The protein requirement of juvenile mud crab Scylla serrata (body weight 5 0.25 AE 0.051g, carapace width 5 9.3 AE 0.04 mm) fed with di¡erent iso-energetic, iso-lipidic diets with graded protein levels (155 5% crude protein at 5% intervals) was determined. The feeding trial was conducted for a period of 63 days to determine the minimum and optimum protein requirement of juvenile S. serrata. The crabs fed with 15% and 20% dietary protein levels showed 100% and 12.5% of mortalities respectively. The mortalities observed in the above treatments were associated with the prolonged intermoult duration (46 and 32 days respectively). All other treatments recorded 100% survival. The best growth performance as well as the nutrient turn-over was recorded in crabs fed with 45% crude protein in the diet. Second-order polynomial regression of speci¢c growth rate (SGR) as well as body protein gain vs. dietary protein levels suggested that 46.9^47.03% dietary protein is required for the best growth response and protein deposition in juvenile S. serrata. An extrapolation of 'SGR' and 'daily protein gain' upon the 'dietary protein level' axis (Y 5 0) showed that 14.71 6.2% dietary protein is necessary for the minimum maintenance metabolism.

The recent emergence of multiple technologies for modifying gene structure has revolutionized mammalian biomedical research and enhanced the promises of gene therapy. Over the past decade, RNA interference (RNAi) based technologies widely dominated various research applications involving experimental modulation of gene expression at the post-transcriptional level. Recently, a new gene editing technology, Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and the CRISPR-associated protein 9 (Cas9) (CRISPR/Cas9) system, has received unprecedented acceptance in the scientific community for a variety of genetic applications. Unlike RNAi, the CRISPR/Cas9 system is bestowed with the ability to introduce heritable precision insertions and deletions in the eukaryotic genome. The combination of popularity and superior capabilities of CRISPR/Cas9 system raises the possibility that this technology may occupy the roles currently served by RNAi and may even make RNAi obsolete. We performed a comparative analysis of the technical aspects and applications of the CRISPR/Cas9 system and RNAi in mammalian systems, with the purpose of charting out a predictive picture on whether the CRISPR/Cas9 system will eclipse the existence and future of RNAi. The conclusion drawn from this analysis is that RNAi will still occupy specific domains of biomedical research and clinical applications, under the current state of development of these technologies. However, further improvements in CRISPR/Cas9 based technology may ultimately enable it to dominate RNAi in the long term.

E⁄cacy of sun£ower oil (diet SF) and soybean oil (diet SB) alone and in combination with cod liver oil (diets M1-2.80:1.40:1.40, M2-2.80:2.24:0.56 and M3-2.80:0. 56:2.24; cod liver oil:sun£ower oil:soybean oil) as lipid supplements (5.6%) in formulated diets (crude fat $ 9.79%) for juvenile Scylla serrata (weight 5 0.28 AE 0.07 g, carapace width 5 9.7 AE 0.1mm) were compared with diet CL, containing cod liver oil alone as the lipid supplement (6 diets  24 crabs stocked individually, randomized block design). Growth performance, nutrient (protein and lipid) intake and gain of crabs fed M1, M2 and M3 were higher (P 0.05) than the crabs fed SF and SB, but were not signi¢cantly di¡erent (P ! 0.05) from crabs fed CL. Dietary fatty acids (FAs) are found to in£uence the FA pro¢le of test crabs. Higher tissue levels of 16:1n-7, 18:1n-9 and 18:1n-7 re£ected the essential FA de¢ciency in crabs fed diets supplemented only with vegetable oils. Results con¢rmed that S. serrata could utilize vegetable oil supplements in the formulated diets as a partial replacement (50%) of cod liver oil without compromising growth and survival. Partial substitution of marine ¢sh oil with suitable vegetable oils can reduce the feed cost considerably, in the context of rising ¢sh oil prices. à Nitrogen-free extract (NFE) carbohydrate content of ingredient (%) 5 100 À (moisture1crude protein1crude lipid1crude ¢bre1 crude ash). The same is applicable for the succeeding tables wherever applicable. wCalculated based on Cuzon and Guillaume (1997): 21.3, 17.2 and 39.5 MJ kg À 1 of protein, carbohydrate and lipid respectively. The same is applicable for the succeeding tables wherever values shown. Means of three analysis.Aquaculture Research, 2010 E⁄cacy of dietary lipid supplements for S. serrata U Unnikrishnan et al.