Science Magazine reports that Chinese researchers have decided that silkworms would be the most optimum food source for space travelers on long-distance voyages.
This makes perfect sense, from a logical standpoint. Silkworms produce very little excrement (compared to chickens and cows), and are not very sensitive to disturbances or environmental conditions (unlike fish). Silkworms "breed quickly, require little space and water, and generate only small amounts of excrement, which could serve as fertilizer." The researchers also found that silkworms are surprisingly nutritious - chock full of protein and amino acids. As an added bonus, their silk can also be made edible.
The researchers have determined that every space traveler "would need to consume 170 silkworm pupae and cocoons a day to fulfill their animal protein needs." Which is an off-putting thought indeed, although silkworms are a staple food in some areas of China, and a snack food in Korea.
(You know, there was much talk on Star Trek about how the food replicators worked by "re-sequencing protein matter" and "recycling waste materials" into food. But they never really mentioned where all that protein comes from. Since recycling waste into food is a slowly losing game, the system would require a certain amount of additional input. I wonder if somewhere, deep in the bowels of the ship, a vast room housed the silkworm brooder.)
If you would like to have a taste (so to speak) of the possible future of space travel, canned silkworms can be purchased over the internet. Steve of "Steve, Don't Eat It" fame, once tried eating a can of silkworms. His report on the experience can be found here.