الفهرس 
SOME FACTORS AFFECTING ON GROWTH, PRODUCTION OF MARINE MICROALGAE AND RELATION TO FISH FEEDINGOnly 14 pages are availabe for public view
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Abstract
Some factors affecting the growth, production, composition of marine microalgae and relationship of fish feeding Microalgae are one of the most important sources of feed in aquaculture. As well as the possibility of being used as a source of biofuels, because they contain a high percentage of fat compared to oil crops, but they need high cost of growth because of the high prices of special environments for growth.
The present study includes an attempt to find cheap alternatives to growth the of algae Nannochloropsis oceanica based on carbon sources (fructose, lactose, glucose, sucrose, starch) and nitrogen sources (poultry manure, rumen liquid), and their impact on the growth and production of red tilapia (O.niloticus xO.mossambicus ), and seabass (Dicentrachus labrax ) fish, and the production of biofuels .
Four research experiments were conducted in cooperation between the Faculty of Agriculture, Alexandria University and the Marine Hatchery at the National Institute of Oceanography and Fisheries, Alexandria, as follows:
The development of algae N. oceanica in laboratory conditions on carbohydrate and nitrogen sources at different rates for 20 days.
Indoor experiments
The experiment 1:
Exp.1.A. Performances of Nannochloropsis oceanica cultured on different sources
( fructose, F , sucrose, Su, glucose, G, lactose, L and starch, St ) and levels ( 25, 50,75 and100%) carbon and F/2 medium indoor laboratory and its effects on growth rate , the production of algae and lipid contents, chemical composition and fatty acids were determined.
The results indicated that at the level of 25% of all carbohydrate sources gave the highest growth and highest protein content to the moss body, while the carbohydrate ratio increased at levels of 75 and 100%. There is no significant difference between 25% and 50% so that 50 can be chosen as the best cost. The results also showed that carbohydrate sources of sucrose and starch gave less growth and production of algae .
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Exp.1.B. Performances of Nannochloropsis oceanica cultured on different sources ( poultry manure,PM and rumen liquor,RL) and levels ( 25, 50,75 and100%) nitrogen of F/2 medium indoor laboratory and its effects on growth rate , the production of algae and lipid contents , chemical composition and fatty acids were determined .
The results indicated that at the 25% level, exporters gave the highest growth and highest protein content to the moss body, while carbohydrates increased at replacement of 75 and 100%. However, there was no significant differences between the level of 25% and 50% and therefore from the economic point of view 50% is to be recommended.
Outdoor experiment
Exp.2.A. Performances of Nannochloropsis oceanica cultured on different sources
( fructose, F, lactose, L and glucose,G ) at four level ( 50:50 %) carbon of F/2 medium outdoor laboratory and its effects on growth rate , the production of algae and oil contents , chemical composition were detriment.
The results indicated that the extracted oil was higher in the growing demand for fructose, followed by glucose and lactose.
Exp.2.B. Performances of Nannochloropsis oceanica cultured on different sources
( poultry manure, PM and rumen liquor, RL ) at four level ( 50:50 %) nitrogen of F/2 medium outdoor laboratory and its effects on growth rate , the production of algae and oil contents , chemical composition were determined.
The results indicated that the percentage of the extracted oil was higher in the growing moss on the rumen liquid soy protein was substituted with moss protein in the diet of red tilapia and seabass in four experiments:
Exp.3. Feeding fish :
Exp. 3.A1. Effect of replacement of Nannochloropsis oceanica meal previously cultured on different sources ( fructose, F, lactose ,L , glucose,G ) and levels ( 25, 50, 75 and 100%) of carbon on the performances of Red tilapia (O.niloticus xO.mossambicus ).
Thirteen diets were used, including 12 diets containing protein from three carbon sources (fructose, lactose, glucose) with a replacement ratio of 25, 50, 75 and 100% compared to the standard diet that did not contain moss, and red tilapia was fed at 0.03 BW three times daily.
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For 30 days. At the end of the experiment, fish growth performance was estimated by weight gain was height increase, average daily gain increase (SGR).
The results indicated when feeding red tilapia fish on a diet containing fructose N.oceanica algae, 100% substitution gave the highest growth rate, best coefficient, highest protein content of the fish body and the lowest fat content, followed by the diet containing 25, 75 and 50%, compared to the standard diet (without algae).
Exp. 3.A2. Effect of replacement of Nannochloropsis oceanica meal previously cultured on different sources (poultry manure, PM and rumen liquor, RL) and levels ( 25, 50, 75 and 100%) of nitrogen on the performances of Red tilapia (O.niloticus xO.mossambicus ).
A total of 9 diets, of which 8 were dietary sources of nitrogen (poultry manure, rumen liquid), were replaced by 25, 50, 75 and 100% substitutions compared to the standard diet that did not contain moss, and tilapia feed at 0.03 BW three times daily, for 30 days. At the end of the experiment, fish growth performance was estimated by weight gain, weight gain was height increase, average daily gain increase (SGR).
The results indicated that when feeding red tilapia fish on a diet containing N.oceanica fed on 100% poultry manure, the highest growth rate, the best coefficient, the highest protein content of the fish body, and the least fat content were found. Followed by 75%, compared to the standard diet (without moss).
Exp.3.B1. Effect of replacement of Nannochloropsis oceanica meal previously cultured on different sources (fructose, F, lactose, L and glucose, G, ) and levels ( 25, 50,75 and 100%) of carbon on the performances of Sea bass (Dicentrachus labrax ).
Thirteen diets, including 12 diets containing protein from three carbon sources (fructose, lactose and glucose), were used with 25, 50, 75 and 100% substitutions compared to the standard non-algae diet, and red tilapia feed at 0.02 BW. Daily, for 30 days. At the end of the experiment, fish growth performance was estimated by weight gain, weight gain was height increase, average daily gain increase (SGR).
The results indicated that when seabass were fed on the fructose algae containing N. oceanica, which fed 75% fructose yielded the highest growth rate, the best coefficient and the highest protein content of the fish body and the lowest fat content followed by diet containing algae
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containing 75% glucose followed by the diet containing 100% fructose-fed algae, compared to standard diet (without algae).
Exp.3.B2. Effect of replacement of Nannochloropsis oceanica meal previously cultured on different sources ( poultry manure ,PM and rumen liqure, RL ) and levels ( 25, 50,75 and 100%) of nitrogen on the performances of Sea bass (Dicentrachus labrax ).
A total of 9 diets, including 8 diets containing two nitrogen sources (poultry manure, rumen liquid), were used at 25, 50, 75 and 100% substitutions compared to the standard diet that did not contain moss, and tilapia feed at 0.02 BW four times daily, for 30 days. At the end of the experiment, fish growth performance was estimated by weight gain, weight gain was height increase, average daily gain increase (SGR).
The results indicated that feeding seabass on the diet containing N.oceanica-algae feed on poultry manure with 100% substitution followed by 50% gave the highest growth rate of fish and the best case coefficient, and chemical composition compared with the standard environment.
Exp.4. Evaluation of biofuels from the experimental algae
Exp.4. A. Oils were extracted after the growing of Nannochloropsis oceanica algae
on three carbon sources ( fructose,F , lactose,L and glucose,G) grown in the laboratory of the National Institute of Marine Science Anfoushi Alexandria.
The objective is to produce and evaluate biofuels from the oil extracted from the algae of the N. oceanica.
The results of the biofuels and fatty acid analysis showed that the highest percentages of biofuel content were obtained from glucose-fed algae due to the increase in SFAs Mysteric acid (C: 14: 0), Palmitic acid (C16: 0) and citric acid (C18: 0). . The highest UFA was achieved by F / 2 (34.7%) followed by fructose (22.4%) followed by glucose (22.2%).
Exp.4.B. Oils were extracted after the growing of Nannochloropsis oceanica algae
on two nitrogen sources ( poultry manure, PM and rumen liquor, RL) ) grown in the laboratory of the National Institute of Marine Science Anfoushi Alexandria.
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The results of biofuels and fatty acids analysis showed that the highest percentages of biofuels content were obtained from algae fed on rumen liquid, while the lowest values of fed algae were recorded algae raised on poultry manure. This is due to the increase in Srists Mysteric Acid Myristic C14: 0), Palmitic acid (Palmitic C16: 0) and Stearic Acid C18: 0). The highest UFA was achieved by F / 2 (34.7%) followed by rumen liquid (17.1%) but the lowest was recorded by poultry manure. The PUFA ratio by rumen fluid was the best result due to the higher PUFA ratio due to the increase in PUFAs -6.
from the results:
N. oceanica algae has been shown to be a good source of biofuels through culture in cost-effective growth environments (fructose, lactose, glucose, poultry manure, rumen fluid) with close percentages of the standard F / 2 medium .
It provides a high percentage of oils that can be used in the production of biofuels, as well as oil-free algae that can be used as a source to provide protein that can be used in feeds of red tilapia fish and weaning feed for seabass larvae through which can enhance the growth performance and chemical composition.