The effects of season on fatty acid composition and ω3/ω6 ratios of northern pike(Esox lucius L.,1758) muscle lipids

In the present study,the effects of season on fatty acid composition,total lipids,and ω3/ω6ratios of northern pike muscle lipids in Kizilirmak River(Kirikkale,Turkey) were investigated.A total of 35 different fatty acids were determined in gas chromatography.Among these,palmitic,oleic,and palmitoleic acids had the highest proportion.The main polyunsaturated fatty acids(PUFAs) were found to be docosahexaenoic acid,eicosapentaenoic acid,and arachidonic acid.There were more PUFAs than monounsaturated fatty acids(MUFA) in all seasons.Similarly,the percentages of ω3 fatty acids were higher than those of total ω6 fatty acids in the fatty acid composition.ω3/ω6 ratios were calculated as 1.53,1.32,1.97,and 1.71 in spring,summer,autumn and winter,respectively.Overall,we found that the fatty acid composition and ω3/ω6 fatty acid ratio in the muscle of northern pike were significantly influenced by season.

Effects of high‑grain diet feeding on fatty acid profiles in milk,blood,muscle,and adipose tissue,and transcriptional expression of lipid‑related genes in muscle and adipose tissue of dairy cows

Background High-grain(HG)diets affect lipid metabolism in the liver and mammary tissue of dairy cows,but its effects on muscle and adipose tissue have not been wide evaluated.Thus,the aim of this study is to clarify this issue.Methods Twelve Holstein cows were randomly divided into two groups:conventional diet group(CON,n=6)and the HG diet group(n=6).On day 7 of week 4,rumen fluid was sampled to measure pH,milk was sampled to meas-ure components,and blood was sampled to measure biochemical parameters and fatty acid composition.After the experiment,cows were slaughtered to collect muscle and adipose tissue for fatty acid composition and transcriptome analysis.Results HG feeding decreased the ruminal pH,milk’s fat content and long-chain fatty acid proportion(P<0.05)and increased the proportion of short-and medium-chain fatty acids in the milk(P<0.05)as compared with CON diets.The concentrations of blood cholesterol,low-density lipoprotein,and polyunsaturated fatty acids in the HG cows were lower than those in CON cows(P<0.05).In muscle tissue,HG feeding tended to increase the triacylglycerol(TG)concentration(P<0.10).Transcriptome analysis revealed changes in the biosynthesis of the unsaturated fatty acids pathway,the regulation of lipolysis in the adipocytes pathway,and the PPAR signalling pathway.In adipose tissue,HG feeding increased the concentration of TG and decreased the concentration of C18:1 cis9(P<0.05).At the transcrip-tome level,the fatty acid biosynthesis pathway,linoleic acid metabolism pathway,and PPAR signalling pathway were activated.Conclusion HG feeding leads to subacute rumen acidosis and a decreased milk fat content.The fatty acid profiles in the milk and plasma of dairy cows were changed by HG feeding.In muscle and adipose tissue,HG feeding increased TG concentration and up-regulated the expression of genes related to adipogenesis,while down-regulated the expression of genes related to lipid transport.These results complement our knowledge of the fatty acid composi-tion of muscle and adipose tissue in dairy cows and expand our understanding of the mechanisms by which HG diets affect lipid metabolism in muscle and adipose tissue.

Growth Response and Fatty Acid Composition of Juvenile Procambarus clarkii Fed Different Sources of Dietary Lipid

An experiment was conducted to evaluate the effects of feeding various sources of dietary lipid on weight gain, feed conversion, survival and fatty acid composition of juvenile red swamp crawfish, Procam-barus clarkii. Six semi-purified diets containing vitamin-free casein, defatted soybean meal, 0. 5% choline chloride, 0. 5% glycine and 0. 5% cholesterol were supplemented with 6. 0% of either anchovy oil, linseed oil, soybean oil, rapeseed oil, safflower oil or pork lard. Each diet was fed to crawfish (3. 07±0. 21 g average weight) in three replicate aquaria for 60 days. Survival rate, weight gain and feed conversion were best for crawfish fed the diet containing anchovy oil. Crawfish fed the linseed oil diet had the second highest weight gain, followed by crawfish on soybean oil, repaseed oil, safflower oil and pork lard diets, respectively. Feed conversion values were a reflection of weight gain. Results showed that both n-6 and n-3 fatty acids are dietary essential for juvenile Procambarus clarkii, although n-3 fatty acids promoted faster growth than n-6. However, highly unsaturated fatty acids (HUFA) (20 : 5n-3 and 22 :6n-3) had better growth-promoting effect than 18 : 3n-3, due probably to the limited ability of crawfish to bioconvert fatty acids to polyenoic forms of longer chain length. The fatty acid composition of the crawfish generally reflected that of the dietary lipids, especially for the diets containing unsaturated fatty acids.

Responses in growth, lipid accumulation,and fatty acid composition of four oleaginous microalgae to different nitrogen sources and concentrations

Nitrogen deficiency is an effective strategy for enhancing lipid production in microalgae.Close relationships exist among lipid production,microalgal species,and nitrogen sources.We report growth,lipid accumulation,and fatty acid composition in four microalgae(Chlorococcum ellipsoideum UTEX972,Chlorococcum nivale LB2225,Chlorococcum tatrense UTEX2227,and Scenedesmus deserticola JNU19) under nitrate- and urea-nitrogen deficiencies.We found three patterns of response to nitrogen deficiency:Type-A(decrease in biomass and increase in lipid content),Type-B(reduction in both biomass and lipid content),and Type-C(enhancement of both biomass and lipid content).Type-C microalgae are potential candidates for large-scale oil production.Chlorococcum ellipsoideum,for example,exhibited a neutral lipid production of up to 239.6 mg/(L·d) under urea-nitrogen deficiency.In addition,nitrogen deficiency showed only a slight influence on lipid fractions and fatty acid composition.Our study provides useful information for further screening hyper-lipid microalgal strains for biofuel production.

Effects of different dietary lipid sources on growth performance and tissue fatty acid composition of juvenile swimming crab Portunus trituberculatus

This study was conducted to evaluate the effects of dietary lipid sources on the growth performance and fatty acid composition of the swimming crab, P ortunus trituberculatus. Four isonitrogenous and isoenergetic experimental diets were formulated to contain four separate lipid sources, including fish, soybean, rapeseed, and linseed oils(FO, SO, RO, and LO, respectively). With three replicates of 18 crabs each for each diet, crabs(initial body weight, 17.00 ±0.09 g) were fed twice daily for 8 weeks. There were no significant differences among these groups in terms of weight gain, specific growth rate, and hepatosomatic index. However, the RO groups' survival rate was significantly lower than FO groups. The feed conversion and protein efficiency ratios of RO groups were poorer than other groups. The proximate compositions of whole body and hepatopancreas were significantly affected by these dietary treatments. Tissue fatty acid composition mainly reflected dietary fatty acid compositions. Crabs fed FO diets exhibited significantly higher arachidonic, eicosapentaenoic, and docosahexaenoic acid contents in muscle and hepatopancreas compared with VO crabs. Linoleic, oleic, and linolenic acids in muscle and hepatopancreas were the highest in the SO, RO, and LO groups, respectively. The present study suggested that SO and LO could substitute for FO in fishmeal-based diets for swimming crabs, without affecting growth performance and survival.

Factors aff ecting lipid and fatty acid composition of Calanus sinicus in the Yellow Sea and the East China Sea in spring

The factors aff ecting lipid and fatty acid composition of copepod Calanus sinicus in the Yellow Sea(YS)and the East China Sea(ECS)were examined in this study.In spring,there were signifi cant diff erences between these two regions for both environmental conditions and food availability.Such regional diff erence signifi cantly infl uenced the lipid and fatty acid profi les of C.sinicus.Our results show that C.sinicus has a higher lipids content in ECS,especially for wax ester and triglyceride lipids,indicating a more active and effi cient predation.According to BIO-ENV analysis,the variation of lipids profi les may be infl uenced majorly by water temperature.Moreover,the fatty acids(FAs)profi les of C.sinicus were also diff erent between YS and ECS,especially in the four major contributors,C22꞉1ω11,eicosapentaenoic acid(EPA),docosahexenoic acid(DHA),and C20꞉1ω9.The considerable amounts of self-biosynthesized FAs of herbivorous copepod(C22꞉1ω11 and C20꞉1ω9)and low DHA/EPA ratio may indicate that C.sinicus in ECS feed mainly on phytoplankton comparing to those in YS.The fatty acid profi les of C.sinicus were aff ected by the diff erences in food availability.

Chemical Composition of the Fatty Oil from Fructus Broussonetiae and Its Effects on Rat Plasma Lipids and Adipose Tissue

Context: Broussonetia papyrifera (L.) Vent. (Moraceae), a traditional Chinese medicinal herb, has been extensively applied for many years to treat various diseases. Its fruits (Fructus Broussonetiae) have been commonly used as an important tonic for the treatment of age-related disorders with long history;recent research has proved that it contains 32% to 35% fixed oils. The fixed oil is composed mainly of unsaturated fatty acids, including linoleic acid, methyl palmitate, oleic acid and linoleic acid ester. Objective: To investigate the chemistry of the fatty oil from Fructus Broussonetiae (FOFB) and its effects on plasma lipids. Methods: The chemical composition of FOFB was examined and identified by GC-MS. Thirty male Wistar rats fed diet containing FOFB and cholesterol were studied for 28 days. The effect of dietary FOFB on plasma lipids and adipose tissue was tested. Results: Twelve compounds of FOFB were examined and identified, the major components of fatty oil, 8,11-octadecadienoic acid (83.75%), palmitic acid (10.22%), octadecadienoic acid (2.97%) and 9-octadecenoic acid (1.69%) were found. FOFB significantly exhibited the activities of decreasing the rat adipose tissue weight, triacylglycerol, total cholesterol, and low-density lipoprotein cholesterol (LDL-C) concentrations while the rat body weight remained unchanged. Discussion: FOFB contained a large amount of PUFA which had the effect on reducing plasma lipids and adipose.

EFFECT OF LIGHT INTENSITY ON THE TOTAL LIPID AND FATTY ACID COMPOSITION OF SIX STRAINS OF MARINE DIATOMS

The effect of light intensity (1500 lx and 5000 lx) on the total lipid and fatty acid composition of six strains of marine diatoms Cylindrotheca fusiformis (B211), Phaeodactylum tricornutum (B114, B118 and B221) Nitzschia closterium (B222) and Chaetoceros gracilis (B13) was investigated. The total lipids of B13, B114, and B211 grown at 5000 lx were lower than those grown at 1500 lx. No evident changes were observed in B118, B221 and B222. Fatty acid composition changed considerably at different light intensity although no consistent correlation between the relative proportion of a single FA and light intensity. The major fatty acids of the 6 strains were 14:0, 16:0, 16:1(n-7) and 20:5(n-3). Cylindrotheca fusiformis had high percentage of 20:4n-6 (9.2-10.9%). The total polyunsaturated fatty acid in all 6 strains decreased with increasing light intensity. The percentage of the highly unsaturated fatty acid eicosapentaenoic acid (EPA) decreased with increasing light intensity in all strains except Chaetoceros gracilis.

Plasma Fatty Acid Composition in Men over 50 in the USA and Japan

Background: Coronary heart disease (CHD) rates differ markedly between the US and Japan. Fatty acid profiles have been linked to risk for CHD. Few studies have compared the plasma fatty acid composition, including trans fatty acids, in Japanese and US subjects. Methods: Fasting blood samples were taken from healthy older (>age 50) American (n = 76) and Japanese (n = 44) men, and plasma levels of 23 fatty acids were analyzed by gas chromatography and expressed as a percent of total fatty acids. Results: As expected, plasma levels of long-chain ω3 fatty acids (docosahexaenoic and eicosapentaenoic acids, DHA and EPA) were higher in Japanese men and ω6 fatty acids (e.g., arachidonic acid, AA) were lower compared with American men. Plasma levels of the major industrially-produced trans fatty acids (IP-TFAs;elaidic and linoelaidic acids) were far higher in American men, and levels of the potentially cardioprotective, primarily ruminant-derived trans fatty acid palmitoelaidic acid (POA) were higher in Japanese. Plasma levels of saturated or monounsaturated fatty acids were also higher in the American men. Conclusion: There are multiple differences in plasma fatty acid profiles between American and Japanese older men. The higher levels of DHA and EPA, along with the lower levels of the IP-TFAs, are consistent with the markedly lower risk for coronary heart disease in Japan vs. the US.

Dietary L-arginine supplementation reduces lipid accretion by regulating fatty acid metabolism in Nile tilapia(Oreochromis niloticus)

Background: Excessive white fat accumulation in humans and other animals is associated with the development of multiple metabolic diseases. It is unknown whether dietary L-arginine supplementation reduces lipid deposition in high fat diet-fed Nile tilapia(Oreochromis niloticus).Results: In the present study, we found that dietary supplementation with 1% or 2% arginine decreased the deposition and concentration of fats in the liver;the concentrations of triglycerides, low-density lipoprotein, total cholesterol, and high-density lipoprotein in the serum;and the diameter of adipocytes in intraperitoneal adipose tissue. Compared with the un-supplementation control group, the hepatic activities of alanine aminotransferase,aspartate aminotransferase, and lactate dehydrogenase, and hepatic concentration of malondialdehyde were reduced but these for catalase and superoxide dismutase were enhanced by dietary supplementation with 2% arginine. Arginine supplementation reduced the total amounts of monounsaturated fatty acids, while increasing the total amounts of n-3 and n-6 polyunsaturated fatty acids in the liver. These effects of arginine were associated with reductions in mRNA levels for genes related to lipogenesis(sterol regulatory element-binding protein-1, acetyl-CoA carboxylase α, stearoyl-CoA desaturase, and fatty acid synthase) but increases in mRNA levels for genes involved in fatty acid β-oxidation(carnitine palmitoyltransferase 1α and peroxisome proliferator-activated receptor α). In addition, hepatic mRNA levels for Δ4 fatty acyl desaturase 2 and elongase 5 of very long-chain fatty acids were enhanced by arginine supplementation.Conclusion: These results revealed that dietary L-arginine supplementation to tilapia reduced high fat diet-induced fat deposition and fatty acid composition in the liver by regulating the expression of genes for lipid metabolism.

Different dietary starch sources alter the carcass traits, meat quality, and the profile of muscle amino acid and fatty acid in finishing pigs

Background: With increasing health awareness among consumers, the demand for healthier, tastier, higher quality and nutritional value pork is increasing. It has been shown that different dietary starch sources can alter the carcass traits and meat quality. However, research on the effects of different starch sources with clear different amylose/amylopectin ratio on the amino acid and fatty acid composition in Longissimus thoracis(L. thoracis) muscle of pigs is limited. This study aimed to investigate the effects of different dietary starch sources on carcass traits, meat quality, muscle amino acid and fatty acid composition, and the mRNA expression levels of genes involved in lipid metabolism and muscle fiber characteristics in finishing pigs. A total of 72 Duroc × Landrace × Large White barrows were randomly allocated to 3 different dietary treatment groups with 8 replicate pens/group and 3 pigs per pen.Tapioca starch(TS), corn starch(CS), and pea starch(PS), with amylose/amylopectin ratio of 0.11, 0.25, and 0.44,respectively, were used as their dietary starch sources for 40 days.Results: Results showed that the PS diet significantly increased(P < 0.05) the final body weight, average daily gain,loin-eye area, and fat-free lean index compared with the TS diet, but significantly decreased(P < 0.05) the feed to gain ratio and backfat thickness. Compared with the TS diet, PS diet also increased(P < 0.05) the pH45 min, marbling scores, the content of intramuscular fat and inosine monophosphate in the L. thoracis, and decreased(P < 0.05) the drip loss and shear force. In addition, compared with the TS diet, PS diet increased(P < 0.05) the proportions of flavor amino acids, DHA, EPA, and n-3 polyunsaturated fatty acid(PUFA) in the L. thoracis compared with TS diet,but decreased(P < 0.05) the ratio of n-6/n-3 PUFA. Furthermore, compared with the TS diet, PS diet also upregulated(P < 0.05) the lipogenic genes(FAS, LPL, SCD, ACCα) and myosin heavy-chain(MyHC)-IIa mRNA expression levels compared with the TS diet, but downregulated(P < 0.05) the CPT1 B and MyHC-IIb mRNA levels.Conclusions: In conclusion, these results provided compelling evidence that the different dietary starch source altered the carcass traits, meat flavor and quality in finishing pigs, and consumption of a diet with higher amylose/amylopectin ratio results in the production of a healthy, higher quality, and nutritional value pork.

Branched chain amino acids alter fatty acid profile in colostrum of sows fed a high fat diet

Background:Branched chain amino acids(BCAAs)are important substrates for milk protein synthesis in the mammary gland,and are tightly related to lipid metabolism.No study has been performed examining the role of BCAAs with high fat diets on milk fat synthesis.This study was designed to investigate the effect of dietary BCAAs on growth performance of piglets,progeny body weight,and milk fat composition in sows fed a high fat diet.Four diets(CON=control diet;HF=high fat diet with 8%soybean oil;HF-MB=HF plus 0.39%BCAAs;HF-HB=HF plus 0.78%BCAAs)were fed to sows from late gestation to weaning.Results:Compared to HF,BCAAs(HF-MB and HF-HB)increased the litter weight(P<0.05)and overall litter weight gain(P<0.05)at weaning and increased colostrum fat content by 27.3–35.8%(P<0.01).Fatty acid profiles between the two doses of BCAAs were similar.Compared with HF,HF-MB tended to decrease the percentage of C18:3n3(P=0.063)and increased the percentage of C18:1n9c(P=0.03).In addition,BCAAs in HF-MB increased the concentration of total fatty acid by 22.1%in colostrum(P=0.03)but decreased that in serum at parturition by 53.2%(P=0.027).The fatty acids in colostrum that increased with BCAAs were C15:0,C17:0,C20:3n6,C20:4n6,C20:5n3 and C22:6n3(P=0.00~0.04).Colostrum fatty acids of C20:0,C21:0,C22:0,C16:1,C20:1,C18:1n9c also tended to be increased(0.05<P<0.1)with BCAAs.The change in sow serum fatty acid profile due to BCAAs was different from that in colostrum.Conclusions:BCAAs in high fat diet of sows altered the fatty acid composition in colostrum and enhanced litter growth.Our study indicated that BCAAs supplementation can enhance mammary fatty acid uptake and mammary fat synthesis and that supplemental BCAAs and fat in late gestation and lactation diets for sows can improve reproductive performance.

Changes of Intramuscular Fat Composition,Lipid Oxidation and Lipase Activity in Biceps femoris and Semimembranosus of Xuanwei Ham During Controlled Salting Stages

Fatty acid composition of neutral lipids （NLs）, phospholipids （PLs） and free fatty acids （FFAs） from intramuscular fat （IMF）, lipid oxidation and lipase activity in muscle Semimembranosus （SM） and msucle Biceps femoris （BF） of dry-cured Xuanwei ham during the 90-d salting stages were analysed. The salt content increased from 0.34 to 3.52%in BF and from 0.10 to 5.42%in SM during the 90 d salting stage, respectively. PLs of IMF in both BF and SM decreased 54.70%（P〈0.001） and 34.64%（P〈0.05）, furthermore, the saturated fatty acids （SFA）, monounsaturated fatty acids （MUFA） and polyunsaturated fatty acids （PUFA） of PLs in both muscles were hydrolysed almost isochronously. FFAs were increased from 0.46 g 100 g-1 lipids to 2.92 g 100 g-1 lipids in BF at the end of salting, which was lower than SM （from 1.29 g 100 g-1 lipids to 9.70 g 100 g-1 lipids）. The activities of acid lipase, neutral lipase and acid phospholipase all remained active in the 90 d. The thiobarbituric acid reactive substances （TBARS） was slowly increased to 1.34 mg kg-1 muscle in BF and to 2.44 mg kg-1 muscle in SM during the salting stage. In conclusion, the controlled salting process prompted the hydrolysis of PLs of IMF notably and increased the lipid oxidation of muscles within some limits.

Variation of lipids and fatty acids composition in the tissues of wild devil stinger(Inimicus japonicas)during sexual maturation

The present study was conducted to characterize the lipid and fatty acid profiles in different tissues(gonad,liver and muscle)of the wild-caught devil stinger during sexual maturation.Wild-caught devil stinger were divided into six groups according to gonad development and gender.Total lipid content was up to 40%dry weight in liver and was significantly higher than in other tissues(ovary,testis and muscle)in both male and female stinger during sexual maturation.During maturation,total lipid content in the female stinger liver decreased,but in males significantly increased in all tissues.Higher proportions of neutral lipids(NL)were observed in the stinger liver,while polar lipids(PL)were mainly quantified in the gonad and muscle of both male and female stinger.The PL content of the ovary significantly decreased with sexual maturation,but NL were significantly increased.The fatty acids composition of the stinger broodstocks were tissue-and lipid class-specific.In the stinger gonad high-unsaturated fatty acids(HUFA),such as ARA,DHA and EPA,are selectively transferred and conserved,indicating the crucial role of these fatty acids during sexual maturation of this fish species.

Comparison of fatty acid composition in total lipid of diapause and non-diapause larvae of Cydia pomonella （Lepidoptera： Tortricidae）

Seasonal changes in the fatty acid composition of the total lipid extracted from the whole body of Cydia pomonella L. larvae were determined by gas chromatography. The six most abundant fatty acids in both non-diapause and diapause larvae of codling moth were oleic （35%-39%）, palmitic （23%-33%）, linoleic （16%-30%）, palmitoleic （5%-10%）, stearic （1.5%-3.0%） and linolenic acids （1.0%-2.5%）. This represents a typical complement of Lepidopteran fatty acids. The fatty acid composition of total lipid of C. pomonella larvae was related to diapause. In similarity to most other reports, the proportion of unsaturated fatty acids increased in diapause initiation state. The total lipid of diapause larvae contained more linoleic acid （25.8% vs. 16.1%） and less palmitic acid （24.7% vs. 33.4%）, than that of non-diapause larvae. The weight percentage of linoleic acid （C 18：2） increased from 16% to 26% from early-August through early-September during transition to diapause, while palmitic acid （C16：0） decreased from 33% to 25% at the same time. These changes resulted in an increase in the ratio of unsaturated to saturated fatty acids （UFA/SFA） from 1.72 in non-diapause larvae to 2.63 in diapause larvae.

饲料中添加不同脂肪源对克氏原螯虾营养物质、脂肪酸组成的影响

为研究脂肪源对克氏原螯虾营养物质和脂肪酸组成的影响,在基础饲料中添加猪油(LO)、豆油(SO)、鱼油(FO)、鱼油和豆油1:1混合油(MO)为脂肪源配制成4种等氮等脂饲料。将600尾克氏原螯虾[(3.50±0.50)g]随机分为4组,每组3个重复,每个重复50尾,按虾体质量的3%饲喂60 d。试验结果表明:MO组和FO组的肌肉与肝胰脏质量比、肌肉胶黏性显著大于LO组(P <0.05)。LO组粗蛋白质和粗灰分含量低于其他试验组(P <0.05),FO组粗脂肪含量低于其他组(P <0.05)。肌肉脂肪酸中:FO组ARA(13.44%)和DHA(5.15%)含量最高。MO组EPA含量最高(9.89%)。FO组(47.31%)和MO组(45.15%)∑PUFA含量显著大于LO组(37.54%)和SO组(39.95%)(P <0.05)。肝胰脏脂肪酸中:FO组ARA(13.44%)和DHA(5.15%)含量最高。MO组EPA含量最高(9.89%)。FO组(47.31%)和MO组(45.15%)∑PUFA含量显著大于LO组(37.54%)和SO组(39.95%)(P <0.05)。综合体组成、质构、脂肪酸组成和脂肪源价格,选用鱼油和豆油1:1混合油作为克氏原螯虾饲料添加的脂肪源,有利于提高克氏原螯虾肌肉胶黏性、∑PUFA、DHA、EPA和ARA的含量。

Effect of Nitrogen Source on Biomass and Lipid Production of a Marine Microalga, <i>Nannochloropsis oceanica</i>IMET1

The effects of the nitrogen sources sodium nitrate (NaNO3) and urea (CH4N2O) on growth, lipid production, and fatty acid composition of Nannochloropsis oceanica IMET1 were investigated. Nitrogen source affected cell density, dry cell weight, and lipid production. Cells grown in the nitrate medium increased dry cell weight and lipid weight in comparison with cells grown in the urea medium. The composition of fatty acids varied with nitrogen sources. IMET1cultured in the nitrate medium mainly contained C18:2 (14.9%) and C16:0 (6.3%) fatty acids, while IMET1 in the urea medium mainly contained C22:0 (33.1%), C18:3 (8.6%), and C16:0 (6.8%). This study demonstrates that nitrogen source can strongly influence lipid production and composition of N. oceanica IMET1.

饲料脂肪源对光唇鱼亲鱼生长及繁殖性能的影响

为研究饲料脂肪源对光唇鱼亲鱼生长和繁殖性能的影响,挑选平均初始体重(38.38±0.28)g的光唇鱼450尾,随机分成5组,每组3个重复,分别投喂在基础饲料中添加鱼油、豆油、花生油、玉米油和菜籽油的5种脂肪源饲料,试验8周。结果表明:投喂不同脂肪源饲料组间增重率、特定生长率及饲料系数无显著差异(P>0.05);光唇鱼成熟卵中除玉米油、菜籽油组均检测出21种脂肪酸,投喂玉米油组成熟卵中5种n-6系不饱和脂肪酸含量最高,其中C20∶2n-6和C20∶3n-6与菜籽油组差异显著(P<0.05);不同脂肪源饲料组间获卵量和受精率无显著差异(P>0.05),在孵化率及仔鱼平游率上玉米油组最高,显著高于菜籽油组(P<0.05)。表明豆油、花生油、玉米油和菜籽油能够部分替代鱼油满足光唇鱼生长和繁殖过程对脂肪酸的需要,其中以玉米油最佳。

葡萄籽原花青素对生长育肥猪半腱肌抗氧化性能、脂类代谢及脂肪酸组成的影响

为了研究生长育肥猪饲粮中添加葡萄籽原花青素(grape seed procyanidins,GSPs)对半腱肌抗氧化性能及脂肪酸组成的影响,该试验选取48头体重为20.85±0.12 kg的健康杜洛克×长白×大白三元杂交猪,随机分为4组,每组3个重复,每个重复4头猪。对照组饲喂玉米-豆粕基础饲粮,GSPs组分别在基础饲粮中添加150、200、250 mg/kg GSPs,预试期7 d,正试期90 d。结果表明:(1)与对照组相比,GSPs添加组猪肌肉半腱肌pH45 min、24 h明亮度值(L*24 h)及24 h红度值(a*24 h)显著提高(P<0.05),24 h黄度值(b*24 h)以及蒸煮损失显著降低(P<0.05);GSPs添加量为200或250 mg/kg时半腱肌剪切力显著降低(P<0.05);(2)添加不同水平的GSPs均能显著提高半腱肌总抗氧化能力及谷胱甘肽过氧化物酶活性(P<0.05),添加200或250 mg/kg GSPs显著提高了超氧化物歧化酶和过氧化氢酶活性(P<0.05);(3)与对照组相比,GSPs添加量为150或200 mg/kg时显著降低了半腱肌的总胆固醇含量(P<0.05),添加量为200或250 mg/kg时显著降低了低密度脂蛋白胆固醇含量(P<0.05),饲粮添加GSPs显著提高了高密度脂蛋白胆固醇含量(P<0.05);(4)150 mg/kg和200 mg/kg GSPs组显著地提高了半腱肌单不饱和脂肪酸和多不饱和脂肪酸的含量(P<0.05);添加GSPs的各组饱和脂肪酸含量以及多不饱和脂肪酸n-6/n-3比值均显著低于对照组(P<0.05)。总之,生长育肥猪饲粮中添加200 mg/kg GSPs能提高半腱肌的抗氧化性能,降低胆固醇含量,尤其是低密度脂蛋白胆固醇含量,改善脂肪酸组成。

Effects of dietary phosphorus level on growth,body composition,liver histology and lipid metabolism of spotted seabass(Lateolabrax maculatus)reared in freshwater

The present study was conducted to determine the effects of dietary phosphorus(P)levels on growth performance,body composition,liver histology and enzymatic activity,and expression of lipid metabolism-related genes in spotted seabass(Lateolabrax maculatus).Seven diets were prepared to contain available P levels of 0.48%(the control group),0.69%,0.89%,1.10%,1.28%,1.51%and 1.77%and feed fish(4.26±0.03 g)to satiety twice daily for 10 weeks.Significantly higher weight gain and specific growth rate were recorded at P levels of 0.69%-1.51%compared to the control group.Feed conversion ratio decreased with increasing P levels up to 0.89%and increased thereafter.The lowest liver lipid content,viscerosomatic index and lipid content of whole-body were obtained in the 0.89%-P group among dietary treatments.P and calcium(Ca)contents in whole body were increased,while liver triglyceride and cholesterol contents were decreased with increasing dietary P levels from 0.48%to 1.77%.The highest activity of hepatic lipase was recorded in the 1.10%-P group among dietary treatments.Compared to the control group,1.10%P enhanced the proportion of HUFA and reduced the proportion of SFA and MUFA.The histological observations showed that P deficiency(0.48%)led to the vacuolization of hepatocytes and increased number of lipid droplets.Meanwhile,overall liver tissue structure was improved when P level increased to 1.28%.Compared to the control group,expression of lipid metabolism-related genes such as FAS,ACC-2 and SREBP-1 was decreased at 0.89%-1.10%P group while an opposite trend was observed in the expression of PPARa2 and CPT-1 genes.The current study showed that 0.89%dietary P levels could promote growth performance of spotted seabass and reduce lipid accumulation in the liver.A broken-line regression analysis based on weight gain showed that the optimum dietary P level(available P)for juvenile spotted seabass reared in freshwater was 0.72%.