WATER HYACINTH ( Eichhornia crassipes ) LEAVES AS AN ALTERNATIVE PROTEIN SOURCE FOR FEEDING EARLY PHASE OF TILAPIA ( Oreochromis niloticus )

INTRODUCTION Recently, wide varieties of non-conventional protein of both plant and animal origin have been evaluated and The most expensive component in fish farming is the used to formulate fish diets. Plant protein concentrate feed due to the high cost protein ingredients such as fish produced from rye grass, alfalfa, water hyacinth, meal and soybean meal (Soliman, 2000). Protein itself marrow stem kale and leucaena leaf were used in diets represents about 50% of feed cost in intensive culture of many fish (Campos et al, 1990).Water hyacinth is a (El-Sayed, 2004).When fish have balanced diet, they free-floating perennial aquatic plant (or hydrophytes) grow fast and stay healthy. In natural waters and well that is widely recognized as one of the world's worst fertilized ponds, phytoplankton, zooplankton, insects, weeds. With broad, thick, glossy and ovate leaves, water crustaceans, copepods and molluscs are consumed by hyacinth may rise above the surface of the water as fish as natural protein foods. In the absence of natural much as 1 meter in height. The Leaves are 10 -20 cm foods in commercial fish farming setup, nutritionally across, and float above the water surface. Water balanced artificial feeds that contain all essential hyacinth reproduces primarily by way of runners or nutrients must be fed to fish for their optimum growth. solons, which eventually form daughter plants. Each Furthermore, feeding fish with natural foods to plant can produce thousands of seeds each year, and commercially oriented intensive fish farms is these seeds can remain viable for more than 28 years. impractical. When practical fish diets are formulated, The common water hyacinth is vigorous growers and all nutrients such as crude protein should be in the known to double their population in two weeks. The optimum level to fulfil the requirements of the fish control of water hyacinth plant is aimed at managing (Hardy, 1980). Recommended dietary crude protein infestations to the acceptable levels of about 10 % cover (CP) requirements for fast and healthy growth of fish instead of its complete eradication (Téllez et al., 2008; vary with fish species. General requirements could be Patel, 2012), as re-infestation occurs easily either from 20-25% CP for a semi-intensive culture with natural vegetative growth or from the seed bank. At a foods, or 40-48% CP for an intensive culture for subsistence level, water hyacinth can be utilized as a fingerlings, or 30-35% CP for juveniles (NAERLS, fertilizer, fodder, paper and fibre source, or for mineral 2002) and 28% for adult tilapia (Twibell and Brown, nutrient removal from polluted water. Water hyacinth 1998). which grows in the polluted water may contain heavy SUMMARY: Water hyacinth (Eichhornia crassipes) is a fast growing invasive aquatic plant often covers water bodies. It has been a problem worldwide. Fast-growing and rapidly expanding omnivorous tilapia is likely the suitable species for aquaculture. Since the fish farmers are adversely affected by high cost feed, the use of water hyacinth as a protein source in fish feed could offer solutions to both the problems. The present study therefore was carried out to perceive the use of water hyacinth as a cheap protein source in the diet of tilapia (Oreochromis niloticus). Four types of fish feeds were formulated replacing the fish meal and soybean meal by water hyacinth at 0% (control, feed 1), 5 % (feed 2), 15 % (feed 3) and 20% (feed 4). Two weeks old tilapia fry of 0.8g ± 0.3g mean body weight were stocked in 12 tanks in four treatments, each with three replicates and fed with respective feed at the rate of 4% of body weight for 63 days (Each tank was stocked with fifteen tilapia fries). Body weight and body length of each fish were measured every fortnight while the initial measurement was taken after one week of acclimatization period. Feed cost for one kg of each feed samples was also calculated. The results revealed that the feed conversion ratio (1.54±0.18, 1.46±0.25, 1.45±0.16 and 1.46±0.42) and growth rates (0.11, 0.106, 0.106 and 0.124 g/day) among fish groups fed with feed 1, 2, 3 and 4 respectively were not significantly different (P>0.05).Costs per kg of feed decreased with the increasing of replacement of fish meal by water hyacinth i.e. Rs. 120, 110, 93, and 84 respectively. There were no significant differences in feed utilization among four types of feed by the replacement of protein source with water hyacinth. Thus, water hyacinth leaves could be used to replace 20% of the high cost protein source in the diet of tilapia.


INTRODUCTION
Recently, wide varieties of non-conventional protein of both plant and animal origin have been evaluated and The most expensive component in fish farming is the used to formulate fish diets.Plant protein concentrate feed due to the high cost protein ingredients such as fish produced from rye grass, alfalfa, water hyacinth, meal and soybean meal (Soliman, 2000).Protein itself marrow stem kale and leucaena leaf were used in diets represents about 50% of feed cost in intensive culture of many fish (Campos et al, 1990).Water hyacinth is a ( El-Sayed, 2004).When fish have balanced diet, they free-floating perennial aquatic plant (or hydrophytes) grow fast and stay healthy.In natural waters and well that is widely recognized as one of the world's worst fertilized ponds, phytoplankton, zooplankton, insects, weeds.With broad, thick, glossy and ovate leaves, water crustaceans, copepods and molluscs are consumed by hyacinth may rise above the surface of the water as fish as natural protein foods.In the absence of natural much as 1 meter in height.The Leaves are 10 -20 cm foods in commercial fish farming setup, nutritionally across, and float above the water surface.Water balanced artificial feeds that contain all essential hyacinth reproduces primarily by way of runners or nutrients must be fed to fish for their optimum growth.
solons, which eventually form daughter plants.Each Furthermore, feeding fish with natural foods to plant can produce thousands of seeds each year, and comm erci ally orie nted inte nsiv e fish farm s is these seeds can remain viable for more than 28 years.impractical.When practical fish diets are formulated, The common water hyacinth is vigorous growers and all nutrients such as crude protein should be in the known to double their population in two weeks.The optimum level to fulfil the requirements of the fish control of water hyacinth plant is aimed at managing (Hardy, 1980).Recommended dietary crude protein infestations to the acceptable levels of about 10 % cover (CP) requirements for fast and healthy growth of fish instead of its complete eradication (Téllez et al., 2008; vary with fish species.General requirements could be Patel, 2012), as re-infestation occurs easily either from 20-25% CP for a semi-intensive culture with natural vegetative growth or from the seed bank.At a foods, or 40-48% CP for an intensive culture for subsistence level, water hyacinth can be utilized as a fingerlings, or 30-35% CP for juveniles (NAERLS, fertilizer, fodder, paper and fibre source, or for mineral 2002) and 28% for adult tilapia (Twibell and Brown, nutrient removal from polluted water.Water hyacinth 1998).
which grows in the polluted water may contain heavy metals such as arsenic, cadmium, lead, mercury, zinc and high (35 -50%), and decreases with increasing fish size.inorganic compounds such as phosphates, and sulphates For tilapia juveniles, the protein requirement ranges from (Lakra et al., 2017;Muramoto and Oki, 1983; Rezania et 30-40%, while adult tilapia requires 20-30% dietary al, 2015).Water hyacinth can effectively remove excess protein for optimum performance (Twibell and Brown, nutrients in a water body.Leaf of water hyacinth can 1998).On the other hand, tilapia brood stock requires 35absorb nutrient more than the petioles can utilize and that 45% dietary protein for optimum reproduction, spawning is why the leaves are always very luxurious in a rich water efficiency, and larval growth and survival (Abdelbody (Okoye et al., 2002).Saha and Ray (2011) indicated Tawwab and Ahmad, 2009).Conventional protein sources that water hyacinth leaf could be used as an alternative such as fish meal and soybean meal are expensive and protein source in the diet of tilapia as its leaf contained becoming limited in availability.Therefore, the need for 55.4% protein on dry matter basis with most essential finding of alternative sources of protein in the animal feed amino acids and particularly rich in leucine (5.1%) and has become a huge challenge for animal nutritionists.phenylalanine (3.1%).Furthermore, Saha and Ray (2011) Thus the present study was carried out to perceive the use added that highest crude protein level is found in the of water hyacinth as a cheap protein source in the diet of leaves and lowest level in the petioles.However, fish don't tilapia culture replacing fishmeal and soybean meals to generally consume water hyacinth directly unless it is determine the percentage of water hyacinth that could be processed in the form of a meal or concentrate.used in the tilapia feed to get highest growth rate.Tilapia is known as 'aquatic chicken' because of its herbivorous and omnivorous habit, feeding lowdown on METHODOLOGY the food chain in the culture systems providing a major source of protein for rural poor in Asia (Sakr et al., 2015).Collection of water hyacinth Historically, tilapia has been of major importance in Water hyacinth plant was collected from uncultivated artisan fishing in Africa and the Levant and is of paddy field (Figure 1) and washed to remove the mud.increasing importance in aquaculture and aquaponics.Very lush or over matured plants were avoided, all the Tilapia can become problematic invasive species in new stem parts were removed and only leaves were taken.warm-water habitats but generally not in temperate Leaves were dried under the hot sun for two weeks.Dried climates due to their inability to survive in cooler waters leaves were ground to make a powder.A sample was 0 below about 21 C (70 °F).Genetically Improved Farmed submitted to the Veterinary Research Institute, Tilapia (GIFT) strain of Nile tilapia is considered to have Gannoruwa, Sri Lanka for proximate analysis.superior growth qualities over the commonly cultured strains of the same species in Asia (Eknath and Acosta, Formulation of feed using water hyacinth 1998).Several factors including fish size or age, dietary Feed 1(0% Water hyacinth) was formulated using the protein source, energy content, water quality and culture "Format feed formulation software" and prepared using conditions have been reported to affect protein raw materials as per the formulation.Percentage of the requirements of tilapia.Protein requirement for maximum raw material in the feed 1(0% water hyacinth) formulation performance of tilapia during larval stages is relatively is mentioned in the Table 1.Feed 1 contains crude protein Measurements of growth rate and statistical and 4 were prepared by adding 5%, 15%, 20% dried water analysis hyacinth leaves to the feed 1, respectively with replacing soy Mean body weight and body length in each tank bean meal and fish meal as indicated in Table 1.Therefore, in every sampling time was calculated.Body Feed 1, 2, 3 and 4 were made to contain same amount of weight and body length change in every 2 weeks protein.Each type of feeds were pelleted and dried.
was analysed using General linear model in which time (weeks) was fitted as a covariate and feed was fitted as a factor in the model using

Experimental design Analysis of the cost of feed Experiment was designed with four treatments each with
Raw materials that were used to formulate each three replicates.Totally twelve fiberglass tanks (for 4 feed samples with their unit price are given in the treatments x 3 replicates) were cleaned and filled with 250 Table 2. liters of de-chlorinated water.Totally 300 tilapia fries from a The cost to formulate 1kg of feed 1, 2, 3 and 4 single batch were purchased and brought from the national were Rs.120, 110, 93, and 84 respectively.Feed fresh water fish breeding Centre of National Aquaculture cost is becoming less with increasing water Development Authority of Sri Lanka in Dambulla.Each tank hyacinth percentage as the expensive protein was stocked with fifteen tilapia fries.Prior to stocking of the sources were replaced by inexpensive water tanks, body weight and body length of the individual fish were hyacinth partially.Feed cost to prepare 1 kg of measured.Tanks were named as 1a, 1b, 1c, 2a, 2b, 2c, 3a, 3b, feed 4 is 36 rupees less than feed 1, saving 30% 3c, 4a, 4b, 4c randomly.The replicates were a, b and c for each from the conventional feed without water treatment.Then the fish in all tanks were fed with feed 1 for a hyacinth.week to acclimatize.The water in all four tanks was very clear without visible plankton.Feed type 1, 2, 3 and 4 were fed to the fish in the treatment groups of 1, 2, 3, and 4 respectively at the Table 2: Unit price of raw materials rate of 4% of their body weight twice daily.In every two weeks, body weight and body length of each fish were Raw material Unit price (Rs/ kg) measured and the amount of feed was adjusted according to the total body weight.Water quality of each tanks were Soybean meal 120 checked and 50% of the water was changed in all tanks twice a Fish meal 290 week.In every water changes precipitated particles in the Maize 60 bottom of the tank were collected and the dried weight was Rice polish 44 measured.Total weight of the precipitated particles in each Rice bran 35 tanks are mentioned in the Table 4.

Sample collection
Mean value of body weight (g), body length Samples were collected every two weeks.The individual (cm) and their standard errors for four types of fish in every tank were caught and the body weight and body feed at the end of the study period are given in the length were measured.Mortality was checked and the dead Table 3. fish was replaced with a fish that was of the same weight and same length, every day.and Ln (BW Feed4) = -0.79+ 0.404 t + 0.0267 t .
Maximum mean body weight was observed in the fish fed with feed 4. Body weight increased from 6 to 8 weeks in an exponential manner (Figure 3 and 4).The simple linear regression model equations in Figure gram/day/fish (g/day/fish) in y axis.Highest growth rate 7 for four types of feed are: Ln (L,Feed1) = 0.87 + 0.15 t, was observed in fish fed with 20% water hyacinth.There Ln (L,Feed2) = 0.87 + 0.146t, Ln (L,Feed3) = 0.89 + 0.14t, were no statistically significant differences between the Ln (L,Feed4) = 0.85 + 0.15t, where 't' is for times of mean growth rates among the four feeds (Figure 8).measurement (1, 2, 3, 4, 5) at two week intervals and 'L' is Maximum growth rate was observed in fish fed with body length.feed 4 (20% water hyacinth).Feed conversion ratios The change in body length also follows exponential (FCR) of the fish fed with feed 1, 2, 3 and 4 are 1.54 ± 0.18, pattern (Figures 5 & 6) and therefore the quadratic model 1.46 ± 0.25, 1.45 ± 0.16 and 1.46 ± 0.42 respectively.was fitted for prediction of weight (on logarithm scale) at There were no significant difference in the FCR between given time (t).The prediction equations for the body the treatment groups.Furthermore, eight fish were dead weight change with time of different feeds are; Ln (L, only in the first week, two fish from each treatment group 2 out of 45 fish.Mortality rate was 4.4% in all treatment Feed1) = 1.17-0.105t + 0.042 t , Ln (L, Feed2) = 1.139 -22 groups.0.082 t + 0.038 t , Ln (L, Feed3) = 1.206 -0.13 t + 0.045 t 2 Deposited particles contain feed particles and faecal and Ln (L, Feed4) = 1.09 0.052 t + 0.035 t where 't' is for material.Weight of deposited particles in each tank is times of measurement at two week intervals and 'L' is body almost same as feed consumption which is same in all length.
treatment (Table 4).This shows the digestibility of the Growth rate of the fish fed on the experimental diets is feed is not significantly different among the four feeds.shown in the Figure 8. Growth rate is presented as  4 et al., 2015) from the polluted water.This process is called as phytoremediation and this will lead to accumulation of toxins and heavy metals in the water Changes of body weight and length with the hyacinth plant (Bioaccumulation).If fish eat these percentage of water hyacinth in the feed plants those toxins and heavy metals accumulate in the There were no significant (P>0.05)differences in body tissues of the fish.These toxins and heavy metals total body weight or length among the fish that were fed are deposited in the human body in higher concentration on the experimental feeds.Body weight gain or length when consuming these fish (Biomagnification).As the measurements were not affected by adding water mortality was not increased with increasing water hyacinth in to the tilapia feed.It was interesting to note hyacinth in the feed, obvious toxicity to the lethal level that even 20% addition of the water hyacinth in the feed was not observed by adding water hyacinth in the tilapia did not significantly (P>0.05)affect the body weight or feed up to 20%.The residuals of the pollutants and length gain of tilapia.
heavy metals in the fish body were not analysed in this study to relate with the pollutants in the water hyacinth.Changes of the growth rate with the percentage of Nevertheless, prior to replacement, it is important to water hyacinth in the feed assess the level of toxins and heavy metals that are There were no significant (P>0.05)differences in present in water hyacinth.Further studies could focus to growth rate among fish fed on the experimental feeds.test the effects of higher level of inclusion and also to Growth rate is not affected by adding water hyacinth in mitigate constrains of water hyacinth, such as presence to the tilapia feed.It was interesting to note that even of toxins and heavy metals to use it as an alternative 20% addition of the water hyacinth in the feed did not source of protein in fish feed.significantly (P>0.05)affect the growth rate of tilapia.
Present study however revealed that water hyacinth could be used up to 20% replacing other protein source.DISCUSSION Soliman (2000) reported that, growth rate of the tilapia fish is reduced with increased replacement of soybean The present study revealed that, no significant meal with black seed meal in the feed.However, Sri difference in growth between fish that were fed with Lankan water hyacinth could be different as the feed 1 (no water hyacinth), 2 (5% water hyacinth), environment and nutrient composition in the soil are 3(15% water hyacinth) and 4 (20% water hyacinth).different.In support of this, Mako et al (2011) reported These results showed that, water hyacinth could be used that crude protein percentage of water hyacinth that was as a protein source by replacing soybean meal and fish collected from four different water sources is different.meal.Similarly, Mohapatra and Patra (2013) reported Nutritional composition of the aquatic plants differs that, the feed with water hyacinth by 15% replacement according to the water source.Present study was of fish meal would be optimum for the maximum cond ucte d usin g wate r hyac inth grow n in the growth of Cyprinus carpio.Alternative plant protein uncultivated paddy field and their nutritional level may sources also have been experimentally used to replace be different to the experimental diets used by Soliman fish meal in the tilapia feed such as alfalfa (Novoa et al., (2000).However, the nutrient composition of water 1990).However, Johansson et al (1991) reported that, hyacinth as well as tilapia growth may be affected by the low quality protein is present in water hyacinth due to Sri Lankan climatic conditions.The results of deposited limited availability of some essential amino acids such particles which were not significantly different among as lysine and the sulphur containing amino acids.Saha the four treatments could be an indirect measurement of and Ray (2011) reported that, water hyacinth contain the palatability and the digestibility of the diet, which several anti-nutrient factors such as tannin and phytic indicates that the palatability and digestibility of diet acid.Tannins affect the protein and dry matter was not affected by the inclusion of water hyacinth up to digestibility either by inhibiting the activity of protease 20%.and possibly other digestive enzymes or by forming indigestible complexes with dietary protein (Krogdahl, CONCLUSION 1989).Phytic acid acts as a chelator, forming protein and mi ne ra l-ph yt ic ac id co mp le xe s wh ic h re du ce Current study reveals that, water hyacinth could be bioavailability of protein and mineral (Spinelli et al., used as a protein source to replace conventional protein 1983).Therefore, we suggest limited use of water source in the tilapia feed successfully.Growth rate of

Figure 1 :
Figure 1: The water hyacinth plants in uncultivated paddy field

Table 3 :
Mean value of body weight, body length and the standard error in each treatment Water hyacinth Mean body weight Mean body Length The simple linear regression model equations in Figure in the feed (%) (g) (cm) 4 for four types of feed are: Ln (BW, Feed1)= -0.92 + 0.54t, Ln (BW, Feed2) = -0.93+ 0.54t, Ln (BW, in body weight follows exponential pattern (Figure 3) lack of fit was significant in simple linear regression model.The quadratic model was fitted for the prediction of weight (on logarithm scale) at given time (t).The prediction equations for the body weight Mean values of the body weight of fish fed with feed 1, change with time of different feeds are: Ln (BW Feed1) = -2, 3, 4 containing 0%, 5%, 15% and 20% water hyacinth, 2 respectively in each sampling is reflected in Figure 2 0.603 + 0.272 t + 0.045 t , Ln (BW Feed2) = -0.67 + 0.313 22 while mean body length is reflected in the Figure 5. Every t + 0.038 t , Ln (BW Feed3) = -0.389+ 0.106 t + 0.069 t 2 sampling was done at two weeks interval.

Figure 2 :Figure 3 :
Figure 2: Mean body weight of fish fed on the experimental feeds

Figure 4 :
Figure 4: Regression between the body weight (g) and time (9 weeks)

Figure 5 :
Figure 5: Mean body length of fish fed with different feeds

Table 1 :
Composition of the control and experimental feeds MINITAB 15 statistical software.

Table 4 :
Total weight of the deposited particles at hyacinth without total replacement of the whole protein bottom of the experimental tank source in a fish feed ration.Our findings indicated that it could go up to 20% of the protein in the feed of tilapia.Experimental tank Mean weight of deposited particles However, it could be studied in the future to find the