“Nutritional gill disease” is caused due to deficiency of:

Correct option is C

Correct Answer: (c) Pantothenic acid
Explanation:
→ Deficiency of Pantothenic acid (Vitamin B5) leads to nutritional gill disease in fish.
→ It causes hyperplasia and degeneration of gill tissues.
Information Booster:
→ Affects respiration efficiency and growth.
Additional Information (Other Options):
(a) Vitamin E: Leads to muscular dystrophy.
(b) Iodine: Causes goiter.
(d) Methionine: Protein deficiency symptoms but not gill disease.