1.

2.

3.

4.

5.

6.

7.

output, that babies of undernourished mothers may suckle harder and/or longer at each feed than babies of well-nourished mothers, thereby increasing prolactin levels. 0

opment of Infants from Poor Rural Areas. Ill: Maternal Nutrition and Its Consequences on Fertility. Nutr. Rep. lnt. 7: 1-8, 1973

8. H. Delgado, A. Lechtig, R. Martorell, E. Brine- man and R.E. Klein: Nutrition, Lactation and Postpartum Amenorrhea. Am. J. Clin. Nutr. 31 :

A.S. McNeilly: Effects of Lactation on Fertility. Br. Med. Bull. 35: 151-154, 1979 R.E. Tyson and A. Perez in Nutrition and Hu- man Reproduction. W.H. Mosley, Editor, pp. l l - 27. Plenum Press, New York, 1978 W.H. Mosley, T. Osteria and S.L. Huffman: In- teractions of Contraception and Breast-Feeding in Developing Countries. J. Biosoc. Sci. 4: 93- 1 1 1 , 1977 R.V. Short in Breast-Feeding and the Mother. Ciba Foundation Symposium No. 45, pp. 73-86. Elsevier, Amsterdam, 1976 J.C. Caldwell and P. Caldwell: The Role of Mari- tal Sexual Abstinence in Determining Fertility: A Study of the Yoruba in Nigeria. Popul. Stud. 31 :

M. Singarimbun and C. Manning: Breastfeed- ing, Amenorrhea, and Abstinence in a Javanese Village: A Case Study of Mojolama. Stud. Fam. Plann. 7: 175-1 79, 1976 A. Chavez and C. Martinez: Nutrition and Devel-

193-21 7, 1977

322-327, 1978 9. K. Prema, A.N. Naidu, S. Neelakumari and B.A.

Ramalakshmi: Nutrition-Fertility Interaction in Lactating Women of Low Income Groups. Br. J. Nutr. 45: 461-467, 1981

10. J. Bongaarts: Does Malnutrition Affect Fecun- dity? A Summary of Evidence. Science 208:

1 1 . P.G. Lunn, A.M. Prentice, S. Austin and R.G. Whitehead: Influence of Maternal Diet on Plas- ma-Prolactin Levels during Lactation. Lancet 1 :

12. P.G. Lunn, M. Watkinson, A.M. Prentice, P. Morrell, S. Austin and R.G. Whitehead: Mater- nal Nutrition and Lactational Amenorrhoea. Lancet 1 : 1428-1 429, 1981

13. A. Chavez, C. Martinez, H. Bourges, M. Coro- nado, M. Lopez and S. Basta: Child Nutrition Problems during Lactation in Poor Rural Areas. Proc. Ninth lnt. Cong. Nutrition, Mexico, 1972. Vol. 2, pp. 90-104. Karger, Basel, 1975

564-569, 1980

623-625, 1980

RABBIT: A MEAT SOURCE FOR THE FUTURE?

Rabbits are prolific and can subsist on foodstuffs not competitive with those consumed by man. Their meat is nutritious and low in fat.

Key Words: coprophagy, fiber, protein, non-protein nitrogen, niacin, choline, non-ruminant herbivores

Meat production from non-ruminant herbi- vores, though unconventional, has potential in contributing to the world’s need for high quality protein. The rabbit, kangaroo, quokka, wallaby and hippopotamus have been discussed in this vein.’ A recent editorial paper in the Journal of Applied Rabbit Research has described the rabbit as having great potential in meeting world food needs, particularly in underdeve- loped tropical co~ntr ies.~ In developed coun- tries, the inherent advantages of the rabbit in converting forage material to meat are

outweighed at the present time by the high la- bor intensity of rabbit production. Moreover, few people in the developed countries prefer to eat rabbit meat. In his review, Cheeke2 lists several potential advantages of the rabbit as a future source of proteinaceous food for human consumption.

Rabbits can subsist on high-forage diets that consist largely of ingredients not useful in hu- man food production. Although rabbits digest the fiber portion of forages p ~ o r l y , ~ - ~ they utilize the soluble carbohydrate and protein of forages with a high degree of efficiency. With all-forage diets, feed-to-gain ratios of 3:l have been achieved in rabbits as compared with feed effi-

270 NUTRITION REVIEWSNOL. 40, NO. S/SEPTEMBER 1982

ciencies of about 12:l in beef cattle. Despite the hindgut fermentation activity and active co- prophagy of the soft feces expelled at non-protein nitrogen in the form of urea contrib- utes little to the nitrogen requirement of rab- b i t ~ . ~ ~ ’ ~ Coprophagy has been estimated to fur- nish about 10 percent of the daily protein re- quirement. It likely contributes a much larger portion, but not all, of the requirement of B vita- mins (such as, niacin”) and choline’* deficien- cies have been readily produced in rabbits.

The rabbit’s ability to utilize forage materials is a great potential advantage in tropical coun- tries where lush tropical vegetation abounds and often goes to waste. Rabbits readily eat weeds, vegetable tops and a great array of tropical forage. In underdeveloped tropical countries, there is generally surplus labor, a shortage of food and an abundance of readily useable forage for use as rabbit food. With a few does, a family can have a year-round sup- ply of meat protein. Because of their continu- ous reproduction and rapid growth rate (rabbits reach market weight about eight or nine weeks after birth), rabbit meat could be made avail- able continuously throughout the year. Hence, the meat is literally stored alive, which gives rise to rabbits having been referred to as “bio- logical refrigerators.”2 Needless to say, refrig- eration equipment for meat storage is not readily available in underdeveloped countries.

Unusual in domestic animal production, fe- male rabbits can be bred back on the day of parturition. Hence, it is theoretically possible to have one litter in the uterus, another nursing the doe and still another being raised from weaning (generally at four weeks) to market weight (that is, eight weeks of age). With their rapid growth rate, equal to that of broiler chick- ens, and their capacity to exist in a constant state of reproduction, intensive rabbit produc- tion is possible on a large scale. Moreover, there are many rabbit breeds and, therefore, considerable diversity in productivity traits ex- ists not only between but also within breeds. Genetic diversity ‘such as this portends likely success in breeding and selection programs.

Rabbit meat contains 18.5 percent crude protein and 7.4 percent fat, the latter being con- sidered low when compared with the fat con- tent of chicken, beef and pork.2 Moreover,

unsaturated fatty acids account for more than 60 percent of the total fatty acids, and choles- terol content (1 36 mg per 100 g) is in the range of other meats. The sodium content (393 mg per kilogram) is also considered low relative to beef and pork.

Because of their potential as a meat-produc- ing animal, more research should be undertak- en on economically feasible rabbit production systems, nutritive requirements, breeding schemes, disease control (particularly enter- itis) and on innovative recipes for preparing meat. In the meantime, backyard family rabbit production in forage-rich underdeveloped tro- pical countries offers hope of improving dietary protein quality and quantity for the people of these areas of the world. 0

1. J.T. Reid: Will Meat, Milk and Egg Production Be Possible in the Future. Proceedings of the Cornell Nutrition Conference, pp. 50-63, 1970

2. P.R. Cheeke: The Potential Role of the Rabbit in Meeting World Food Needs. J. Appl. Rabbit Res. 3: 3-5, 1980

3. J.E. Owen: Rabbit Production in Tropical Devel- oping Countries. Tropical Science 18: 203-21 0, 1976

4. L. Voris, L.F. Marcy, E.J. Thacker and W.W. Waino: Digestible Nutrients of Feedingstuffs for the Domestic Rabbit. J. Agr. Res. 61 : 673-684, 1940

5. L.M. Slade and H.F. Hintz: Comparison of Di- gestion in Horses, Ponies, Rabbits and Guinea Pigs. J. Animal Sci. 28: 842-843, 1969

6. H.F. Hintz, H.F. Schryver and C.E. Stevens: Di- gestion and Absorption in the Hindgut of Non- Ruminant Herbivores. J. Animal Sci. 46: 1803- 1807, 1978

7. A. Eden: Coprophagy in the Rabbit: Origin of Night Feces. Nature 145: 628-629, 1940

8. J.F. Herndon and E.L. Hove: Surgical Removal of the Cecum and Its Effect on Digestion and Growth of Rabbits. J. Nutr. 57: 261-270, 1955

9. F. Lebas and M. Colin: Effect of Addition of Urea to a Diet Poor in Protein for Growing Rabbits. Ann. Zootech. 22: 281 -288, 1973

10. J.O.L. King: Urea as a Protein Supplement for Growing Rabbits. Br. Vet. J. 127: 255-265,1971

11. J.G. Wooley: Niacin Deficiency in Rabbits and Response to Tryptophan and Niacin. Proc. SOC. Exp. Biol. Med. 65: 31 5-31 7, 1945

12. E.L. Hove, D.H. Copeland and W.D. Salmon: Choline Deficiency in the Rabbit. J. Nutr. 53: 377-389, 1954

NUTRITION REVIEWSNOL. 40, NO. 9 /SEPTEMBER 1982 271