No it is not compulsory to go for MBA course to apply for Indian administrative service examination . there is no link between IAS and MBA course . there is no use of doing MBA before IAS examination.

You can apply for IAS examination after passing graduation level degree in any discipline..
Age - limits:
21-30 years as on 1st August of the year of Examination.

Scheme of CS (Preliminary) Examination
The Preliminary Examination consists of two papers of objective type maximum of 400 marks.
General Studies Paper - I 200 Marks
General Studies Paper - II 200 Marks

Scheme - CS (Main)
Paper-I
One of the Indian Languages to be selected by the candidate from the 18 languages included in the VIIIth Schedule to the Constitution (Qualifying Paper) 300 Marks
Paper-II English (Qualifying Paper) 300 Marks
Paper-III Essay 200 Marks
Papers IV & V General Studies (300 Marks for each paper) 600 Marks
Papers VI, VII, VIII & IX
Any two subjects (each having 2 papers) to be selected from the prescribed optional subjects (300 marks for each paper) 1200 Marks
Total Marks for Written Examination 2000 Marks
Interview Test 300 Marks
Grand Total 2300 Marks