Provided are: a feed exhibiting an improved body weight gain effect on organisms to be fed compared with conventional products； a method for manufacturing the same； and a feeding method using the feed. A feed comprising a fermentated product of cassis fruits is used. As the cassis fruits, for example, a residue after squeezing cassis juice can be used. In particular, a fermented cassis product obtained by using koji mold (Aspergillus oryzae) is suitably usable therefor.
