Shabbat 141 - The advice of Rav Chisda
The Talmud lists multiple pieces of advice given by Rav Chisda, on frugal diet and abstinence, on keeping the clothes good-looking throughout the year, by buying expensive materials which last longer, and even to his daughters, couched in veiled terms, on the importance of foreplay. All of these, however, have mystical connotations. For example, when Rav Chisda says that he did not eat much vegetables either when he was poor or when he was rich, he means being poor and rich in Torah knowledge. The reason not to indulge in vegetables was that to achieve the tikkun, correction of the souls that are reincarnated in a vegetable, one has to possess the power to elevate them two levels, in the hierarchy of plants-animals-man, whereas for meat one only has to achieve one-step elevation. Today the logic is reversed, and the adverse spiritual effect of meat on our bodies outweighs the needs of the tikkun, so that the student is advised to be vegetarian throughout the week, and eat meat or foul only on Shabbat.
One may put food in front of an animal, but only if it is completely edible and does not have in it an admixture of dirt or remains of other animal's feeding - for then it would be muktzeh - something set aside from Shabbat use.
Similarly, if one has straw on his bed, he may not move it with his hand - because it is muktzeh - but he is allowed to lie down on it or move with his body - for unusual ways to move a muktzeh are permitted. If that straw qualifies as animal fodder, he can move it even with his hand.
Art: Jean-Baptiste-Simeon Chardin - Still life of Vegetables for the Soup