J. Algal Biomass Utln.  2011, 2 (1): 10 – 20                                                   Algae in fish nutrition 
               © PHYCO SPECTRUM INC                                         
                                                                                                                                            
                     Composite algal supplementation in nutrition of Oreochromis mossambicus  
                                          1                          2                             2                             2
                  Sudeshna Sen Roy , Atreyee Chaudhuri , Sudeshna Mukherjee , Sumit HomeChauduri  and 
                                                                                   1 
                                                                      Ruma Pal
                 1                                                             2
                   Phycology Laboratory, Department of Botany and    Aquatic Bioresource Laboratory, Department of 
                          Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata-700 019, India 
                                                           Email: rpalcu@rediffmail.com 
                            Key words: Algal feed; composite algal mix; nutrition; Oreochromis; proximate composition 
                                                                       Abstract 
               Composite algal mix has been used as feed supplement in nutrition of Oreochromis mossambicus  and its 
               effect on growth performance, feed efficiency, nutrient utilisation and body composition was investigated 
               in a 12 week feeding trial. Three isonitrogenous diets containing 0 % (conventional feed, CF), 35% (value 
               added feed, VAF) and 100% (algal feed, AF) algal supplementation were used in combination with other 
               conventional  fish  feed  ingredients.  The  algal  genera  used  were  Phormidium  valderianum,  Spirulina 
               subsalsa,  Navicula  minima,  Chlorococcum  infusionum  and  Rhizoclonium  riparium  in  a  ratio  of 
               35:35:12:12:6  for  experimental  feed  formulation.    Fish  fed  with  VAF  showed  an  increased  growth 
               performance (P < 0.05), feed efficiency and nutrient utilisation compared to 0 % and 100% supplemented 
               diets.  Carcass lipid  levels  decreased at 35% supplementation level. The results suggested that, 35 % 
               supplementation of conventional feed with composite algal mix can be used in mossambique tilapia diet. 
                
               Introduction                                                       make  up  about  60%      of  an  intensive 
                                                                                  aquaculture  regimen  (Güroy  et  al.  2007). 
                        Fish  has  long  been  used  as  the                      Traditionally,       animal       protein      sources, 
               cheapest  source  of  protein  for  human                          particularly  fishmeal  are  used  as  the  major 
               nutrition  worldwide  –  still  with  a  gap  in                   ingredients  of  aqua  feeds  (Glencross  et  al. 
               production  and  supply  (Tidwell  and  Allan,                     2007).  Fishmeal  is  one  of  the  most 
               2001).  A major determinant of successful                          expensive  ingredients  in  formulated  fish 
               growth  and  intensification  of  aquaculture                      feeds in one hand and its regular use reduces 
               production depends on aqua feed. Feed costs                        the diversity of marine fauna on the other. 
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               J. Algal Biomass Utln.  2011, 2 (1): 10 – 20                                                   Algae in fish nutrition 
               © PHYCO SPECTRUM INC                                         
               Therefore, to reduce the cost of aqua feeds,                       in developing country like India and others. 
               non conventional sources of proteins are in                        Therefore,  exploration  of  local  algae  for 
               high     demand.  Plant  feed  stuffs  are                         aquaculture usage is much more relevant for 
               considered  as  economically  viable  and                          useful cheap production of aquaculture feed. 
               environment  friendly  feed  ingredients  and                               In India, most of the fish farmers use 
               can  be  considered  as  essential  biomass  for                   the mixture of rice bran and mustard oil cake 
               future aquaculture feed formulation ( Tacon                        for  tilapia  farming  together  with  natural 
               et al. 2006).                                                      fauna  of  the  pond.  In  the  present  study  to 
                        Algae have emerged as an alternative                      formulate  cheap  and  better  feed,  35% 
               protein source since long back and their use                       supplementation  with  algal  biomass  was 
               is  quite  popular  in  modern  aquaculture                        tested for value addition to the conventional 
               industry  .Potential  algal  genera  contain                       feed       using        Tilapia        (Oreochromis 
               about 30-70% protein, 10-20% lipid, 5-15%                          mossambicus) as model fish. Five algal taxa 
               carbohydrate         and      high       amount        of          with  high growth rate and relatively cheap 
               carotenoids        with     antioxidant        property            production  cost  were  chosen  as  feed 
               (Becker, 2004). Most commonly used algal                           ingredients. The new composite mixture was 
               genera  include  microalgae  like,  Chlorella,                     formulated  after  several  trials.  A  total 
               Nannochloropsis,          Pavlova,        Tetraselmis,             (100%) replacement of conventional feed by 
               Thalassiosira,          Isochrysis,        Dunaliella,             composite  algal  biomass  was  also  used  to 
               Haematococcus, Scenedesmus,  etc. (Brown                           understand the efficacy of algal meal as fish 
               et  al.  1997;  Yamaguchi, 1997; Borowitzka,                       feed. Three marine genera viz. Phormidium 
               1998; Apt and Behrens 1999; Muller-Feuga,                          valderianum,         Spirulina       subsalsa        and 
               2000; Soletto et al. 2005). But most of the                        Navicula minima and two fresh water genera 
               reports are available on use of single algal                       Chlorococcum                infusionum               and 
               genus  as  fish  feed  ingredients  ,therefore                     Rhizoclonium  riparium  were  taken  as 
               availability  of  algal  biomass  may  be  the                     experimental materials.  
               major constrain  in using them (Appler and                         Materials and methods 
               Jauncey,  1983;  Appler,  1985;  Güroy  et  al.                    A mixture of two cyanobacterial genera viz. 
               2007;  Azaza  et  al.  2008).Moreover,  the                        Phormidium  valderianum  Gomon,  1892, 
               production cost including the harvesting of                        Spirulina subsalsa Ørsted ex Gomont 1892 
               the  unicellular    micro-algae  are  quite                        and  three  eukaryotic  algal  genera  viz. 
               expensive making them almost unaffordable                          Navicula  minima  Grunow  in  Van  Heurck, 
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               J. Algal Biomass Utln.  2011, 2 (1): 10 – 20                                                   Algae in fish nutrition 
               © PHYCO SPECTRUM INC                                         
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               1880  (Bacillariophyceae),  Chlorococcum                           0.38 m ) containing 80 L water with a flow 
               infusionum  Schrank  1811  (Chlorophyceae)                         rate of about 1L min-1. All the fishes were 
               and Rhizoclonium riparium (Roth) Kützing                           starved  for  24h  prior  to  the  onset  of  the 
               ex Harvey 1849 (Chlorophyceae) were used                           feeding trial. A 12- weeks feeding trial was 
               as  the  experimental  feed  supplements.                          carried out in triplicate groups of 20 fishes 
               Oreochromis mossambicus Peters 1852 was                            each  (1.8-1.9  g).  Three  experimental  sets 
               used as model fish.                                                were  prepared  for  each  experimental  diet. 
               Collection and culturing of algae                                  Set 1 was fed with conventional feed (CF) 
                                                                                  and considered as control feed; set 2 was fed 
               The      experimental        algal     genera      were            with      algal     feed      (AF)      with      100% 
               collected from eastern parts of India, isolated                    supplementation  and  set  3  was  fed  with 
               following standard protocols and micro algal                       value  added  feed  (VAF)  with  35%  algal 
               cultures were raised for biomass utilization.                      supplementation. All groups of fish were fed 
               Unialgal  batch  cultures  of  Cyanobacteria                       their  respective  diets  to  apparent  satiation 
               were grown using ASN III (Ott, 1965), for                          twice  a  day  at  0900h  and  1700  h.  The 
               Navicula ASN III media was supplemented                            uneaten  food  was  collected  after  1h  of 
               with  SiO4  and  for  Cholorococcum  BBM                           feeding      and  dry  matter  content  was 
               (Bold, 1942) were used. Rhizoclonium was                           determined        (AOAC,  1995)  for  feed 
               collected from Kakdweep, West Bengal and                           consumption  calculation.  The  fishes  were 
               used in feed ingredients as natural resource.                      weighed  every  fortnight  after  a  24-h 
               Experimental  fish,  rearing  condition  and                       starvation  period  to  determine  the  daily 
               feeding regime                                                     ration.     Water      quality      was     monitored 
                                                                                  throughout the feeding experiments with the 
               Juvenile Oreochromis mossambicus of same                           water temperature, dissolved oxygen and pH 
               age group (1.7-1.8 g ± 0.54 ) were purchased                       being maintained at 26±1°C, 6.8±1.1 mg L-1 
               from  a  government  fish  breeding  farm                          and 7.1±0.4 respectively.  
               (Kolkata, India). They were acclimatized for 
               2 weeks in the laboratory condition and were                       Experimental diets 
               fed with commercial diet for proper rearing.                       The pre-weighed dry algae were mixed in a 
               The  experimental  trial  was  conducted  in                       proportion       of     Phormidium:          Spirulina: 
               large     rectangular       flow      through      fibre           Navicula:  Chlorococcum:  Rhizoclonium  :: 
               reinforced plastic (FRP) tanks (0.6 x 0.5 x                        35:35:12:12:6 to prepare the composite algal 
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               J. Algal Biomass Utln.  2011, 2 (1): 10 – 20                                                   Algae in fish nutrition 
               © PHYCO SPECTRUM INC                                         
               mix  using  a  food  mixer.  The  algae  free                      and  protein  efficiency  ratio  (PER).  Fishes 
               conventional feed (CF) and 2 experimental                          were      randomly         selected      from       each 
               diets viz. value added feed (VAF) containing                       experimental tank and decapitated for such 
               35%  replacement  of  CF  with  composite                          analysis  after  84  days  of  experimentation. 
               algal  mix  and  algal  feed  (AF)  i.e.  100%                     The formulae used are as follows: 
               replacement  of  CF  were  prepared  using  a                      1.  WG  =  [(Final  body  weight  (g)  -  Initial 
               feed pelletiser  machine. All the feeds were                       body weight (g))/ Initial body weight (g)] x 
               formulated  to  meet  the  40%  protein                            100 
               requirement           of        juvenile         tilapia 
               (Fitzsimmons,  1997).  The  formulation  and                       2.  SGR=  [(ln  Final  body  weight  (g)  -  ln 
               chemical composition of feeds are shown in                         Initial body weight (g) / Number of days] x 
               table 1.                                                           100                                                        
               Analytical procedures                                              3.  FCR  =  Dry  feed  fed  (g)  /  Live  body 
               Analysis  of  dry  matter (by  oven  drying  at                    weight gain (g) 
               105  °C  for  24  h),  crude  protein  (Kjeldahl                   4.  PER  =  Body  weight  gain  (g)  /  Crude 
               apparatus,  nitrogen  X  6.25),  crude  lipid                      protein fed (g) x 100 
               (extraction with petroleum ether by Soxhlet                        Statistical Analysis  
               apparatus),  crude  fibre  (by  an  automatic 
               analyzer, Fibertec, Tecator, Sweden) and ash                       All growth data were subjected to one-way 
               (incineration in a muffle furnace at 600° C                        analysis      of    variance      (ANOVA).  The 
               for 4 h) were performed for both feed and                          significance  of  difference  between  means 
               carcass  (AOAC,  1995).  Water  quality                            was determined by Duncan’s multiple range 
               parameters were measured following APHA                            test  (P  <  0.05)  using  SPSS  for  Windows 
               (1998).                                                            (Version 10.0) (Duncan, 1955).  
               Evaluation of growth performance                                   Results 
               Growth performance and feed utilization of                         The nutritive values of the formulated feeds 
               experimental        fish     were     evaluated       by           are shown in table 1. A 35% replacement of 
               standard  methods  (Siddhuraju  and  Becker,                       CF with algal mix (VAF) showed maximum 
               2003)  in  terms  of  final  fish  weight  (g),                    crude lipid (10.32%), gross energy (24.29 kJ 
               weight gain (WG, %), specific growth rate                          g-1),   calcium  (7.08%)  and  phosphorus 
                                -1
               (SGR, % day ), feed conversion ratio (FCR) 
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