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Betta splendens , also known as the Siamese fighting fish, is an anabantoid native to Southeast Asia and is among the top ten freshwater ornamental fish species imported into the USA for the aquarium trade. Although B. splendens is a staple in the ornamental aquaculture industry, larval production continues to rely heavily on the use of Artemia spp. nauplii. Digestive physiology data can be used to minimize the use of costly live feeds during larval production by indicating when larvae can digest complex feeds like microdiets (MDs). A 30-day trial was conducted to determine the timing of the maturation of the digestive tract. Standard microplate assays were conducted to quantify pepsin, trypsin, and lipase activities and histology was used to describe digestive tract morphology. Pepsin activity and the development of gastric glands indicated the presence of a functional stomach between 15 and 18 DPH (days post-hatch). Next, a 42-day dietetics trial was conducted to determine which of three commercially available MDs best promoted growth and survival in larval B. splendens compared to an Artemia spp. reference diet. Survival was statistically similar for larvae fed Gemma Micro compared to the Artemia spp. reference diet and all MD treatments yielded significantly higher growth compared with the reference diet. Finally, a 25-day weaning trial was conducted where MD was introduced at three timepoints surrounding the development of the digestive tract. Larvae were subjected to one of five treatments: Artemia spp. reference diet, MD from first-feeding, or MD introduction at 12, 15, or 18 DPH. MD introduction at 15 and 18 DPH yielded similar survival and growth compared to the Artemia spp. reference diet. MD from first-feeding yielded statistically lower survival and growth compared to all other treatments. These results suggest that B. splendens can transition to a MD as early as 15 DPH without reducing growth or survival. • A series of trials were conducted to develop efficient feeding protocols for larval B. splendens. • B. splendens can utilize microdiet from first feeding. • Feeding B. splendens microdiet at 15 days post hatch yielded the highest survival. [ABSTRACT FROM AUTHOR]

Cultured freshwater ornamental fish are primarily fed Artemia at early life stages. Development of alternative feeding strategies could decrease the Artemia reliance of ornamental producers, reduce labor costs, and improve industry resilience by diversifying larval feeding options. In this study, Corydoras aeneus, Synodontis eupterus, Synodontis nigriventris, Epalzeorhynchos bicolor, Pterophyllum scalare, and Trichogaster lalius larvae were offered one of four diets at first feeding: newly hatched Artemia or one of three microparticulate diets (MDs). After 14 days of feeding, survival and standard length (SL) were evaluated, and partial budget analyses (PBA) were conducted to evaluate the economic feasibility of replacing Artemia with MDs. For all species except E. bicolor, at least one MD performed as well as or better than Artemia with regard to the parameters in question. E. bicolor exhibited reduced survival when fed MDs compared to Artemia, although SL did not vary significantly among treatments. PBAs indicated that replacing Artemia with MDs at first feeding resulted in an average net benefit of $0.043 ± 0.004 for all species except E. bicolor, which resulted in a net cost of $0.048. These results indicate that MDs represent a physiologically and economically feasible alternative to Artemia for larval culture of many freshwater ornamental fishes. [ABSTRACT FROM AUTHOR]

Senegalese sole ( Solea senegalensis ) is a highly valuable flatfish species targeted for aquaculture diversification in Southern-European countries. Although its adaptation to captivity was foreseen in the 1970´s, its commercial production at a relevant industrial scale is extremely recent. One of the factors causing this delay in commercialisation was a severe bottleneck occurring during weaning, where incipient larval growth performances and survivals were impairing farming during the first decades of farming. However, a significant evolution has recently occurred for Senegalese sole weaning, with larval growth rates, survivals and quality drastically increasing, and good results becoming more reproducible. These progresses were only possible following significant R&D efforts leading to increased knowledge on larval nutritional physiology, weaning strategies, feeding practices and microdiet formulation and production. To this end, this work reviews the advancements that contributed for the evolution occurring in Senegalese sole weaning during the last decades. This overview shows that, for instance, while in the year 2000 larval weaning would only be achieved at around 60 days after hatching (DAH), with fish achieving 1 g (wet weight basis) at around 120 DAH, nowadays it is possible to perform an early weaning starting immediately after settling (15 DAH) and achieving 1 g at 65 DAH. Future perspectives on Senegalese sole weaning should target an optimisation of microdiet nutritional and physical properties to a further adequacy for the pelagic larvae, where the predatory capacity is reduced and lower particle sizes lead to fast and high nutrient leaching. Nevertheless, this work shows that early life-feed replacement is a reality for Senegalese sole, although it remains uncertain if it will ever occur at the onset of exogenous feeding. [ABSTRACT FROM AUTHOR]

A large effort has been dedicated in the past years to the development of nutritional balanced inert diets for marine fish larvae in order to suppress the nutritional deficiencies of live feed. In this study growth performance, Artemia intake, protein digestibility and protein retention were measured for Senegalese sole ( Solea senegalensis Kaup), in order to provide insight into how protein utilization affects growth performance. Three feeding regimes were tested: ST – standard live feed; ArtRL – live feed and 20% Artemia replacement with inert diet (dry matter basis) from mouth opening; ArtRH – live feed and 58% Artemia replacement with inert diet from mouth opening. Artemia intake and protein metabolism were determined at 6, 15 and 21 days after hatching using 14C-labelled Artemia protein and subsequent incubation in metabolic chambers. At the end of the experiment, sole fed exclusively with live feed were significantly larger than sole from Artemia replacement treatments. Protein digestibility decreased during sole ontogeny, and more sharply in ArtRH sole. Concomitantly retention efficiency increased during ontogeny but with a slight delay in ArtRH sole. Senegalese sole larvae growth and protein utilization is depressed when co-fed high levels of inert diet and Artemia, mostly during metamorphosis climax. [ABSTRACT FROM AUTHOR]

As an important step toward development of a formulated diet for hatchery culture of the mud crab, Scylla serrata, this paper reports on laboratory experiments to assess the potential of a microbound diet (MBD) as a replacement for Artemia nauplii fed to megalopal larvae of S. serrata. The effects of different proportions of dietary MBD and Artemia on survival and moulting success of megalopa to the crab stage were investigated. In the first experiment, megalopae were reared communally and fed either 100% MBD, 100% Artemia or different combinations of the two (75%:25%, 50%:50%, 25%:75%). The experiment was terminated when all larvae had either metamorphosed or died. Larvae fed a combination of 25% MBD and 75% Artemia consistently showed the highest survival among all treatments throughout the experiment. Survival of larvae fed 100% MBD was the lowest early in the experiment but improved to become the second highest toward the end of the culture period. Overall survival of larvae fed 100% MBD did not differ significantly from that of larvae fed 100% Artemia. Moulting to the crab stage began on day 7 for larvae in the treatment receiving a 50%:50% combination of MBD and Artemia. On day 8, all larvae in treatments receiving greater than 25% MBD had some first stage crabs. Larvae fed Artemia only were the last to moult to the juvenile crab stage, but moulting occurred simultaneously on day 10. Because of cannibalism observed in the first experiment, a second experiment was conducted where megalopae were reared individually and fed either 100% Artemia or 100% MBD. Ninety percent of larvae from both treatments successfully moulted to the crab stage. Again, megalopae fed MBD began moulting 1 day ahead of those fed Artemia. The results of these studies show that the MBD used contained all necessary nutrients to sustain successful moulting of S. serrata megalopae to the crab stage. The acceptability of MBD by S. serrata larvae suggests significant potential for using the MBD in future experiments to investigate larval nutritional requirements of this commercially important crab species. Indeed, the more rapid moulting of larvae fed MBD in both experiments suggests that the MBD may have contained certain beneficial nutrients that were not provided by Artemia alone. The fact that no significant differences in survival between megalopae fed 100% MBD and those fed 100% Artemia in both communal and individual rearing experiments suggests that total replacement of Artemia with MBD is possible for S. serrata megalopae. This could result in substantial savings in operating costs for S. serrata hatcheries. [Copyright &y& Elsevier]

Two commercial liquid diet supplements were evaluated as a partial replacement for live foods fed to larval and postlarval Pacific white shrimp, Litopenaeus vannamei. Larvae were stocked in 20-L buckets at a density of 113 shrimp/L and fed one of four diets (5 replicate buckets per diet): (1) a control diet consisting of the diatom, Chaetoceros neogracile, and live Artemia; (2) the control diet plus Treflan (a fungicide); (3) LiquaLife liquid larval diet supplements with reduced concentrations of C. neogracile and Artemia; and (4) Epifeed liquid larval diet supplements with reduced concentrations of Artemia. Diets were evaluated by comparing shrimp rostro-caudal length and survival to PL-8, survival to osmotic and pH stress, as well as shrimp gut fullness, gut lipid content, and fouling. Rostro-caudal length and survival to PL-8 were not significantly different among the four treatments. However, mean survival to PL-8 was 12-34% greater in the Epifeed treatment than in the other three treatments. Shrimp fed Epifeed exhibited greater survival (P < 0.05) when exposed to 7 ppt water for two hours than shrimp in the control treatments. In contrast, there was no significant difference in survival (P > 0.05) among the four treatments when shrimp were exposed to a pH of 3.35 for two hours. Although shrimp fed liquid diet supplements had more fouling (P < 0.05) than shrimp in either of the control treatments, commercial liquid diet supplements can be used in penaeid shrimp hatcheries to partially replace Artemia without compromising shrimp growth or survival. [ABSTRACT FROM PUBLISHER]