THE ROI;E OF SMALL ANIMAL
SPECIES IN -ON
AND FOOD PRODUCTTON’
Rkardo Bressani2
The small, less frequently consumed animal species should be explored as possible cost-saving sources of animal protein fo'or the
Latin American and Casibbean diet. The amino acid content of their meat is comparable to-indeed, slightly bettet than-that of beef, pork, and chicken.
Introduction
Although proteins of vegetable origin can give a diet that has adequate protein in terms of amount, they are generally con- sidered to be low in quality because they lack certain essential amino acids, mainly lysine. Animal proteins, on the other hand, are good sources of these amino acids, as it will be shown. The addition of animal protein, even in small amounts, can effectively improve the quality of a cereal and legume diet. However, the problem is that animal protein, the result of consump- tion and reorganization of vegetable protein in the animal, is more expensive to produce than vegetable, which is the direct product of the plant. Hence it must be sold at a higher price and is less available to low- income populations. Accordingly, there has been interest for some time in promoting the production of protein from the small animal species.
‘Condensed from Pan American Health Organiza- tion, VIII Inter-American Meeting on Foot-and- Mouth Diseaseand Zoonoses Control, PAHO Scientific Publication 316, Washington, 1976, pp. 33-44; also ap pearingin Spanish in Bol Of&nit Panam E?(l), 1977.
2Chief, Food Sciences Division, Institute of Central America and Panama, Guatemala City, Guatemala.
The present paper analyzes the nutritive characteristics of the protein from small animal species as compared with that of species commonly bred for human consump- tion. It also looks at the information available with a view to determining whether or not the minor species offer any substantial advantage over the other species.
The Current Diet
For the purposes of this paper, it is necessary to consider the type of diet con- sumed by the majority of the population in the developing countries. Table 1 presents data from nutritional surveys carried out in the rural population of Guatemala: one of the diet consumed by preschoolers (1) and the other of what the overall population eats (2). The preschool diet is basically made up of 14 foods, among them: cereals (42 per cent of the total weight), starchy foods (19 per cent), grain legumes (15 per cent), vegetables (6.5 per cent), and products of animal origin (close to 4 per cent). The average diet for the overall population includes cereals (57 per cent of the total weight), starchy foods and sugars (6.8 per cent), grain legumes (5.1 per cent), vegeta-
Table 1. Average food consumption per person
per day in rural areas of Guatemala.
Foods
Tortillas
Bread
Beans Coffee Sugar Beef broth Beef Em Vegetables Rice, noodles Fruits Bananas Potatoes Bean soup
Preschool Average for the childrena rural area
(g/day) (g/day)
103.5 496
19.5 40
47.9 50
2.6 -
28.9 53
26.4 -
4.8 40
7.8 17
21.2 63
16.1 16
13.0 19
16.4 26
4.3 14
12.5 -
aFrom Santa Maria Cauquk.
bles and fruits (10.9 per cent), and products of animal origin (18.4 per cent). These data have many limitations, probably among the most important being that they are aver- ages-some individuals will obviously con- sume more than others, while there are many who do not eat any animal protein at all.
Since the young population is most susceptible to nutritional deficiencies, the comments that follow will focus on the preschool diet.
Of the 325 g ingested by this group in a day, 32 per cent is corn and 10 per cent other cereals, with beans following next in importance. proximate analysis of this diet indicates that 210 g (64.7 per cent) is water and 115 g dry matter. ,The latter provides 14 g protein, 2.9 g total fat, 2.6 g minerals, and 455 KCal. The protein efficiency ratio of the diet is 1.58, equivalent to a calculated biological value of 48 per cent. The diet is deficient in both protein and calories (I), and experiments in rats have also shown it to be deficient in vitamins and minerals. The proteins, in turn, are deficient in the essential amino acids lysine and tryptophan (3).
Nor is it an aesthetically attractive diet, especially when animal protein is absent
and the total intake is reduced to mainly corn and beans. Besides, it is a high-bulk, low-energy diet. And it is monotonous and low in palatability-all the more so when one considers that it is eaten morning, noon, and night, day after day, year in and year out.
The general population diet shown in the same table does not differ greatly from this one in terms of the foods included or nutritive quality. But both diets do contain some animal protein and such food is incor- porated in the dietetic habits of the people. These populations should not be expected to continue living on subsistence diets of cereals and legumes. The supply of animal protein must be increased through intensive research aimed at improving productive efficiency in the raising of both large and small animals.
The Desired Diet
A more desirable diet, based on nutri- tional and other considerations, has been proposed based on the existing possibilities (4). This diet, which is described in Table 2, contains 2,217 KCal, 66.25 g protein, and approximately 17 g total fat. It comprises 14 foods, some of which offer appreciable amounts of animal protein. Although the component foods are similar to those des- cribed in Table 1, this diet is nutritionally superior, more attractive, and more worthy of consumption.
Sources of Animal Protein
Bressani l ROLE OF SMALL ANIMALS IN NUTRITION 295
Table 2. Average diet for the population as a whole, Table 3. Some nonconventional animal species
Guatemala, 1970 consumed by man in Latin America.
Foods Consumption
(g/day)
Milk (liquid) 267a
%iT 26
Beef 45
Beans 61
Vegetables 124
Fruits 52
Plantain a4
Potatoes 56
Tortillas 200
Rice 44
Wheat flour 70
Sugar 65
Fat 13
Coffee 4
Nutritional value calories
Protein Fat
Other essential nutrients
2,217 KCal 66.25 g 17 g Sufficient amounts ‘53 g powdered milk.
other species are consumed when they are available. These animals undoubtedly con-
tribute relatively high amounts of meat to the diet when they are plentiful, but popu-
lation growth and uncontrolled hunting have taken their toll and many of these
species may soon be extinct. It is unfortu- nate that no special efforts have been made to preserve and exploit them, with the possible exception of rabbits-which, how- ever, are probably the species least accepted
and consumed by most populations.
Armadillo Guinea pig Rabbit Iguana Lizard Hare Pigeon Badger Capybara
Dasrpls sexcinctw cavia spp.
Osyetolofagus cuniculw Lacerta iguava
Varonux salvator Lepu.s timidus
Columbidae spp.
Cuniculus paca Hidrochaeris hidrochaeti
Chemical Composition
Table 4 shows data on the chemical com- position of meats from various species, large
and small, that are produced commercially. The protein content of the larger species is slightly lower than that of small ones. The most striking difference, however, is in the fat content, which is much higher in the meats of larger animals and contributes
greatly to their energy value. Over all, however, the differences in total protein are minimal and in this sense the nutritional value is similar.
Likewise, in terms of essential amino acid
content there are no differences between the two groups of animals (Table 5). Thus it may also be concluded that their quality of protein is similar and that it has the same
supplementary value.
All this being true, then there is no basis in terms of nutritive value or chemical com- position for selecting or recommending one
Table 4. Protein and fat content and energy value of meats of various animal species.
Meat Protein
(%)
Fat (%)
Energy value
(calories/100 g)
Beef 18.7 18.2 24.4
Pork 17.5 13.2 194
Poultry 18.2 10.2 170
Armadillo 29.0 5.4 172
Guinea pig 19.0 1.6 96
Rabbit 20.4 8.0 159
Iguana 24.4 0.9 112
Table 5. Essential amino acidcontent of meats from various animal species. W m&W
Amino acid
Beef
Type of meat
Milk
Poultry Pork Iguana Rabbit
Arginine 395 348 431
Histidine 213 164 109
Isoleucine 301 334 356
Leucine 507 460 563
Lysine 556 497 625
Methionine 169 157 188
Cystine 80 82 88
Total 249 239 276
349 199 553 607 590 163 -
-
350 230
160 191
340 398
410 581
510 550
190 275
77 20
267 295
Phenylalanine 275 250 288
Tyrosine 225 209 247
Total 500 459 535
705 -
-
220 210 430
313 299 612
Threonine 287 248 319 468 320 263
Tryptophan 70 64 85 67 95 104
Valine 313 318 388 334 400 445
kind of meat over another. The only valid bases would be acceptability of the species by the consumer and/or productive effi- ciency.
Composition of the Diets Consumed by large and Small Animal Species
Table 6 offers data for evaluating the production efficiency of various animals as sources of meat-namely, the protein, fat, and crude fiber content of commercial feeds given to four animal species during the growth, development, and finishing stages. In terms of protein content there are no great differences per species among the higher values corresponding to the needs of the young animal or among the smaller values for adult animals. Nor are there any substantial differences with respect to fat
(although the figures for rabbits and ruminants are lower than those for swine and poultry). But interestingly, the crude fiber content is larger in the feed for rabbits and ruminants than in that for monogastric animals like swine or the one given to poultry. In other words, the diets for swine and poultry contain larger quantities of ingredients with low fiber content than those consumed by rabbits and ruminants.
The data also suggest that the feeds for swine and poultry contain ingredients con- sumed in larger amounts by humans than do those used for rabbits and ruminants. Table 7 provides information from the guarantee labels of feed compounds pro- duced commercially for the different ani- mals. Again it can be seen that the diets for swine and poultry contain ingredients with less fiber than those for rabbits and ruminants. Furthermore, the diets of these
Table 6. Content of various nutrients in commercial feed rations prepared for consumption by four different animal species.
Pork Poultry Rabbit Supplement for
beef cattle
Crude protein 16.5-18.0 21.0 17.0 16.0-24.0
Fat 3.5-4.0 3.5 2.0 2.5
Bressani l ROLE OF SMALL ANIMALS IN NUTRITION 297
Table 7. List of ingredients in feed compounds for four different animal species.
Ingredient Swine Poultry Rabbit Beef cattle
Ground grains
Processed grain byproducts
Proteins of vegetable oripin
Proteins of animal origin
Sugarcane molasses
Fat
Ground forage
Urea
xx xx x x
xx xx x x
xx xx x x
x x - -
x x x x
x x - -
- - xx xx
- - - x
x = concentration present in the diet.
xx = high concentration present in the diet.
latter species contain products derived from ground forages.
More specific data on the nutritional requirements of the four species are shown in Table 8. The need for digestible energy is lower for rabbits and ruminants than for swine and poultry, again suggesting the importance of cereal grains-which are about the best available sources of energy and are also foods consumed by man -in the diets of swine and poultry. The total of digestible nutrients, which is greater for swine and poultry than for rabbits and ruminants, also confirms this observation.
From the foregoing facts it may be concluded that there is need to stimulate the production and supply of meat from rabbits and ruminants, since these species compete the least for types of food that humans eat.
There are other considerations, however, that also enter the picture.
Production Characteristics of Different
Animal Species
Another important point to analyze in regard to sources of animal protein is the
relative production capacity. Comparison will again be made among swine, poultry, rabbits, and beef cattle.
Table 9 shows that food intake varies with animal size and speed of growth. The quan- tities of feed given are small for poultry and rabbits in comparison with swine and ruminants. However, it must be remem- bered that feed for ruminants has a higher fiber content than that for swine. The same difference prevails between poultry and rabbits, the latter having a rather higher feed intake than the former.
Swine need five to six months in order to reach market weight; chickens, eight to 10 weeks; rabbits, four months; and beef cattle, 18 to 24 months. Thus the rate of economic turnover is highest for poultry, next highest for rabbits, lower for swine, and lowest of all for cattle. From this point of view the first two species have a higher yield. Finally, the feed conversion rates
favor poultry, followed by swine, rabbits, and cattle, in that order.
On the basis of these considerations, then, together with the diets that must be fed and the prices fetched for the different meats, in
Table 8. Energy and protein requirements, food intake, and food conversion of four different animal species.
Swine Poultry Rabbit Beef cattle
Digestible energy (KCal/lcg) 3500-3300 3500-3100 2900-2600 2600
Crude protein (%) 18-13 18-13 16 11-13
Total digestible nutrients
Table 9. Production characteristics of four different animal species.
Food intake (g/day)
Conversion ratio
Days until slaughter
Eviscerated carcass (%) Increase/day (g)
Swine Poultry Rabbit Beef cattle
1250-3500 35-100 115-175 7.2-13.7 kg
4.0 2.5 4.0 10
100 70 70 730
52 75 55 50
700 40 32 1000
terms of meat alone rabbits do not offer major advantages over other animal species, but poultry and swine do have certain points in their favor. One of the concerns behind popularizing the production of small animal species has been to have protein from animals other than cattle, which is greatly in demand on the foreign market and therefore beyond the reach of low-income groups. Although it is not universally true, at least in all animal production systems, the economy is based on intensive development of the industry. Moreover, some of the animal species proposed are not the best for the purpose ,because they are not habitually consumed
by many populations.
There are other species that could be considered but that up to the present have been subject to little domestication or efforts to make them productive. One of these- which in time may become extinct-is the native pig.
survive. Recent studies by INCAP have suggested that native pigs may be useful as sources of animal protein and fat, two nutrients that are deficient in the diet of low-income groups. Not only are they less expensive to raise than purebreds, they are also very well known and accepted by precisely those who are most in need nutritionally. Table 10 gives data on the protein needs of native swine in comparison with purebreds. With 6.1 per cent protein in its diet, the native pig could produce much better than the purebred (12). Efforts should be made to preserve this animal, which, as it has been said, is a good source of protein and fat and is well known and accepted by many population groups in Latin America.
Advantages and Disadvantages of the Different Animal Species
This animal, which represents about 80 The facts presented so far indicate that to 90 per cent of the swine population in from the nutritional point of view the meat Latin America, has received little attention derived from the different animal species is even though it has important genetic char- practically the same, whether used alone or acteristics from having become adapted to as a protein supplement. From this stand- conditions in which purebred pigs cannot point there is little advantage in recom-
Table 10. Weight gain, feed intake and feed efficiency of Duroc and native swine fed dieta at two protein levels.=
Swine Protein Weight Feed intake Feed
in diet (%) gain (kg) 0%) efficiency
Duroc 14.6 90.8 288.1 3.17
Native 14.6 59.7 234.7 3.93
Duroc 6.1 31.3 118.6 3.78
Native 6.1 31.4 128.4 4.09
Bressani l ROLE OF SMALL ANIMALS IN NUTRITION 299
mending one species over another. How- ever, there are other considerations. The differences which favor the smaller animal species over the larger are: (a) lower feed intake; (b) rapid growth rate; (c) high feed conversion rates; and (d) larger number of animals per unit area. Between poultry and rabbits, the former requires more cereals in the diet and does not eat as much fiber. However, poultry is more accepted and already forms an integral part of people’s diets, whereas rabbits and similar animals are much more rarely consumed. Both animals can be kept in or near the home, as is the custom in rural areas. Rabbits offer advantages over poultry in that their skin is also utilized. On the other hand, poultry also provides eggs, which are another animal protein of high nutritional quality.
These arguments may not be sufficiently persuasive, however, to get people to change their traditional dietary habits. In view of this problem, as well as the pressure of an annually increasing population that must be fed, efforts should also continue toward improving the protein quality of vegetable sources, encouraging supplementation of the current diet with even the smallest amounts of animal protein, and increasing productive efficiency with conventional livestock through the selection of improved strains, disease control, proper animal nutrition, the development of comprehen- sive and intensive production systems for both large and small animal species, and finally, utilization of Latin America’s natural resources for feeds that will not compete with human nutrition.
SUMMARY
While a diet of high protein value can be achieved from vegetable resources, the supple- mentary effect of protein of animal origin is undeniable. Its higher cost, however, places it beyond the reach of large sectors of the popula- tion in Latin America and the Caribbean area. Following a discussion of the current diet consumed by the majority of the population in most countries of the Hemisphere, which consists largely of grains and legumes, consideration is given to the possible use of smaller species that offer a more favorable food-meat conversion ratio. Comparison of the meat from several non- conventional species such as the armadillo,
guinea pig, rabbit, and iguana against beef, pork, and chicken reveals virtually no difference in amino acid content, although the familiar foods are somewhat higher in fat, and hence energy value. The smaller animal species offer
the advantages of: lower feed intake coupled with higher feed conversion rates, increased turnover because of their faster growth, and the possibility of raising larger numbers of animals per unit of land area. However, habit is a strong force to contend with, and the arguments cited may not be sufficiently persuasive to convince people to include such species in their diets.
Attention must continue to be addressed to improving the protein quality of vegetable sources, encouraging supplementation of the traditional diet with even the smallest amounts of animal protein, and increasing regular livestock production through disease control, the introduction of more resistant strains, the adoption of comprehensive production systems, and the development of high-quality, low-cost feeds from sources that do not compete with human nutrition.
REEERENCES
(I) Murillo, B., M. T. Cabezas, and R. mala City, Ministerio de Salud Ptiblica y Asis- Bressani. Influencia de la densidad cal6rica tencia Social, Instituto de NutriciBn de Centro sobre la utilizacidn de la proteina en dietas ela- America y Panama, and Oficina de Investigacio- boradas a base de maiz y frijol. Arch Latinoam nes Internacionales de 10s Institutos Nacionales
Nutr 24:223-241, 1974. de Salud (U.S.A.), 1969.
diets of low nutritive value through the use of fortified maize and Opaque-2 maize. In: R. Bressani, J. E. Braham, and M. Behar (eds.), National Imjwovement of Maize. Guatemala City, Institute of Nutrition of Central America and Panama, 1972. pp. 256-272.
(4) Flores, M. Personal communication.
(5) Elias, L. G., R. Jarqufn, R. Bressani, and C. Albertazzi. Suplementacibn de1 arroz con concentrados proteicos. Arch Latinoam Nub
l&27&3, 1968.
(6) Bressani, R., and E. M. de Villarreal. Nitrogen balance of dogs fed lime-treated corn supplemented with proteins and amino acids. J Food Sci 28611-615, 1963.
(7) Goyco, J. A., and C. F. Asenjo. La suplementaci6n de la racidn rural puertorrique- iia con protetna de pescado. Arch Latinoam Nutr 17:241-251, 1967.
(8) Lee, Chung-Ja, J , M. Howe, K. Carlson, and H. E. Clark. Nitrogen retention of young men fed rice with or without supplementary chicken. Am J Clin Nutr 24:318-323, 1971.
(9) Braham, J. E., M. Flores, L. G. Elias, S. de Zaghi, and R. Bressani. Mejoramiento de1 valor nutritivo de dietas de consumo humano. II. Suplementacion con mezcla vegetal INCAP 9 y leche. Arch Latinoam Nutr 19:253-264, 1969.
(10) De Souza, N., L. G. ElIas, and R. Bressani. Estudios, en ratas, de1 efecto de una
dieta basica de1 medio rural de Guatemala, su- plementada con leche de vaca y una mezcla de protdnas. Arch Latinoam Nutr 20:293-307, 1970.
(II) Wu Leung, W. T., and M. Flores. Food Composition Table for Use in Latin America. Washington, Institute of Nutrition of Central America and Panama and Interdepartmental Committee on Nutrition for National Defense of the U.S. National Institutes of Health, 1961.
(12) Gdmez Brenes, R., R. Jarquln, J. M. Gonzalez, and R. Bressani. Comparacidn de1 cerdo criollo y Duroc Jersey en cuanto al crecimiento y utilizacidn de1 alimento. Turriab
ba 24:29-34, 1974.
(13) Bressani, R. La situation mundial de ali- mentos. Paper presented at the IX Reunion AsociaciBn Latinoamericana de Fitotecnia (Pa- nama City, 1974).
(14) Bressani, R. Evaluation nutritional de1 maiz Opaco-2 en niiios y adultos. In: Simfiosio sobre Desarrollo y Utilizaci6n de Makes de Alto
Valor Nutritivo. Chapingo, Mexico, Secretarta de Agricultura y Ganaderia, 1973. pp. 21-39.
