Monogastric animals are the most efficient transformers of raw ingredients, rich in starches/sugars and proteins, into meat and eggs. Only milk may be produced with a similar efficiency by ruminants.
However, the usual feeding techniques of monogastric animals require the utilization of cereals and costly protein meals as the basis of the diet. In many developing countries this usually leads to direct competition with human consumption and the expenditure of foreign currencies for importation of the raw materials.
On the other hand, poultry and pig meats and eggs can be intensively and rapidly produced and distributed in large and small cities and can improve quite strongly and dramatically the nutritional status of these populations. Therefore an effort to use locally produced byproducts through monogastric species has to be considered as a major priority, even at the expense of lower rates of individual animal productivity.
The following suggestions are a non-exhaustive list of proposals to help progressing in that direction.
Each country should prepare a rough inventory of all crop residues and agroindustrial byproducts that can be utilized by monogastric animals. The main objective of this inventory is to identify all the possible ingredients and the quantities available for usein poultry and pig diets.
The crop residues and byproducts usable by monogastrics can be divided into four main groups:
These include all the products coming from the slaughter houses mainly in the big cities, from large animals and poultry. Typical products are meat, bone and blood meals. These may be as single products or they may be mixed (eg: meat and bone meal). Feather meal is sometimes produced at poultry slaughter plants. There are also hatchery byproducts elaborated from dead birds and eggs.
Fishmeal is produced in many countries. Usually it is produced from the byproducts of fish canning enterprises and other processing activities, in which case the ash content (from the bones) can be quite high. In some countries, like Peru, the fish meal originates from whole fish harvested specifically to make meal for animal feeding; these meals can have quite high oil contents.
Many originate from the milling industry such as bran, rice polishings, wheat millings, maize gluten, sorghum gluten, etc.
Others are from the edible oil industry eg: the meals obtained after extraction of oil from the seeds of soybean, cotton, sunflower etc.
There are useful byproducts from the sugar industry, such as molasses and sugar beet pulp.
Byproducts from fruit processing include reject bananas, citrus and pineapple pulps, reject apples and some other fruits discarded as unsuitable for marketing for human consumption.
By-products from the fermentation industry are the yeasts from brewing and distilling. In some countries, yeasts are produced as a primary product for animal feeding (eg: torula yeast from fermentation of molasses).
In this category can be grouped feed resources such as sugar cane juice; foliage from some legumes and food crops such as sweet potato and cassava; waste food from catering establishments in large institutions; larvae from the artificial breeding of flies; livestock excrement; earthworms reared artificially, and so on.
When a byproduct is identified which is thought might be useful in mongastric feeding, some preliminary investigaton should be carried out to ensure that it is practically possible to use the byproduct. This survey should precede any chemical or other analysis. Some of the points to take into account are:
4.3.1 Amounts available
Is the byproduct available in sufficient quantities to make a worthwhile contribution to ration formulation? Gaps can exist between the theoretical availability based on extraction rates and the actual amounts of the material that are produced.
4.3.2 Distribution
Is the by-product available within a reasonable distance from the site of production?
4.3.3 Infrastructure
Is there infrastructure (roads, handling facilities, transport) already in place to deal with the byproduct or will this have to be developed?
4.3.4 Level of technology
Will the byproduct have to undergo any preparatory treatment to make it suitable for inclusion in a ration? If so is the technology available locally to perform this treatment economically? Does it need equipment, investments? What is the cost of the treatment?
4.3.5 Availability
Will the product be available on a year-round basis at a standard price? Beware of seasonal fluctuations which may cause prices to rise to uneconomic levels at certain times of the year; and breakdowns in the supply which may cause changes in the diet formulation.
4.3.6 Toxic substances
Are there any toxic substances present in the product? (This can be determined by chemical analysis.) If so, is it necessary to remove these at the intended level of inclusion in the ration, and if it is, can this be done economically?
4.3.7 Quality
What is the likely nutritional value of the product? This can be determined by chemical analysis and by feeding trials. Will the nutritional quality vary during the year to a degree that might jeopardize its inclusion in a ration?
4.3.8 Alternative uses:
Are there alternative uses for the byproduct which may compete with its utilization as feed? What are the perspectives for such alternative uses?
4.3.9 Cost
In view of all the above points, is the product competitive economically with other available materials? In some cases, when one starts to buy what was previously a waste product, the producer may take advantage of the demand and raise the price to an uneconomic level.
4.4.1 Determination of toxicity (lethal dose)
Biological tests can be done with different animals (ducklings, chicken, egg embyros) to estimate amounts of contaminated byproducts which are safe to utilize as feed ingredients. This method can be applied to determine the efficacy of the detoxification process used for the contaminated produce.
4.4.2 Detection and determination of:
alkaloids
glucosides
goitrogenic substances
4.4.3 Determination of toxic metabolites produced by fungi (eg: Aspergillus and Penicillin)
aflotoxins
penicillic acid
4.4.4 Other tests for harmful substances
Determination of potential toxicity of some mycotoxins produced by fungi. This information helps to establish the best method of preservation to prevent spoilage.
Determination of fungicides and other chemical substances used in plant protection.
Determination of nitrite and nitrate in green plants when large doses of N-fertilizer have been used.
Determination of cyanogenic substances present in some green plants (alfalfa, clover, grasses).
Determination of toxic metabolics produced by bacteria (salmonella strain) as well as presence of salmonella in some products of animal origin.
Determination of some medicaments (eg: coccidiostats) in poultry litter or excrements which are used as feed components.
4.5.1 Ensiling
Use of microbiological or chemical treatments is an effective method for destroying glucosides, alkaloids and some mycotoxins.
4.5.2 Ammonification
This is a very effective method for destruction of aflatoxins.
4.5.3 Use of high temperatures
Autoclaving or drying processes can be applied to animal byproducts and some oilseeds (eg: soybean, rapeseed).
