Celss nutrition system utilizing snails

Acta AstronauticaVol. 29, No. 8, pp. 645-650, 1993 Printed in Great Britain.All rights reserved

0094-5765/93 $6.00+ 0.00 Copyright © 1993PexsamonPress Ltd

CELSS NUTRITION SYSTEM UTILIZING SNAILSI" Y. MIDORIKAWA JGC Corp., Project Development, 2-2-10htemachi-chi, Yodaku, Tokyo 100, Japan

T. FuJII JGC Corp., Planning and Business Development Office,2-2-I Ohtcmachi-chi,Yodaku, Tokyo I00,Japan A. OHtRA Institute of Highland Agriculture, Tokyo, Japan and K. NITTA National Aerospace Laboratory, Space Technology Research Group, Tokyo, Japan

(Received for publication 3 February 1993) Abstract--At the 40th IAF Congress in Malaga, a nutrition system for a lunar base CELSS was presented. A lunar base with a total of eight crew members was envisaged. In this paper, four species of plants---rice, soybean, lettuce and strawberry--were introduced to the system. These plants were sufficient to satisfy fundamental nutritional needs of the crew members. The supply of nutrition from plants and the human nutritionalrequirements could almost be balanced. Our study revealed that the necessaxyplant cultivation area per crew member would be nearly 40 m3 in the lunar base. The sources of nutrition considered in the study were energy, sugar, fat, amino acids, inorganic salt and vitamins; however, calcium, vitamin B2, vitamin A and sodium were found to be lacking. Therefore, a subsystem to supply these elements is of considerable value. In this paper, we report on a study for breeding snails and utilizing meat as food. Nutrients supplied from snails are shown to compensate for the abovementioned lacking elements. We evaluate the snail breeder and the associated food supply system as a subsystem of dosed ecological life support system.

1. BACKGROUND~

At the 40th I A F Congress, Malaga, Spain (1989), we proposed a food system for lunar bases [1]. The system consisted of four kinds of plants--rice, soybean, lettuce and strawberry. This system supplies sufficient nutrition for the lunar crew members, with the exception of vitamin B2, calcium, sodium chloride and other minerals. Most people need food supplied both from plants and animals. Only "vegetarians" are satisfied with a diet consisting solely of foods of plant origin. In this paper we propose a new idea, which is to include an escargot (snail) breeder as a food supply subsystem in a lunar CELSS. We have been operating an escargot breeding system for 7 years under controlled conditions, utilizing artificial feed for the escargots. Escargots have been eaten by Europeans for a long time. We believe that escargots will offer an effective source of nutri-

ents for crew members in a future lunar base and on long interplanetary missions.

2. DESCRIPTION OF THE F_SCARGOT

In this study, we use the word "escargot" since it suggests snails for food. The escargots utilized are of the Bourgogne species. Its scientific name is Helix pomatia L. The first batch of escargots was imported from Europe to our laboratory 7 years ago and they have now multiplied to about 400,000 escargots. Figure 1 shows our laboratory and a typical escargot. Snails belong to the phylum Mollusca [2], as does the cuttlefish, and to the class Gastropoda, which includes the scallop. Snails have lungs and perform pulmonary respiration. They are one of the land shells that evolved into many forms.

tPaper IAF/1AA-91-576presented at the 42nd Congress of the International Astronautical Federation, Montreal, Canada, 7-11 October 1991. :~The list of symbols is given in the Appendix at the end of this paper. 645

3. METHOD OF STUDIES

(1) Analysis of nutrition supplied from escargots. (2) Study of CELSS for a lunar base, including an escargot subsystem [l].

646

Y. MIDORIKAWA et al. Table 1. Nutrient composition of escargot; Helix pomatia L. Energy, protein, lipids, carbohydrate and ash Energy (kcal) Moi (g) Prot (g) Fat (g) Carb.H. (g) Ash (g)

Meat 66 83.0 11.4 0.5 3.9 1.2

Spawn 37 85.8 4.3 0.2 4.5 5.2

Shell 0.6

87.4

Table 2. Nutrient composition of escargot; Helix pomatia L. Minerals (all values in rag) Meat

Ca P Na K Mg S

Se Mo I

F Cu Zn CI

550 212 62 93 48 180 0.01 ND ND 0.6 1.2 2.1 52

Spawn

Shell

110 500 26 13

34,400 0.4 43 79 42

Table 3. Nutrient composition of escargot; Helix pomatia L. Vitamins Meat

Fig. 1. The breeding laboratory of escargot and a typical escargot (Helix pomatia L.). (3) S t u d y o f m a t e r i a l b a l a n c e in a f o o d a n d w a s t e system. (4) Biological s t u d y o f e s c a r g o t s u n d e r m i c r o gravity c o n d i t i o n s . (5) D e v e l o p m e n t o f a n e s c a r g o t b r e e d e r f o r a s p a c e vehicle. (6) D e v e l o p m e n t o f a n e s c a r g o t b r e e d e r w i t h a food processor. 4. STUDIES T a b l e s 1 - 4 s h o w the results o f a n u t r i t i o n a l a n a l y sis o f m e a t , s p a w n , a n d shell o f a n e s c a r g o t b r e d in o u r l a b o r a t o r y . V i t a m i n B E a n d c a l c i u m exist in a b u n d a n c e in e s c a r g o t m e a t , as d o e s c a l c i u m in the shell o f the e s c a r g o t . Figure 2 shows nutrients supplied from four kinds o f p l a n t s (rice, s o y b e a n , lettuce, a n d s t r a w b e r r y ) a n d e s c a r g o t s . It also s h o w s t h a t v i t a m i n B 2 a n d c a l c i u m are effectively s u p p l e m e n t e d b y e s c a r g o t s , a l t h o u g h s o d i u m r e m a i n s insufficient a n d m u s t be s u p p l i e d f r o m t h e outside.

Vit. A R.E. (/~g) Carot (#g) Efect. A. (IU) Vii. B~ (rag) Vit. B2 (mg) Vii. B6 (#g) Vit. B12 (#g) Nia (mg) Pat. A (mg) Bio (gg) Fol. A (#g) Vit. C (rag) Vit. D (IU) Vit. E (mg)

8.4 53 57 0.15 0.55 0.14 4.9 1.40 0.40 7.9 9.0 0 50 ND

Table 4. Nutrient composition of escargot; Helix pomatia L. Amino acids (all values in g) Meat

Arg Lys His Phe Tyr Ileu Met Val Ala Gly Pro Glu Ser Thr Asp Try Cys Lco

0.95 0.97 0.37 0.70 0.59 0.64 0.23 0.76 0.74 1.00 0.61 1.89 0.71 0.67 1.54 0.23 0.20 1.10

CELSS nutrition system utilizing snails Blank area ~ m:e Soy Bran Lm~ Stnmemy

lul~ly from the IJlntll

647

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" His. lieu. Leu. Met. Phil. Thr. Try. Val. Lys. "' Vitamin A, B1, NIo, C. "t'* P, Fe, K, Mg, Mn, Zn, Cu.

Fig. 2. Nutrients supplied by snails. In our previous study, which considered rice, soybean, lettuce, and strawberry, the following quantities of each element were lacking: Calcium 215 rag/crew member/day Sodium 1079 rag/crew member/day Vitamin B2 0.6 mg/crew member/day. Regarding vitamin A, 1000 IU per crew member per day is supplied; however, this level is slightly lower than the optimum required quantity. If the snail subsystem provides 110 g of edible parts per crew member per day, which is equivalent to four to five mature snails, the quantity supplied of each nutrient element is as shown below: Calcium 590 mg/crew member/day Sodium 70 rag/crew member/day Vitamin A 57 mg/crew member/day Vitamin B2 0.6 rag/crew member/day. A sufficient supply of calcium and vitamin B2 is effectively achieved. It is very difficult to obtain calcium and vitamin B2 from plants because the amount of those elements contained therein is small.

Since snails, on the other hand, are animal and land shell, they have particularly large content of calcium and vitamin B2. Figure 3 shows the material balance of food and waste in the CELSS facility incorporating the escargot subsystem. The gathering of wild species of snails is seen worldwide, but breeding snails artificially is a new technology. Artificially bred snails are usually fed raw plant parts; we have su___oc,~d_ed, however, in breeding snails in a controlled environment by supplying artificial feed. Large numbers of snails can be bred in a limited space. In the CELSS facility in the lunar base, it will be possible to feed to the snails the inedible parts of plants. The quality of inedible plant parts available and the quantity of necessary feed for the snails are well matched. Figure 4 shows an escargot returned from space. Five snails and spawn were launched on 18 May 1991, on the Soviet Soyuz rocket and remained in the space orbital station Mir for 1 week. They returned to Earth on 26 May 1991. The snails and spawn are now being studied in our laboratory.

648

Y. M1DORIKAWAet

al.

Four Species of Plant Total Biomass

Unit in g / crewmember day

3568

Human Edible 985

Human Inedible 2583

!

_ _ 1 _ _

Feed for Snails 69O

Waste 1893

Snails Human Edible 110

Human Inedlble 28

Excretion 224

Energy Consumption 318

1r

Fig. 3. Material balance in food/waste system. Figure 5 shows a life support block diagram of the breeder. The breeder will integrate a snail chamber, a food processing section, utility storages, and a monitor/record unit. A floor area of about 1 m 2 is required for the snail breeder for eight crew members. They can be of

closed type, if necessary. In addition to supplying nutrients, an advantage of breeding snails is that the snails can be considered to be the crew member's pets, and instrumental in maintaining their psychological well being. The spawn of snails is excellent in taste and rich in nutrients. By including cooked snails in

Fig. 4. An escargot that flew in space.

CELSS nutrition system utilizing snails

649

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~

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Air Inlet

Monitor Air Outer

~ r

i

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Fmd

Water

Storage

Storage

weln

-I Waste

Food Storage

Processor

Freezer Power

Automatic Mode

Manual Mode By Crew

Contr~

Remote Operation Mode from Ground Fig. 5. Life support block diagram of the breeder.

the crew's menu, their diet will be enriched and the c o m f o r t o f lunar life enhanced. The shell o f the snail can even be used as dishware, as well as being an additional source o f calcium. The snail breeding system that has been developed and o p e r a t e d by the a u t h o r s is, f r o m the viewpoint o f providing lacking nutrient elements and recycling inedible parts o f plants, fully compatible with the nutrition supply system based on the four species o f plants.

REFERENCES

1. Y. Midorikawa, T. Fujii, M. Terai, K. Omasa and K. Nitta, A food/nutrient supply plan for lunar base CELSS. 40th IAF Congress, Malaga (1989). 2. M. Azuma, Natural Color Picture Book of Landshells in Japan. Hoikusha, Japan. 3. A. Ohira, Y. Midorkawa, T. Fujii and K. Nitta, Conceptual design of snail breeder aboard space vehicle.

21st International Conference on Environmental Science, San Francisco, Calif. (1991). 4. Weekly foods of the world. Asahi Encyclopedia No. 11 0981).

APPENDIX

Symbols Moi Prot Fat Carb.H.

= moisture = proteins -- fat and oil = carbohydrate

Vitamins Vit. A = Vitamin A R.E. = Retinol Carot = carotene Efect. A = effective Vitamin A Vit. B~ = Vitamin Bn, thiamine Vit. B2 = Vitamin B2, riboflavin Vit. B6 = Vitamin B6, pyridoxine Vit. Bp = Vitamin Bn2, cobalamine Nia = niacin Pat. A = pantothenic acid Bio = biotin Fol. A =folic acid Vit. C = Vitamin C, ascorbic acid Vit. D = Vitamin D, tocopherol Vit. E = Vitamin E

Amino acids Arg = Lys = His = Phe = Tyr = IIeU= Met = Val = Ala = Gly = Pro = Glu = Ser = Thr = Asp = Try = Cys = Leu =

arginine lysine histidine phenylalanine tyrosine isoleucine methionine valine alanin¢ glycine proline glutamic acid serine threonine aspargic acid tryptophane cystine leucine

Y. MIDORIKAWA et al.

650

Minerals Ca P Na K Mg S

= = = = = =

calcium phosphorus sodium potassium magnesium sulphur

Se Mo I F Cu Zn Cl

= = = = = -=

sclcn molybdenum iodine furrus copper zinc chloride.