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Aquaculture has been accepted the world over as a means for increasing fish production and a developing country like Nigeria with her immense resources offer tremendous possibilities for fish culture (Dada and Gnanadoss, 1983). Aquaculture expansion has been in slow process as private sector fish farmers face major constraints, such as lack of seed and quality feed (FAO, 2003). Fish is an important source of both food and income to many people in developing countries. In Africa, as much as 5% of the population, some 35 million people depends wholly or partly on the fisheries sector for their livelihood (FAO, 1996a). It is estimated that by 2050, when world population is projected to be over 9 billion, Africa will have to increase food production by 300%, Latin America by 80% and Asia 70% to provide minimally adequate diets for the projected population of 2 billion, 810 million and 5.4 billion people in the respective regions (Anon,1997).
The consumption and demand for fish as a cheap source of protein is on the increase in Africa, because of the level of poverty in the land. The vast majority of the fish supply in most cases comes from the rivers in the continent. While capture fisheries based on species that are presently exploited seem to have reached their natural limits (FAO, 1996b), there is considerable potential to expand aquaculture in Africa in order to improve food security (Kapetsy, 1994; Engle 1997, Jamu and Ayinla, 2003). Although potentials abound in the continent for the development of viable fish farming, one of the major hindrances to the development of aquaculture industry in Africa is the lack of locally produced high-quality fish feed. Fish requires high quality nutritionally balanced diet for growth and attainment of market size within the shortest possible time. Therefore local production of fish feed is very crucial to the development and sustainability of aquaculture in Africa especially, in the rural areas. For aquaculture to thrive and bridge the already existing wide gap between fish demand and supply especially in the Sub-Saharan Africa, the vital role of locally produced fish feed in reducing production cost, thereby making fish farming attractive to both private and commercial investors and ultimately boost fish production cannot be overemphasized.
Catfish family Clariidae is very popular in Nigeria due to its culture characteristic which has endeared it to many fish farmers. Catfishes of the genus Clarias (Siluroidei, Claridae) are widespread in tropical Africa and Asia (Sudarto, 2007). Clarias gariepinus, generally considered to be the most important clariid species for aquaculture in Nigeria. Clarias gariepinus is a freshwater catfish with great aquaculture potentials (Teugels et al., 1990; Williams, 1997). The species is widely accepted by fish farmers and consumers because of its taste, fast growth rate and moderate price. They are widely cultured owing to their high market price, fast growth rate, disease resistance ability and ability to withstand adverse pond conditions especially low oxygen content.
Traditionally fish meal had always been the commonest and most popular source of protein for commercial fish feed production. Johnston (2004) reported that global supply of fish meal would not be sufficient to satisfy demand during the course of 2004, despite a slow fish meal market in Europe at present, according to the organization which represents the word's fish meal manufacturers. Johnston (2004) further opined that the global tightness (of fish meal) could be exacerbated by the possible lifting of a current EU ban on fish meal in ruminants diets in January 2005. Whatever the scenario globally, fish meal will always be the costliest single ingredient protein input in fish feed production.
However, the scale of commercial fish culture is hampered by, among other factors, the non-availability of suitable and cost-effective supplementary feed. Consequently most small-scale and homestead fish farmers resort to the primordial practice of feeding with single ingredient feeds which are usually in meal or bran form. The use of well-compounded pelleted feed considerably increases the profit margin of fish production. However, fish feeds are expensive and can account for over two-thirds of the variable costs in fish culture operations ( Balogun et al., 1992).
AIMS AND OBJECTIVES
The aims and objectives of this experiment is as follows:
To compound fish feed with varying dietary protein level (30%CP, 35%CP, 40%CP and 45%CP) using local protein sources like blood meal, soybean meal and groundnut meal.
To determine the growth response of Clarias on readily available local protein sources like blood meal, soybean meal and groundnut meal in practical feeds in Glass aquaria.
2.0 LITERATURE REVIEW
Protein which is the most expensive component of fish feed is very important for fish growth. It is a complex organic molecule that is made up of different amino acid linked together by polypeptide bond. In nature, over 200 amino acid occur (Craig and Helfrich, 2002), but only about 20 amino acid are common. 10 are essential while 10 are non-essential amino acid.
Dietary protein is used by fish for growth, energy and maintenance (Kaushik and Medale, 1994). Protein requirement for maximum growth of any species is a logical step to the development of a cost-effective feed for the fish, and entails determining the minimum amount required to produce maximum growth and not be used for energy (Sang-Min and Tae-Jun, 2005). Thus, any reduction in dietary protein level without affecting fish growth can substantially reduce the cost of feed. However, management, environmental factors and fish size can affect dietary nutrient levels for optimum performance.
Several researchers have carried out work on dietary crude protein requirement of catfishes. Jamabo and Alfred-Ockiya (2008) researched on the effects of dietary protein levels on the growth performance of Heterobranchus bidorsalis (Geoffroy- Saint-Hilaire, 1809) fingerlings from the Niger Delta. Fingerlings of Heterobranchus bidorsalis were fed six isocaloric diets at different crude protein levels at 5% of body weight to determine the growth performance. Growth rate and weight gain increased progressively with dietary protein level to a maximum at 40%. Significant differences (p<0.05) were recorded for the growth indices. The nutrient utilization parameters had variable results among the treatments. There was no significant difference in apparent feed conversion ratio and the nitrogen metabolism but apparent protein efficiency ratio showed significant variations. The overall results indicated that fish fed 40% dietary protein diet performed best in weight gain, food conversion ratio and nitrogen metabolism.
Otubusin et al., (2009) studied on Feeding Trials using Local Protein Sources to Replace Fishmeal in Pelleted Feeds in Catfish (Clarias gariepinus Burchell 1822) Culture. The feeding trial was conducted to determine the growth response of catfish (Clarias gariepinus) on readily available local protein sources like blood meal (BM), soybean meal (SB), and groundnut cake (GC) in practical feeds in net-hapas (L x B x H = 1m x 1m x 1m) hung on bamboo raft in a concrete tank (L x B x H: 4.4m x 2.4m x 1.2m). Fish meal (FM) was used as control. The isonitrogenous diets (about 40% crude protein) were formulated to contain 25% inclusion of each protein source (singly, per feed) and a constant amount of layer's concentrates (18.62%), corn bran (55.87%) and biomix (vitamin premix) 0.50%. Each practical feed was tested in replicates of 50 fingerlings (average weight per fish = 0.20kg) per net cage arranged in a completely randomized design. The fish were fed twice daily at a feeding rate of 10% of fish biomass for 50days. Relative growth rate (RGR), daily weight gain (DWG), specific growth rate (SGR), survival, feed conversion ratio (FCR), protein efficiency ratio (PER) and body composition of catfish juveniles were measured. There were no significant differences (P>0.05) in the final mean weight, SGR, FCR and survival among the fish under all treatments. However, fish fed with blood meal and fish meal in feeds separately had significantly higher (P<0.05) values of DWG, RGR and PER than those fed SB and GC separately. The results showed that 100% of fish meal can be replaced by blood meal with no adverse effects on growth, survival and feed conversion ratio of Clarias gariepinus juveniles.
Zulfikar (2001) investigated the interactions of dietary protein and energy and their utilisation by African catfish, Clarias gariepinus (Burchell, 1822) (12.43 ± 0.05 g), a series of four nutritional experiments (triplicate groups of 20 fish per 30-L tank at 28 ± 1°C, for 8 weeks) were carried out using fish meal based diets. Optimum dietary protein to energy ratio (P/E ratio) and optimum lipid to carbohydrate ratio (L/CHO ratio) were investigated. Based on optimised dietary P/E ratio and L/CHO ratio, optimum feeding regime and compensatory growth were also investigated in this species. In the experiments to optimise P/E ratio and L/CHO ratio fish were offered each diet at 5% of their body weight per day adjusted fortnightly. In the optimum feeding regime experiments, fish were offered each diet to appetite or to a restricted level. The restricted regimes were achieved by offering fish decreasing fixed feeding rates with increasing dietary protein level. Studies on compensatory growth were conducted in two phases each of 4 weeks. In the first phase, triplicate groups of 30 fish and in the second phase triplicate groups of 20 fish (per 30- L tank) were offered the diet in six mixed feeding schedules at two feeding regimes i.e. appetite and restricted. The restricted regime was achieved by offering fish 1% (maintenance ration) of their body weight per day adjusted after fortnightly weighing. Optimum dietary P/E and L/CHO ratios were 20.54-mg protein/kJ of GE and 0.40 g/g respectively, with a crude protein level over 40% and gross energy of more than 20 kJ/g GE. The results of investigating feeding regimes suggest that dietary protein level could be reduced from over 40% to 35% by feeding to appetite based on the above optimised dietary P/E and L/CHO ratios. Addition of dietary energy as lipid at varying protein levels resulted in increased growth, protein and energy utilisation in C. gariepinus. Based on optimised dietary P/E ratio, dietary carbohydrate levels were increased (with concomitant reduction in dietary lipid levels) resulting in a trend towards higher growth performance, protein and energy utilisation. Protein and energy utilisation did not vary (P > 0.05) with feeding regime or dietary protein level. C. gariepinus showed partial compensatory growth under alternating periods of feeding a restricted (maintenance requirements) and appetite ration and also showed higher feed, protein, lipid and energy utilisation efficiencies in comparison to appetite feeding.
MATERIALS AND METHODS
3.1 DESCRIPTION OF STUDY AREA
This research work was carried out at the Institute of Oceanography fish farm in the University of Calabar, Cross River State of Nigeria. It is located at latitude 04Ëš55.9ËN and longitude 08Ëš26ËE along the coastal plain of Nigeria bordering the gulf of Guinea. This area is the peninsular within the Calabar and great kwa River, it is 42m above the sea level
The study area climate is characterized by a long wet season from April to October and a dry season from November to March. Mean annual rainfall is about 2000m (Akpan and Ofem, 1993). A short period of drought occurs in the wet season around August/September, which is called August drought. There is usually a cold dry dust period between December and January referred to as harmatan season. Temperature ranges from 22ËšC in the wet season to 35ËšC in the dry season. Relative humidity is above 60% at all season with close to 90% during the wet season (Akpan, and Ofem, 1993 and Ama-Abasi et al, 2004).
The study area vegetation is the rain forest close to the mangrove belts. Mangrove with major species such as Rhizophora racemosa, A. Africana, Rhizophora harissonii, Laguncularia racemosa while the main nypa palm is Nypa fruticaus. Panamas species is a major free species that forms the mix forest of the area.
3.1.4 HUMAN ACTIVITIES
Human activities in the study area include farming, hunting, boat building, and sand mining.
3.2 EXPERIMENTAL DESIGN
This experiment lasted for 10 weeks and was carried out in the Hatchery complex of the Institute of Oceanography, University of Calabar where 8 aquaria measuring 96 x 50 x 29 cm3 were used. Four different kinds of fish feed labelled A, B, C, D were formulated with varying dietary protein level i.e. 30%CP (Feed A), 35% CP (Feed B), 40% CP (Feed C) and 45% CP (Feed D). The experiment was carried out in duplicate and the fishes were fed twice daily at 5% of their body weight.
3.3 EXPERIMENTAL FISH
A total of 80 fingerlings of the African catfish Clarias gariepinus was collected from the Institute of Oceanography Hatchery Complex, University of Calabar and used for this experiment.
3.4 EXPERIMENTAL DIET COMPOSITION FORMULATION TECHNIQUE
3.4.1 EXPERIMENTAL DIET COMPOSITION
Experimental diet was composed of the following ingredients; Blood meal (BM), soybean meal (SBM), Groundnut meal (GNM), vitamin premix, palm oil, wheat offal (WO), Vitamin C, lysine, wheat flour, sodium chloride (NaCl), and Bone ash.
DIET FORMULATION AND PREPARATION
Four different experimental feed (A, B, C and D) were formulated with varying dietary protein (30%CP, 35%CP, 40%CP and 45%CP) using pearson square method (Felaye, 1992). After collection and processing of the ingredients, they were weighed and mixed as shown in table 1. After mixing, the feeds were moulded by hand and thereafter sun dried to reduce moisture content and also to prevent growth the of mould.
TABLE 1: percentage composition of the feed ingredient in the four experimental feed.
WEIGHT OF INGREDIENTS (g)
Blood Meal (BM)
Soya Bean meal (SBM)
Groundnut Meal (GM)
Wheat Offal (WO)
Sodium Chloride (Nacl)
Total Percentage Composition
3.5 DETERMINATION OF GROWTH INDICES
The following growth indices were calculated at the end of the experimental period. Length gain (cm), weight gain (g), growth rate (GR), specific growth rate (SGR), mean growth rate (MGR) and percentage weight gain(%).
3.5.1 WEIGHT GAIN
weight gain was obtained by subtracting the initial weight from the final weight and is given below;
Weight gain(g) = final weight(g)(w2) - Initial weight(g)(w1)
3.5.2 Specific growth rate (SGR)
This given as the percentage of weight gain per day
SGR = lnw2-lnw, x 100 (brett et al 1969 styczynska et al, 1969)
Where W2 = final weight at end of time T2
W1 = initial weight at beginning of Time T1
ln = base of natural logarithm
3.5.3 MEAN GROWTH RATE (MGR)
This was calculated as the average weight gain in million gram per day.
M.G.R = W2 -W1 x 100 mg/g day (Ricker, 1973)
0.5 (W2+ W1)t
Where W2 = final weight (g)
W1 = initial weight (g)
T = experimental period in days
3.5.4 GROWTH RATE
This is given as W2 - W1 x 100
Where W2 = final weight
W1 = initial weight
3.6 WATER QUALITY DETERMINATION
Water quality parameters determined were pH, water temperature and dissolved oxygen. pH was measured using pH meter, water temperature was measured using mecury in glass thermometer, dissolved oxygen was measured using oxygen meter and ammonia level was determined colorimetrically.
Data obtained from the experiment was analysed using analysis of variance (ANOVA) for significant differences at 0.05 probability level.
MEAN GROWTH PERFORMANCE INDICES
Growth indices examined in this experiments include weight gain (g), growth rate (G.R), specific growth rate (S.G.R) and mean growth rate (M.G.R). The maximum weight gain was obtained in fish fed diet D containing 45%CP (79.62 + 1.14g) followed by fish fed diet C containing 35%CP (63.30 + 0.90g). Fish fed diet B gained (51.88 + 2.08g) of weight while fish fed diet A showed the least weight gain (41.10+ 1.82g). Growth rate (G.R) was also highest in fishes fed diet D containing 45%CP (1.195+ 0.074) while the least value was obtained in fishes fed diet A (0.587 + 0.026).
For specific growth rate (SGR), fish fed diet D containing 45%CP also showed the highest value (2.706 + 0.04) while the least specific growth rate was obtained in fish fed diet A (2.107+0.060). Mean growth rate (MGR) also followed the same pattern with fish fed diet D containing 45% CP showing highest value (22.12 + 1.2) while least value was also obtained in fish fed diet A (16.93 + 0.65). Table2 and figure 1 shows the mean growth performance indices of Clarias gariepinus fed diets containing varying crude protein level.
Table 5:- Mean growth performance indices of Clarias gariepinus fed with diet containing varying crude protein level
Figure 1 : Mean growth performance indices of Clarias gariepinus fed with diet containing varying crude protein level
4.2 PHYSICOCHEMICAL PARAMETERS
Physicochemical parameters measured in this research work were pH, temperature (T0C) Ammonia (NH3) and dissolved oxygen (DOmg/l).
In aquarium A, pH ranged between 6.30 - 6.71, temperature ranged from 27.8 - 30.20C, Ammonia (NH3) was 0.00 while dissolved oxygen ranged from 2.2-2.5 mg/l.
In aquarium B, pH ranged between 6.88 - 7.10, temperature ranged from 26.4 - 28.60C, Ammonia (NH3) ranged from 0.030-0.010mg/l while dissolved oxygen ranged from 2.4-2.7 mg/l.
In aquarium C, pH ranged between 6.60 - 7.30, temperature ranged from 27.3 - 29.60C, Ammonia (NH3) ranged from 0.030-0.060mg/l while dissolved oxygen ranged from 2.3-2.5 mg/l.
In aquarium D, pH ranged from 7.01-7.50, temperature ranged from 27.6 - 28.90C, ammonia (NH3) ranged from 0.030 - 0.060mg/l
Figure 2: Mean Physicochemical Parameters
DISCUSSION, SUMMARY AND CONCLUSION
Experimental diets were compounded using locally available ingredients such as Blood meal, soybean meal, goumdnut meal etc. Blood meal is uniquely rich is lysine having twice the lysine content of white fish meal and almost three times the level in dehulled soybean meal (Crashaw, 1994). Allan (1998) reported that blood meal in feeds was well utilized by barramundi and Atlantic salmon which were adapted to carnivorous diets. Bureau et al. (199) working on apparent digestibility of rendered animals protein ingredients for rainbow trout (Onchorhynchus mykiss) concluded that
spray- dried blood products were highly digestible (Apparent digestibility coefficient, ADC protein = 97 - 99%). The processing method of the blood product used in this study was that which was by far the best as reported by Okuneye and Bamiro (1990).The summary of growth responses of fish fed diets with varying crude protein level as presented in table 2 showed that all the experimental fish responded to the four experimental diets although some showed remarkable differences. The results show significant differences among treatments in the growth indices-weight gain. Mean weight gain increases as protein level increases from 41.10 +1.82g to a maximum of 79.62 +1.14g at 45% crude protein level.
Also, the recorded increase in growth rate values with increase protein level are similar to the observations of Faturoti et al. (1986) for Clarias lazera fingerlings, Obasa and Faturoti (2000) for Cryptocoryne walkeri and Erondu et al.,(2006) for Chrysicthys nigrodigitatus. Specific growth rate follows the same trend, it increases as protein level increased to a maximum of 2.706 + 0.040 when protein was 45% and decreased to 1.950 + 0.101 when protein level was 30%. On the whole C. gariepinus fingerlings fed with 45% crude protein diet performed better than fish fed at low protein level diets. Protein was more efficiently utilized by C. gariepinus at 45% crude protein level than others. This trend is in tandem with results observed by Degani et al., (1989) on C. lazera. Moreover, findings from this study agrees with Kaushik and Medale, (1994) that dietary protein is used by fish for growth, energy and maintenance.
In view of the results obtained in this work, it is obvious that C. gariepinus fingerlings performed best when fed on 45% crude protein diet. It is believed that a compounded diet of 45% crude protein would provide nutrients that will ensure optimum growth of C. gariepinus in production systems without natural food. The results of the present study therefore could provide useful assistance to fish farmers especially in the culture and management of C. gariepinus.
The mean water quality parameters values observed for temperature DO and pH within the recommended range for effective fish culture (Boyd and Lichtkoppler, 1979; Viveen et al., 1985).
5.2 SUMMARY AND CONCLUSION
In summary, protein is very necessary for the growth of C. gariepinus. However, a compounded diet of 45% crude protein using locally available feedstuff like Blood meal, soybean meal groundnut meal etc. would provide all the essential nutrients required for optimum growth of C. gariepinus in production systems without natural food.