MyChemicalBromance wrote...
Joker describes vat-grown meat on human ships, implies it is common. (1:21)
That gives an out for Levo-Amino Acids (Everyone except Quarians and Turians)
(Quoted from ME2 Codex)
There are few wide-open spaces in quarian spacecrafts; liveships are the exception. Each ship is a massive hydroponics facility, growing thousands of tons of genetically modified staple crops under artificial light and in highly enriched soil.
The surface of a liveship is studded with docking bays so as many shuttles as possible can distribute the foods throughout the flotilla on a daily basis. When received, the crops are sterilized with radiation, ground up into nutritious paste, and pumped into quarian suits through feeding tubes. In return, waste products are that could be used as fertilizer or compost are returned to the liveships through an efficient (if odorous) recycling program.
Liveships do not hold animals. The quarians consume a vegan diet, driven not by ethics but by practicality. Captive animals require living space, and consume large amounts of water and plant matter. The quarians cannot afford such an inefficient resource-to-calorie ratio, to say nothing of a live animal's disease or allergen potential. As a result, when the flotilla arrives in a star system where life is based on the same dextro-amino acids that the quarians consume, pastes based on animal proteins fetch highly inflated prices, and the vendors are typically mobbed by quarians wanting a new taste sensation. The sickness that often follows these binges is treated much the same way as hangovers are in human culture; painful, but part of the overall experience of excess.
And that covers Dextros.
You have to consider the concept of biomass. Given that Rannoch is on the other side of the galaxy, it will take the Quarians those two decades to travel from Earth to Rannoch. Without the convenience of mass relays to restock on certain necessities, Quarians will need to institute a strict breeding policy to prevent their biomass supply from running out (in the simplest term, every extra pound of Quarian means there's one pound less of biomass available to grow as food... unless Quarians resort to cannibalism).
The scenario of the Quarians helping feed the Turians (and help them return to Palaven before embarking on a journey back to Rannoch) requires one massive assumption: the production capacity of the Quarian agricultural ships. We don't know how many of the Quarians' civilians hopped off at Rannoch before the fleet jumped to Earth, nor do we know how many Turians there are that need to be fed; nor do we know if, Quarians being Quarians, the agricultural ships' hydroponic facilities were left on Rannoch to feed the still-immune-deficient Quarian civilians.
There are too many assumptions to make regarding the survivability of the dextro-based aliens, but one thing is definite: there is no future for Quarians and Turians on Earth, returning to their homeworld is their only option if their soldiers' wish to return to their normal lives.