EFFECT OF DIETARY INGREDIENT COMPOSITION AND PROTEIN LEVEL ON GROWTH AND FOOD CONVERSION RATIO IN PEARLSPOT (ETROPLUS SURATENSIS) (BLOCH)

摘要

Five feeds (crude protein 27.3 - 32.8%, digestible energy 375+5 kcal/100g) were formulated using fish meal, groundnut cake, wheat bran, rice bran, fish oil, tapioca flour, vitamins and minerals to study the effect of ingredient composition on growth and feed conversion ratio (FCR) in pearlspot (Etropius suratensis). The first feed had only plant ingredients and the rest of the four feeds had graded levels offish meal, replacing groundnut cake at 10% intervals. The feeds, in moist form, were fed to juveniles of pearlspot having an average weight of 7.0 +- 0.5 g in a 40 day feeding trial. The growth offish increased from 35.9 +- 2.4% to 97.3 +- 4.2% and the FCR improved from 9.3 +- 0.06 to 1.7 +- 0.22 as the fish meal was increased from 0 to 40% in the feed. The growth and FCR of fish fed with feed having only plant ingredients was poor, although there was no apparent difference in acceptability and consumption of this feed compared to the other feeds. Survival of fish ranged from 60 to 100%. Six isocaloric feeds were formulated with crude protein levels varying from 21.2% to 47.5% using a protein base with fish meal (75%), groundnut cake (13%) and wheat bran (12%) and other ingredients . In a 40 day feeding trial with pearlspot (average with 7.5 +-1.0), the feed having 31.8% crude protein and 388.1 kcal/100g energy (protein-energy ratio-1g:12.2kcal) recorded the highest growth of 196.7 +- 2.3% and lowest FCR of 1.25 +- 0.22. The fish fed with this feed also showed maximum whole body crude protein. The survival of fish fed with lowest protein feed was 93% and it was 100% in all the other feeds. Feeding trials with dry and moist (40% water) forms of feed had shown that moist feed was accepted readily by fish and consumed quickly. The growth and FCR of fish fed with moist feed were superior compared to those fed with dry feed.