Characteristics of Tilapia Fish

Characteristics of genus Tilapia FishTilapia is generic name of an Afri kindle cichlids endemic classify. This group is composed of ternion aquaculture principal(prenominal) kind of Oreochromis, Sarotherodon and Tilapia. Various characteristics differentiate these three genera, exactly the main critical concerns to reproductive conduct. all(prenominal) species of genus Tilapia ar nesting in builders a brood p bent guards the fertilized eggs in the nest. both(prenominal) species of Sarotherodon and Oreochromis argon m knocked emerge(p)hing incubators eggs gets fertilized in the nest but the parents instantly adjourn up those eggs in mouths and keep them through brooding and for some days afterwards hatching. Brooding in mouth is found depictd in Oreochromis species, while in case of Sarotherodon either male or both female and male are holding brooders (SRAC, 2005).During the last half of 20th century slant farmers all(prenominal) over the tropical and trucking rig-t ropical being get down commenced farming genus Tilapia (FAO, 2000). Today, commercial achievement of important genus Tilapia goes to genus Oreochromis beyond Africa, and more(prenominal) than 90 percent of the farmed genus Tilapia are Nile genus Tilapia outside of Africa. (Balarin and Haller, 1982) report that Nile tilapia is the approximately popular tilapia species for aquaculture and is wide distributed in many countries other than native Africa.AdaptabilityOreochromis niloticus is a quickly ontogenesis species which can live in various types of irrigates. It is extremely adaptable and can use a wide lay out of various nourishment sources (along with plants), but establishs mainly on phyto plunkton along with benthic algae. Even though Nile tilapia is assumed as a fresh pee species it has shown a great permissiveness towards salt and can survive in briny situations (Beveridge et. al., 2000). Stickney et al., (1979) reported that Nile tilapia can tole enjoin to a wi de range of environmental reasons, fast offshoot rate, efficient to convert organic matter into high pure tone protein and develop a favorable taste. eating HabitsTilapia has broad figure food organisms that are natural, along with plankton, some aquatic benthic invertibrates, macrophyte, plank tonic and benthic larval look for, breaking up organic matter, and detritus. With dim auxiliary exhausting, natural food beings typically account for 30 to 50 percent of growth of tilapia. Tilapia is often refer departure as click feeders as they can efficiently reap water plankton. The gills of tilapia release a mucous which traps plankton. Then mucous fecund with plankton or bolus, is swallowed (EL-Sayed A.F.M., 2006).Tilapia is an omnivore style feeds on both plants and animal(prenominal)s food sources. However, feeding behavior depends with size and maturate. Larvae normally feed on phytoplankton (algae), fingerlings feed on zooplankton (artemia, moina, and rotifer), and whi le adults consume both plants and animal food sources near the surface because are floating feeders. In this regard, Caulton 1976 Saha and Dewan 1979 Brummett 1995 Turker et al. 2003 bumped that little tilapia filtered substantially more phytoplankton regarding than grownr ones. In addition, Azim et al. (2003) looked into government issue of periphyton quantity and size of tilt (7 and 24 g) on ingestion rate by Nile tilapia, and they observed that ingestion rate betwixt small tip significantly increased with tautness of periphyton, but not for slant with strength size.Protein RequirementsIncluding Tilapia Proteins are important nutrients for all living organisms for their structure and function. unremitting use of protein is being used for maintenance, growth and re doing. Therefore, continuous supply of proteins or their component amino acids are necessary. Many studies indicated that fish does not conduct true protein necessary, but instead needs a well equilibrized ad mixture of dispensable and indispensable amino acids. Insufficient intake of protein will aftermath in retardation of growth due to withd crude(a) of protein from a few(prenominal)er full of life weaves to maintain the function of critical parts. Too much supply of protein, however, just now part will be used to synthesize new tissues and close will be converted to energy (NRC, 1983).Many surfaceings have been carried out active the optimum dietetical protein aim for tilapia. This aim for tilapia appears to be influenced by size or age of the fish and ranges from 28% to 50%. For fry dietetical protein aims ranging from 36 to 50% have been shown to produce silk hat level growth (Davis and Stickney, 1978 Santiago and Laron, 1991 El-Sayed and Teshima, 1992). That for juvenile 29 to 40% has been primed(p) to produce optimum growth (Cruz and Laudencia, 1977 Teshima et al., 1978) for puppyish adult fish up to 40g 27.5 to 35% appears to be upper encumber (Jauncey and Ross, 1982 Siddiqui et al., 1988 realize and Tuan, 1988 Twibell and Brown, 1998).Practical diets for grow out of tilapia usually suffer 25 to 35% crude protein. In ponds, however, fish may have access to natural food that is rich in protein, thus dietary protein levels as low as 20 to 25% have been estimated to be able (Newman et al., 1979 Lovell, 1980 Wannigama et al., 1985).Proteins are made up of amino acids. Arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine are the amino acids have been shown to be necessity for fish (Moyle and Cech 1982). The main problem is that quantity for each type necessary differs from species, and excessive quantity ability be damaging a fishs wellness (Moyle and Cech 1982).Scoliosis (curvature of the spine) can resolution due to lack of amino acids in fish (Moyle and Cech 1982). Proteins are vital in the fish growth. Research has shown that due to authoritative proteins lack, growth will be s crawny. In the nature, omnivorous fish mainly feed on ample alive organisms, protein enriched, that provide a valuable energy source (Moyle and Cech 1982). However, many commercial foods lack ample protein as it is expensive. Fish use large amount of energy to crush large and complex proteins. Due to this, carbohydrates and lipides are replaced as energy sources (Moyle and Cech 1982).Lipid extremityOn other hand, lipids are found in tissues of both animal and plant and are bideible completely (Moyle and Cech 1982). Symbiotic bacteria are present in guts of many herbivorous fish that helps to digest the carbohydrates and liberate its energy to fish. Lipids supply higher energy than do carbohydrates, and withal render fat acids, that are used for the energy construction militia in fish. Predaceous fish normally have a maximum growth rate due to their diet of live fish, which are course high in lipids (Moyle and Cech 1982).Dietary lipids are the main source of prerequisite fatt y acids needed by fish for normal growth and development. They are vital carriers and assist in absorption of vitamins with fat-soluble. Lipids, especially phospholipids, are important for cellular structure and maintenance of membrane flexibility and permeability. Lipids serves as precursors of steroid hormone hormones and prostaglandins, improve the flavor of diets and ask the diet texture and fatty acids story of fish (Webster I. et al., 2002). Takeuchi et al. (1983) reported that essential fatty acid essential of Nile tilapia was found to be 0.5% linoleic acid (1826). round out diets and Feeding LevelsComplete diets are important in semi intensive culture systems of Nile tilapia, for a provision of all essential nutrients to the fish. In order to develop such diets it is also necessary to know the specific nutrient urgencys of the animal and optimize feed varietyulation in order to obtain fast growth of high quality fish at low costs, (Moore, 1985).Nutrient need of suppl ementary feed for Nile tilapiaMany studies have been done to find out the suitable optimum nutrient level for tilapia. Fineman and Camacho (1991) observed that 30% protein with 3500 kcal was better than 30% protein with 3000 kcal for supplementary feed for Oreochromis niloticus in brackish water ponds. Watanabe et al. (1990) found that nett mean weight were high in 28% protein to 32% protein under all densities. Hanley (1990) found that increasing dietary lipid has no significant effect on growth rate, feed passage ratio and protein gain. De Silva and Perera (1985) and Siddiqui et al.(1988) cited by Zonnveld and Fadholi (1991) found that optimum protein levels for fry and young Nile tilapia reared at maximum growth should be 28-30% respectively.Water timbre RequirementsNile tilapia would grow well in water with a temperature range of 20-35c and optimum between 28 and 30C and productiveness can be assumed at a maximum deep down this temperature range (Ballarin and Haller, 1982). Tilapia cannot survive at a temperature below 10c for more than few days. When it exposed to cold water, disease opponent is impaired and death may result in only few days (Lovell, 1989)The tolerance level of DO for Nile tilapia is as tear down as 0.1 mg/L (Magid and Babiker, 1975). Chevrvinski (1982) reported that O. niloticus could survive by victimisation atmospheric type O when dawn DO concentration drops to less than 1 mg/L. Colt (1987) paraded that Nile tilapia growth reduces as DO level reaches below 5mg/L.. However, its survival depends on the duration of low dissolved oxygen in the culture system. In tanks, fish survive at the oxygen level of 1.2 mg/L by gulping oxygen from the nimbus for up to 36 hours if other water quality parameters remain at an optimum level (Balarin and Haller, 1982). Nile tilapia has a fatal pH limit at approximately 4 and 11 respectively and pH between 6.5 and 9 is the desirable range for fish culture (Swingle, 1969)Nile tilapia is more toler ant of high ammonia level than any other species of fish. The lethal ammonia level for tilapia is 2.3 mg NH3-N/L., but it was reported that by prolong exposure, it can tolerate levels of up to 3.4 mg/L (Stickney, 1985). A level of unionized ammonia above 0.5 mg/L absolute frequency results in mortality when fish are besides stressed by low oxygen, handling (Ballarin and Haller, 1982).Nile tilapia is not directly affected by alkalinity and tolerance level as high as 700 to 3,000 mg/L CaCo3 (Morgan, 1972). A total alkalinity range of 20 400mg/L is considered satisfactory for most aquaculture purpose (Tucker and Robinson, 1990 cited by Lawson, 1995).Phosphorous requirementThe dietary requirement for match in tilapia varies from 0.9% (Watanabe et al., 1980), 0.45-0.6% (Viola and Arieli, 1983), 0.3-0.5% (Robinson et al 1984, Robinson et al., 1987) to 0.46% (Haylor et al., 1988) depending on species, fish size, food small-arm or expression of a reported requirement, available or fina l dietetic morning star. The diet containing the complete mineral premix contained 0.9% total phosphorus, whereas the pale atomic number 20 and phosphorus diet contained 0.5% overall phosphorus.Although fish could partly take on phosphorus from its environment (Lall, 1979, Lall, 1989, Lall, 19911, dissolved phosphorus is usually at real low levels of about 0.005-0.05 Mg/L, which is inadequate to meet their requirement (Nose and Arai, 1979 cited in Lall, 1991). Hepher (1954) (as cited in Hepher and Sandbank, 1984) noted that even in fish ponds fertilized with phosphates, the level of phosphorus does not increase much above its normal low level due to absorption to soil colloid and precipitation as insoluble compounds. phosphorus is a component of phosphoproteins, nucleic acids and phospholipids, which play important situations in energy metabolism. increase of dietary phosphorus has been reported to decrease the lipid content of musculus and viscera, whereas muscle protein c ontent increased (Murakami, 1970 cited in Lall, 1979 Takeuchi and Nakazoe, 1981 cited in Viola et al., 1986 Shu, 1987 Hung, 1989 Wee and Shu, 1989).Calcium requirementThe requirement for calcium in tilapia reared in calcium-free water was found to be 0.65% for 0. areus (Robinson et al., 1984, Robinson et al., 1987). In the calcium and phosphorus uncomplemented diet, the calcium level was about 1%. At this level, even without supplementation, it appears that the calcium level in the soybean-based diet would be sufficient to meet the requirement. The availability of dietary calcium to fish has not been studied. Furthermore, under normal conditions, one cannot demonstrate a calcium requirement in fish (Cowey and Sargent, 1979 Robinson et al., 1984, Robinson et al., 1987 Yarzhombed and Bekina, 1987) because of calcium wasting disease from the water (Dabrowska et al., 1989 Luquet, 1991).In Nile tilapia, calcium uptake takes place in the skin, curiously by the opercular membrane (McCorm ick et al., 1992). In contrast to phosphorus, it seemed, because, that the calcium requirement could be met from the rearing water. Activities such as liming of ponds are homogeneously sources of calcium. The similarity of calcium levels in the final carcass of fish feed the calcium supplemented, calcium non-supplemented diets and the non-fed fish further support the likeliness of calcium uptake.The calcium is a mustiness in the fish diet for balancing the calcium and phosphorus ratio. Maintaining an optimum Calcium and Phosphorus ratio is important in diets for red sea bream, eels, and brook trout but not for catfish, carp, and rainbow trout (NRC, 1973, NRC, 1983 Ogino and Takeda, 1976 Viola et al., 1986 Hepher, 1988 Lall, 1991). In tilapia, the role of the Ca P ratio is not well defined and merits further study (Robinson et al. 1987). However, noted that in freshwater fish, dietary Ca P ratio does not generally impair growth or tissue concentration as long as dietetic phospho rus is adequate and calcium is present in the rearing water.Feeding standards of supplementary feed for Nile tilapiaThis is a set of tables, which include the quantity of each dietary component required for each age and species of fish for different levels of achievement and maintenance. When complemented by tables of feeds man, then it is possible to formulate accurate rations for individual or fish groups, an essential process for a least-cost ration feeding curriculum operation. Marek (1975) composed a feeding graph of common carp and tilapia. The chart was having estimation of natural food in the pond and subtracted from the calculated feed requirements for maintenance and expected growth. The charts are based on the weight of fish, and changes are adjusted according to the daily growth of fish. In most cases, therefore ration is fixed for a longer period of time (Hepher, 1982).Feeding rate of Nile tilapiaUnderfeeding of fish can result in drudgery loss. Overfeeding will cau se a costly feed wastage and a potential cause of water pollution in addition, a condition ensuing loss of animals or needing expensive corrective measures. Hence, both feed as well as under-feeding has serious economic effects that affect the farm viability. Bard et al (1976) stated that most of the supplemented feed is not fully eaten by fish some drop to the bottom of the water contributes to development of phytoplankton, hence promoting growth of fish both direct and mediate way.Sometimes a vague instruction might be read, like feed 5% of biomass per day as a dry feed. This might be applied during whole growing rhythm method of birth control. This would most likely result in near famishment in the early stages and gross excessive feeding and later water quality problems. Feeding rates must not be steady throughout the whole of the growth cycle till table size. They must be changed according to the fish age and its size to conditions of water. Brown et al (1979) demonstrated t hat it is uneconomical to balance diets fed to fish in ponds according to the absolute nutrient requirement of the fish.Stocking density and sizeFeeding level of fish in the semi intensive system increases with the increase of density of fish. As t density of fish in the semi intensive culture increases per unit area, the food requirement of fish also increases. This increase of biomass does not relate with the increase of raw food and in many cases is associated with a decrease in the production of food from nature due to limited supply to the overgrowing biomass stated (1979) that when the biomass of fish increased, each fish gets a smaller amount of natural food, which may not meet its nutrition requirement. This deficit can be cover by supplementary feed.Natural Food in a semi intensive cultureAlgae or phytoplankton is an microscopic weeds form the base of the fish food chain. Adequate temperature, sunlight, and nutrients are basic for all spirt plants needed for growth. In pre sence of the sufficient light and comely temperature, chemical fertilizers (nitrogen, phosphorous and potassium) nutrients are readily assimilated by phytoplankton and increasing their abundance. muck up comprises the same nutrients, is released and present to phytoplankton during and after decomposition. As phytoplankton absorbs fertilizer nutrients and reproduces to create dense communities pond water changes to brownish or greenish intensity. This is known as phytoplankton bloom.There are three basic feeding pathways by which stimulant of fertilizer in the pond provides nutrition for fishDirect intake of organic matter by fishAutotrophic productivity of algae pursuant to fertilization and their consumption by filter feeding fish.heterotrophic productivity of micro organisms and benthic micro organisms from manure inputs and their successive consumption by fish.These three basic feeding pathways can operate in a single aquaculture system, even though their relative importanc e shut away a subject of intense debate Colman and Edwards, (1987). In Israel experimental stimulate reported that the heterotrophic pathway of organic manure was found to be more efficient than an autotrophic pathway, Schroeder (1980). It was stated that low fish production by an autotrophic food chain was due to the sunlight limitations of phytoplankton with filter feeding fish mainly depend on heterotrophic organisms that are not light dependent. Therefore, the autotrophic food chain is required to provide the necessary DO which limit to the heterotrophic feed chain Colman and Edwards, (1987).The fertilized ponds with nutrients stimulate the microscopic plants growth in the water (phytoplankton). Phytoplankton is food for other water creatures (zooplankton and larger animals) that fish eat. Water becomes turbid or greenish color (called a bloom) Martin et al (1999) because of abundant growth of microscopic plants. Evaluation of the nutritionary value of natural food is a diffi cult because each fish species has its own nutrition requirement from its diet Determination of biomass of phytoplankton, zooplankton and benthos in the fish pond must be related to the food requirement of fishes. Until now, there is not a reliable method developed for stopping point of secondary production, although primary production can be estimated. Spataru et al (1979) reported that supplementary feed can replace some of the natural food. Aquino and Neilso (1982) support that Oreochromis niloticus grow well in cages on food.The primary producers which are sourcing of food to different type of fish are not digested equally by fish. unforgiving green algae Anabaena, Microcystis, Oscillator was reported to be indigestible because they have copious moulage, cellulose wall, or firm periblast, (Zhang, 1989). Recent research work in China indicated that Tilapia can digest green-algae (Zhang, 1989).Mellamena, (1990) reported that algae contain protein, fat, Carbohydrates varies 22% t o 48%, 2% to 16%, and 14% to 24% respectively. Zooplankton has more protein and fat content than any other phytoplankton except one gabber. Diatoms which have the more silicious cell wall contain higher quantities of inorganic matter. Tamiya, (1975) found that the average protein content of algae is about 50% on a dry matter basis. The biological value of algae is about 81.5% meaning that 124gram of algal protein corresponds to 100 grams of egg protein. The amino acid composition of algae is similar to that of FAO reference protein except, there is a slight need in cystine and methionine.Lipids found in phytoplankton are typical ester of glycerol and fatty acids having a carbon number from C14 to C20. The major acids in diatoms are palmitic (160), hexadecanoic (161), Becker (1989). Blue green algae have a larger amount of unsaturated fats (25% to 68%) oftotaltriglyceride up to 80% of the totalalgae lipids. Lipid content of Cyanobacteria and green algaein outdoor mass culture is 7% to 15% lipids (Becker, 1989). (Nostocsp., Calothrex sp., Oscallaria and Spirulina sp., Urenima sp.) and 20% to 25% lipids in green algae (Scenedesmus),to 10% in dry weight.All plankton feeders fish reported to digest diatoms such as Silver carp and tilapia (Power, 1960, 1966). Tilapia zillii in Israel revealed that it had a capacity to disintegrate after gelatinous matrix colonies of blue green algae, especially Microcystis (Spataru, 1978).