APPARENT DIGESTIBILITY COEFFICIENTS OF SEVEN PROTEIN SOURCES FOR JUVENILE HYBRID GROUPER (EPINEPHELUS FUSCOGUTTATUS♀x EPINEPHELUS LANCEOLATUS♂).

The apparent digestibility coefficients (ADCs) of Tenebrio molitor meal (TMM), Hermetia illucens meal (HIM), Clostridium autoethanogenum protein (CAP), Methylococcus capsulatus meal (MCM), Chlorella vullgaris meal (CVM), Cottonseed protein concentrate (CPC) and Peruvian fishmeal (PFM) were determined in juvenile hybrid grouper (Epinephelus fuscoguttatus♀xEpinephelus lanceolatu♂). A basal diet (including 50% fishmeal) and seven test diets (700 g/kg of the basal diet and 300 g/kg of each test ingredient) were formulated with 0.1% yttrium oxide (Y₂O₃) as an inert marker. The juvenile hybrid groupers, with initial average body weight of (9.95±0.50) g, were randomly distributed into 0.3 m³ fiberglass tanks, each tank with 30 fish. The faeces samples were collected twice-daily by siphoning following feeding fish after five days of domestication. The ADCs of dry matter of seven test ingredients were ranked as CVM>TMM=CAP=CPC>HIM=MCM=PFM (P<0.05). CVM showed the highest ADCs of dry matter (DM), crude protein (CP) and most amino acids (including methionine and threonine) except crude lipids (CL), whereas HIM had the relatively lower ADCs of DM, CP and most amino acids except CL. CAP had a higher lysine digestibility than the other six test ingredients, and was only lower than CVM in the ADC of CP. The ADC of DM in PFM was significantly lower than that in CVM (P<0.05), and showed no differences with that in CAP (P>0.05). Besides, PFM showed a lower ADC of CP than the ADCs of CP in CVM, CAP and MCM (P<0.05), and showed a lower ADC of lysine than that in CAP as well as a lower ADC of threonine than those in CAP and CVM (P<0.05). Overall, this study showed the advantage of CVM and CAP among the seven protein sources on the digestibility of feed available in hybrid grouper. [ABSTRACT FROM AUTHOR]