Dietary inclusion effect of krill meal and various fish meal sources on growth performance, feed utilization, and plasma chemistry of grower walleye pollock (Gadus chalcogrammus, Pallas 1811)

A feeding trial was conducted to assess the effect of dietary inclusion of various aquatic animal protein sources on growth performance, feed utilization, body proximate composition, and plasma chemistry in grower walleye pollock (Gadus chalcogrammus, Pallas 1811). A total of 180 grower fish averaging 154.0 g in weight were chosen randomly and distributed into 12 flow-through tanks of 300 L (15 fish per tank). Four experimental diets were prepared in triplicate. Pollock meal (PM), anchovy meal (AM), krill meal (KM), and jack mackerel meal (JM) were used as the main protein source in the experimental diets, denoted PM, AM, KM, and JM diets, respectively. These diets were fed to fish twice a day at a satiation level for eight weeks. The weight gain and specific growth rate (SGR) of fish fed the KM and JM diets were higher than were those of fish fed the other diets. Daily feed intake (DFI) and daily protein intake (DPI) of fish fed the KM and JM diets were higher than were those of fish fed the PM and AM diets. The strong second polynomial correlation between the contents of 4 free amino acids (arginine, glutamic acid, histidine and leucine) in protein sources and WG, SGR, DFI and DPI were observed. The experimental diets had no effect on proximate composition of the muscle and liver. Plasma analysis did not differ between the experimental diets. In conclusion, KM and JM showed the greatest protein sources than among the ingredients assessed, and consequently KM and JM yielded the higher growth (WG and SGR) and feed intake (DFI and DPI).