients more effectively into the desired animal products (Priority 3).
Priority 1 involves technologies applied to:—
Rumen manipulation including supplementation to encourage optimal microbial growth, manipulation of the microbial mix in the rumen to ensure high microbial growth efficiency and a high biological value of the protein and ensuring that a high proportion of the microbes that grow in the rumen are made available to the host animal.
Feed processing—this largely includes the development of bypass protein supplements for ruminants. This involves local research to find, produce and exploit local protein resources for this purpose.
Manipulation of plant genomes to develop the capacity for proteins to be resistant to rumen microbial attack.
Priority 2 involves:—
Rumen manipulation including supplementation to encourage optimum microbial biomass in the rumen, and manipulation of the fibrolytic activity of the mix of rumen microbes.
Feed processing—this largely involves identification and modification of methods that can be applied locally to treat low quality forage to improve its digestibility.
Priority 3 involves
Genetic and recombinant DNA technologies applied to the rumen microbes and the animal to ensure high feed intake and efficient partitioning of the available nutrients into products. This work has a prerequisite of optimal nutrition (as defined here and not meaning concentrate feeding)
The use of injectable chemicals/hormones that partition nutrients.
Examples of the various research approaches are given within the text. These examples are used to emphasise the need for modification and development of the established concepts for local environments with their own feed and management resources.
Aspects of modern nutritional biotechnology applicable to developing countries are discussed. It is emphasised that the promise of modern biotechnology is not diminished even though that research scientists are finding that application is fraught with difficulties. Most “once-thought-to-be” major breakthroughs have had to go back to basic research to provide knowledge particularly on the control of expression of genes transferred by recombinant means into the genome of animals and micro-organisms. This suggests a major time lag for application well beyond the year 2000 which has often been quoted as the year when biotechnology research will be being applied.
Finally, the need for support systems to guarantee the ability of a country to protect inventions from exploitation by others are briefly discussed. It is felt that the entry of multi-national companies into biotechnology research and development has major implication for developing countries. Secrecy and competition from multinationals will make it difficult for developing countries to capitalise on inventions. Knowledge of biotechnology within a country should, however, allow a country to capitalise in many other ways on knowledge generated in laboratories in developed countries.
The overall conclusion is that aid-funds for research should be targeted at modifying and applying to the local conditions, present concepts which can massively effect animal production in developing countries. This will require to a large degree original research particularly within the feedtechnology/biotechnology area.
not only digestibility, but (also)