International Journal of Marine Science 2016, Vol.6, No.25, 1-8
4
2.7 Biochemical analyses
The biochemical composition in terms of total proteins (Lowry et al., 1951), total carbohydrates (Dubois et al.,
1956) and total lipids (Folch et al., 1957) was estimated for both fishes and the formulated feeds.
2.8 Statistical analyses
The given data were expressed in terms of the mean of three replicates ±SD (standard deviation). Data concerning
the morphometric and biochemical analysis such as protein, lipid, carbohydrate for seabass fingerlings were
analyzed by one-way ANOVA followed by Duncan multiple range test and paired sample t-test between control
and experimental groups at p<0.05 by using SPSS Inc. program version 14.
3 Results and Discussion
Growth, health and reproduction of fish and other aquatic animals are primarily dependent upon an adequate
supply of nutrients through feed both in terms of quality and quantity, irrespective of the culture system in which
they are grown (Kader
et al
., 2005). Using balanced formulations based on alternative protein sources, primarily
of plant origin, has resulted in an improvement in the overall nutritional quality of practical diet formulations
(Samocha
et al
., 2004) as well as considerable reduction in formulation costs. Agricultural by products are one of
the cheapest source of ingredients and they are nutritionally rich as well. One fundamental consideration is that
algae are the base of the aquatic food chain and are a food resource that fish are adapted to consume.
The chemical composition of macro algae varies with species, physiological status and environmental conditions;
however in general, the macro algae are rich in non-starch polysaccharides, vitamins and minerals (Wong and
Cheung, 2000). Hamauzu and Yamanaka (1997) reported that early feeding trials with macro algae meal resulted
in improvement of vitality, disease resistance and carcass quality whereas Yildirim
et al
. (2009) reported poor
growth and feed utilization for rainbow trout fed with 10% inclusion level of
Ulva lactuca
. This may be due to the
regional and species level differences in the nutritional quality. Moreover marine algae contain essential amino
acids and they are reported to have the capacity of texturising well and can be used as a binder for different
ingredients in formulated diets (Penaflorida and Golez, 1996).
The growth of fish depends upon the ingredients and their percentages in the formulated feed (Glencross
et al
.,
2007) (Table 1). The present study shows that the juveniles responded well to the formulated diets of seaweed
Lobophora variegata
and the results are in accordance with Shapawi and Zamry (2016). The ingredients present
in the formulated diets significantly influenced the performance of the juveniles which showed final body length
and weight increases (Table 2).
The digestibility of a particular feed ingredient is reflected by fish growth. Improvement in growth due to seaweed
inclusion was previously noted in fishes by Nakagawa
et al
., (1984, 1987) and Hashim and Mat Saat (1992). Even
at low inclusion levels seaweed meal has resulted as an excellent feed binder and additive (Shapawi
et al
., 2015).
Survival rates obtained in this study with the formulated diets seem to indicate that there were no overwhelming
negative effects in utilization of nutrients by the seabass
Lates calcarifer
juveniles
.
Higher survival rate was
reported in experimental fishes which could be due to the growth promoting substances present in the seaweed.
Studies of Chitra (1996) also showed that fish meal mixed with the powder of the marine alga
Sargassum wightii
gave better growth and weight increment in
Oreochromis mossambicus
(Table 3). This increase in specific growth
rate (SGR) may be due to the enzymatic break down of food, availability of nutrients for absorption (Das
et al
., 1987).
Seaweed supplemented diets resulted in higher growth in fishes than the control diet, indicated that the addition of
seaweed along with the plant by products enhanced the performance of feed utilization. Binders play an important
role in pellet preparation. In the present study, egg albumin and tapioca flour were used as binder for pellet
formulation. Experimental feeds showed better water stability than the control feeds, due to their high lipid
content. Olin
et al.,
(1995)
observed that the incorporation of the seaweed in formulated diets increased the water
stability of pellets because of the nature of the phytochemicals and stabilizers present in them.
