Optimal Light Intensity and Nitrogen-to-Phosphorus Ratio for Growth of Nitzschia capitellata Hust.

Objective] The aim was to explore the potential of Nitzschia capitel ata as excel ent baits and bioenergy, and the optimal light intensity and nitrogen-to-phos-phorus （N/P） ratio suitable for its growth were researched as wel . [Method] With light intensity gradient set, Nitzschia capitel ata was cultured with the same nutrients at （25 ±1） ℃ and light cycle at 12 h/d to select optimal light intensity. Then, Nitzschia capitel ata was cultured with the same condition, and nitrogen-to-phospho-rus ratios at 5∶1, 6∶1, 7∶1 and 8∶1. [Result] With light intensity at 3 000 lx, specific growth rate and standing stock achieved the highest at 0.51 d-1 and 7.97×104 cel s/ml. The growth condition with nitrogen-to-phosphorus ratio at 6∶1 was the most suitable for Nitzschia capitel ata growth. [Conclusion] The optimal light intensity and nitrogen-to-phosphorus ratio were 3 000 lx and 6∶1, respectively, for Nitzschia capitel ata.

Effects of salinity and nutrients on the growth and chlorophyll fluorescence of Caulerpa lentillifera

Caulerpa lentillifera is a green algae that distributes worldwide and is cultivated for food. We assessed vegetative propagation of C. lentillifera by measuring the specific growth rate （SGR） and chlorophyll fluorescence of the green algae cultured at different salinities and nutrient levels. The results indicated that C. lentillifera can survive in salinities ranging from 20 to 50, and can develop at salinities of 30 to 40. The maximum SGR for C. lentillifera occurred at a salinity of 35. Both chlorophyll content and the ratio of variable to maximum fluorescence （F_v/F_m） were also at a maximum at a salinity of 35. Photosynthesis was inhibited in salinities greater than 45 and less than 25. Both the maximum SGR and maximum chlorophyll content were found in algae treated with a concentration of 0.5 mmol/L of NO3-N and 0.1 mmol/L of PO_4-P. The photosynthetic capacity of photosystem Ⅱ （PSⅡ） was inhibited in cultures of C. lentillifera at high nutrient levels. This occurred when NO_3-N concentrations were greater than 1.0 mmol/L and when PO4-P concentrations were at 0.4 mmol/L. As there is strong need for large-scale cultivation of C. lentillifera, these data contribute important information to ensure optimal results.

Effects of salinities on the growth and nutrient composition in the muscle of Exopalaemon carinicauda

The effect of salinity on the growth and muscle nutritional quality of theExopalaemon carinicauda was studied through testing the survival rate, specific growthrate, muscle nutrient composition, amino acid composition and content by the culturingin different salinities(0-30).The results showed that the survival rate of salinity (0-30)had no significant difference (P>0.05), and the specific growth rates at salinity 15 andsalinity 20 were significantly higher than others(P>0.05); the muscle moisture contentand the crude fat content significantly decreased(P<0.05), while the muscle crudeprotein content significantly increased with an increase in the environment salinity from0 to 30(P <0.05).The crude ash content with salinity increase had a slight increase; themuscle crude protein content (18.2) at salinity 15 was significantly higher than that atsalinity 0,5, or 10(P <0.05), but there was no significant difference between salinity 15and salinity 20(P>0.05). No significant difference was found in total amino acid contentor total essential amino acid content from salinity 0 to 30(P>0.05). Total delicious aminoacid content at salinity 15-30 was significantly higher than those at salinity 0-10(P<0.05), while there was no significant difference from salinity 15 to 30(P>0.05). Theresults suggest that the suitable salinity for muscle nutritive value ranges from 15 to 30,and the Exopalaemon carinicauda can potentially be cultured above the salinity 15.

Impacts of Date Palm Seeds （Phoenix dactyliferous L.） on Growth Indices and Nutrient Utilization of Common Carp Cyprinus carpio L,

This study was carried out to study the effect of adding different levels of date palm seed （Phoentix dactyliJProus） powder in the diet of common carp （Cyprinus carpio） at fish laboratory of Animal Production Department, College of Agricultural Sciences, Sulaimani University, Sulaimani, Iraq. The actual experimental feeding trials were conducted for 70 d and the adaptation period for 21 d. A total of 81 common carp fingerlings weighted 62 ± 2 g were divided into three experimental groups. The control treatment T1 was with 0 g date palm seed, T2 with 2.5 g date palm seed per kg diet and T3 with 5 g date palm seed per kg diet. Each treatment was in three replicates in which three common carp fingerlings were stocked in each aquarium which fed the experimental diets twice daily. The results indicated that weight gain （WG） and specific growth rate （SGR） in the third treatment （T3） group were significantly higher than those of fish fed control diets. T2 consumed more diet than other treatments with 306.940 g with higher feed conversion ratio （FCR）; T3 was higher significantly in food efficiency. No significant （P 〈 0.05） differences obtained from consumed protein while the protein efficiency ratio was significantly higher in T3 with 319.323. Control was higher significantly in flesh weight without viscera with the third treatment; in flesh weight without head and viscera each the control and the second treatment was significantly higher than the third treatment. As a conclusion, the date palm seeds powder have a positive effect on growth performance of common carp.

Development of growth rate, body lipid,moisture,and energy models for white sturgeon (Acipenser transmontanus) fed at various feeding rates

The objectives were to develop and evaluate: 1) growth rate models, 2) body lipid, moisture, and energy models for white sturgeon fed at various feeding rates(FR; % body weight [BW] per day) and then evaluate responses at proportions of optimum feeding rate(OFR) across increasing BW(g). For objective1,19 datasets from the literature containing initial BW, FR and specific growth rate(SGR; % BW increase per day) were used. For objective 2.12 datasets from the literature(11 from objective 1) containing SGR,FR,final BW,body lipid(%),protein(%),ash(%),moisture(%),and energy(kJ/g) were used. The average rearing temperatures was 19.2 ± 1.5 ℃(mean ± SD). The average nutrient compositions and gross energy of the diets were 45.7 ± 4.3% protein,14.8 ± 3.2% lipid, and 20.4 ± 1.3 kJ/g,respectively. The logistic model was used for objectives 1 and 2 to develop a statistical relationship between SGR and FR, then an iterative technique was used to estimate OFR for each dataset. For objective 2, the statistical relationship between body lipid, energy, and moisture and FR was established. Using the OFR estimate, SGR, body lipid, energy and moisture were computed at various FR as a proportion of OFR, Finally, a nonparametric fitting procedure was used to establish relationships between SGR, body lipid, energy and moisture(responses)compared with BW(predictor) at various proportions of OFR. This allows visualization of the effect of under-or over-feeding on the various responses. When examining the differences between OFR at 100%and various proportions of OFR, SGR differences decrease and moisture differences increase as BW increases. Lipid and energy differences decrease as BW increases. To our knowledge, these are the first description of changes in nutrient compositions when white sturgeon are fed at various FR. Because physiological and behavioral properties that are unique to sturgeon, results from this study are specific to sturgeon under the conditions of this study and cannot be compared directly with salmonids even if some of the results are similar. This research provides insight to designing future nutritional studies in sturgeon.

SuperSAGE digital expression analysis of differential growth rate in a European sea bass population

One of the goals of the aquaculture industry is to understand and control growth associated traits through selective breeding.In the present study the molecular basis of growth heterogeneity in the European sea bass(Dicentrarchus labrax)was addressed.To establish growth heterogeneity in a group of hatchery bred sea bass individuals were tagged and their specific growth rates(SGR)determined at monthly intervals.Gene expression in the brain,liver and white muscle from fish with the most divergent sustained SGR(6 individuals of the first and last quartile)was assessed using SuperSAGE(Serial Analysis Gene Expression)combined with next generation SOLiD4 sequencing.A total of approx.11 million edited tags(26 bp),on average 2 million tags per SAGE library,that represented 47.071 unique transcripts were identified.Comparison of transcripts in fish with high and low SGR yielded 344,698 and 601 differently expressed tags(0.01%false discovery rate and 4-fold change)in brain,liver and muscle,respectively.The tags were mapped onto the sea bass genome and approximately one third of the tags could be assigned to annotated genes.Pathway enrichment analysis revealed in liver,muscle and brain intricate gene expression changes in endocrine regulatory pathways involved in growth,metabolic and the stress axis,underlying divergent SGR in sea bass.

Ascertaining the potential effects of temperature on growth,survival and feeding of different juvenile clown fish

Objective:To determine the physiological and ecological responses of marine ornamental fishes to the change of water temperature with its potential effects on the growth,survival and feeding in clown fish.Methods:Three different sea anemone fish(Premnas biaculeatus,Amphiprion clarkii,Amphiprion akallopisos)were reared in confinement at water temperatures of 26,28,30,32,and 34℃using thermostat and they were maintained up to the marketable size,and growth,survival and feeding were evaluated during the experimental period.Results:The results illustrated that water temperature influenced the physiological performance of juveniles of three different sea anemone fish significantly.The growth and survival rates of juveniles of three different clown fish significantly increased with the increase of water temperature from 26℃to 34℃(P<0.05).Water temperature also influenced the feeding of three different clown fish significantly with feed conversion ratio increased from(0.071±0.020),(0.075±0.030)and(0.079±0.028)to(0.057±0.040),(0.047±0.030)and(0.045±0.028)for Premnas biaculeatus,Amphiprion clarkii and Amphiprion akallopisos respectively with increase of water temperature from 26℃to 34℃(P<0.05).Specific growth rates(P<0.05)increased significantly with increase of water temperature and positively correlated with the feed conversion ratio,indicating that growth rates are significantly increased with increase of temperature.Conclusions:This study deliberately reveals that the physiological response of juveniles of clown fish as the change of water temperature and substantiated that water temperature influenced juvenile growth,survival and feeding significantly.This study also put forward that the reduced growth,survival and feeding of juveniles at lower temperature which have ecological impacts on clown fish juveniles in settlement and population replacement in the wild.

MODELING AND PARAMETER IDENTIFICATION FOR MULTISTAGE SIMULATION OF MICROBIAL BIOCONVERSION IN BATCH CULTURE

The bioconversion of glycerol to 1,3-propanediol is a complex bioprocess. The item of product inhibition in the equation of Specific rate of cell growth is overlapped in [L. Wang, J. X. Ye, E. M. Feng and Z. L. Xiu, An improved model for multistage simula- tion of glycerol fermentation in batch culture and its parameter identification, Nonlinear Anal. Hybrid Syst. 3（4） （2009） 455462]. Therefore, in this work, the specific rate of cell growth is modified by the mechanism of multistage simulation of microbial bioconversion and the previous time-dependent model is converted to the autonomous standard form. The properties of the solutions for the nonlinear dynamic system are discussed and the identifiability of the parameters is proved. Finally the feasible optimization algorithm is constructed to find the optimal parameters for the system. Numerical result shows that the improved model with identified parameters can describe the batch culture better, compared with the previous results.