Effect of dietary Ulva and Spirulina on weight loss and body composition of rainbow trout, Oncorhynchus mykiss (Walbaum), during a starvation period


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Guroy D., Guroy B., Merrifield D. L. , ERGÜN S. , Tekinay A. A. , YİĞİT M.

JOURNAL OF ANIMAL PHYSIOLOGY AND ANIMAL NUTRITION, vol.95, no.3, pp.320-327, 2011 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 95 Issue: 3
  • Publication Date: 2011
  • Doi Number: 10.1111/j.1439-0396.2010.01057.x
  • Title of Journal : JOURNAL OF ANIMAL PHYSIOLOGY AND ANIMAL NUTRITION
  • Page Numbers: pp.320-327
  • Keywords: rainbow trout, fasting, weight loss, fatty acids, algae meal, RED-SEA BREAM, TILAPIA OREOCHROMIS-NILOTICUS, VITAMIN-C, ACANTHOPAGRUS-SCHLEGELI, LIPID-METABOLISM, NILE TILAPIA, PROXIMATE COMPOSITION, MEAL SUPPLEMENTATION, CHLORELLA-EXTRACT, FEED-UTILIZATION

Abstract

P>A study was conducted to determine the effect of dietary algal supplementation on weight loss and proximate composition in rainbow trout, Oncorhynchus mykiss, during starvation. An algae-free control diet (C) and four experimental diets, including varying levels of raw Ulva meal (5% = U5; 10% = U10) and Spirulina meal (5% = S5; 10% = S10) were formulated. Fish were fed to satiation for 12 weeks and then subjected to a 3-week starvation period. Body weight, viscerosomatic index (VSI, %), hepatosomatic index (HSI, %), dress-out (DO, %) and chemical composition of carcass were analysed at the end of each starvation week. The accumulated weight loss of the fish fed dietary algae was almost 50% less than the control group (p < 0.05) after 2 and 3 weeks starvation. No significant differences in weight loss were observed among the fish fed different algal diets during the starvation period. Total body protein and ash contents remained constant in all groups throughout the starvation period. Fish in all treatments lost a significant level of total lipids and changes of liver fatty acid profiles were also observed. Results indicate that low level inclusion of algae in aquafeeds may have economical advantages in terms of reducing weight loss in fish when subjected to a short-term fasting period, that sometimes is necessary after a heavy rainfall or when fish stocks are held back to meet market demand.