Since most indexing services provide abstracts free of charge, the abstract is especially important because it is generally the first contact a potential reader has with your paper.
It is important to provide the reader with an abstract that contains an accurate description of the content of the paper and which stimulates the reader to go to Scielo to read and/or obtain a copy of the paper. Hopefully, the reader will cite your paper. The problem is that the abstract cannot have more than 250 words and thus each word must be weighed carefully.
In one paragraph without subheadings, references or undefined abbreviations the abstract should contain:
1. A statement of justification and the objective(s) of the research and justification.
2. A description of the most important method(s) used.
3. Identification of the experimental species studied: age, weight, sex if relevant, and the number of subjects in each experimental group.
4. A report of the most important statistically significant new results (not necessarily all results), preferably in numerical form reporting both control and experimental values.
5. A closing statement with a conclusion which is not simply a restatement of the results.
These suggestions are meant to provide an accurate statement of the content of your paper. They will stimulate serious scientists to read the paper. Please do not worry about giving away your results - ethical scientists will give you credit for your work.