CRUDE PALM OIL AS A DIETARY LIPID SOURCE IN THE PRACTICAL DIETS OF HYBRID GROUPER, Epinephelus fuscogutattus X Epinephelus lanceolatus

A long-term feeding trial (4 months) was conducted to evaluate the performance of crude palm (CPO) oil-based diets (fish meal and soybean meal were used as sources of protein) during the grow-out period of hybrid grouper, Epinephelus fuscogutattus X Epinephelus lanceolatus in sea net cages. The diet was formulated with 50% crude protein and 16% crude lipid. Fish oil (FO) was substituted with crude palm oil at 25% increment level and represented as 25CPO, 50CPO, 75CPO and 100CPO. Meanwhile, the control diet (100% fish oil) was labeled as FO. Hybrid grouper of about 200g average weight were randomly distributed into triplicate groups of 30 fish in square net cages (2.0 m depth and 1.5 m diameter) and were fed once a day. Growth monitoring was carried out on a monthly basis. At the end of feeding trial, the fish were also sampled for blood analysis and organoleptic test by using a 5-point hedonic scale of 44 untrained panels.

No significant difference (p>0.05) was detected in term of growth performance of fish fed with different experimental diets. At the end of feeding trial, the percentage of body weight gain (BWG) and specific growth rate (SGR) ranged from 170.42 ± 4.17% to 181.63 ± 8.33% and 0.82 ± 0.04%/d to 0.86 ± 0.02%/d, respectively. Numerically, the fish fed with 50CPO diet had the highest BWG and SGR. Meanwhile, the fish fed with 75CPO diet has the lowest BWG and SGR. Survival rates of the fish were above 90%. The food conversion ratio (FCR) of experimental diets ranged from 1.82 ± 0.08 to 1.91 ± 0.02, with no significant differences were observed (p>0.05). There were also no significant differences seen on the body indices, fillet yield as well as the condition factor of the fish. The results of the blood analysis were in the form of total cholesterol, total protein, red blood cell and hematocrit counts. Except for the total cholesterol, no significant differences (p>0.05) were detected in these parameters among the experimental diets. The total cholesterol for the fish fed with FO and 50CPO were significantly higher (p<0.05) than the fish fed with 75CPO and 100CPO. The findings from organoleptic test showed that all fillets were well accepted by the consumers without any significant differences detected in the tested attributes (odour, appearance, flavor, texture and overall acceptance).  In conclusion, crude palm oil is an excellent source of lipid to replace fish oil in the grow-out diet for hybrid grouper, Epinephelus fuscogutattus X Epinephelus lanceolatus .