Protein-rich Diets: Feed as Well as Food

富含蛋白质的食谱：饲料与食物

As demand for protein grows, what people eat matters. So does what gets fed to animals

随着人们对蛋白质需求的增长，吃什么变得很重要。给动物喂什么也同样重要

Between now and 2050 the planet’s population is expected to rise by a third, from 7.6bn to 9.8bn. Those extra mouths will need feeding, and not just with staples. As people grow richer, their demand for protein rises, particularly for meat and fish. Beef consumption in Asia, for example, is expected to jump by 44% over the next decade alone. 

从现在到2050年，全球人口预计将增长三分之一，从76亿增至98亿。这些新增人口需要养活，且不能光靠主粮。随着人们越来越富裕，蛋白质尤其是肉类和鱼类的需求上升。例如，仅在未来十年，亚洲的牛肉消费量预计就将增长44%。

Raising animals to be eaten already has huge effects on the world’s environment. The number of farm animals soared during the 20th century. More than 20bn chickens, 1.5bn cattle and 1bn sheep are alive today. A quarter of the world’s land is used for grazing them. They consume 30% of the world’s crops. They guzzle water – you need about 15,000 litres of the stuff to produce a kilo of beef, compared with only 1,500 litres for a kilo of maize or wheat. And their eructations do nothing for the climate. Livestock are responsible for 14.5% of all anthropogenic greenhouse gases, according to the UN Food and Agriculture Organisation (FAO).

饲养肉用动物已对世界环境产生了巨大的影响。二十世纪，农场动物（家禽家畜）数量剧增。目前全球有超过200亿只鸡、15亿头牛和10亿只羊。饲养这些禽畜占用了世界上四分之一的土地，消耗了全世界30%的农作物。它们还大量消耗水资源——每生产一公斤牛肉大约需要1.5万升水，而生产一公斤玉米或小麦只需1500升。这些动物的嗳气也对气候毫无益处。联合国粮农组织称，牲畜造成了14.5%的人为温室气体。

How then may the planet be fed sustainably? One set of answers revolves around convincing people to put different things on their plates. Vegetarians have the simplest solution of all, but try telling people in sub-Saharan Africa that they should stick to cassava. Encouraging people to eat more fish rather than more meat is a better answer. Human consumption of fish has now overtaken that of beef, and aquaculture accounts for half of all the fish people eat. But almost 90% of wild stocks are fished either at or beyond their sustainable limits. And farmed fish, particularly salmon, are often fed on smaller fish that themselves are caught at sea. A fashionable idea is for Westerners to eat more insects, which contain up to three times as much protein as beef and already form an integral or supplementary part of up to 2bn people’s diets, according to the FAO. But for that to happen, many will have to get over the “yuck” factor.

那么，怎样才能可持续地为人类提供食物？有一套应对方案围绕着说服人们吃不同的食物展开。素食者的解决办法最简单，不过试试告诉撒哈拉以南非洲的人们应该只吃木薯会怎样。更好的答案是鼓励人们多吃鱼而不是多吃肉。人类对鱼类的消费量现在已超过牛肉，而这些鱼有一半来自水产养殖。然而，近90%的野生鱼类的捕捞量已达到或超过了可持续的限度。养殖鱼类，特别是三文鱼，经常被喂食从海里捕获的小鱼。一个时兴的想法是让西方人多吃昆虫。昆虫的蛋白质含量是牛肉的三倍，而且根据粮农组织的数据，昆虫已经成为20亿人饮食中不可或缺的部分或他们的补充食物。但要实现这一点，许多人将必须克服“恶心”的感觉。

Another set of answers involves using technology to create artificial protein. Investors such as Bill Gates and Richard Branson have backed artificial-meat startups that grow beef and poultry from animal cells. Tyson Foods, a meat processor, is an unlikely fan of plant-based proteins. Scientists are also looking at genetic modifications to animals – to increase the muscle of cattle or to reduce infections among farmed fish.

另一系列答案涉及到运用技术来创造出人工蛋白质。比尔·盖茨和理查德·布兰森等投资者都资助了人造肉方面的创业公司，这些公司通过动物细胞培育牛肉和禽肉。出乎意料的是，肉类加工企业泰森食品公司也是植物性蛋白质的支持者。科学家们也在研究针对动物的基因改造技术，以提高牛的肌肉量或减少养殖鱼类的感染。

Innovations such as these have enormous potential, if they can be industrialised and win over wary consumers. But changing what humans eat is not the only route to feeding a growing population more sustainably. Another, less obvious, approach is to alter what animals themselves eat. It is here that technology may have the biggest impact soonest.

如果这样的创新能够工业化并赢得谨慎的消费者的支持，它们就有巨大的潜力。但是，要以更可持续的方式养活日益增长的人口，改变人类的饮食并非唯一途径。另一个不那么显而易见的方法是改变动物的饲料。正是在这方面，技术可能会以最快的速度产生最大的影响。

One source of improvement lies in the more efficient use of crops to feed animals. The proliferation of mills that process grain into feed is helping in places such as sub-Saharan Africa, for example. Data-intensive farming is helping improve agricultural yields of feed crops like soyabeans by carefully monitoring the use of water and fertiliser.

一个改进的途径是更高效地利用农作物来饲养动物。例如，在撒哈拉以南非洲等地，把谷物加工成饲料的工厂数量激增，对这些地区很有助益。通过仔细监测水和化肥的使用，数据密集型农业能帮助提高大豆等饲料作物的产量。

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