Nicotinamide in relation to dietary nicotinic acid and nine other vitamins and larval development of Ceratitis capitata (Diptera: Tephritidae).
This study was undertaken to understand why Ceratitis capitata larvae reared on a diet fortified with nine vitamins except nicotinic acid had 100% mortality, while those reared on a 10-vitamin-free diet had 66% survival (Chang, C. L.; Li, Q. X. Ann. Entomol. Soc. Am. 2004, 97, 536-540). Our results showed that nicotinamide was detected at a level of 0.07 microg/g in second-instar larvae reared on the 10-vitamin-free diet and 0.30 microg/g in the corresponding spent diet, while it was not detected in either the larvae reared on the diet fortified with 707 microg/g of nine vitamins (nicotinic acid absent) or the corresponding spent diet. Nicotinamide was detected at concentrations of 0.13 and 0.15 microg/g in the larvae fed the diets that were fortified with 707 microg/g of nine other vitamins and 2 and 20 microg/g of nicotinic acid, respectively, but it was not found in the larvae fed the 0.2 microg/g of nicotinic acid diet. Nicotinamide was detected at concentrations of 0.44, 0.52, and 0.55 microg/g in the spent diets that were fortified with the nine vitamins (707 microg/g) and 0.2, 2, and 20 microg/g of nicotinic acid, respectively. Nicotinamide adenine dinucleotide (NAD) was in the live larvae, but not in the dead larvae. These findings indicate that dietary nicotinic acid is converted to nicotinamide, which, in turn, is used to synthesize NAD, and suggest a positive relationship between C. capitata larvae survival rates and concentrations of dietary nicotinic acid and nitcotinamide in the larvae as well as in the spent diets. The result shows that nicotinamide derived from supplemental nicotinic acid is essential for the development and survival of C. capitata larvae. Nicotinamide may be a biomarker for larval survival and development.