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Abstract: An 8-week comparative slaughter experiment was carried out to determine the optimal dietary dry matter (DM) crude protein (CP) and lipid for growth and nutrient retention of malabar grouper. Fingerlings of mean (±SD) starting weight of 17±1.3 g were fed twice daily to satiety one of 16 pelleted dry feeds (∼ 93% DM) that provided a 4×4 factorial comparison of serially incremented CP (from 44 to 60%) and lipid (from 7 to 23%) with three tank replicates (10 fish per tank). Tanks (100 L) were situated within an enclosed laboratory and provided with bio-filtered, constant temperature (29±0.7 °C) recirculated seawater and with supplementary aeration. Fish survival averaged 94±5.3% and was unaffected by treatment. Modelling of the fish''s response to dietary CP and lipid showed that growth, feed conversion ratio (FCR) and dietary energy retention were all optimized when dietary CP was 55–56%; DM feed intake was highest for diets with the highest protein (60%) and lowest lipid (7%) content while N retention was maximized at 49% CP. The optimal dietary lipid level was about 12% for growth rate and N and energy retentions, and 17.5% for FCR. Changes in the whole body (WB) composition of the fish were more direct: protein composition decreased linearly as dietary protein increased (with increasing dietary lipid tending to have an opposing effect), while lipid composition increased linearly as dietary protein and lipid both increased. Thus, WB lipid was highest for fish fed the highest protein (60%) and the highest lipid (23%) diet while WB protein was greatest for fish fed the lower protein (44 or 50%) and highest lipid (23%) diets. Recommended dietary protein, lipid and protein to energy ratio specifications for optimal productivity of juvenile malabar grouper are 55%, 12% and 28 g CP:MJ gross energy, respectively. [Copyright &y& Elsevier]

Abstract: On-growing of wild-caught juvenile spiny (Palinuridae) lobsters to market size is an emerging aquaculture industry in Asia, Oceania and Central America but most notably in Vietnam where a US$90 million per annum industry flourishes. The sustainability of the supply of wild juveniles is an ever present threat to industry expansion, which ultimately may be overcome through successful life cycle closure. However, another and perhaps more imminent impediment is the present reliance on fresh fishery by-catch as a source of food for lobster culture. The decreasing availability and increasing cost of the by-catch, together with the downstream environmental impacts caused by this type of feeding, has focused attention on the need for more sustainable and environmentally-friendly pelleted feeds. Efforts to develop palatable and high performance pelleted dry feeds for spiny lobster grow-out have not met with a lot of success until recently. This paper reviews the progress that has been made and identifies where further research effort is needed. [Copyright &y& Elsevier]

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. [ABSTRACT FROM AUTHOR]

Abstract Juvenile barramundi (∼220–280 g start weight) were fed extruded dry-pelleted diets containing varying amounts of fish meal and meat meal in three experiments (E). E1 and E2 were each 66-day farm studies utilizing 16 floating cages (400 fish per cage) in an aerated freshwater pond. E3 examined the same diets as fed in E2 but under controlled water temperature (28 ± 0.7 °C) and photoperiod (12:12) laboratory conditions in a 42-day study involving 24 aquaria (eight fish per aquarium). In all studies, the same 430 g kg-1 crude protein (CP), 15 kJ g-1 digestible energy (DE) control (Ctl) diet (containing 35% Chilean anchovy fish meal) was compared with two high-inclusion meat meal diets and a proprietary diet. The meat meal diets evaluated in E1 were a high-ash (260 g kg-1 ) meat meal that contained 520 g kg-1 CP and a low-ash (140 g kg-1 ) meat meal that contained 600 g kg-1 CP when included at either 450 or 400 g kg-1 , respectively, in combination with 100 g kg-1 Chilean fish meal in diets that were isonitrogenous and isoenergetic with the Ctl diet. Growth rates and feed conversions were similar (P > 0.05) for all diets. In E2 and E3, the 520 g kg-1 CP meat meal was included at 500 g kg-1 without any marine protein source in diets formulated to provide either 15 or 16.2 kJ g-1 DE and the same CP/DE ratio (29 mg kJ-1 ) as the Ctl diet. Fish performance ranking of diets was similar in both experiments, with the 16.2 kJ g-1 DE diet supporting better (P < 0.05) growth rates than the Ctl diet and feed conversion ratios equivalent to the Ctl diet but better (P < 0.05) than all other diets. [ABSTRACT FROM AUTHOR]