125 Indian J. Fish., 63(1) : 125-131, 2016 Note Growth performance and digestive enzyme activities of fringe-lipped carp Labeo fmbriatus (Bloch, 1795) in periphyton based nursery rearing system B. GANGADHAR, N. SRIDHAR, UMALATHA, C. H. RAGHAVENDRA, H. J. SANTHOSH AND P. JAYASANKAR * ICAR-Central Institute of Freshwater Aquaculture, Regional Research Centre, Hesaraghatta Lake P. O. Bangalore - 560 089, Karnataka, India * ICAR-Central Institute of Freshwater Aquaculture, Kausalyaganga, Bhubaneswar - 751 002, Odisha, India e-mail: gbarlaya@yahoo.co.in ABSTRACT Nursery rearing of Labeo fmbriatus was undertaken in outdoor cement tanks with soil base, where periphyton growth was enhanced by providing sugarcane bagasse as substrate. The growth parameters in terms of fnal weight of fsh, weight gain and biomass were the highest under Substrate + Feed treatment. Growth of fsh under Substrate only treatment was comparable with that of the Control. No difference was observed with respect to fnal length and survival of fsh between treatments. Activity of digestive enzymes corroborated the growth pattern. Enhancing periphyton growth can be an alternative for artifcial feeding in nursery rearing of L. fmbriatus. Keywords: Digestive enzymes, Fringe-lipped carp, Growth, Labeo fmbriatus, Nursery rearing, Periphyton The strategic goals for research and development to enhance fsh production from freshwater aquaculture systems include ‘system’ and ‘species’ diversifcation and prioritisation. Periphyton-based aquaculture is a ‘diversifed system’ which is advantageous in terms of production and has also ensured better resource utilisation as well as eco-friendly protein production (Saikia et al., 2011). It is a recent concept and eco-friendly approach in pond aquaculture, which exploits the ability of herbivorous fshes to scrape or graze a two-dimensional layer of periphyton than fltering algae from a three dimensional planktonic environment (Azim et al., 2005; Abwao et al., 2014). This technology through provision of artifcial substrates is gaining importance, particularly in developing countries, since it is a promising technology for resource poor farmers and a way of utilising the otherwise unharvestable nutrients. Growth performance of Oreochromis mossambicus (Huchette et al., 2000; Keshavanath et al., 2004), Catla catla, Labeo rohita, Cirrhinus mrigala and Cyprinus carpio (Ramesh et al., 1999; Umesh et al., 1999; Azim et al., 2005; Asaduzzaman et al., 2009; Gangadhar and Keshavanath, 2012; Keshavanath et al., 2012), Labeo calbasu (Wahab et al., 1999), mahseer (Keshavanath et al., 2002) and Labeo fmbriatus (Keshavanath et al., 2002; Mridula et al., 2003) have been evaluated with different substrates. Among these, browsers with fringed lips such as rohu, calbasu, fmbriatus and tilapia grew better than others and the production ranged from 50 to 77% higher in substrate- based culture systems compared with control systems. Species diversifcation has been prioritised as an issue to be addressed for aquaculture development (Ayyappan et al., 2009). In recent years, freshwater aquaculture sector of many South-east Asian countries has witnessed inclusion of several new species into the culture systems. In India too, attempts have been made for species diversifcation in the carp polyculture system by inclusion of new candidates that includes the fringe-lipped carp, L. fmbriatus. This species is suitable for cultivation in confned waters (Basavaraju et al., 1995). According to van Dam et al. (2002), detritus and benthos feeders can also thrive on periphyton, besides specialist herbivores. L. fmbriatus is reported to graze on diatoms and algae that grow on submerged rocks and twigs (Bhatnagar and Karamachandani, 1970). Keshavanath et al. (2002) reported that L. fmbriatus grows well in periphyton based systems. Mohanta et al. (2008) have demonstrated that it can be cultured with other major carps in ponds. The species has high potential for composite culture along with other carps, and its culture is slowly picking up in India. Rearing of spawn in nurseries is an important and crucial step in fsh culture. Survival of fsh is the DOI:10.21077/ijf.2016.63.1.48231-19