Difference between revisions of "Food"

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The amount of '''Food''' for [[human]] beings that can be brought from [[Earth]] to [[Mars]] is limited, and the logistics of a continued food transport for the long term is [[Financial effort estimation|expensive]]. By definition, an [[autonomous colony]] needs it's own food production. Reasons for this are cost reduction and the achievement of [[independence from Earth]]. Last but not least, locally produced food can be of higher quality and fresh, including a natural mix of [[vitamins]] and [[minerals and trace elements in food|minerals]].
 
The amount of '''Food''' for [[human]] beings that can be brought from [[Earth]] to [[Mars]] is limited, and the logistics of a continued food transport for the long term is [[Financial effort estimation|expensive]]. By definition, an [[autonomous colony]] needs it's own food production. Reasons for this are cost reduction and the achievement of [[independence from Earth]]. Last but not least, locally produced food can be of higher quality and fresh, including a natural mix of [[vitamins]] and [[minerals and trace elements in food|minerals]].
 +
 +
Food on Mars will be produced in [[Greenhouse|agricultural facilities]] that may be greenhouses, grow rooms or biological reactors, and probably a mix of all three.
  
 
==Food requirements==
 
==Food requirements==
−
An average human requires about 2,7 kg of food per day, or 985 kg per year.  A good target might be one tonne of food per year per colonist, to account for losses.  Plants are composed of edible parts and non edible parts.  The non edible portion is counted as biomass, and can be used for industrial production or recycled into the food production system.  On average, of the solid parts of plants (not water) about 50% of a plant is edible and the rest is biomass.  The following table presents a suggested diet based on the Canadian Food Guide.  
+
*An average human requires about 2,7 kg of food per day, or 985 kg per year.  A good target might be one tonne of food per year per colonist, to account for losses.   
 +
*Plants are composed of edible parts and non edible parts.  The non edible portion is counted as biomass, and can be used for industrial production or recycled into the food production system.  On average, excluding water, 50% of the plant is edible mass and the rest is biomass.  The following table presents a suggested diet based on the Canadian Food Guide.
  
 
{| class="wikitable"
 
{| class="wikitable"
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'''food (gram)'''
 
'''food (gram)'''
−
|'''kiloCalorie/kg'''
+
|'''(kilo)Calorie/kg'''
−
|'''Calories'''
+
|'''(kilo)Calories'''
 
per day
 
per day
 
|-
 
|-
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|'''2 294'''
 
|'''2 294'''
 
|}
 
|}
−
Note: Calories as expressed in food guides and nutritional documents are actually kiloCalories.  so the Calories of column 4 in this table are actually kiloCalories.
+
Notes:
 +
*Calories as expressed in food guides and nutritional documents are actually kiloCalories.  so the Calories of column 4 in this table are actually kiloCalories.
 +
*One Kilocalorie = 4184 J.  2294 calories is 9 600 000 Joules, that is about 110 J/s of 110 Watts.
  
 
==Food that can be brought from Earth==
 
==Food that can be brought from Earth==
Line 63: Line 68:
 
*[[:category:plants|Vegetable]] can be grown in [[greenhouse]]s, grow rooms or on [[green wall|green walls]] in order to close the [[carbon cycle]].
 
*[[:category:plants|Vegetable]] can be grown in [[greenhouse]]s, grow rooms or on [[green wall|green walls]] in order to close the [[carbon cycle]].
 
*[[Protein|Proteins]], fat and carbohydrates can be produced by a [[biotechnology|biotechnological factory]] also known as [[biological reactors]].
 
*[[Protein|Proteins]], fat and carbohydrates can be produced by a [[biotechnology|biotechnological factory]] also known as [[biological reactors]].
−
*[[:category:animals|Animals]], such as chicken or [[fish]], may be raised in sections of greenhouses.
+
*[[:category:animals|Animals]], such as chicken or [[fish]], may be raised in sections of greenhouses.  Some can be fed with inedible plant parts, sometimes at reduced efficiency.
−
*It takes 2000 to 3000 liters of [[water]] to produce 1 kg of meat, it  takes 100 liters of water to grow 1 kg of grain. Water will be a very valuable commodity on Mars, so the first generation of settlers may well be vegetarian by necessity.  This may be mitigated by water recycling.
+
*It takes 2000 to 3000 liters of [[water]] to produce 1 kg of meat, it  takes 100 liters of water to grow 1 kg of grain. Water may be a very valuable commodity on Mars, so the first generation of settlers might be vegetarian by necessity.  This may be mitigated by water recycling.
  
 
*Growing [[insects]] and their larvae (e.g. flour worms or [[flies|fly maggots]]) can provide valuable proteins and might consume mostly [[waste biomass recycling|waste biomass‎]].  Pigs might be a more palatable alternative, of fish.
 
*Growing [[insects]] and their larvae (e.g. flour worms or [[flies|fly maggots]]) can provide valuable proteins and might consume mostly [[waste biomass recycling|waste biomass‎]].  Pigs might be a more palatable alternative, of fish.
 
*[[Algae]] can produce large amount of food and oil.  However, is is impossible to survive only on algae alone in the long term(reference needed).
 
*[[Algae]] can produce large amount of food and oil.  However, is is impossible to survive only on algae alone in the long term(reference needed).
 
*Some food (possibly [[Genetic engineering|genetically modified]]) may be grown in the Martian atmosphere. Results from the Phoenix lander indicate that some vegetables may be grown in caves safe from radiation(ref needed).
 
*Some food (possibly [[Genetic engineering|genetically modified]]) may be grown in the Martian atmosphere. Results from the Phoenix lander indicate that some vegetables may be grown in caves safe from radiation(ref needed).
−
*The [[nuclear food cycle]] could produce food and [[oxygen]] using [[nuclear power]]
+
*The [[nuclear food cycle]] could produce food and [[oxygen]] using [[nuclear power]].
  
 
==Nutrition and Energy Calculations==
 
==Nutrition and Energy Calculations==
Line 89: Line 94:
 
|365
 
|365
 
|-
 
|-
−
|Energy per year
+
|Energy per year (E)
 
|kiloca
 
|kiloca
 
|839500
 
|839500
 
|839,500,000
 
|839,500,000
 
|-
 
|-
−
|Yearly energy production
+
|Yearly energy production (p)
 
|kilocal/m2
 
|kilocal/m2
 
|4700
 
|4700
 
|4700
 
|4700
 
|-
 
|-
−
|'''Area to feed humans'''
+
|'''Net area to feed humans (E/p)'''
 
|'''m2'''
 
|'''m2'''
−
|'''179'''
+
|'''180'''
−
|'''178,617'''
+
|'''180,000'''
 
|}
 
|}
 +
*The value of 180 m2 per person is the minimum area with high intensity lighting required to produce the minimum amount of food for one person. 
 +
*In other units, 10 000 m2 (one hectare) / 180 m2 = 55.  So one hectare of intensive agriculture can feed up to 55 people, per year.
 +
*Higher densities can be obtained using hydroponics and shelves or higher levels of lighting and optimized fertilization.  This may  not be sustainable in normal soil.
 +
*Using animals to produce protein would increase the area required, while fish may combine habitats with plants for a null impact on total area.
 +
*Higher levels of production are probably required for storage for Martian winters or sand storms, when food production might stop.
 +
*There is a large uncertainty in these numbers as agriculture on Earth is not an exact science, and no crops have ever been grown on Mars.
 +
*Additional surface allocations should be made for service and storage areas, circulation and maintenance of equipment required for food production. So the gross are might be 200-250 m2/person.
  
 
==Food and crop energy and yields==
 
==Food and crop energy and yields==
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|'''kilocalorie'''
 
|'''kilocalorie'''
 
'''/m2/y'''
 
'''/m2/y'''
−
|'''Notes'''
+
|'''Notes (it is not clear in the data if these areas include service areas, roads, preparation, temporary storage, etc.)'''
 
|-
 
|-
 
|Apples, pears
 
|Apples, pears
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|
 
|
 
|-
 
|-
−
|soya
+
|[[Soybean]]
 
|
 
|
 
|3
 
|3
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|
 
|
 
|-
 
|-
−
|Corn
+
|Flax
 +
|
 +
|1.3
 +
|0,13
 +
|5340
 +
|4100
 +
|For oil, seeds and linen. Calories is for seeds.  Linen fiber not included in yield and is likely higher.  Ref.: Alternative Agriculture, Iowa State university, Flax.
 +
|-
 +
|Hemp
 +
|
 +
|1.3
 +
|0,1
 +
|5530
 +
|4240
 +
|For oil, seeds and hemp fiber. Calories is for seeds.  Hemp fiber yields are about 12 tonnes/h or 1 tonne/h for combined seed/fiber crops.  Ref.: Alberta dept. of agriculture, Canada.
 +
|-|Corn
 
|
 
|
 
|12
 
|12
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|For wood type products
 
|For wood type products
 
|}
 
|}
−
Many of the higher yield in this table are the result of multiple crops per year.
+
*Many of the higher yield in this table are the result of multiple crops per year.
 +
*These a edible food crop yields.  The actual average biomass crop yields are at least double these.  Potatoes are about 80% edible yield while most plants are between 35% and 50%.
  
−
These a edible food crop yields.  the actual biomass crop yields are about double these.  Potatoes are about 80% edible yield while most plants are between 35% and 50%.
+
== Meat production ==
−
 
 
−
==Meat production==
 
 
Meat production may someday be artificial, but may for some time come from [[animals]].  Vegetable alternatives exist for meat,  and usually require less energy for their production.  Therefore producing meat may be a question of demand and opportunity, rather than a question of need.  Animals can produce meat from unused biomass, but the demand for other uses may be higher than the demand for meat production.  
 
Meat production may someday be artificial, but may for some time come from [[animals]].  Vegetable alternatives exist for meat,  and usually require less energy for their production.  Therefore producing meat may be a question of demand and opportunity, rather than a question of need.  Animals can produce meat from unused biomass, but the demand for other uses may be higher than the demand for meat production.  
 
{| class="wikitable"
 
{| class="wikitable"
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|
 
|
 
|}
 
|}
−
[[w:Feed_conversion_ratio|Feed conversion ratio]] (FCR) is a measure of efficiency.  It is the ratio between the mass of feed and the mass of product output.  For dairy cows, for example, the output is milk, whereas in animals raised for meat (such as beef cows, pigs, chickens, and fish) the output is the flesh, that is, the body mass gained by the animal, represented either in the final mass of the animal or the mass of the dressed output (from Wikipedia).  
+
[[w:Feed_conversion_ratio|Feed conversion ratio]] (FCR) is a measure of efficiency.  It is the ratio between the mass of feed and the mass of product output.  For dairy cows, for example, the output is milk, whereas in animals raised for meat (such as beef cows, pigs, chickens, and fish) the output is the flesh, that is, the body mass gained by the animal, represented either in the final mass of the animal or the mass of the dressed output (from Wikipedia).  Feed conversion ratios also vary with the quality of the feed.  A number of animals can eat vegetable products such as fibers and other vegetable parts that cannot be digested by humans.  Therefore some of the food energy for animals will come form the inedible parts of food crops.  
 
{| class="wikitable"
 
{| class="wikitable"
 
|+
 
|+
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*[[w:Beyond_Meat|Beyond meat]], a vegetable meat substitute, may be considered as artificial in some ways, but is more a modified food.  Entirely vegetarian diets are possible.
 
*[[w:Beyond_Meat|Beyond meat]], a vegetable meat substitute, may be considered as artificial in some ways, but is more a modified food.  Entirely vegetarian diets are possible.
 
*[[In-vitro meat]] is possible, but requires large amounts of energy for its production.  Modified vegetables, such as Beyond Meat might produce a better substitute.
 
*[[In-vitro meat]] is possible, but requires large amounts of energy for its production.  Modified vegetables, such as Beyond Meat might produce a better substitute.
 +
 +
==Energy requirements==
 +
Using hydroponics and greenhouses or vertical farms, an average yield of 60 tonnes per hectare per year should be possible (ref).
 +
This corresponds to a yield of 6 kg/m2/y.  If the average illumination is 250 W/m2, then the average energy required for food production is:
 +
*250 W/m2 x 24 x 365 x 3600 / 6kg/m2 = 1300 MJ/kg
 +
*4000 kCal = 16.73 MJ. Then 1300/ 16.73 = 77.  So it takes at least 77 times the energy in the food to produce the food, or an efficiency of about 1.3%, the rest of the energy goes into biomass and heat.
  
 
==See also==
 
==See also==

Latest revision as of 06:51, 29 November 2024

A mix of fresh raw vegetarian food.

The amount of Food for human beings that can be brought from Earth to Mars is limited, and the logistics of a continued food transport for the long term is expensive. By definition, an autonomous colony needs it's own food production. Reasons for this are cost reduction and the achievement of independence from Earth. Last but not least, locally produced food can be of higher quality and fresh, including a natural mix of vitamins and minerals.

Food on Mars will be produced in agricultural facilities that may be greenhouses, grow rooms or biological reactors, and probably a mix of all three.

Food requirements

  • An average human requires about 2,7 kg of food per day, or 985 kg per year. A good target might be one tonne of food per year per colonist, to account for losses.
  • Plants are composed of edible parts and non edible parts. The non edible portion is counted as biomass, and can be used for industrial production or recycled into the food production system. On average, excluding water, 50% of the plant is edible mass and the rest is biomass. The following table presents a suggested diet based on the Canadian Food Guide.
Food, canadian food guide Weight of

food (gram)

(kilo)Calorie/kg (kilo)Calories

per day

Fruit 500 500 250
Vegetables 750 300 225
Protein (meat and beans) 200 4 000 800
Dairy 750 420 315
Grains 240 2 100 504
Oils 40 5 000 200
Total 2 480 925 2 294

Notes:

  • Calories as expressed in food guides and nutritional documents are actually kiloCalories. so the Calories of column 4 in this table are actually kiloCalories.
  • One Kilocalorie = 4184 J. 2294 calories is 9 600 000 Joules, that is about 110 J/s of 110 Watts.

Food that can be brought from Earth

  • Several varieties of dehydrated food.
  • Food that contains large amounts of fat and carbohydrates, such as nuts and dried meats.
  • Concentrated fruit juice.
  • Lightweight, high energy foods with a long shelf-life.

Local Production Methods

  • Vegetable can be grown in greenhouses, grow rooms or on green walls in order to close the carbon cycle.
  • Proteins, fat and carbohydrates can be produced by a biotechnological factory also known as biological reactors.
  • Animals, such as chicken or fish, may be raised in sections of greenhouses. Some can be fed with inedible plant parts, sometimes at reduced efficiency.
  • It takes 2000 to 3000 liters of water to produce 1 kg of meat, it takes 100 liters of water to grow 1 kg of grain. Water may be a very valuable commodity on Mars, so the first generation of settlers might be vegetarian by necessity. This may be mitigated by water recycling.
  • Growing insects and their larvae (e.g. flour worms or fly maggots) can provide valuable proteins and might consume mostly waste biomass‎. Pigs might be a more palatable alternative, of fish.
  • Algae can produce large amount of food and oil. However, is is impossible to survive only on algae alone in the long term(reference needed).
  • Some food (possibly genetically modified) may be grown in the Martian atmosphere. Results from the Phoenix lander indicate that some vegetables may be grown in caves safe from radiation(ref needed).
  • The nuclear food cycle could produce food and oxygen using nuclear power.

Nutrition and Energy Calculations

Calorie calculation
Unit 1 person 1000 persons
Human calorie intake kilocalorie/day 2300 2300000
Days per year 365 365
Energy per year (E) kiloca 839500 839,500,000
Yearly energy production (p) kilocal/m2 4700 4700
Net area to feed humans (E/p) m2 180 180,000
  • The value of 180 m2 per person is the minimum area with high intensity lighting required to produce the minimum amount of food for one person.
  • In other units, 10 000 m2 (one hectare) / 180 m2 = 55. So one hectare of intensive agriculture can feed up to 55 people, per year.
  • Higher densities can be obtained using hydroponics and shelves or higher levels of lighting and optimized fertilization. This may not be sustainable in normal soil.
  • Using animals to produce protein would increase the area required, while fish may combine habitats with plants for a null impact on total area.
  • Higher levels of production are probably required for storage for Martian winters or sand storms, when food production might stop.
  • There is a large uncertainty in these numbers as agriculture on Earth is not an exact science, and no crops have ever been grown on Mars.
  • Additional surface allocations should be made for service and storage areas, circulation and maintenance of equipment required for food production. So the gross are might be 200-250 m2/person.

Food and crop energy and yields

The following table has been compiled from various sources. The values are high but remain bellow record yields and are usually for open field intensive agriculture unless otherwise noted. Most of the energy in plants is stored in the form of carbohydrates, that store about 4000 kilo-calories per kg.

On Mars, these crops could be grown year round, with supplemental artificial lighting, no weather, extra CO2 concentration and optimum irrigation and fertilization. Some Yields might then be significantly higher.

Food and crop yields
Food type Tonnes

/ha/y

kg

/m2/y

kilocalorie

/kg

kilocalorie

/m2/y

Notes (it is not clear in the data if these areas include service areas, roads, preparation, temporary storage, etc.)
Apples, pears Australia 65 6.5 571 3714 https://www.goodfruit.com/calculate-target-yield/
Ontario 25 2.5 580 1450
Oranges, citrus Florida 130 13 470 6110 https://www.hort.purdue.edu/newcrop/morton/orange.html#Yield
Israel 50 5 470 2350 https://www.haifa-group.com/citrus-tree-fertilizer/crop-guide-growing-citrus-trees
Banana Puerto Rico 70 7 1000 7000 https://www.hort.purdue.edu/newcrop/morton/banana.html#Yield
Strawberries England 30 3 330 990 https://vegetablegrowersnews.com/article/tunnels-varieties-double-uk-berry-yields/
California 90 9.0 330 2970 Hydroponic https://cals.arizona.edu/strawberry/Hydroponic_Strawberry_Information_Website/Costs.html
Australia 150 15.0 330 4950 http://www.nuffieldinternational.org/rep_pdf/1450740021NickyMannFinalReport.pdf
Dwarf fruit trees California 72 7.2
Potato UK

US

50

70

5.0

7

850 4250

5950

https://potatoes.ahdb.org.uk/sites/default/files/GB%20Potatoes%202016-2017.pdf

These are for 1 crop per year, 120 days per crop. So it might be possible to reach 200 tonnes/ha for 3 crops per year in intensive agriculture. So 17 000 kilocalories/m2.

Sweden 26 [1] 2.6
Sweet potato california 27 2.7 860 2346 https://ucanr.edu/repository/fileaccess.cfm?article=54045&p=%20MKCWZJ
Tomatoes 150 15.0 180 2700
Water melon 36 3.6 300 1071
Cabbage 90 9.0 250 2250 https://www.kzndard.gov.za/images/Documents/Horticulture/Veg_prod/expected_yields.pdf
Beans 20 2.0 3470 6940 Hydroponic : https://uponics.com/hydroponics-yield/
watercress 25 2.5 110 275 https://ipmdata.ipmcenters.org/documents/cropprofiles/HIwatercress.pdf
Lettuce hydroponic[2] 400 40 150 6000
US 40 4 150 600 Typical field grown
Alfafla (luzerne) Jordan 180

40

18

4

230

290

4140

1160

Hydroponic : https://www.hindawi.com/journals/isrn/2012/924672/

Soil grown : https://wikifarmer.com/alfalfa-harvest-yield-per-acre/

canola 3 0.3 8840 ? 2652
Rice China 17 1.7 1300 2210 http://www.xinhuanet.com//english/2017-10/16/c_136683786.htm
Wheat US-Europe 10 1.0 3400 3400 Two crops per year, summer and winter. Often another crop (oats, maize, barley) and wheat
US 150 15 3400 50 000 Maximum theoretical, hydroponic in lab conditions, Bugbee_Monje_LimitsCropProductivity_BioScience_1992.pdf
US 80 8 3400 27 000 NASA[3] This test cites the Bugbee study. Main difference is lower lighting levels. Doubling the lighting increases yields by about 80%.
Canada[4] 5.9
6[5] 0.6
Oats 4.3 0.4 3890 1673
3.2
Barley 7 0.7 3540 2478
Soybean 3 0.3 4460 1338
Flax 1.3 0,13 5340 4100 For oil, seeds and linen. Calories is for seeds. Linen fiber not included in yield and is likely higher. Ref.: Alternative Agriculture, Iowa State university, Flax.
Hemp 1.3 0,1 5530 4240 For oil, seeds and hemp fiber. Calories is for seeds. Hemp fiber yields are about 12 tonnes/h or 1 tonne/h for combined seed/fiber crops. Ref.: Alberta dept. of agriculture, Canada.
12 1.2 960 1152
Fodder Corn Canada[4] 50 5
Bamboo[6] 4 For wood type products
  • Many of the higher yield in this table are the result of multiple crops per year.
  • These a edible food crop yields. The actual average biomass crop yields are at least double these. Potatoes are about 80% edible yield while most plants are between 35% and 50%.

Meat production

Meat production may someday be artificial, but may for some time come from animals. Vegetable alternatives exist for meat, and usually require less energy for their production. Therefore producing meat may be a question of demand and opportunity, rather than a question of need. Animals can produce meat from unused biomass, but the demand for other uses may be higher than the demand for meat production.

Energy in meat and meat products and dairy products.
Food type kg

/m2

kilocalorie

/kg

kilocalorie

/m2

Notes
Meat 5000
fat 9000
protein 4000
Salmon 2080
Tilapia 1290
chicken 2390
milk 420
Eggs 1550

Feed conversion ratio (FCR) is a measure of efficiency. It is the ratio between the mass of feed and the mass of product output. For dairy cows, for example, the output is milk, whereas in animals raised for meat (such as beef cows, pigs, chickens, and fish) the output is the flesh, that is, the body mass gained by the animal, represented either in the final mass of the animal or the mass of the dressed output (from Wikipedia). Feed conversion ratios also vary with the quality of the feed. A number of animals can eat vegetable products such as fibers and other vegetable parts that cannot be digested by humans. Therefore some of the food energy for animals will come form the inedible parts of food crops.

Feed conversion ratios
Livestock FCR
Beef 4.5–7.5 calculated on live weight gain[7]
Dairy
Pigs 3.8-4.5 About 1 for piglets, grows higher and higher with time[8]
Sheep 4-6, 40 4-6 on grain, 40[9] on straw. This is an example of the difference between the production from high value food and the production

from lower value biomass.

Poultry 1.6-2 A hen can lay up to 330 eggs per year. Maturation is about 40 days.

Note than hens and many birds may require gravity for feeding/drinking, and transportation to Mars may be a problem.[10]

Criquets 0,9-1.0 Seems unlikely to be below 1....[11]
Fish 1-1.5 Tilapia is 1[12]. Salmon about 1,3[13]. Higher for fish to fish conversion, almost 4 in many piscicultures.
Rabbits 2.5-3

Artificial food

There is no existing complete food than might be considered artificial.

  • See vitamins for the basic vitamin requirements that need to be obtained from food.
  • Industrial proteins and carbohydrates are not produced directly from base chemicals but require biological reactors. There are a number of experiments being done to produce artificial food from the output of biological reactors, but these have not, to this time(2019), been proven to be more economical that naturally produced food.
  • Beyond meat, a vegetable meat substitute, may be considered as artificial in some ways, but is more a modified food. Entirely vegetarian diets are possible.
  • In-vitro meat is possible, but requires large amounts of energy for its production. Modified vegetables, such as Beyond Meat might produce a better substitute.

Energy requirements

Using hydroponics and greenhouses or vertical farms, an average yield of 60 tonnes per hectare per year should be possible (ref). This corresponds to a yield of 6 kg/m2/y. If the average illumination is 250 W/m2, then the average energy required for food production is:

  • 250 W/m2 x 24 x 365 x 3600 / 6kg/m2 = 1300 MJ/kg
  • 4000 kCal = 16.73 MJ. Then 1300/ 16.73 = 77. So it takes at least 77 times the energy in the food to produce the food, or an efficiency of about 1.3%, the rest of the energy goes into biomass and heat.

See also

References

  1. ↑ Press release from Statistics Sweden and Swedish Board of Agriculture
  2. ↑ Comparison of Land, Water, and Energy Requirements of Lettuce Grown Using Hydroponic vs. Conventional Agricultural Methods Guilherme Lages Barbosa,1 Francisca Daiane Almeida Gadelha,1 Natalya Kublik,1 Alan Proctor,1 Lucas Reichelm,1 Emily Weissinger,1 Gregory M. Wohlleb,1 and Rolf U. Halden1,2,*
  3. ↑ Continuous Hydroponic Wheat Production Using A Recirculating System C. L. Mackowiak L. P. Owens C. R. Hinkle The Bionetics Corporation, Kennedy Space Center, Florida
  4. ↑ 4.0 4.1 https://ourworldindata.org/yields-and-land-use-in-agriculture
  5. ↑ Report from State of Sweden
  6. ↑ http://afribam.com/index.php?option=com_content&view=article&id=49:bamboo-for-plantations&catid=22&Itemid=116
  7. ↑ Beef production feed rate https://web.archive.org/web/20190805235813/https://lib.dr.iastate.edu/cgi/viewcontent.cgi?referer=https://en.wikipedia.org/&httpsredir=1&article=1027&context=driftlessconference
  8. ↑ Pig FCRhttps://web.archive.org/web/20150917051750/http://www.pigprogress.net/Breeding/Sow-Feeding/2009/4/Taking-control-of-feed-conversion-ratio-PP005927W/
  9. ↑ Cronjé. P. B. and E. Weites. 1990. Live mass, carcass and wool growth responses to supplementation of a roughage diet with sources of protein and energy in South African Mutton Merino lambs. S. Afr. J. Anim. Sci. 20: 141-168
  10. ↑ https://finchwench.wordpress.com/2011/09/06/cosmoquails/
  11. ↑ http://buglady.dk/wp-content/uploads/2015/02/van-Huis-2013-Potential-of-insects-as-food-and-feed.pdf
  12. ↑ https://web.archive.org/web/20151106233121/http://www2.ca.uky.edu/wkrec/TilapiaTankCulture.pdf
  13. ↑ http://www.fao.org/fishery/culturedspecies/Salmo_salar/en
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