Dietary sodium acetate and sodium butyrate improve high-carbohydrate diet utilization by regulating gut microbiota, liver lipid metabolism, oxidative stress, and inflammation in largemouth bass(Micropterus salmoides)

Background Adequate level of carbohydrates in aquafeeds help to conserve protein and reduce cost. However, studies have indicated that high-carbohydrate(HC) diet disrupt the homeostasis of the gut–liver axis in largemouth bass, resulting in decreased intestinal acetate and butyrate level.Method Herein, we had concepted a set of feeding experiment to assess the effects of dietary sodium acetate(SA) and sodium butyrate(SB) on liver health and the intestinal microbiota in largemouth bass fed an HC diet. The experimental design comprised 5 isonitrogenous and isolipidic diets, including LC(9% starch), HC(18% starch), HCSA(18% starch;2 g/kg SA), HCSB(18% starch;2 g/kg SB), and HCSASB(18% starch;1 g/kg SA + 1 g/kg SB). Juvenile largemouth bass with an initial body weight of 7.00 ± 0.20 g were fed on these diets for 56 d.Results We found that dietary SA and SB reduced hepatic triglyceride accumulation by activating autophagy(ATG101, LC3B and TFEB), promoting lipolysis(CPT1α, HSL and AMPKα), and inhibiting adipogenesis(FAS, ACCA, SCD1 and PPARγ). In addition, SA and SB decreased oxidative stress in the liver(CAT, GPX1α and SOD1) by activating the Keap1-Nrf2 pathway. Meanwhile, SA and SB alleviated HC-induced inflammation by downregulating the expression of pro-inflammatory factors(IL-1β, COX2 and Hepcidin1) through the NF-κB pathway. Importantly, SA and SB increased the abundance of bacteria that produced acetic acid and butyrate(Clostridium_sensu_stricto_1). Combined with the KEGG analysis, the results showed that SA and SB enriched carbohydrate metabolism and amino acid metabolism pathways, thereby improving the utilization of carbohydrates. Pearson correlation analysis indicated that growth performance was closely related to hepatic lipid deposition, autophagy, antioxidant capacity, inflammation, and intestinal microbial composition.Conclusions In conclusion, dietary SA and SB can reduce hepatic lipid deposition;and alleviate oxidative stress and inflammation in largemouth bass fed on HC diet. These beneficial effects may be due to the altered composition of the gut microbiota caused by SA and SB. The improvement effects of SB were stronger than those associated with SA.

Effects of Dietary Carbohydrate-to-Lipid Ratio on the Growth Performance and Feed Utilization of Juvenile Turbot(Scophthalmus maximus)

A 9-week feeding trial was conducted to investigate the effects of dietary carbohydrate to lipid ratio(CHO:LIP) on the growth performance and feed utilization of juvenile turbot Scophthalmus maximus(initial body weight 8.75 g ± 0.04 g). Four isonitrogenous and isoenergetic low protein level(39%) diets were formulated with increasing ratios of dietary carbohydrate to lipid(2:18, 6:18, 18:12 and 28:6). A high protein level(50%) diet with the 2:12 ratio of carbohydrate to lipid was used as the control. Results showed that the survival rate, contents of moisture, crude protein and ash in muscle were not significantly affected by dietary treatments. With the dietary CHO:LIP ratio increased from 2:18 to 18:12, weight gain rate significantly increased(P < 0.05). Higher dietary CHO:LIP ratio(28:6) resulted in the significantly decreased weight gain rate(P < 0.05). Meanwhile, this treatment also resulted in the highest daily feed intake and liver glycogen content, as well as the lowest feed efficiency(P < 0.05). Muscle glycogen content in fish fed the diet with 2:12 or 2:18 CHO:LIP ratio was significantly lower than those fed with the other three diets(P < 0.05). The present results confirmed that the juvenile turbot can utilize carbohydrate. Furthermore, the appropriate ratio of dietary carbohydrate to lipid was important to the growth and feed utilization of turbot. The proper CHO:LIP ratio based on the growth performance in the present study was determined to be 18:12 when the dietary protein level was 39%.

The Effects of Growth Performance and Organosomatic Indices of Atlantic Salmon Juvenile by Using Different Carbohydrate-to-Lipid Ratios in Feeds

The effect of different carbohydrate-to-lipid ratios in feeds on the growth performance and organosomatic indices of Atlantic salmon, Salmon salar, was determined in this experiment. Four iso- energetic feeds were manufactured with increasing carbohydrate level (18%, 21%, 14%, 26%). Lipid level was decreasing from 14% to 11% for each diet for energetic balance. Fish were reared in triplicate tanks for each diet treatment for 49 days. The diet which contained 26% carbohydrate and 11% lipid provided the highest specific growth rate (SGR = 0.66% ± 0.04% per day) to the fish. However, the feed efficiency (FER) ranked from 0.71 to 0.91 had no significant differences between diets. Similarly, the values of condition index (K), relative gut length (RGL) and hepatosomatic index (HSI) had no significant differences between groups. The relationship between liver and carcass weight showed that with the increasing of fish carcass weight, the liver weight increased. According to this experiment, it suggests that based on an optimum level of carbohydrate in diet, the juvenile salmon has a better growth fed by a diet with a higher carbohydrate-to-lipid ratio.

Effects of Dietary Carbohydrate-lipid Ratio on Growth, Body Composition and Digestive Enzyme Activities of Juvenile Peanut Worm,Sipunculus nudus

[Objective] This study was conducted to investigate the effects of dietary carbohydrate-lipid( C / L) ratios on growth performance,body composition and digestive enzyme activities of juvenile peanut worm. [Methods]Juvenile peanut worm with average body weight of( 16. 77 ± 0. 40) mg were fed with five isonitrogenous and isoenergetic diets formulated to contain different carbohydrate / lipid( C / L) ratios( 0. 68,1. 02,1. 62,2. 61 or 4. 35) for 8 weeks. [Results] The dietary C / L ratios had no significant effects on survival of juvenile peanut worm( P 】 0. 05). With the increasing of dietary C / L ratios,weight growth rate( WGR)and specific growth rate( SGR) increased when dietary C / L ratios were between 0. 68 and 2. 61,and then decreased significantly with dietary C / L ratio further increased. When the dietary C / L ratio was 2. 61( carbohydrate level was 20. 64%,lipid level was 7. 92%) both WGR and SGR produced the maximum value,they were 451. 78 ± 16. 85% and 3. 41 ± 0. 06 % / d,respectively. The dietary C / L ratios had significant effects on body moisture,body protein content and body lipid content( P 【 0. 05),but no significant effects on body ash content of juvenile peanut worm( P 】 0. 05). Different C / L ratios had significant effects on amylase activity and lipases activity of juvenile peanut worm( P 【 0. 05),but no significant effects on protease activity( P 】 0. 05). [Conclusion]The regression model analysis showed that the most suitable dietary C / L ratio which can make juvenile peanut worm acquire the best weight growth rate is 2. 42.

Arginine Intake and Carbohydrate to Lipid Ratios Affect Gene Expression of Anabolic Hormones in Largemouth Bass, Micropterus Sahnoides

Nutritional factors influence regulation of growth hormone （GH）, insulin-like growth factor-Ⅰ （IGF-Ⅰ） and insulin （INS） in fish. But so far there are no published studies describing how single indispensable amino acids and different carbohydrate to lipid ratios influence those systems. Therefore, the present study aimed to evaluate whether arginine （Arg） intake and carbohydrate to lipid ratios would affect expression of GH, IGF-Ⅰ and INS in largemouth bass.

Effects of salinity fluctuation and dietary protein/ carbohydrate ratio on the survival and growth of Juvenile Litopenaeus vannamei

A factorial study was conducted to determine the effects of salinity （constant （SO） and fluctuating （S10）） and isoenergetic diet of different protein/carbohydrate ratios （P/C： 4.1, 1.9, 1.0 and 0.6） on the survival and growth of juvenile Litopenaeus vannamei. The experiment lasted for 35 days. The results showed that I） At S0 and S10, specific growth rate and apparent digestibility coefficient exhibited decreasing trend, while food conversion ratio exhibited increasing trend, with decreasing P/C ratio. At SO, food consumption and specific growth rate of the shrimp fed 4.1 P/C were significantly higher than those fed 1.0 and 0.6 P/C, whereas at S10, no significant differences were detected among different treatments; II） At 4.1 and 1.9 P/C, food consumption and specific growth rate were higher in the shrimp maintained at SO as compared with those at S10, while at 1.0 and 0.6 P/C, an inverse trend was observed. Among four P/C ratios, food conversion ratio of the shrimp at SO was the lowest.

Causal associations between intermediate very-low-density lipoprotein cholesterol-to-total lipids ratio and peptic ulcer:A bidirectional Mendelian randomization study

BACKGROUND Previous epidemiologic investigations have consistently demonstrated a strong association between the ratio of cholesterol to total lipids in medium very-lowdensity lipoprotein(VLDL)and the occurrence of peptic ulcers(PU).However,the precise causal relationship between these factors remains ambiguous.Consequently,this study aims to elucidate the potential correlation between the ratio of cholesterol to total lipids in medium VLDL and the incidence of peptic ulcer.AIM To investigate the ratio of cholesterol to total lipids in medium very-low-density lipoprotein(VLDL)association with PU via genetic methods,guiding future clinical research.METHODS Genome-wide association study(GWAS)datasets for the ratio of cholesterol to total lipids in intermediate VLDL and peptic ulcer were retrieved from the IEU OpenGWAS project(https://gwas.mrcieu.ac.uk).For the forward Mendelian randomization(MR)analysis,72 single nucleotide polymorphisms(SNPs)were identified as instrumental variables.These SNPs were selected based on their association with the ratio of cholesterol to total lipids in intermediate VLDL,with peptic ulcer as the outcome variable.Conversely,for the inverse MR analysis,no SNPs were identified with peptic ulcer as the exposure variable and the ratio of cholesterol to total lipids in intermediate VLDL as the outcome.All MR analyses utilized inverse variance weighted(IVW)as the primary analytical method.Additionally,weighted median and MR-Egger methods were employed as supplementary analytical approaches to assess causal effects.Egger regression was used as a supplementary method to evaluate potential directional pleiotropy.Heterogeneity and multiplicity tests were conducted using the leave-one-out method to evaluate result stability and mitigate biases associated with multiple testing.RESULTS The genetically predicted ratio of cholesterol to total lipids in medium VLDL was significantly associated with an elevated risk of peptic ulcer(IVW:OR=2.557,95%CI=1.274-5.132,P=0.008).However,no causal association of peptic ulcer with the ratio of cholesterol to total lipids in medium VLDL was observed in the inverse Mendelian randomization analysis.CONCLUSION In conclusion,our study reveals a significant association between the ratio of cholesterol to total lipids in medium VLDL and an elevated risk of peptic ulcers.However,further validation through laboratory investigations and larger-scale studies is warranted to strengthen the evidence and confirm the causal relationship between these factors.

Neutrophil-to-lymphocyte ratio and carbohydrate antigen 19-9 as prognostic markers for advanced pancreatic cancer patients receiving first-line chemotherapy

BACKGROUND A decline in serum carbohydrate antigen 19-9(CA19-9)levels during systemic chemotherapy is considered as a prognostic marker for patients with advanced pancreatic cancer.Neutrophil-to-lymphocyte ratio(NLR)has been extensively studied as a simple and useful indicator of prognosis in various cancers including pancreatic cancer.AIM To assess the prognostic significance of NLR and CA19-9 in patients with advanced pancreatic adenocarcinoma received first-line chemotherapy according to CA19-9 positivity.METHODS We retrospectively analyzed patients diagnosed with advanced pancreatic cancer who received first-line chemotherapy between January 2010 and July 2017 at the Catholic University of Seoul St.Mary’s Hospital.Patients were divided according to CA19-9 positivity(CA19-9-positive vs-negative groups)and pre-and posttreatment NLR levels.To determine cut-off value of NLR and CA19-9 reduction,time-dependent receiver operating characteristic curve was applied.We evaluated overall survival(OS)and progression-free survival(PFS)for each group using Kaplan-Meier method,and we performed multivariate analyses on the entire cohort.RESULTS We included 271 patients in this study.Cut-off value of NLR and CA19-9 reduction was determined as 2.62 and 18%.Multivariate analysis showed that post-treatment NLR<2.62 and reduction of≥18%of baseline CA19-9 were significantly associated with OS and PFS.Post-treatment NLR≥2.62 showed hazard ratio(HR)of 2.47[95%confidence interval(CI):1.84-3.32,P<0.001]and CA19-9 decline(≥18%)showed HR of 0.51(95%CI:0.39-0.67,P<0.001)for OS.When CA19-9-positive patients were divided into groups according to CA19-9 response(responder vs non-responder)and post-treatment NLR(<2.62 vs≥2.62),CA19-9 responder and post-treatment NLR<2.62 group showed better survival than CA19-9 non-responder and post-treatment NLR≥2.62 group(OS 11.0 mo vs 3.9 mo,P<0.001;PFS 6.3 mo vs 2.0 mo,P<0.001).The combination of CA19-9 decline and post-treatment NLR showed a significant correlation with clinical response in CA 19-9 positive group.Within the CA19-9-negative group,the posttreatment NLR<2.62 group showed better survival than the post-treatment NLR≥2.62 group(OS 12.7 mo vs 7.7 mo,P<0.001;PFS 6.7 mo vs 2.1 mo,P<0.001),and post-treatment NLR showed correlation with clinical response.CONCLUSION In advanced pancreatic cancer patients positive for CA19-9 and treated with systemic chemotherapy,the combination of post-treatment NLR<2.62 and 18%decline of CA19-9 at the first response evaluation is a good prognostic marker.Post-treatment NLR<2.62 alone could be used as a prognostic marker and an adjunctive tool for response evaluation in CA19-9-negative patients.

Time and Dose-related Effects of the Pyrethroid Fluvalinate on Haemolymph Carbohydrates and Gut Lipids of Honeybees,Following in vivo Injection of very Low Doses

The injection to emerging adult workerbees with fluvalinate doses ranging from 1 femtomol to 1 nanomol per individual resulted in a reduction of haemolymph carbohydrate concentrations, particularly at the lowest dose 1 hour after injections. At the same time, a large increase was observed for triacylglycerols and to a much lesser extent for steroids and phospholipids with 0.1 picomol per bee. By contrast, fatty acids, steroids and triacylglycerols exhibited a depress at the higher dose. Most responses were thus biphasic, showing that much attention should be paid to the effects of very low doses of pesticide.

CONTENTS OF CARBOHYDRATES AND LIPIDS IN THE BODIES OF TWO PLANKTONIC CRUSTACEANS

The carbohydrate and lipid contents in two planktonic crustaceans, i. e. Pseudeuphausia sinica and Acetes chinensis sampled from Xiamen coastal waters were estimated. In P. sinica, the contents of carbohydrates (in dry weight)and lipids varied from 2.19-2.33% and 21.2-21.9 % respectively; in A. chinensis from 1. 74-2. 55% and 14. 43-15. 10% respectively. The analyses of fatty acids by gas-chromatograph (Model 103)showed that eight fatty acids of 14 : 0, 15 : 0 , 16 : 0, 17 : 0, 18 : 0, 18 : 2, 20 : 2 and 22 : 2 were found in these two animals, that 16 : 0,18 :0 ,18 :2 ,and 20 : 2 formed the major constituents with 91.08 % (P. sinica)and 74.80 % (A. chinensis) of the total fatty acids, and that the values of odd carbon types ( 15 : 0 and 17: 0) were fairly low, 4. 47% and 3. 36% respectively. Three monosaccharides : glucose, fructose, and galactose detected by high-liquid chromatograph (Waters 208) accounted for more than 60 % of the total carbohydrates, especially the glucose, exceeding by 40 %.

Hypoxia tolerance in fish depends on catabolic preference between lipids and carbohydrates

Hypoxia is a common environmental stress factor in aquatic organisms,which varies among fish species.However,the mechanisms underlying the ability of fish species to tolerate hypoxia are not well known.Here,we showed that hypoxia response in different fish species was affected by lipid catabolism and preference for lipid or carbohydrate energy sources.Activation of biochemical lipid catabolism through peroxisome proliferator-activated receptor alpha(Pparα)or increasing mitochondrial fat oxidation in tilapia decreased tolerance to acute hypoxia by increasing oxygen consumption and oxidative damage and reducing carbohydrate catabolism as an energy source.Conversely,lipid catabolism inhibition by suppressing entry of lipids into mitochondria in tilapia or individually knocking out three key genes of lipid catabolism in zebrafish increased tolerance to acute hypoxia by decreasing oxygen consumption and oxidative damage and promoting carbohydrate catabolism.However,anaerobic glycolysis suppression eliminated lipid catabolism inhibition-promoted hypoxia tolerance in adipose triglyceride lipase(atgl)mutant zebrafish.Using 14 fish species with different trophic levels and taxonomic status,the fish preferentially using lipids for energy were more intolerant to acute hypoxia than those preferentially using carbohydrates.Our study shows that hypoxia tolerance in fish depends on catabolic preference for lipids or carbohydrates,which can be modified by regulating lipid catabolism.

Effects of Dietary Carbohydrates Sources on Lipids Compositions in Abalone, Haliotis discus hannai Ino

A study was conducted to evaluate the effects of dietary carbohydrates on triglyceride, cholesterol and fatty acid concentrations in abalone, Haliotis discus hannai Ino. Six semi-purified diets with different carbohydrates （dextrin, heat-treated wheat starch, wheat starch, corn starch, tapioca starch and potato starch, respectively）, all containing a carbohydrate level of 33.5%, were fed to abalone （initial shell length： 29.98mm±0.09mm; initial weight. 3.42g±0.02g） for 24 weeks in a recirculation system. The results indicate that serum triglyceride concentrations were significantly （P〈0.05） higher in the abalone fed with dextrin, heat-treated wheat starch and wheat starch than those fed with corn starch, and serum cholesterol concentrations were significantly （P〈0.05） higher in the abalone fed with dextrin, heat-treated wheat starch than those fed with corn starch. Fatty acid C20：4n-6 in the foot mus- cles were significantly （P〈0.05） lower in the abalone fed with dextrin than those fed with wheat starch, corn starch, tapioca starch and potato starch. Fatty acid C20：4n-6 in hepatopancreas was significantly （P〈0.05） lower in abalone fed with heat-treated wheat starch than those fed with corn starch, tapioca starch and potato starch. Fatty acid C22：6n-3 in the foot muscles were significantly （P 〈 0.05） lower in the abalone fed with dextrin and beat-treated wheat starch than those fed with wheat starch and potato starch.

Effects of Ovariectomy and 17β-Estradiol Replacement on the Activity of Dopamine D2 Receptors in the Selection of Macronutrients Carbohydrates, Lipids and Proteins in Females Rats

17β-estradiol modulates the activity of D2 receptors in the regulation of food intake and body weight. The functional lack of 17β-estradiol in postmenopausal women could create a dietary imbalance and cause body weight gain. This study aimed to better understand the interferences that could exist between 17β-estradiol, D2 receptors and the selection of carbohydrate, fat and protein consumption, as well as their consequences on body weight gain by using an animal model of the menopause. Ovariectomy exacerbates the consumption of foods rich in lipids. Thus confirming an inhibitory action of 17β-estradiol (E2) on the consumption of these types of foods. This consumption stimulates body weight gain, which is promoted by the high caloric content of these foods and not by the amount consumed. Our results showed a direct involvement of D2 receptors in food choice. This choice would be made according to the two (2) isoforms of the D2 receptors. The D2/BR isoform directs towards a high carbohydrate consumption, without causing a gain in body weight. While D2/SUL, promotes high fat food consumption, causing an increase in body weight. In women, 17β-estradiol modulates the activity ratio between these two D2 receptor isoforms to ensure energy and homeostatic balance, stabilizing food intake and body weight.

Effect of vitamin A and E on carbohydrate and lipid metabolism in diet-induced obese wistar rats

In the present study, we investigated the biochemical alterations and gene expression of carbohydrate and lipid metabolism after oral administration of vitamin A and E for 2 months in diet-induced obese Wistar rats. Vitamin A and E administration reduced significantly the increase in body weight and food intake and normalized the alterations in lipid profiles in obese rats compared to normal rats. Moreover, both vitamins decreased the fat accumulation in liver tissues of obese rats. Finally, they up-regulated mRNA expression of Pyruvate Kinase (PK) and Glucose Transporter-2 (GLUT-2), and increased lipolysis and cholesterol metabolism through up-regulation of lipoprotein lipase (LPL), Sterol Responsible Element Binding Protein-1a (STREBP-1a) and STREBP-1c mRNA expression. In conclusion, vitamin A and E regulate gene expression of carbohydrate and lipid metabolism, and also ameliorate changes associated with obesity induced by high fat diet in Wistar rats.

8.3.Protein,carbohydrate and lipid metabolism

920049 Clinical studies on the relationshipbetween serum lipids and lipid peroxidation.GUO Hong (郭虹),et al.Cardiovasc instit &Fuwai Hosp,CAMS,Beijing.Chin Cir J 1991; 6(5):373-375.This paper presented the relationship amongserum lipid fractions,lipid peroxides (LPO)

Protein,carbohydrate and lipid metabolism

930463 The relation of polymorphism of LDLreceptor gene with serum cholesterol levels.FAN Leming(范乐明),et al.Atherosclerosis ResCenter,Nanjing Med Coll,Nanjing,210029.NatlMed J China 1993;73(4):242—244.PvuII polymorphism of LDL receptor gene andserum lipid levels were analysed in 115 nor-molipidemic subjects and 57 individuals with hy-percholesterolemia.A significant relationshipwas found between P2 allele and lower serumcholesterol level,suggesting that the LDL recep-tor might contribute to the variation in choles-terol levels in normolipidemic population.Al-

Protein,carbohydrate and lipid metabolism

930043 Analysis of familial aggregation ofserum lipids.WANG Jianhua(王建华),et al.Tianjin Med Coll,Tianjin,300070.Chin J Car-diol 1992;20(4):234-236.

Protein,carbohydrate and lipid metabolism

950255 Effects of TPN and indomethacin on stressresponse and protein metabolism after surgery.QUANZhufu(全竹富),et al.General Hosp,Nanjing Com-mand,Nanjing,210002.Med J Chin PLA 1995;20(1):24-26.The study was planned to evaluate effects of TPNand indomethacin on stress response after trauma,andprotein metabolism in patients who had received totalgastrectomy for cardiac cancer of stomach.19 caseswere divided into control,TPN,and

Association of glycosylated hemoglobin level with lipid ratio and individual lipids in type 2 diabetic patients

Objective:To study the correlation of lipid ratios and individual lipid indexes of patients with type 2 diabetes with glycosylated hemoglobin(HbA_(1c)).Methods:Samples were collected from 128 type 2 diabetic patients(aged 19-90 years;male 72,female 56).The sera were analyzed for HbA_(1c),total cholesterol(TC),triglycerides(TG),high-density lipoprotein cholesterol(HDL-C) and low-density lipoprotein cholesterol(LDL-C).According to the HbA_(1e) level,the patients were divided into three groups,group A(HbA_(?)<7%,n=31),group B(7%<HbA_(1c)<10%,n=48),and group C(HbA_(1c)>10%,n=49).The correlation of HbA_(1c)with lipid ratios & individual lipid indexes were analyzed.Results:With the increased level of HbA(1c),LDL-C had a significantly increasing trend(P<0.05);whereas TC went up with the increased HbA(1c),without any significant differences between three groups.There was no significant correlation between HbA_(1c) and TG or HDL-C. With the increased level of HbA_(1c),TC/HDL-C,LDL-C/HDL-C ratios were gradually increased, with significant differences among groups(P<0.05).The lipid ratios,especially LDL-C/HDL-C ratio was more susceptible to impaired lipid metabolism in T2DM patients than individual lipid. Conclusions:LDL-C/HDL-C ratio is helpful in assessing and reducing the risk of cardiovascular disease caused by impaired lipid metabolism in type 2 diabetic patients.

Characterization of the Growth,Chlorophyll Content and Lipid Accumulation in a Marine Microalgae Dunaliella tertiolecta under Different Nitrogen to Phosphorus Ratios

Microalgal lipids are regarded as main future feedstock of biofuels for its higher efficiency of accumulation and sus- tainable production. In order to investigate the effect of various nitrogen to phosphorus ratios on cells growth, chlorophyll content and accumulation of lipids in Dunaliella tertiolecta, experiments were carried out in modified microalgal medium with inorganic nitrogen （nitrate-nitrogen） or organic nitrogen （urea-nitrogen） as the sole nitrogen source at initial N：P ratios ranging from 1：1 to 32：1. The favorable N：P of 16：1 in the nitrate-N or urea-N medium yielded the maximum cell density and specific growth rate. Decrease in chlorophyll content were observed at the N：P of 4：1 in both nitrate-N and urea-N cultures. It was also observed that the maximum lipids concentration was obtained at the N：P of 4：1 in both nitrate and urea nutrient medium. The lipid productivity and lipid content of cultures in the urea-N medium at the N：P of 4： lwere markedly higher than those from cultures with other N：P ratios （p〈 0.05）. The results of this work illustrate the possibility that higher ratios of nitrogen to phosphorus have enhancing effect on cells growth of D. tertiolecta. Conversely, higher lipid accumulation is associated with a decrease in chlorophyll content under lower ratios of nitro- gen to phosphorus. The results confirm the hypothesis of this study that a larger metabolic flux has been channeled to lipid accumu- lation in D. tertiolecta cells when the ratios of nitrogen to phosphorus drop below a critical level.