International Journal of Marine Science 2016, Vol.6, No.35, 1-8
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The proximate compositions of the cyanobacterial fed shrimp were higher for lipid (13%) and carbohydrate (31%)
than controls (Fig. 3a, 3c). Proximate composition of shrimp particularly total content was significantly high in
shrimp fed. This findings support by earlier studies when shrimp are fed with microalgae feed (Souza and
Loneragan, 1999; Tobias-Quinitio and Villegas, 1982). However, in the present study, protein content in shrimp
tissue was not significantly changed due to cyanobacterial feed (Fig. 3b). A similar observation has also been
made in edible flesh of shrimp fed with different type of microalgal diets (Sivakumar et al., 2011). The cost
involved in the production of cyanobacterium was less as compared to that in the commercial feed and hence, the
usage of cyanobacterium in shrimp feed is advantageous.
Fig. 3 showing the percentage of carbohydrate (a), protein (b) and lipid (c) of the
Penaeus monodon
gain or loss due to
cyanobacterial supplementary feed. The values are significant between control and treatment (
p
<0.05) but not for protein.
Microalgae grown to late-logarithmic growth phase typically contain 30 to 40% protein, 10 to 20% lipid and 5 to
15% carbohydrate (Brown et al., 1997; Renaud et al., 1999). In the algal culture of stationary phase, the proximate
composition can change significantly; for example when nitrate is limiting, carbohydrate levels can double at the
expense of protein (Harrison et al., 1990; Brown, 1993). There seems no strong correlation between the proximate
composition of microalgae and nutritional value, although algal diets with high levels of carbohydrate are reported
to produce the best growth in juvenile oyster (
Ostrea edulis
) (Enright et al., 1986) and polyunsaturated fatty acid
(PUFAs) are also present in adequate proportions in larval scallops (
Patinopecten yessoensis
) (Whyte and Bourne,
1989).
In the present study, the unicellular cyanobacterial feed increased the length growth of shrimp (16.95%) as
compared to the control (Fig. 1a). This is in accordance with earlier studies with
Phormidium valderianum
(Thajuddin and Subramanian, 2005). The cyanobacterial pellet feed tested with the freshwater prawn
Macrobrachium malcomsonii
has shown that there is a 2-fold growth of the prawn, as compared to the live feed
control (Subramanian, 1998). Similarly, the
Phormidium sp.
, fed shrimp
Penaeus monodon
exhibits significant
growth (Sivakumar et al., 2011). Microalgae supplementing in fish diet improve the growth and maturation of
Mekong Giant Catfish (Meng-Umphan and Saengkrachang, 2008; Ungsethaphand and Hangsapreuke, 2008;
Tongsiri, 2010).
The present study has concluded that
Synechocystis salina
is a suitable supplementary feed for aquaculture
shrimps based on increased gross conversion efficiency, decreased food conversion ratio and higher levels of
carbohydrate and lipid in the cyanobacteriun-fed shrimps.
