Broth made from meat is not a violation of the Lenten rules of abstinence.
Abstinence laws consider that meat comes only from animals such as chickens, cows, sheep or pigs—all of which live on land. Birds are also considered meat. Abstinence does not include meat juices and liquid foods made from meat. Thus, such foods as chicken broth, consommé, soups cooked or flavored with meat, meat gravies or sauces, as well as seasonings or condiments made from animal fat are technically not forbidden. However, moral theologians have traditionally taught that we should abstain from all animal-derived products. . . (USCCB)