Live Feed

Artificial larval feeds are no match to live food organisms in terms of acceptance, nutritional and other factors. Feeding habit of fishes in natural water bodies is different among the species but all the fishes require protein rich live food for their better growth, efficient breeding and survival (Mandal et al., 2009). Advances in live food enrichment technique have helped to boost the importance and potential of live food organisms in the raising of larval aquatic species. The success in the hatchery production of fish fingerlings for stocking in the grow-out production system is largely dependent on the availability of suitable live food for feeding fish larvae, fry and fingerlings (Lim et al., 2003). The availability of large quantities of live foods organisms such as marine rotifer (Brachionus plicatilis and Brachionus rotundiformis) and Artemia nauplii to meet the different stages of fry production has contributed to the successful fry production of at least 60 marine finfish species and 18 species of crustaceans (Dhert, 1996). A common procedure during the culture of both larvae of fish and prawns is to add microalgae (i.e. “green water”) to intensive culture systems together with the zooplankton prey (Tamaru et al., 1994), has become popular practice these days

Euryhaline rotifer belonging to the genera Brachionus are often used as live feed for first feeding marine finfish larviculture. Two common rotifer enrichments, a single usage of docosahexaenoic acid (DHA)-enriched Chlorella vulgaris and a combination of DHA-enriched C. vulgaris and salmon roe emulsion oil were used to assess: (i) nutritional status of rotifers and, (ii) performance when rotifers were fed to Pagrus major and Paralichthys oli- vaceus larvae from 2 to 15 days after hatching (DAH). Both rotifer enrichment treatments were found to be nutritionally effective with high unsaturated fatty acid (HUFA) content, especially in the combined treatment with significantly higher eicosapentaenoic acid (EPA). Despite deficient levels of EPA, DHA-enriched C. vulgaris was found to be a suitable enrichment for rotifer and also had positive response in survival, growth and trypsin activity in both P. major and P. olivaceus. DHA-enriched C. vulgaris only treatment had higher rotifer population growth (13% higher), egg bearing capacity (7% higher), almost double the soluble protein content and generally higher free amino acid content. Oxidation of lipids in the combined diet due to its high-saturated fatty acid content could be a possible cause to the inferior performance of the combined treatment. Both P. major (20.1 ± 10.1%) and P. olivaceus (12.3 ± 3.87%) suffered low survival and lower gut content in the combined treatment especially during periods of significant growth in both species (7–11 DAH). Despite high HUFA content in the combined treatment, this study revealed that consideration of free amino acids and soluble protein content as parameters of nutritional indicators for first feeding P. major and P. olivaceus should not be dis- counted.

The aim of this study are to investigate metabolic oxygen consumption rate, energy content and growth performance of Hybrid tilapia (Oreochromis sp) with mealworm (Tenebrio molitor) and artificial food. Two separate feeding trial were conducted in 28 days, the feeding trial was divided into 14 days for each feeding trial using 60 hybrid tilapia (Oreochromis sp). Metabolic oxygen consumption rate and ammonia excretion were calculated and digestibility of the two diets were conducted. For Metabolic oxygen consumption rate and ammonia excretion were significantly higher in fish fed with artificial food. In term of digestibility, protein and lipid showed significant effect  (p<0.005) while glycogen was insignificant ( p> 0.005)  The general evaluation showed that mealworm (Tenebrio molitor) have the potential to replace or to supplement fish meal. Through the result, hybrid tilapia fed with mealworm showed good results in survival and overall growth performances throughout 14 days of feeding trial

Two common live feeds, the Brachionus plicatilis species complex SS-type and L-type were used to assess whether there were any differences in protein hydrolysis and digestive trypsin activity in first feeding Japanese flounder. There were no significant differences in hydrolysis activity at 2, 3 and 7 days after hatching (DAH). At 5 DAH, hydrolysis activity was significantly higher in larvae fed SS-type (p < 0.05) at 50 kDa in 1.5-and 3-h incubation whereas L-type treatment had not completely hydrolyzed the proteins after 3 h at the same molecular weight. Larvae fed SS-type had significantly higher (p < 0.05) trypsin activity at 3, 5, 6, 7 DAH. Contribution of live prey to trypsin fraction in larvae showed significantly higher (p < 0.05) fraction for SS-type at 5 DAH (2.18 ± 0.44%) and 6 DAH (2.04 ± 0.29%) and the effect of exogenous trypsin from live prey was relatively low when compared to the total trypsin activity in larvae. This study discusses the differences in ability to digest proteins in Japanese flounder when fed different rotifer morphotypes and highlights the adaptability of this species to alternative rotifer morphotypes during its early developmental stages.

This study was carried out to evaluate the population growth and egg ratio of Brachionus rotundiformis by feeding with three different diets, i.e., live microalgae Nannochloropsis sp., Baker’s yeast, and powdered spirulina. A total of nine conical flasks of 1 L volume were divided into three treatment groups for determining the feeding performance for eight consecutive days. Each experimental group was stocked with B. rotundiformis at an initial density of 10 ind. mL−1. Water temperature, pH, salinity, and light were maintained at (24–29) °C, (7.5–8.5), 30 ppt, and 4000 lx, respectively. Feed was provided twice per day at 9:00 AM and 7:00 PM. The highest mean (±SE) population growth of rotifer was achieved at the end of the culture period (on the 8th day) fed live Nannochloropsis sp. (122 ± 12 ind. mL−1), which was significantly higher compared to the Baker’s yeast and powdered spirulina (p < 0.05). The mean egg ratio of B. rotundiformis fed three diets was significantly differ at different rearing periods (p > 0.05). The highest mean (±SE) egg ratio of B. rotundiformis was observed in the live Nannochloropsis fed group (0.89 ±
0.01) at the end of the rearing period, which was significantly higher than that of Baker’s Yeast and powdered Spirulina fed group (p < 0.05). Among the three diets, live Nannochloropsis had shown the dietary superiority over Baker’s yeast and powdered
spirulina in culturing B. rotundiformis. The results of this study suggest that live Nannochloropsis could be the most suitable diet for the laboratory culture of B. rotundiformis.

A preliminary growth study was conducted with juvenile Oreuchromis mossambicus using a livefood Strepucepkalus dicku!umus. Experimental fish showed better growth, survival and food conversion ratios, a8 well as a significant increase in protein (129'0), free sugars (34.40/0) and protein bound sugars (101%). However, there was a decline in the lipid content (-3.99%). Energy budget analysis revealed that about 90% of the consumed energy (as live-food) was assimilated by the experimental fishes. It is likely that the fish used 45% of the total energy assimilated for metabolic activities associated with growth.

To understand the feeding and digestive strategies of Scylla serrata larva and juvenile at various stages, gut evacuation time (GET) at different developmental stage were determined in the present study. GET in larval S. serrata ranged from 80 min in early zoeal stages to about 120-135 min in megalopa and crab first instar stages. GET differed significantly between stages and between diet but the interaction of stage and diet was not significant. GET for the artificial food is significantly longer than that for the live food. Movement of both the artificial (AF) and live food (LF) along the gut were traced from the hepatopancreas (HP) to the 2nd, 3rd, 4th and 5th abdominal segments (A.S.), midgut (MG), hindgut (HG), near telson and during evacuation. There were very slight differences between the movement of both food at Z1 and Z2. Starting from Z3 to Z5, LF moved faster than the AF but at the megalopa stage, both foods moved from HP to the 5th A.S. at the same time; the AF group exhibited delayed movement from MG until evacuation. At the C1 stage, both foods were only visible at the MG and their separation in time became marked i.e. the AF moving markedly slower than did the LF exhibiting GET values of 135 and 120 min, respectively. Thus, it appeared that the feeding strategy of the S. serrata larvae and juvenile modulated GET and digestive enzyme activities in response to the apparent digestibility of food presented.

This experiment is designed to observe the suitability of different diets on survival rate of marine oligochates worm in laboratory scale using flowing water system. The oligochaetes worms were cultured in five different diet treatments (commercial pellet, seaweed, goat dung, soybean meal and combination diet) each having triplicates. The oligochaetes were cultured for 90 days. The highest survival rate of oligochaetes culture were found significant (p &lt; 0.001) in the combined diet containing goat dung (20%), seaweed (Gracilaria sp.: 20%) and soybean meal (20%). Results of the present study suggest that the combination diet is the best compared to single diet in order to obtain the maximum survival rate of marine oligochaetes worm. The present finding is important in providing the baseline data for marine oligochaetes culture. Further study might be extended in detail to investigate the reproductive cycle since marine oligochaetes is highly potential in mass culture production.