真鲷鱼苗饲料中ω—3HUFA的适宜含量

以前的试验得出了真鲷鱼苗饲料中适宜的蛋白质和脂质含量分别约为52%和15%。但是摄食含15%或20%脂质、添加3.2——4.2%ω—3HUFA(高度不饱和脂肪酸)的饲料,鱼的生长率和饲料效率比含2.2%ω—3HUFA 的饲料高。这些结果表明真鲷的生长率取决于ω—3HUFA 含量,而ω—3HUFA的需求量随脂质含量而提高。在淡水鱼中,为获得最高生长率所需的亚麻酸含量随着饲料脂质的含量而提高,而这个关系在海水鱼中还未报道过。     

实用饲料对养殖草鱼体组织脂肪酸组成的影响

为探究生产一线所使用的实用饲料对养殖草鱼体组织脂肪酸组成的影响，试验对两种草鱼育成期商品饲料（CY1和CY2）及该饲料饲喂草鱼的肝胰脏、腹腔脂肪组织、肾脏、肠道、脾脏、肌肉、鳃、眼、脑9种组织的脂肪酸组成进行了检测和分析。结果显示，CY1和CY2饲料亚油酸（LA）含量分别为35.13%和35.07%，亚麻酸（LNA）含量分别为4.93%和9.01%，花生四烯酸（ARA）含量分别为1.10%和10.88%，n-3高不饱和脂肪酸（HUFA）含量分别为2.12%和0.80%。饲料与组织脂肪酸组成相关性分析显示，腹腔脂肪组织和肠道组织的脂肪酸组成与饲料脂肪酸组成相关系数最高，脑组织最低。为了判明脂肪酸的组织沉积特征，对组织重要脂肪酸含量与饲料相应脂肪酸含量的比值进行散点分析，发现脂肪酸离散程度由高到低依次为HU-FA、LA和LNA、饱和脂肪酸（SFA）和单不饱和脂肪酸（MUFA）。组织及饲料SFA、MUFA、HUFA比值大于1，LA、LNA比值小于1。不同组织器官相比较，腹腔脂肪组织的SFA、HUFA比值最低， MUFA、LA、LNA比值较高；相反，在脑组织中，HUFA比值较高，而LA、LNA比值最低。研究表明，两种商品饲料LNA的添加水平较低，LA的添加水平较高。鱼体组织的脂肪酸组成基本反映了饲料脂肪酸组成，但脂肪酸的组织沉积模式存在差异，分析可能与不同类型脂肪酸的利用与转化特点不同有关。建议生产中有针对性地选择饲料油脂，以满足草鱼生长及维护健康状态的脂肪酸需求。     

荷那龙罗非鱼体内不同组织脂肪酸组成的差异分析

实验以荷那龙罗非鱼(Oreochromis hornorum)为研究对象,在自然正常的养殖条件下,随机的抽取15尾荷那龙罗非鱼,取背侧肌、肝胰脏、肠和内脏脂肪组织四个组织的样,来分析不同组织的脂肪酸组成差异。结果发现:四个组织中所含脂肪酸种类最多的为内脏脂肪组织,其次是肝胰脏和肠,最后是肌肉;几种组织中含量最高的均为16和18碳的脂肪酸。在荷那龙罗非鱼的内脏脂肪组织中,含量最高的为油酸(C18:1)、亚油酸(C18:2)、亚麻酸(C18:3);EPA和DHA在肌肉中含量最高;肠组织中含有最高的饱和脂肪酸(SFA),其次是肌肉;单不饱和脂肪酸(MUFA)在内脏脂肪组织中含量最高;多不饱和脂肪酸(PUFA)在肌肉中含量最高。     

牛磺酸对草鱼生长、品质、消化酶和代谢酶活性的影响

本文旨在研究牛磺酸对草鱼的营养效应。选用体长12.5~13.0 cm,体重38.1~38.9 g的草鱼432尾,随机分为8个处理组,每组54尾,设3个重复,每个重复18尾。在饲料中添加0、200、400、600、800、1 000、1 400、1 800 mg/kg的牛磺酸,以0 mg/kg添加组为对照组,试验期30 d,研究牛磺酸对草鱼生长、品质、消化酶和代谢酶活性的影响。结果表明:(1)牛磺酸促进草鱼生长(除1 800 mg/kg添加量外)。添加量为600 mg/kg时,特定生长率(SGR)、肌肉、肝胰脏RNA/DNA比值、饲料效率(FE)和蛋白质效率最高(P<0.05);(2)饲料中添加牛磺酸后,草鱼体水分含量下降,体蛋白、体脂含量增加(P<0.05),灰分含量、内脏指数、肥满度各试验组之间差异不显著(P>0.05);(3)添加适宜牛磺酸(600~800 mg/kg),显著提高肝胰脏和肠道脂肪酶、淀粉酶的活性(P<0.05);(4)牛磺酸具有促进草鱼肝胰脏和肌肉转氨酶、碱性磷酸酶活性的作用。综合以上结果,草鱼饲料中牛磺酸的最适添加量为600 mg/kg。     

饲料脂肪水平对草鱼幼鱼生长和肝胰脏组织形态的影响

为研究草鱼实用配方中脂肪的适宜含量，试验以草鱼实用配方配制基础饲料，在基础饲料中分别添加0%、1%、2%、3%、4%和5%的豆油，制成6种试验饲料。试验选取初始体质量（104.0±7.7）g的草鱼720尾，随机分为6组，每组6个重复，每个重复20尾鱼，养殖周期60 d。结果 表明：（1）在饲料脂肪水平为5.72%～7.65%时，草鱼的增重率、特定生长率及蛋白质效率均显著高于未添加脂肪组（P <0.05），饲料系数呈现与之相反的趋势。（2）在饲料脂肪含量为6.48%时，草鱼增加单位体质量所消耗的饲料蛋白质质量显著低于其他各组（P <0.05）。（3）草鱼肝胰脏组织切片显微观察显示，6组草鱼肝胰脏细胞均排列整齐、大小均一、细胞膜分界明显，总体较健康，但有随饲料脂肪水平提高，细胞质中白色部分增多现象。本试验条件下，综合比较生长和饲料利用率，草鱼幼鱼饲料脂肪最适含量为6.3%～6.5%。     

鳟鱼的必需脂肪酸需要量

饲料中添加不同含量的亚油酸(C18:2)、亚麻酸(C18:3)、花生四烯酸(C20:4)以及富含二十碳五烯酸(EPA,C20:5)、二十二碳六烯酸(DHA,C22:6)的 n-3高度不饱和脂肪酸(HUFA)饲喂鳟鱼,观察生长发育和肝脏中脂肪的含量,进行必需脂肪酸需要量的研究。试验共进行二次。第一次试验选用平均体重0.95克幼鳟鱼。对照组的精制饲料中添加5%硬脂酸(18:1),试验组的精制饲料中单独或联合添加0.5～1%的亚油酸、亚麻酸和 HUFA 代替硬脂酸。试验期为14周。第     

鲤鱼的脂肪酸代谢

本文探讨了饲料中添加各种脂肪酸,对鲤鱼体成分和脂质生物合成酶活性的影响。 试验选用体重约45g鲤鱼。供试的脂肪酸有硬脂酸、亚油酸、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)的混合物(简称:HUFA,高度不饱和脂肪酸)。对照组为几乎不含脂肪酸的     

新疆牧区传统酸奶干酪的营养成分及脂肪酸含量分析

本文对新疆主要牧区牧民传统方法制造的酸奶干酪营养成分及脂肪酸组成进行了分析研究。结果表明,大多数酸奶干酪样品中水分含量在5％FAT,质地干硬。pH值和总酸含量分别为3．9±0．2和5．6％±0．4。粗灰分、粗蛋白质和总脂肪含量分别为5．7％,52．0％和18．6％,其中粗脂肪含量的变化幅度较大（6．3％-31．1％）。酸奶干酪脂质中检测出近20种脂肪酸,其中油酸（C18：1）含量最高,占总脂肪酸的32．7％。不饱和脂肪酸总量的81．1％。     

饲料n-3高不饱和脂肪酸水平对较大规格军曹鱼生长性能、血清生化指标以及肌肉和肝脏脂肪酸组成的影响

本试验旨在考察饲料n-3高不饱和脂肪酸(HUFA)水平对较大规格军曹鱼生长性能、血清生化指标及肌肉和肝脏脂肪酸组成的影响,以确定较大规格军曹鱼饲料中n-3HUFA的适宜水平。以白鱼粉、酪蛋白和去皮豆粕为主要蛋白质源,调节饲料中鱼油和玉米油的添加量,制成n-3HUFA水平分别为0.49%、0.73%、0.98%、1.41%、1.51%、2.06%及2.83%的7种等氮等能的试验饲料,投喂初重为70 g的军曹鱼8周。每种饲料投喂3个网箱(重复),每个网箱放养30尾鱼。结果显示:1)增重率(WGR)和特定生长率(SGR)随饲料n-3HUFA水平的升高呈先升高后降低趋势,0.73%～1.51%组的WGR和SGR显著高于0.49%和2.83%组(P0.05)。2.83%组的成活率(SR)显著低于其他各组(P0.05)。鱼体粗脂肪含量随饲料n-3HUFA水平的升高呈先上升后下降的趋势,0.98%和1.41%组鱼体粗脂肪含量显著高于2.06%和2.83%组(P0.05)。2) 0.49%组血清谷丙转氨酶(ALT)活性显著高于2. 06%组(P 0. 05); 0. 49%组血清甘油三酯(TG)显著高于其他各组(P0.05);血清总胆固醇(CHOL)含量随饲料n-3HUFA水平的升高呈先升高后下降趋势,以0.73%组最高,显著高于0.49%、2.06%和2.83%组(P0.05); 0.98%组血清高密度脂蛋白(HDL)含量显著高于其他各组(P0.05); 0.98%～2.83%组血清低密度脂蛋白(LDL)含量显著高于0.49%和0.73%组(P0.05)。3)肌肉和肝脏C14∶0和C21∶0含量均以2.83%组最高,各组肌肉和肝脏C16∶0含量和饱和脂肪酸总量(∑SFA)无显著差异(P 0.05)。肌肉和肝脏C18∶1n-9、单不饱和脂肪酸总量(∑MUFA)及C18∶2n-6含量均随饲料n-3HUFA水平的升高而下降。随饲料n-3HUFA水平的升高,肌肉和肝脏n-6多不饱和脂肪酸总量(∑n-6PUFA)呈先上升后稳定趋势,C20∶5n-3(EPA)、C22∶5n-3、C22∶6n-3(DHA)含量及n-3多不饱和脂肪酸总量(∑n-3PUFA)和n-3HUFA总量(∑n-3HUFA)均呈逐渐升高趋势。综上,饲料中添加n-3HUFA有助于提高较大规格军曹鱼的生长性能,降低体脂沉积,促进脂肪代谢,并可影响肌肉和肝脏脂肪酸组成。以SGR为评价指标,由折线模型得出较大规格军曹鱼饲料中n-3HUFA的适宜水平为0.95%。     

镁对草鱼生长和脂肪代谢的影响

本试验在以酪蛋白和明胶为蛋白源的纯化口粮(镁含量76.9 mg/kg)中添加不同水平的镁(0、150、300、600、1 200和2 400 mg/kg),研究了镁对草鱼生长和脂肪代谢的影响.选取540尾体重为(10.68±0.14)g的草鱼,随机分入6个处理,每个处理3个重复,每个重复30尾鱼.进行为期10周的生长试验.结果表明:1)日粮中添加适量镁显著提高草鱼的特定生长率、增重率和饲料效率(P<0.05),当饲料镁含量为692.0 mg/kg时,以上3项指标均达到最大值;2)日粮中添加适量镁能增加草鱼体脂沉积率、血脂水平、肝胰脏脂肪酶和节果酸脱氧酶活性(P<0.05),降低肝胰脏脂蛋白酯酶活性(P<0.05),但对肠道脂肪酶活性没有显著影响(P>0.05).由此可知,日粮中适当添加镁能显著促进草鱼生长,添加量为600 mg/kg(日粮镁含量692.0 mg/kg)时效果最好;镁能够增慢草鱼肝胰脏的脂肪合成能力,降低其脂肪转运能力;镁使肝脂蛋白酯酶活性降低,导致高血脂.     

饲料中添加龙须菜对草鱼生长性能、血清生化指标及肌肉脂肪酸组成的影响

为考察饲料中添加龙须菜对草鱼生长性能、血清生化指标及肌肉脂肪酸组成的影响,试验共配制了6种龙须菜添加比例分别为0(对照组)、1%、2%、3%、4%和5%的等氮等脂饲料,投喂平均体重为(15.94±0.10)g的草鱼8周。每种饲料投喂4个水箱(重复),每箱30尾鱼。结果显示:1)饲料中不同添加比例龙须菜对草鱼的增重率(WGR)、特定生长率(SGR)、存活率(SR)及饲料效率(FE)没有显著影响(P0.05)。2)各试验组的肝体指数(HSI)均高于对照组,对照组与除5%添加组外的其他试验组的差异均达到显著水平(P0.05)。3)全鱼、肝脏及肌肉的粗蛋白质含量各组间皆无显著差异(P0.05),而饲料中不同添加比例龙须菜对全鱼粗灰分与粗脂肪、肝脏粗脂肪及肌肉水分含量有显著影响(P0.05)。4)血清总蛋白(TP)、总胆固醇(TCHO)、甘油三酯(TG)以及低密度脂蛋白(LDL)含量以5%添加组最低,显著低于对照组(P0.05),其他试验组与对照组没有显著差异(P0.05)。5)饲料中龙须菜添加比例影响了草鱼肌肉脂肪酸的组成,除C14∶1、C20∶0、C20∶2外,其他肌肉脂肪酸的含量均受到饲料中龙须菜的添加比例的显著影响(P0.05),其中肌肉多不饱和脂肪酸(PUFA)含量及n-3/n-6 PUFA均在3%添加组获得最高值。1%、2%、3%、4%和5%添加组肌肉C20∶5(EPA)、C22∶5(DPA)、C22∶6(DHA)以及EPA+DHA的含量都显著高于对照组(P0.05)。由此得出,饲料中添加一定比例的龙须菜对草鱼的生长性能没有显著影响,但能降低血脂含量,影响草鱼肌肉脂肪酸的组成,并能提高功能性脂肪酸DHA、EPA及PUFA的含量;饲料中添加3%的龙须菜能更好地增加肌肉功能性脂肪酸含量,而添加5%的龙须菜则草鱼生长相对较好,降低血脂效果更加明显。     

草鱼幼鱼对饲料中核黄素的需要量

配制核黄素含量分别为0.54、2.32、4.08、5.78、9.28和19.35 mg/kg的6种纯化饲料,投喂初始均重为(11.21±0.16)g的草鱼幼鱼8周,通过研究核黄素对其生长性能、肝胰脏中D-氨基酸氧化酶(D-AAO)与肠道中消化酶活力及体成分的影响,以确定草鱼幼鱼对饲料中核黄素的需要量。每种饲料设3个重复,每个重复放养20尾鱼。结果表明:0.54和2.32 mg/kg组草鱼幼鱼的成活率显著低于其他各组(P0.05);随着饲料中核黄素含量的增加,草鱼幼鱼的增重率、特定生长率、饲料效率、肝胰脏中D-AAO及肠道中消化酶活力均先升高后趋于稳定,当饲料中核黄素含量为5.78 mg/kg时,以上指标均达到最大值;5.78 mg/kg组的肝体比显著高于0.54 mg/kg组(P0.05),但饲料中核黄素含量对脏体比、肥满度及全鱼的水分、粗蛋白质、粗脂肪和粗灰分含量无显著影响(P0.05)。折线模型回归分析表明,草鱼幼鱼获得最佳生长时对饲料中核黄素的需要量为5.54 mg/kg;肝胰脏中D-AAO活力达到最佳时对饲料中核黄素的需要量为5.99 mg/kg。     

Influence of oils on the Taihe Silky Fowl production performances and fatty acids composition of the meat*

Focus on the enrichment of eggs and poultry meat with polyunsaturated fatty acids has increased given their important roles in the human health. The inclusion of polyunsaturated fatty acids (especially n‐3 fatty acids, n‐3 FA) is achieved by different biological methods. The objective of this study was to investigate the effects of inclusion of different oils into the feed on the production performances and fatty acids composition of the meat in Taihe Silky Fowl. A total of 80 fowls were selected at 8 weeks and randomly divided into four groups and fed with basal diet, basal diet + 4% fish oil, basal diet + 4% soybean oil and basal diet + 4% palm oil within 3 weeks respectively. The results showed that: the fowls fed with the diet inclusion of 4% fish oil had higher total gain, average daily gain, the second and the third week average daily gain than those in control group (p < 0.05). Also, inclusion of fish oil could improve the content of C22:5 n‐3 and C22:6 n‐3 polyunsaturated fatty acids in the meat significantly compared with the other three groups (p < 0.01). Meanwhile, C18:3 n‐3 and C18:4 n‐3 polyunsaturated fatty acids were also higher than in the other three groups (p < 0.05 and 0.01). Oils Supplementation could enhance C14:0 and C16:0 (p < 0.05) level, but they did not affect the total saturated fatty acids in the meat. Compared with the control group, fish oil inclusion could lower the C18:2 n‐6 level, higher the C18:3 n‐6, C22:4 n‐6 and C22:5 n‐6 polyunsaturated fatty acids in the meat (p < 0.05). Moreover, diets supplied with 4% fish oil reduced the total n‐6 polyunsaturated fatty acids level and enhanced the total n‐3 polyunsaturated fatty acids level in the meat, which resulted in that the ratio of n‐3/n‐6 was improved, and could meet the need of human body.     

日粮ω6/ω3对爱拔益加肉仔鸡肉品质、血液脂质指标及脂肪酸组成的影响

本试验研究了日粮不同ω6/ω3多不饱和脂肪酸(PUFA)比值(ω6/ω3)对6周龄爱拔益加(AA)肉仔鸡肉品质、血液脂质指标及脂肪酸组成的影响.采用重量替代法使各处理日粮ω6/ω3比例分别为∶30∶1、20∶1、10∶1、5∶1和2.5∶1.选用体重接近的1日龄AA鸡母雏180只,随机分为5个处理,每个处理6个重复,每个重复6只鸡,试验期为6周,分1～4周和5～6周2个阶段.测定肉品质性状及腿肌脂肪酸组成.结果表明,随着日粮ω6/ω3的降低:(1)肌肉滴水损失极显著下降(P<0.001);当ω6/ω3为5∶1时,pHt最低,日粮ω6/ω3对肌肉肌内脂肪含量、肌苷酸含量没有显著影响(P>0.05);血液总胆固醇显著降低(P<0.001);(2)腿肌,ω3 PUFA极显著增加(P<0.001),尤其是C18∶3、C20∶5和C22∶5,ω6 PUFA显著下降(P<0.05),ω6/ω3从3.50降至1.60,多不饱和脂肪酸与饱和脂肪酸的比值在1.0左右(0.96～1.04);(3)极显著地增加了腿肌中C18∶3向C20∶5和C22∶5的转化效率(P<0.001),长链ω3 PUFA(除了C18∶3)在腿肌的含量高达7.24%.日粮ω6/ω3和腿肌中C20∶5和C22∶5的关系可分别用y=2.946 7 x-1.0413(R2=0.9901)及y=-0.642 3 Ln(x)+2.56(R2=0.993 6)表示.本试验证明降低日粮ω6/ω3,能在一定程度改善肉品质,并有效地增加腿肌中人体必需的ω3长链PUFA沉积,获得了营养丰富的鸡肉.     

Manipulation of the n-3 polyunsaturated fatty acid content of muscle and adipose tissue in lambs

Fifty Suffolk-crossbred wether lambs, with an initial live weight of 29 +/- 2.1 kg, were allocated to one of five concentrate-based diets formulated to have a similar fatty acid content (60 g/kg DM), but containing either linseed oil (high in 18:3n-3); fish oil (high in 20:5n-3 and 22:6n-3); protected linseed and soybean (PLS; high in 18:2n-6 and 18:3n-3); fish oil and marine algae (fish/algae; high in 20:5n-3 and 22:6n-3); or PLS and algae (PLS/algae; high in 18:3n-3 and 22:6n-3). Lambs were slaughtered when they reached 40 kg. Growth performance and intake were similar (P > 0.35) among treatments. By contrast, gain:feed was higher (P < 0.05) in lambs fed the fish oil compared with the linseed oil or PLS/algae diets. Total fatty acid concentration (mg/100 g) in the neutral lipid of the longissimus muscle was not affected by treatment (P > 0.87) but was least (P < 0.05) in the phospholipid fraction in lambs fed the linseed oil diet. Lambs fed either diet containing marine algae contained the highest (P < 0.05) percentage of 22:6n-3 in the phospholipid (mean of 5.2%), 2.8-fold higher than in sheep fed the fish oil diet. In lambs fed the fish/algae diet, the percentage of 20:5n-3 was highest (P < 0.05), contributing some 8.7, 0.8, and 0.5% of the total fatty acids in the muscle phospholipid, neutral lipids, and adipose tissue, respectively. The percentage of 18:3n-3 in the phospholipid fraction of the LM was highest (P < 0.05) in lambs fed the linseed oil diet (6.9%), a value double that of sheep fed the PLS diet. By contrast, lambs fed the PLS diet had twice the percentage of 18:3n-3 in the muscle neutral lipids (3.8%) than those offered the linseed oil diet, and 5.5-fold greater than lambs fed the fish/algae treatment (P < 0.05), an effect that was similar in the adipose tissue. The percentage of 18:2n-6 was highest (P < 0.05) in lambs fed the PLS diet, where it contributed 33.7, 10.1, and 11.2% in the muscle phospholipid, neutral lipids, and adipose tissue, respectively. The highest (P < 0.05) muscle PUFA-to-saturated fatty acid (P:S) ratio was obtained in lambs fed the PLS diet (0.57), followed by the PLS/algae diet (0.46), and those fed the fish oil or linseed oil diets had the lowest ratios (0.19 and 0.26, respectively). The favorable P:S ratio of lambs fed the PLS/algae diet, in conjunction with the increased levels of 20:5n-3 and 22:6n-3, enhanced the nutritional qualities of lamb to more closely resemble what is recommended for the human diet.     

半胱胺对宁乡猪血清生化指标和肝脏脂肪代谢的影响

本试验旨在研究饲粮中添加半胱胺对宁乡猪血清生化指标和肝脏脂肪代谢的影响。选取同批次平均体重约43.0 kg宁乡阉公猪30头,随机分为2组,每组5个重复,每个重复3头。对照组饲喂基础饲粮,试验组在基础饲粮中添加80 mg/kg半胱胺,试验期8周。结果表明:1)与对照组相比,试验组血清中葡萄糖含量提高了21.91%(P0.01),低密度脂蛋白含量提高了26.22%(P0.01),总胆固醇含量提高了9.75%(P0.10),尿素氮含量降低了14.14%(P0.05)。2)与对照组相比,试验组肝脏中饱和脂肪酸中肉豆蔻酸、棕榈酸和花生酸含量分别降低了72.09%(P0.01)、13.12%(P0.05)和71.13%(P0.01),十七烷酸含量提高了11.77%(P0.10);单不饱和脂肪酸含量升高了40.37%(P0.01),其中反油酸含量降低了85.90%(P0.01),油酸含量提高了55.80%(P0.01);多不饱和脂肪酸含量降低了7.56%(P0.05),其中亚油酸含量降低了18.56%(P0.01),二十二碳六烯酸(DHA)和二十碳三烯酸含量分别提高了96.13%和37.99%(P0.01)。3)与对照组相比,试验组过氧化物酶增殖体激活受体α(PPARα)表达量显著增加(P0.05)。综上,在宁乡猪肥育猪饲粮中添加半胱胺能提高肝脏中DHA的含量,可能是通过调控肝脏脂肪代谢基因PPARα的表达,进而影响机体的脂肪代谢。     

Profile of fatty acid lipid fractions of omega-3 fatty acid-enriched table eggs

The omega-3 fatty acid (FA) enrichment of yolk is a key means one of the main objectives to improve the nutraceutical properties of eggs. We evaluated the effect of the dietary inclusion of extruded linseed fed to laying hens on the fatty acid composition of the polar and non-polar lipid classes of the eggs. Two groups of 36 Lohmann White Leghorn layers (65 weeks old) were each fed one of two different diets for a period of 12 weeks. The two diets consisted of a conventional cereal-based diet concentrate (C) and a diet concentrate containing 5% linseed (L). The inclusion of linseed in the diet increased the content of α-linolenic (C18:3n-3), eicosapentaenoic (C20:5n-3) and docosahexaenoic (C22:6n-3) acids in neutral lipids, while a concomitant decrease in arachidonic acid (C20:4n-6) was observed. As regards the polar fraction, the fatty acid composition was slightly affected by the dietary treatments except for C18:0 (+1.14 fold), C18:2n-6 (+1.23 fold), C18:3n-3 (+2.8 fold) and C22:6n-3 (+1.41 fold). Principal component analysis demonstrated that very long-chain FAs were more representative of polar lipids, except for C20:5n-3, while neutral lipids were characterized by dietary n-3 FA (C18:3n-3).     

Protein and lipid sources affect cholesterol concentrations of juvenile Pacific white shrimp, Litopenaeus vannamei (Boone)

Two experiments were conducted to evaluate the effects of protein and lipid sources on cholesterol, AA, and fatty acid content, and on biological performance of juvenile Pacific white shrimp, Litopenaeus vannamei (Boone). In Exp. 1, seven isonitrogenous and isocaloric diets were prepared using fish meal; soybean meal; casein; fish meal + soybean meal; fish meal + casein; soybean meal + casein; and fish meal + soybean meal + casein. In Exp. 2, seven isonitrogenous and isocaloric diets were prepared using fish oil; soy oil; poultry fat; fish oil + soy oil; fish oil + poultry fat; soy oil + poultry fat; and fish oil + soy oil + poultry fat. Nine shrimp (average BW 570 mg) were stocked per 60-L tank, with three tanks per diet in each experiment. Shrimp were fed to apparent satiation twice daily for 28 d. Protein sources affected shrimp cholesterol, feed consumption, feed efficiency, protein consumption, protein efficiency ratio, and crude body fat (P < or = 0.05), but not weight gain, survival, hepatosomatic index, body protein, ash, and AA composition. Body (without hepatopancreas) cholesterol concentrations were the highest in shrimp fed the diet containing fish meal (0.81%), lowest for those fed the casein diet (0.64%), and intermediate in the other dietary treatment groups (range 0.71 to 0.74%). Lipid source also affected shrimp body cholesterol, body fatty acid profiles, and fatty acid profiles in the hepatopancreas (P < or = 0.05), but not growth performance, body protein, fat, ash, and cholesterol concentrations in the hepatopancreas. Shrimp fed the fish oil diet had the highest body cholesterol (0.75%), whereas those fed the soy oil or poultry fat diets were lowest (0.66 and 0.65%, respectively). Results indicate that by replacing fish meal and fish oil with soybean meal and soy oil, shrimp growth performance is not affected, but body cholesterol concentration is reduced.     

Fatty acid status in captive and free-ranging black rhinoceroses (Diceros bicornis)

The fatty acid (FA) patterns of plasma/serum triglycerides (TG), phospholipids (PL) and cholesteryl esters (CE) of captive and free-ranging black rhinoceroses (Diceros bicornis) were investigated. Free-ranging animals (n = 28) stemmed from four different regions. Captive animals sampled included specimens from North American (n = 11) and three different European facilities (n = 6). The European animals were tested on 1-4 different diets, resulting in a total of 15 blood samples. Regardless of differences between the free-ranging animals from different regions, differences between captive and free-ranging animals were relatively uniform: captive animals had higher overall proportions of polyunsaturated fatty acid (PUFA), due to levels of linoleic acid (LA, 18:2n6) that were drastically increased as compared to free-ranging animals. In contrast, levels of alpha-linolenic acid (ALA, 18:3n3) were consistently lower on conventional zoo diets. n6/n3 ratios for TG, PL and CE were 1.6, 10 and 8 in samples from free-ranging animals, respectively, as compared to 4.1-16.3, 16-148 and 40-277 in samples from captive animals. There was a distinct correlation between the proportion of grain-based products (commercial concentrates, plain grains and bread) in the diets of the European animals and the measured levels of n6 PUFA. An animal from a facility with a very low proportion of grain products in the diet nevertheless had high LA readings, most probably due to the use of sunflower oil as 2% (dry matter basis) of its diet. One animal that received a high proportion of grass meal pellets due to an oral disease had increased ALA contents after the diet change. These results allow conclusions on the suitability of diets fed in captivity: the black rhinoceros is prone to several uncommon diseases that have been suspected to be linked to oxidative damage, possibly due to the disposition of this species to excessive iron storage. An unnatural dietary loading with PUFAs would exacerbate this problem. Additionally, n6 FAs are known as precursors of pro-inflammatory mediators, and their overrepresentation could therefore exacerbate any inflammatory processes. Therefore, the current practice of using grain-based feeds as major ingredients in captive rhinoceros diets is discouraged. Diet items containing ALA (a precursor of anti-inflammatory mediators) such as, fresh grass, fresh browse, the respective silages should be included at higher levels in diets for captive black rhinoceroses. Grass meal pellets, although a good source of ALA and linked with high levels of ALA in an animal of this study, must be chosen with care for black rhinoceroses due to their particular proneness for high iron contents.     

Effects of dietary sunflower seeds and tylosin phosphate on production variables, carcass characteristics, fatty acid composition, and liver abscess incidence in crossbred steers

A 2 x 2 factorial experiment with 48 crossbred steers (with Hereford, Angus, and Charolais genetics, and an initial BW of 373 +/- 8.4 kg) was conducted to evaluate the effects of dietary sunflower seeds (SS) and tylosin phosphate (TP) on production factors, carcass characteristics, liver abscess incidence, and fatty acid composition of the muscle (pars costalis diaphragmatis; PCD) and subcutaneous fat. Individually penned steers were fed either a control diet of 84.5% rolled barley, 14% barley silage, and 1.5% mineral and vitamin mix on a DM basis, or an SS diet, in which SS replaced 15% of the diet. Half the animals fed each diet received TP at 11 mg/kg of DM as a top dressing. Interactions were significant for all production factors. A reduction (P = 0.008) in DMI was observed from 10.1 +/- 0.4 kg/d, in steers fed the control diet, to 8.9 +/- 0.3 and 8.6 +/- 0.3 kg/d, in steers fed the SS and SS + TP diets, respectively. Greater (P = 0.014) ADG was observed for steers fed the control diet than for those fed the SS or SS + TP diet (1.4 vs. 1.1 and 1.2, SE = 0.1 kg/d, respectively); however, G:F ratios were greater (P = 0.011) in steers fed the control diets than in those fed the SS diets. Steers fed the control and SS diets had the heaviest and lightest HCW (347 +/- 6.9 vs. 325 +/- 8.4 kg; P = 0.025), respectively. Lean meat yield (%) of steers fed SS was greater (P = 0.117) than in steers fed the control diets, whereas total lean yield [(HCW x lean meat yield)/100] was similar (P = 0.755). Provision of the SS or SS + TP diet eliminated (P = 0.08 for interaction) liver abscesses compared with the 36 and 9% incidence in steers fed the control or control + TP diet, respectively. Fatty acid weight percentages (wt%) followed similar patterns in PCD and subcutaneous fat. Feeding the SS diets led to greater (P = 0.001) wt% of 18:0 and 18:2n-6, but reduced the wt% of 16:0, 9-cis (c)-18:1, and 18:3n-3 in PCD compared with that in steers fed the control diets, but the wt% of 9c,11-trans (t), and 10t,12c CLA were increased (P = 0.001) by 36 and 400% in PCD. Dietary SS increased (P < 0.001) the wt% of trans-18:1 isomers. The 10t-18:1 and 11t-18:1 isomers were the greatest, but dietary TP elevated (P = 0.004) only 10t-18:1, and total trans-18:1 (excluding 11t-18:1) was 0.47 +/- 0.06 g/100 g of PCD. Dietary SS for finishing steers reduced the incidence of liver abscesses without affecting total lean yield of the carcass, with modest increases in trans fatty acids and in potentially beneficial fatty acids (11t-18:1 and CLA).