Utilization of different dietary lipid sources at high level in herbivorous grass carp (Ctenopharyngodon idella): mechanism related to hepatic fatty acid oxidation

Herbivorous grass carp (Ctenopharyngodon idella) has been reported to exhibit low capacity to utilize high dietary lipid, but different lipid sources might affect this limited capacity. In order to compare the effects of different lipid sources with different lipid levels, juvenile grass carp were fed one of nine diets containing three oils [lard, plant oil mixed by maize and linseed oil, and n‐3 high unsaturated fatty acid‐enriched (HUFA‐enriched) fish oil] at three lipid levels (20, 60 and 100 g kg^?1 dry diet) for 8 weeks. Decreased feed intake, poor growth performance, hepatic pathology and higher blood lipid peroxidation were found in 60 and 100 g kg^?1 fish oil groups. Conversely, in lard and plant oil groups, even at 100 g kg^?1 dietary lipid level, feed intake and growth performance did not decrease, despite histological observation revealed hepatic pathology in these groups. Plasma triglyceride and cholesterol contents increased significantly in all 100 g kg^?1 dietary lipid groups. In the comparison of hepatic FA β‐oxidation among three oil groups at 60 g kg^?1 dietary lipid level, impaired mitochondrial and peroxisomal FA oxidation capacity was observed in fish oil group. The results confirmed the relatively low capacity of grass carp to utilize high dietary lipid, and furthermore excess HUFA intake will result in more serious adverse effects than other FA.     

短期添加高水平亚麻籽对奶牛生产性能、牛奶脂肪酸组成和瘤胃发酵的影响

本试验旨在研究短期添加高水平亚麻籽对奶牛生产性能、牛奶脂肪酸组成和瘤胃发酵的影响。选取健康、体重相近的荷斯坦牛奶牛30头,随机分为3组,每组10头。分别饲喂牧场基础饲粮（CK组）、添加3 000 g/d （13.01% DM）完整亚麻籽饲粮（WF组）和添加3 000 g/d （13.01% DM）粉碎亚麻籽饲粮（GF组）。试验周期为7周,第1周为环境适应期,第2~6周为饲粮适应期,第7周为试验期,记录试验期日采食量和产奶量,于试验最后1天采集奶样和瘤胃液样品,利用气相色谱-质谱联用（GC-MS）测定乳和瘤胃液中脂肪酸组成。结果表明：①与CK组相比,添加3 000 g/d亚麻籽对奶牛干物质采食量和产奶量均无显著影响（P>0.05）,GF组乳脂率和乳蛋白率较CK组有降低的趋势（0.05<P<0.1）。②WF和GF组乳中α-亚麻酸（ALA）和ω-3多不饱和脂肪酸（ω-3 PUFA）的产量较CK组均显著提高（P<0.05）,且GF组ALA和ω-3 PUFA的产量显著高于WF组（P<0.05）。③WF组瘤胃pH显著低于CK和GF组（P<0.05）,氨态氮（NH₃-N）浓度显著高于CK和GF组（P<0.05）。综上所述,饲粮中短期添加高水平完整亚麻籽和粉碎亚麻籽均不影响奶牛干物质采食量和产奶量,但提高了乳中ALA含量,GF组提高效果较WF组更明显。添加高水平粉碎亚麻籽有降低乳蛋白率和乳脂率的趋势,高水平完整亚麻籽影响了奶牛瘤胃内环境。在实际生产中,应控制亚麻籽的添加量及其饲喂形式,在提高乳中ALA含量的同时,减少亚麻籽对瘤胃发酵的影响。     

Polyunsaturated fatty acid metabolism in Atlantic salmon (Salmo salar) undergoing parr-smolt transformation and the effects of dietary linseed and rapeseed oils

Duplicate groups of Atlantic salmon parr were fed diets containing either fish oil (FO), rapeseed oil (RO), linseed oil (LO) or linseed oil supplemented with arachidonic acid (20:4n-6; AA) (LOA) from October (week 0) to seawater transfer in March (week 19). From March to July (weeks 20–34) all fish were fed a fish oil-containing diet. Fatty acyl desaturation and elongation activity in isolated hepatocytes incubated with [1-¹⁴C]18:3n-3 increased in all dietary groups, peaking in early March about one month prior to seawater transfer. Desaturation activities at their peak were significantly greater in fish fed the vegetable oils, particularly RO, compared to fish fed FO. Docosahexaenoic acid (22:6n-3:DHA) and AA in liver and gill polar lipids (PL) increased in all dietary groups during the freshwater phase whereas eicosapentaenoic acid (20:5n-3; EPA) increased greatly in all groups after seawater transfer. The AA/EPA ratio in tissue PL increased up to seawater transfer and then decreased after transfer. AA levels and the AA/EPA ratio in gill PL were generally higher in the LOA group. The levels of 18:3n-3 in muscle total lipid were increased significantly in the LO, LOA and, to a lesser extent, RO groups prior to transfer but were reduced to initial levels by the termination of the experiment (week 34). In contrast, 18:2n-6 in muscle total lipid was significantly increased after 18 weeks in fish fed the diets supplemented with RO and LO, and was significantly greater in the FO and RO groups at the termination of the experiment. Gill PGF production showed a large peak about two months after transfer to seawater. The production of total PGF post-transfer was significantly lower in fish previously fed the LOA diet. However, plasma chloride concentrations in fish subjected to a seawater challenge at 18 weeks were all lower in fish fed the diets with vegetable oils. This effect was significant in the case of fish receiving the diet with LOA, compared to those fed the diet containing FO. The present study showed that during parr-smolt transformation in Atlantic salmon there is a pre-adaptive increase in hepatocyte fatty acyl desaturation/elongation activities that is controlled primarily by environmental factors such as photoperiod and temperature but that can also be significantly modulated by diet. Feeding salmon parr diets supplemented with rapeseed or linseed oils prevented inhibition of the desaturase activities that is induced by feeding parr diets with fish oils and thus influenced the smoltification process by altering tissue PL fatty acid compositions and eicosanoid production. These effects, in turn, had a beneficial effect on the ability of the fish to osmoregulate and thus adapt to salinity changes.     

Effect of dietary fish and vegetable oil on the growth performance,body composition,fatty acids profile,reproductive performance and larval resistance in pearl gourami (Trichogaster leeri)

This study investigated the effect of two lipid sources on reproduction performance and growth in pearl gourami. For this purpose, 180 fish (3.32 ± 0.25 g) were fed with three isoenergetic (19.80) and isonitrogenous diets (480 g/kg protein) including FO (80 g/kg fish oil), FS (40 g/kg fish oil and 40 g/kg soybean oil) and SO (80 g/kg soybean oil) for 10 weeks before maturation. At the end of the trial, there was no significant difference in weight gain, feed conversation ratio and body composition between fish fed FO and FS diets. Individuals fed dietary FO had significantly higher levels of n‐3 long‐chain polyunsaturated fatty acids in the muscle (130.5 g/kg lipid) and ovary (140.4 g/kg lipid) as compared with those fed SO diet (64.5, 103.6 g/kg, respectively) (p < .05). Feeding pearl gourami with FO and FS diets enhanced regarding absolute fecundity, relative fecundity, the fertilization rate, larvae total length and survival at 3 day posthatch (p < .05). Also, 17 beta‐estradiol in plasma of fish fed dietary FO (6.2 ng/L) was higher than those fed SO diet (1.7 ng/L) (p < .05). In conclusion, we suggest FS diet for broodstock nutrition of pearl gourami as a model for asynchronous multi‐batch spawning fish.     

Screening for Health-Promoting Fatty Acids in Ascidians and Seaweeds Grown under the Influence of Fish Farming Activities

The present study aimed to contrast the fatty acid (FA) profile of ascidians (Ascidiacea) and seaweeds (sea lettuce, Ulva spp. and bladderwrack, Fucus sp.) occurring in a coastal lagoon with versus without the influence of organic-rich effluents from fish farming activities. Our results revealed that ascidians and seaweeds from these contrasting environments displayed significant differences in their FA profiles. The n-3/n-6 ratio of Ascidiacea was lower under the influence of fish farming conditions, likely a consequence of the growing level of terrestrial-based ingredients rich on n-6 FA used in the formulation of aquafeeds. Unsurprisingly, these specimens also displayed significantly higher levels of 18:1(n-7+n-9) and 18:2n-6, as these combined accounted for more than 50% of the total pool of FAs present in formulated aquafeeds. The dissimilarities recorded in the FAs of seaweeds from these different environments were less marked (≈5%), with these being more pronounced in the FA classes of the brown seaweed Fucus sp. (namely PUFA). Overall, even under the influence of organic-rich effluents from fish farming activities, ascidians and seaweeds are a valuable source of health-promoting FAs, which confirms their potential for sustainable farming practices, such as integrated multi-trophic aquaculture.     

Impact of different inclusion levels of oil palm (Elaeis guineensis Jacq.) fronds on fatty acid profiles of goat muscles

The effects of different inclusion levels of oil palm fronds (OPF) on the fatty acid profile of the longissimus dorsi (LD), biceps femoris (BF) and infraspinatus (IS) muscle of goats fed for 100 days are described. Twenty‐four individually housed Kacang crossbred male goats (averaged 21.7 ± 0.97 kg BW) were allocated to three groups receiving either a 100% concentrate control diet (CON), diet with 25% inclusion level of OPF (HAF) or a diet with 50% inclusion of OPF. The diets were adjusted to be isocaloric and isonitrogenous and fed at 3.0% of BW daily. Samples of LD, BF and IS muscles were taken at slaughter for the determination of fatty acid profiles. The total saturated fatty acids (SFA) in the LD and BF muscles of the OPF group were significantly (p < 0.05) lower than the CON group. For all muscles, C18:3n‐3 and total n‐3 polyunsaturated fatty acid (PUFA) were significantly higher (p < 0.05) in the OPF group than the CON group with minimal impact on the C18:2n‐6 and total n‐6PUFA. Consequently, the n‐6:n‐3 ratio significantly (p < 0.05) decreased in the OPF group compared to the CON group. The LD muscle had a significantly higher conjugated linoleic acid 18:2 c19t11 compared to other muscles. There were no interactions between muscle x diet except for total SFA. It is concluded that OPF at 25–50% inclusion levels may decrease the SFA and increase the n‐3PUFA content in chevon, with no apparent adverse effects on the growth performance of the animals, can be used as a feed ingredient to support goat farming in countries that lack grazing pasture.     

高细胞密度微藻培养生产ω—3多不饱和脂肪酸

ω－３多不饱和脂肪酸（ＰＵＦＡ）对人体心血管,神经,免疫系统疾病及癌症有一定的预防及治疗效果,利用微藻培养ＰＵＦＡ是最有发展前途的研究方向,实验证明以现有的发酵设备和技术为基础,进行微藻的高细胞密度培养可极大地提高微藻细胞的生物量及ＰＵＦＡ的产量。本文论述了微藻异养培养的条件,策略及研究现状。     

膨化全脂大豆对高产奶牛乳脂中PUFA含量的影响

[目的]研究在高产奶牛日粮中添加膨化全脂大豆对乳脂中多不饱和脂肪酸（PUFA）含量的影响。[方法]选择胎次、体重相近．产犊50天左右的泌乳高峰期中国荷斯坦奶牛12头随机分为四组，采用4×4复合拉丁方试验设计．研究日粮中添加膨化全脂大豆对高产奶牛乳脂中PUFA5含量的影响。在TMR全混合日粮中加入不同比例（0、1kg、1．7kg、2．5kg）的膨化全脂大豆，每期试验21天，共四期。每期试验第15、17、19、21天取奶样。利用气相质谱联用技术（GC／MS）测定乳脂中PUFA5的相对含量。[结果]试验结果表明。膨化全脂大豆添加组与对照组相比，长链不饱和脂肪酸的相对含量显著增加（P〈0．05）．中短链饱和脂肪酸的相对含量下降极显著（P〈0．01）。膨化全脂大豆各添加组间相比．1．7kg膨化全脂大豆添加水平下C18：2相对含量高于2．5kg膨化全脂大豆的添加水平，但差异不显著（P〉0．05）：C18：1t9在添加量为1．7kg水平下分别与1kg、2．5kg添加量相比有显著差异（P〈0．05）。[结论]在高产泌乳奶牛日粮添加1．7kg膨化全脂大豆能够取得最佳的牛乳PUFA含量。     

从小球藻中提取和富集多不饱和脂肪酸的研究

研究了从海水小球藻Chlorellaspp.中提取和富集多不饱和脂肪酸（PUFA）的方法,就提取剂体系、用量、提取次数等对小球藻粗脂肪提取率的影响以及尿素包合法中尿素、甲醇与脂肪酸甲酯的质量比对PUFA、EPA富集效果的影响进行了研究。结果表明：采用氯仿-甲醇提取剂体系,结合超声波萃取法,小球藻粗脂肪的提取率最高,提取次数为两次比较合适,与标准溶剂量相比,总溶剂量可减少42%。在室温（20~22℃）下,尿素与脂肪酸甲酯的质量比为6∶1,尿素与甲醇的质量比为1∶4时,PUFA占总脂肪酸的含量由脲包前的50%提高到82.9%;EPA占总脂肪酸的的含量由脲包前的39%提高到71.6%,EPA富集系数为1.84。     

The Influence of Forage/Concentrate Ratio and Full Fat Soya By-Pass Supplementation on the Fatty Acids Profile from the Carcase of Fatting Lambs

There was organized a 2×2 factorial type experience in which it has been aimed the influence of forage/concentrates ratio and the effect of supplementing the ratio with full fat soya by-pass （FFS） on the production performance and carcass fatty acid profile of fattening lambs. 32 Tsigai lambs were divided into 4 groups and were fed with 2 different diets regarding the forage/concentrates ratio （35/65 and 65/35, on a DM basis）, containing or not 5% FFS （full fat soya treated with formaldehyde 12.5%）. Including FFS in diet and the ratios rich in concentrates determined a significant improvement in weight gain （P〈0.01）, in the degree of food recovery and in fatty acid profile from the carcass. It has been significantly increased （P〈0.01） the weight of polyunsaturated fatty acids （PUFA） from intramuscular fat （longissimus dorsi-LD and femoral biceps-FB） and the deposit fat （subcutaneous-SC and perirenal-PR） and decreased the proportion of saturated （SFA） and monounsaturated fatty acids （MUFA）. Most significant differences were recorded about PUFA from Omega-3 series （C18：3 n-3, EPA C22：3 n-3, DPA and DHA） and CLA isomers （conjugated linolenic acid： C 18：2 C9, tl I＋C 18：2 t10, C 12）. The best profile of fatty acids, considered in light of the influence on human health （high concentration of Omega 3 fatty acids and CLA and low in SFA） was established in LD, for lambs fed with diets high in concentrates and which contained FFS （HC/S）.