Ammonia nitrogen excretion rate - An index for evaluating protein quality of three feed fishes for the black sea turbot


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Yigit M. , Koshio S., Aral O., Karaali B., Karayucel S.

ISRAELI JOURNAL OF AQUACULTURE-BAMIDGEH, vol.55, no.1, pp.69-76, 2003 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 55 Issue: 1
  • Publication Date: 2003
  • Title of Journal : ISRAELI JOURNAL OF AQUACULTURE-BAMIDGEH
  • Page Numbers: pp.69-76
  • Keywords: ammonia excretion rates, feeds, protein sources, turbot, water quality, FLOUNDER PARALICHTHYS-OLIVACEUS, TROUT ONCORHYNCHUS-MYKISS, BASS DICENTRARCHUS-LABRAX, SCOPHTHALMUS-MAXIMUS L., DIETARY-PROTEIN, RAINBOW-TROUT, JUVENILE TURBOT, JAPANESE FLOUNDER, SALMO-GAIRDNERI, BODY-COMPOSITION

Abstract

Total ammonia nitrogen excretion rates were measured in young Black Sea turbot (74.79 g avg

wt) reared in brackish water (17 ppt salinity) at 11±0.3°C. Duplicate groups of turbot were fed a

fixed quantity of teleosts, either anchovy (Engraulis encrasicolus), goby (Gobius sp.) or whiting

(Merlangius merlangus). Feeds were offered to the turbot as wet feed. Cumulative ammonia-N

excretion over a 6-hour period was significantly lower (p<0.05) in fish fed goby (3.64±0.27 mg-

N/100 g fish) and whiting (3.83±0.13 mg-N/100 g fish) than that in fish fed anchovy (4.48±0.06

mg-N/100 g fish). The ammonia-N excretion rate in all groups peaked two hours after feeding,

but the peak value in the group fed anchovy was significantly higher (p<0.05) than in the other

two groups. No differences were observed among diets in samples taken 3, 4, 5 and 6 hours

after feeding. Significantly lower excretion levels in the goby and whiting groups could be related

to the protein quality of these species which may be higher than that of the anchovy for turbot

nutrition.

Total ammonia nitrogen excretion rates were measured in young Black Sea turbot (74.79 g avg wt) reared in brackish water (17 ppt salinity) at 11+/-0.3degreesC. Duplicate groups of turbot were fed a fixed quantity of teleosts, either anchovy (Engraulis encrasicolus), goby (Gobius sp.) or whiting (Merlangius merlangus). Feeds were offered to the turbot as wet feed. Cumulative ammonia-N excretion over a 6-hour period was significantly lower (p<0.05) in fish fed goby (3.64+/-0.27 mg-N/100 g fish) and whiting (3.83+/-0.13 mg-N/100 g fish) than that in fish fed anchovy (4.48+/-0.06 mg-N/100 g fish). The ammonia-N excretion rate in all groups peaked two hours after feeding, but the peak value in the group fed anchovy was significantly higher (p<0.05) than in the other two groups. No differences were observed among diets in samples taken 3, 4, 5 and 6 hours after feeding. Significantly lower excretion levels in the goby and whiting groups could be related to the protein quality of these species which may be higher than that of the anchovy for turbot nutrition.