Replacement of Fish Meal and Fish Oil in Practical Diets for Japanese Sea Bass (Lateolabrax japonicus): III. Utilization of alternative fats in diets of Japanese sea bass

Title: Replacement of Fish Meal and Fish Oil in Practical Diets for Japanese Sea Bass (Lateolabrax japonicus): III. Utilization of alternative fats in diets of Japanese sea bass

Principle Investigator: Min Xue

Year: 2002

Objective:
The objectives of the present study were to investigate the effects of replacement offish oil by 3 territorial animal fats (lard, tallow and poultry fat), 2 plant oils (soy oil and com oil) and a mix-fat (tallow, 60%; soy oil, 20%; fish oil, 20%) on growth and fatty acid profiles in muscle and liver of Japanese sea bass.

Lay Summary/Industry Summary: The present study showed that 50% of alternative fats replacement did not significantly affect fish growth performance, feed intake (palatability) and hepatosomatic index. Feed conversion rate and protein efficiency ratio in fish consuming the poultry fat diet were significantly lower than those of soy oil and com oil diets. Apparent digestibility of dry matter for pork lard was highest, and significantly higher than poultry fat diet. Significant differences in carcass moisture and liver lipid content were observed among the dietary treatments. The fatty acid composition of fillet largely reflected that of the diets, while that of liver were almost not affected. Except poultry fat group, other alternative fats using group got lower producing cost than fish oil group. The price of soy oil in the international market is going up after May 2003. It brings along the increasing price of other plant oil price. Relatively the costs of territorial animal fats were lower, but the safety using of territorial animal sources should be considered.

Scientific Abstract: The studies were conducted to study the effects of replacement of fish oil by 3 territorial animal lipids (lard, tallow and poultry fat), plant oils (soy oil and com oil) and a mix-fat (tallow, 60%; soy oil, 20%; fish oil, 20%) on growth and fatty acid profile in fillet and liver of Japanese sea bass. 7 basal diets were formulated, 10% of anchovy fish oil was used in control diet, 5% of alternative fats were used in other 6 diets. In the 8 weeks growth experiment, 28 tanks of fish were equally divided into 7 groups. Before and after the trial, fish of each tank were batch weighed and the samples of muscle and liver were collected to do the chemical analysis, for example moisture, crude protein, crude lipid, ash, and fatty acid composition.
Specific growth rate (SGR), feed intake and hepatosomatic index (HSI) fed the various experimental diets were not significantly different (P>0.05). FCE and PER of alternative groups were not significantly different from that of FO group, but the FCE and PER in fish consuming the PF diet were significantly lower than those of SO and CO diets. Alternative fat significantly affect the apparent digestibility of dry matter (ADCd), but did not show significant effect on the apparent digestibility of protein (ADCp) and apparent digestibility of lipid (ADC1) . ADCd of PL diet was highest, and significantly higher than PF diet. Significant differences in carcass moisture and liver lipid content were observed among the dietary treatments. The fatty acid composition of fillet largely reflected that of the diets, while that of liver were almost not affected.