Amino Acid Requirements of Gilthead Bream (Sparus aurata) Juveniles

In one trial 360 gilthead bream fingerlings received two different feed mixtures containing two different levels of protein (diet A 400 and B 360 g?kg?1). The average initial live weight was about 2.2 ± 0.1 g fish?1 in each replicate of all treatments. Sixty fish per tank were stocked randomly in 6 fiberglass tanks (1 m3 each). Fish were fed with experimental diets at rate 8% of the body weight daily. The Amino Acids (AA) content was analyzed in the diets, whole fish and muscle at the end of the growth period (60 days). The results indicated that at the end of experiment gilthead bream fingerlings had reached an average live weight 18.5 and 16.2 g fish?1 for fish fed diet A and B respectively. Also the increase of protein levels in the feed to 40% caused a significant increase in the content of Indispensable Amino Acid (IAA) and dispensable amino acid (as %v of whole fish and muscle of wet weight). Two methods were subsequently used to estimate the quantitative IAA requirements of gilthead bream fry based on the hypothesis that (a) the dietary requirement pattern of IAA reflected the tissue pattern and (b) the rate of daily deposition in the fish could be equated with the dietary requirement as percentage of 100 g?1 diet. The quantitative IAA requirement (%) of gilthead bream (Sparus aurata) diets was as follow: Lysine 2.27, Methionine 1.09, Therionine 0.61, Leucine 2.4, Isoleucine 0.47, Histidine1.6, Arginine 1.39, Phenylalanine 1.43, Valine 1.22 and Tryptophane 0.42.

Effect of Chitosan Supplemented Diet on Survival, Growth, Feed Utilization, Body Composition &Histology of Sea Bass (Dicentrarchus labrax)

The effect of chitosan incorporated into feed formulation on the growth, feed utilization, body composition and histological response of sea bass (Dicentrarchus labrax) was investigated. Final fish weight, feed conversion ratio (FCR), specific growth rate (SGR), protein efficiency ratio (PER), protein productive value (PPV), and energy utilization (EU) of sea bass feed chitosan supplemented diet and the control diet were determined at the end of experiment. Data presents mean ± SD from triplicate determination (n = 3) for 75 days feeding trial. Different concentrations (0.5, 1.0, 2.0, 3.0 & 4.0) and control without chitosan incorporated with total fish feed in the form of dry diets were fed for 75 days. Average final weight (FW) was significantly higher at diet 3 (1 g?kg?1 chitosan) and the lowest in control fish group, specific growth rate (SGR) was significant at diet 3. Also, protein efficiency ratio (PER), protein productive value (PPV), and energy utilization (EU) showed the same trend. The chemical body composition, crude protein, dry matter, crude fat and ash were significant (P ≤ 0.01) different compared to control groups. The present investigation suggested that the chitosan incorporated into diets of sea bass fish certainly enhanced the non specific responses and reduced mortality and also improved the growth performance of fish.

Partial and Total Replacement of Jojoba Meal （Simmondsia chinensis） Instead of Fishmeal in Nile Tilapia （Oreochromis niloticus） Fingerlings Diets

The present study was carried out to investigate the total and partial replacement of Jojoba meal （JM）, Simmondsia chinensis, with fishmeal （FM） at different levels （0%, 25%, 50%, 75%, and 100%） on growth performance, feed utilization, and carcass composition of Nile tilapia, Oreochromis niloticus fingerlings. Fingerlings with an average weight of 1.65 ± 0.01 g/fish stocked at a rate of 10 fish/aquarium for 84 days experimental period. All experimental diets were isocaloric （437.69 kcal/100 g Dry Matter, DM） and isonitrogenous （30.5% crude protein） and supplemented with 0.5% L-Methionine and 0.5% L-Lysine Hcl. Results showed that there were a significant differences （P 〈 0.05） in final body weights, average daily gain （g fish^-1 dayl）, specific growth rate （SGR, % day^-1）, feed conversion ratio （FCR）, protein efficiency ratio （PER）, protein productive value （PPV%） and energy retention （ER%） among the tested groups. Nile tilapia fingerlings fed on the diet containing 25% S. chinensis protein exhibited comparable growth performance to those fed FM protein based diet. Carcass composition of crude protein decreased significantly （P 〈_ 0.05） with increasing JM replacement level above 50%, while replacement 25% JM does not affect DM and Crude Protein of fish flesh. On the other hand, increasing JM replacement level up to 75% increased Ether Extract % significantly （P 〈 0.05） and increasing JM up to 100% increased ash content significantly （P ≤ 0.05） while energy content （EC） decreased. It could be concluded the replacement of 25% Jojoba meal instead of fishmeal in Nile tilapia fingerlings diets is possible without any adverse effects on its growth performance or feed utilization.

Effect of Stocking Density on Growth Performance, Production Trait, Food Utilization and Body Composition, of Meagre (Argyrosomus regius)

A 10-week rearing trial was conducted in cages with average initial weight of 9.15 ± 0.2 g/fish and average initial length of 9.2 ± 0.02 cm/fish of meagre, Argyrosomus regius, to examine the effect of three stocking density on growth performances, production traits, feed utilization and body composition. Nine cages 24 m3 each (4 × 6 × 1.5 m, long, width and height) were stocked with either 1200, 3600 and 6000 fish for each cage to give a stocking rate of 50, 150, and 250 fish/m3 respectively and fish fed daily, slightly in excess of satiation to eliminate the possibility of food supply being a limiting factor to growth. The results revealed that, mean final weight (g/fish), gain in weight, SGR (%per day), feed conversion ratio, protein efficiency ratio and total feed intake (g/fish) were significantly (P ≤ 0.01) influenced. The best at the lowest stocking density, while, the total production and net production exhibited significantly the opposite trend. Harvest and production estimates increased with increasing stocking density. Fish body composition% of moisture, protein, fat and ash were significantly (P ≤ 0.01) influenced by stocking density. From the above results and the economic information of the study, it can be concluded that stocking density of 50 fish/m3 of meagre exhibited the highest net profit and would seem to be the most desirable density in the system studied.