Optimum dietary protein and lipid specifications for grow-out of humpback grouper Cromileptes altivelis (Valenciennes)

Abstract

Fingerling Cromileptes altivelis of less than 50 g have been shown to require feeds of 50–56% crude protein (CP) and 9–15% lipid. The requirements of larger, market‐size fish have not been reported. A total of 324 hatchery‐produced C. altivelis were weight sorted into three groups of 136, 175 and 225 g start weight and equally (12 seacage−1) and randomly distributed to floating net seacages in accordance with a 3 × 3 factorial arrangement of CP (42%, 47% or 53%; estimated digestible CP of 40%, 46% or 52%) and lipid (8%, 12% or 16%; equivalent to estimated digestible energy (DE) contents of 14.0, 15.8 or 17.5 MJ kg−1). Changes in dietary CP and lipid content were achieved at the cost of wheat flour by proportionally varying the protein mixture (essentially a 0.62:0.22:0.16 ratio of fish meal, mysid meal and casein respectively) and oil mixture (a 2:1 ratio of fish oil and soybean oil respectively). Fish were fed twice daily to satiation for 180 days. There was no significant (P>0.05) interaction between the main effects of dietary protein and lipid for any growth, nutrient retention or whole‐body composition measurements. Increasing dietary CP significantly improved the survival rate (80.6%, 88.9% and 87.0%), specific growth rate (SGR; 0.24%, 0.28% and 0.31% day−1), feed conversion ratio (FCR; 2.77, 2.21 and 2.00) and DE retention (18.2, 21.3 and 23.2%), respectively, but did not significantly affect digestible protein retention. Increasing dietary lipid increased SGR (0.25, 0.29 and 0.29% day−1) and the whole‐body lipid (and energy) composition, and reduced the survival rate (87.0%, 88.9% and 80.6%), respectively, but FCR and retentions of digestible protein and DE were not significantly affected. These results indicate that humpback grouper of 150–400 g require a dietary specification of not less than 51% digestible protein (∼53% CP), 10–12% lipid and digestible protein:DE of 31–32 g MJ−1 for optimal growth.

Effect of dietary lipid level on growth performance and feed utilization of juvenile kelp grouper Epinephelus bruneus

“…Growth performance, feed efficiency, and nutrient retention decreased linearly with increasing dietary lipid levels from CL130 to CL270. Similar results were reported in juvenile orange-spotted grouper [16], humpback grouper [17], and juvenile Malabar grouper [19]. These observations suggest that groupers show similar trends in lipid utilization.…”

“…In this study, whole-body and liver lipid contents increased with increasing crude lipid level from 60 to 210 g/kg, and were highest in the CL210 diet group. Similar results have been reported in juvenile Malabar grouper [19,31], orangespotted grouper [16], and humpback grouper [17]. When the high-lipid diet (CL270 diet) was fed, liver lipid content decreased.…”

“…The optimal crude lipid levels were 152 g/kg for specific growth rate and 154 g/kg for protein efficiency ratio. The optimal crude lipid level was similar to that of humpback grouper [17] and higher than that of juvenile Malabar grouper [19,31] when dietary crude protein levels were similar.…”

“…Juvenile orange-spotted grouper E. coioides showed lower growth performance with a higher dietary lipid level of 160 g/kg, and the optimum crude protein and lipid levels were 480 and 110 g/kg, respectively [16]. The optimum crude protein and lipid levels for humpback grouper Cromileptes altivelis are 530 and 120 g/ kg, respectively [17]. Furthermore the optimum DP/DE ratio for white grouper E. aeneus decreased with fish growth [18].…”

PENGARUH KADAR PROTEIN DAN LEMAK PAKAN TERHADAP PERTUMBUHAN DAN KOMPOSISI BADAN IKAN KERAPU MACAN, Epinephelus fuscoguttatus

“…Kebutuhan rasio protein/energi dalam pakan untuk pertumbuhan optimal ikan kerapu macan ini relatif sama dengan beberapa ikan karnivora laut lainnya. Beberapa peneliti melaporkan antara lain pada ikan kerapu Epinephelus malabaricus ukuran 17-84 g membutuhkan rasio protein/energi pakan 26,2 g/MJ dengan kadar protein 55% (Tuan & Williams, 2007) (Usman et al, 2005). Keseimbangan protein dan energi dalam pakan sangat penting untuk mengoptimalkan pemanfaatan protein bagi pertumbuhan ikan dan memaksimalkan pemanfaatan lemak dan karbohidrat sebagai sumber energi (Shiau & Lan, 1996;Schuchardt et al, 2008).…”