Growth performance and survival of guppy ( Poecilia reticulata ) : different formulated diets effect

Growth performance of guppy fries was assessed by providing four different types of formulated diets comprised of some available ingredients (fish meal (FM), prawn meal (PM), meat and bone meal (MBM), wheat flour (WF), corn flour (CF), starch (S) and soya bean oil) and the result was compared with supplied commercial diet as control. After 30 days experimental period, diet 1 (FM: PM=6:1) showed the best result in case of length gain (0.48 cm) in guppies whereas lowest (0.01 cm) was reported from diet 2 (PM: MBM= 4:3). The body weight gain in guppies was also found higher (0.004 g) in diet 1 than other diets. Specific growth rate (SGR) of all formulated diets was between 1.03% to 4.8% while 0.7% was found in commercial diet. Maximum survival rate (95%) was recorded in formulated diet 1 whereas 80% was investigated in control .Growth trend of guppies from all the supplied formulated diets resulted better rather than the imported commercial diets. So, Commercial diets might be replaced by experimental diets for the better production of guppy.


Introduction
Guppies (Poecilia reticulata) are one of the popular ornamental fishes produced in many Asian countries as live bearing species (Chong et al., 2004).As a freshwater fish of the family Poecilidae, guppies (Poecilia reticulata) are easy to keep and breed in aquaria (Adil et al., 2014) and are becoming more popular having addaptive capability and affordable price.They generally accept all kind of foods including dried and live.The feed requirements vary in quantity and quality according to their feeding habits and digestive anatomy as well as their size and reproductive state and also affected by environmental variations such as temperature and the amount and type of natural food available (Gonzalez and Allan, 2007).Therefore, it is necessary to focus on the feed supply according to energy requirement.In ornamental fish, a correct formulation of the diet improves the nutrient digestibility; supply the metabolic needs and reducing the maintenance cost and at the same time the water pollution (Yohana and Wilson, 2011).It is also essential to provide the fish larvae appropriate size of feed for better growth and survival.Guppies can easily survive in confinement and culturists do not need to pay much attention for it's nutritional management but poor and unbalanced feed create problems related to lower growth and survival rates.Consequently, the production is related to quatily feed and total cost of feed formulation.This is a major economical concern for aquarium culturists.For this reason, formulated feeds are specifically designed for the productivity of ornamental fishes and are manufactured to result in optimal growth at minimal costs (Mohideen et al., 2014).
Furthermore, ornamental fish culture has started to grow as an industry globaly.There are potentials of this sector for economy of the country like Bangladesh.About 6 billion of global trade is contributed by ornamental fishes (Venkataramani et al., 2010).The start of the millennium projected an annual global exports of USD 176 million which compounded annually at a growth rate of 6.2% and reached around 342 million USD in 2010 (Tissera, 2012).Development of aquaculture technology, water management systems, better understanding of nutrition and aquatic disease management have helped this industry to reach every part of the world ( Tissera, 2010).Thus a wide range of aquarium fishes are culturing with both commercial and decorative aspects.Besides, the industrial development of guppy is influenced by suitable feed and feeding at their developmental stages from fry to adult.Several studies already established on the impacts of different feeds on the growth of edible fishes but studies related to dietary formulation performance in ornamental fishes are scarce (Nancy et al., 2015).According to this regard, research is essential for the better understanding of nutritional requirements and growth pattern of important ornamental fishes.Therefore, the present study was carried out to investigate the effect of different formulated diets on water quality and the growth and survival performance of guppy fries.

Experimental design and fry collection
Total 300 guppy (P.reticulata) fry were purchased from commercial suppliers of Chittagong aquarium fish shops, Bangladesh and acclimatized in a large glass aquarium in laboratory condition for one day.Then the fries were divided into five experimental groups including a control, each with three replicates.The divisions were designed on the basis of formulated feeding trial.The study was conducted with 20 guppy fries (almost uniform size) in each 12 L (13 inch X 8 inch X 9 inch) rectangular glass aquarium of 10 L fresh tap water for 30 days in the laboratory of Aquaculture in Chittagong Veterinary and Animal Sciences University, Bangladesh.Length and weight of individual guppies were recorded before starting of the experiment using measuring scale and electric balance.Separate aquariums were marked regarding five different diets.Among those experimental diets, four types were formulated using different commonly available ingredients.Continuous aeration was provided by 2 aquarium air pump and diffusers.Excreta and leftover feed were removed weekly from the bottom of each aquarium through siphoning.In every 4 days, one third volume of water was changed from each experimental unit.

Diet preparation and feeding
Five types of diets were provided to guppy fries in the present study.Diet 1, diet 2, diet 3 and diet 4 were prepared using ingredients according to Table 1 whereas control was a commercially available pelleted feed (Fish meal, corn gluten meal, corn meal, soyabean meal, shrimp meal, vitamin, mineral and astaxanthin were used as ingredients, according to the level).Fish and prawn meal (FM:PM=6:1), prawn meal and meat and bone meal (PM:MBM= 4:3), meat and bone meal, prawn meal and fish meal (MBM:PM:FM=4:2:1) and wheat flour, prawn meal and fish meal (WF:PM:FM= 4:1:2) were used as key ingredients in diet-1, diet-2, diet-3 and diet-4 respectively.The quantity of corn flour, starch powder and soya bean oil were kept constant to prepare 1 kg diet.No preservatives, synthetic vitamins and minerals were added.Feeds were made pellet through standard process and kept in fully air tight container after air drying in room temperature.Feeding was carried out thrice a day at 9:30am, 1:00pm and 5:00pm throughout the experimental period.Fry were initially fed at a rate of 100% of their body weight however the rate minimized gradually to 80%, 60% and 40% in every consecutive week interval.Fish health was monitored regularly though eye observation and dead fish were taken away immediately without any replacement.

Water parameters
The water quality parameters (temperature, dissolved oxygen, pH and turbidity) were recorded daily throughout the experiment.The dissolved oxygen and temperature was measured using portable meter (EcoScense DO 200A, USA).pH was observed by pen pH meter (LT-Lutron pH-207, Taiwan) and turbidity assessed through turb meter (Turb 430IR,USA).

Growth parameters
During the investigation, length and weight of individual guppy fry from all the respective aquariums were measured and recorded on the first day, followed by once again at the end of the experiment.Survival was also evaluated.Survival and Growth rate of Poecilia reticulata fry was calculated respectively for a period of 30 days using following equations: (i) Body weight increase (BWI) (g) = W t -W 0 (Tacon, 1990) (ii) Percent body weight increase (PBWI  (Ai et al., 2006) Here, W t and W 0 were mean final and initial fish weight (g) and L t and L 0 were mean final and initial length (cm) respectively; N t and N 0 were final and initial numbers of fry in each treatment aquarium respectively and t is the experimental duration in days.

Data processing and statistical analysis
The derived data from the feeding trials were incorporated in Microsoft office excel sheets.Processed data then were analyzed to compare the effect of different experimental diets on the growth and survival of guppy fry.Growth parameters and water quality parameters according to five different diets were compared by using oneway ANOVA.Statistical data analysis was accomplished with SPSS software version 16.0 to evaluate the significant differences among treatments.

Physicochemical properties of water
Water quality parameters were recorded to assess the overall growth pattern of guppies.Highest pH (8.33) and temperature (30.14C) were observed in control whereas the lowest (7.95) was reported in diet 2 (Figure1).Highest DO (4.84 mg/L) and lowest turbidity (3.3 FNU) were investigated in diet 2 whereas lowest DO (4.44 mg/L) and highest turbidity (11.38 FNU) were found in diet 4 (Figure 2).pH in all diets was positively correlated with DO (p<0.05) and turbidity (p<0.01) while negatively correlated with water temperature (p<0.01)(Table 2).The parameters were in between optimum range and similar trend was found in case of pH and temperature rather than DO in Bishnoi (2014) (pH7.9,DO7.4 mg/L and temperature 27C).The water quality parameters were kept within the tolerable range.Therefore, there was no effect of water quality parameters on the growth and survival of guppy fries.

Growth performance
The growth performances were analyzed and compared with control diet.Growth pattern, survival and weight gain (%) had significantly varied among all experimental diets.The highest body weight increase (0.068 g) was found in diet 1 whereas the lowest (0.021 g) was found in diet 4. As the stocking density remained same, the variations resulted for the ingredient composition of the diets.In diet 1, FM was the major component and indicated the highest final weight (0.089 g).It might be due to high crude protein content ingredient.This was agreed by Mohideen et al. (2014) who stated that high crude protein content, feed acceptability and other factors are responsible for higher growth rate in case of sailfin moly (another popular ornamental fish).Besides, second highest (0.078 g) final weight was observed in diet 2 though the major ingredient was WF as a major source of carbohydrate.On the other hand, lowest final weight (0.13 g) was investigated from the control and the percentsge of boby weight gain was also lowest (Table 3).Diet 1 resulted the highest (76.4%) percent body weight increase while lowest (19.23%) was reported from commercial diets (Figure 3).The maximum percent length gain (25.53 cm) was measured from fries fed with diet 1 followed by diet 3, diet 4 and diet 2. Besides, 12.37 cm percent length gain was observed from commercial diet (Figure 4).The poor growth from commercial feeds might be reuslted because commercial feeds are not always prepared following recommended requirement of major nutrient components.Among those, protein is considered as one of the crucial nutrients for the early stages of fish.Altaff et al., 2015 also observed the same thing that generally, the commercial feeds contain a minimum of fishmeal and additional animal by-products.According to Goldblatt et al. (1979), pelleted feeds lose essential nutrients like water soluble vitamins and amino acids during exposure to water within a short period.Bergot (1986) demonstrated that artificial feed changes the relationship between the animal and its environment.Specific growth rate (SGR) was recorded highest (4.8%/day) in diet 1 followed by 2.01 %/day in diet 3, 1.29 %/day in diet 2 and 0.7 %/day in control (Figure 5).In the present experiment, guppies fed with commercial feed had the survival rate of 80% which is similar with survival of both diet 3 and diet 4. By contrast, the highest survival rate (95%) was reported from diet 1 and 90 % guppies were recorded remaining live from diet 2 at the end of the 30 days experiment (Figure 6).The results indicated that mortality rates were higher in fishes feed with commercial feed rather than formulated diets.Altaff et al. (2015) investigated the similar results in mollies when those were fed with commercial pellet feed and different types of formulated feeds.Growth parameters data from different diets were positively and significantly correlated with each other throughout the experiment (p<0.01)(Table 4).It is resulted from the study that diet 1 evidenced the better growth rate in guppy fries compared with the other prepared diets and control.Moreover, formulated diets reported the better growth pattern than that in commercial feed.No toxicity, abnormal behavior and disease prevalence was recorded and mortality rate was also lower during the study.

Conclusions
The study showed that, among the formulated diets those which are prepared mainly by fish meal, prawn meal and meat and bone meal resulted better growth than the commercial pelleted feed.The higher cost involvement, poor growth, less survival and higher mortality rate of imported commercial feeds brought less success in guppy farming as well as in ornamental aquaculture industry.On the other side, the less cost involvement and quality assured formulated feeds can bring a lot of change in this sector.Thus, the experimental diets could be used in commercial guppy farming by improving survival rate and growth performance.The further studies could be done by optimizing of stocking density and nutritional analysis of dry feed with different feeding level and scaling up of the rearing protocols to get better production of guppy.

Figure 1 .Figure 2 .
Figure 1.pH and temperature from different diets