Evaluation of potential use of feeder guppies as a source of highly unsaturated fatty acids for high value fishes
H.M.P. KITHSIRI* AND G. VENKATESHWARLU
The present study was carried out to find out whether the fatty acid profiles of mature guppies (Poecilia reticulata) and the resulting fry could be altered through feeding different lipid sources with a view to use them as a highly unsaturated fatty acids (HUFA) enriched feeder fish. Four iso-calorific, iso-lipidic and iso-proteic diets were formulated using coconut oil, sunflower oil, linseed oil, and cod liver oil as lipid sources for preparing Diet-CO, Diet-SO, Diet-LO and Diet-FO respectively. The experimental diets were designed in such a way that each diet had different classes of fatty acids such as saturated fatty acids (SAFA), n-6 poly unsaturated fatty acids (PUFA), n-3 PUFA and HUFA. Three replicates were used for each dietary treatment and the fish were fed twice a day until satiation. The fish fed with Diet-CO were characterized by SAFA, 18:1 n-9, 18:2 n-6 and 20:4 n-6 fatty acids. The fish fed with Diet-SO contained significantly higher amounts of 18:2 n-6, 18:3 n-6, 20:3 n-6, 20:4 n-6, 22:4 n-6, 22:5 n-6, n-6 PUFA and n-6 HUFA than the fish fed with the other three diets. The fish fed with Diet-FO contained a significantly higher amount of 16:1 n-7, 20:1 n-9, 22:1 n-9, monounsaturated fatty acids (MUFA), 20:3 n-3, eicosa pentaenoic acid (EPA), docosa hexaenoic acid (DHA), HUFA, n-3 HUFA and n-3/n-6 than the fish fed with the other three diets. The present study demonstrated that the muscle fatty acid profiles of guppy can be altered through feeding with different lipid sources. The guppy fed with Diet-CO and Diet-SO can be used as SAFA, MUFA and n-6 PUFA source while the guppy fed with Diet-LO and Diet-FO could be used as SAFA, MUFA and n-3 PUFA sources for feeding high value fish. The resulting fry from all diets can be used as n-3 PUFA and n-6 PUFA sources for feeding both freshwater as well as marine fish. The resulted fry fed with Diet-CO and Diet-FO can be used as HUFA source to feed marine fish since they do not have the ability to synthesize HUFAs. The present study demonstrated that plant based oil sources particularly coconut oil, sunflower oil and linseed oil can be used as a cheap lipid sources for preparation of feed for guppy to alter the fatty acid profile and their resulting fry could be used as good sources of n-3 and n-3 PUFA for feeding high value fishes.