波纹巴非蛤的形态分析与营养成分评价

文章分析了波纹巴非蛤（Paphia undulate）的形态性状、出肉率及蛤肉的主要营养成分,并综合评价了其营养价值。结果显示,波纹巴非蛤的出肉率达35．73％;蛤肉中蛋白质占鲜质量的12．8％;18种氨基酸总量约占干质量的46．21％,其中8种必需氨基酸（EAA）占氨基酸总量的34．67％,4种鲜味氨基酸占氨基酸总量的41．94％;牛磺酸（Tau）的质量分数较高,占干质量的3．03％;不饱和脂肪酸（UFA）占脂肪酸总量的51．9％,C22：6（DHA）和C20：5（EPA）共占32．8％;矿物质丰富,尤其是钾（K）元素的质量分数高达3．407mg·g-1。     

Effect of a dietary phospholipid supplementation on growth and fatty acid composition of European sea bass (Dicentrarchus labrax L.) and turbot (Scophthalmus maximus L.) juveniles from weaning onwards

Two 40-day feeding trials using extruded diets were conducted to assess the effect of a dietary phospholipid (PL) supplementation on growth, survival and fatty acid composition of European sea bass (Dicentrarchus labrax) and turbot (Scophthalmus maximus) from weaning onwards. Two dietary treatments (FO and PL) were tested; both had an identical extruded basis (92.5% total diet weight) coated with a different lipid fraction (7.5% total diet weight). Diet PL contained 2% egg yolk PL (69% pure). In diet FO the PL was replaced by hydrogenated coconut oil. The isolipidic diets contained an equal amount of fish oil ethyl esters providing 1.6% (% diet dry weight) of n-3 highly unsaturated fatty acids (HUFA). A diet water stability test showed no effect of the PL supplementation on the leaching of the dietary fatty acids. In both fish species weight, but not survival, significantly increased as a result of PL supplementation. Weaning onto the experimental diets resulted in similar changes in the relative percent levels of fatty acids in both species. In general, the percentage of saturated fatty acids levelled off after a rapid increase, while monoenes increased after an initial decrease. Total n-3 polyunsaturated fatty acids (PUFA) decreased and total n-6 PUFA remained almost constant. The major effect of the dietary PL on fish fatty acid composition was a 50% increase in n-6 and n-3 HUFAs compared to the PL-free FO diet. The rise in n-6 HUFA may have reflected the higher moiety in the dietary PL. On the other hand this was not the case for the n-3 HUFA since they represented only low levels in the PL fraction (0.1%) compared to that provided by the ethyl esters (1.6%) suggesting a more efficient incorporation of the PL n-3 HUFA than of the ethyl ester n-3 HUFA. A second hypothesis is that the dietary PL may have favored the incorporation of the dietary ethyl ester n-3 HUFA.     

日粮中添加鱼溶浆粉和鱼油对草鱼生长、肝脏脂肪含量和血清理化指标的影响

本实验探讨以猪肉粉为动物蛋白源的草鱼日粮中添加鱼溶浆粉和鱼油以补充鱼类所需的部分生长因子,对草鱼生长、肝脏脂肪含量和血清理化指标的影响,以期达到节约鱼粉的目的。在实用配方模式下,设计6种等氮等能饲料,分别是添加6%猪肉粉(6P)、3%猪肉粉+3%鱼溶浆粉(3P3SW)、6%鱼溶浆粉(6SW)、3%猪肉粉+3%鱼溶浆粉+2%鱼油(3P3SW2O)、6%鱼溶浆粉+2%鱼油(6SW2O)和6%鱼粉(6F,对照)。在池塘网箱中饲喂(80.0±2.0)g的草鱼72 d。结果表明,6P和6F在SGR、FCR、PRR、ERR和HSI方面均无显著差异(P>0.05)。添加鱼溶浆粉后,3P3SW、6SW与6F相比,SGR提高了9.1%～9.6%,FCR下降了8.5%～11.2%,差异显著(P<0.05),但3P3SW和6SW无显著差异(P>0.05),同时,在PRR、FRR和ERR方面,3P3SW、6SW均有一定程度提高。添加鱼油后,3P3SW2O、6SW2O和3P3SW、6SW比,SGR分别下降了9.7%、15.4%,FCR分别上升了6.9%、31.1%,除3P3SW2O和3P3SW的FCR之外,其余差异显著(P<0.05);在PRR和ERR方面,3P3SW2O、6SW2O均有一定程度下降;同时,3P3SW2O、6SW2O的FRR和肝脏粗脂肪含量都出现不同程度增高,HSI增大,血清TBA、CHOL、HDL和LDL与肝脏粗脂肪呈现出相同趋势,且上述指标均是6SW2O组最高,与其余各组均存在显著差异(P<0.05)。此外,在对饲料中游离氨基酸和生物胺与FCR和SGR的相关性分析中,发现游离Lys、Tau和Put与FCR和SGR的Pearsion相关系数都大于0.8,且符合二次函数关系。因此,鱼溶浆粉对草鱼的促生长作用优于鱼粉,在无鱼粉日粮中添加少量的鱼溶浆粉能满足草鱼需求,节约鱼粉用量,这种促生长作用与饲料中游离Lys、Tau和Put的关系密切;由于鱼油促使脂肪在体内和肝脏沉积,加重肝脏脂质代谢负担,加上其易氧化变质特性,限制了它在水产饲料中的使用。     

细鳞鲑幼鱼n-3 HUFA需求量的研究

为确定细鳞鲑(Brachymystax lenok)n-3 HUFA需求量以减少鱼油使用和降低养殖成本,研究饲料中不同水平的n-3 HUFA对细鳞鲑的生长性能、体成分和肌肉脂肪酸组成的影响。以脱脂鱼粉、脱脂豆粕、明胶和酪蛋白为主要蛋白源,通过调节饲料中的猪油和浓缩油EPA、DHA水平,使饲料n-3HUFA的含量分别达到0.25%、0.50%、0.75%、1.00%、1.25%、1.50%,配制出6种等氮等能的试验饲料(D 0.25、D 0.50、D 0.75、D1.00、D 1.25和D 1.50),分别投喂细鳞鲑幼鱼(60.0 g±2.8 g)84 d。结果显示:饲料中n-3HUFA不同水平对细鳞鲑成活率和饲料系数没有显著影响,但是显著影响了其末重(FW)、增重率(WGR)和特定生长率(SGR)。随着添加饲料中n-3HUFA水平的升高,FW、WGR和SGR有先升高后下降的趋势,且3者在饲料中n-3HUFA水平为0.75%均最大。随着饲料中n-3 HUFA水平的升高,鱼肌肉18∶1n-9的含量逐渐下降,而22∶6n-3的水平相应升高。结果表明,以WGR为评价指标时,用二次曲线模型推测出细鳞鲑对饲料n-3 HUFA的需求量约为0.69%。     

Effect of dietary saturated and monounsaturated fatty acids in juvenile barramundi Lates calcarifer

Barramundi (Lates calcarifer), a catadromous teleost of commercial interest, perform well when fed a wide range of dietary oils. However, the range of alternative oils now being explored is typically rich in saturated and monounsaturated fatty acids (SFA and MUFA). In this study, the response of juvenile barramundi (47.0 g per fish initial weight) fed isolipidic and isoenergetic diets with 82 g kg^?1 added oil was tested. The experimental test diets had a 2 : 1 or 1 : 2 ratio of SFA to MUFA (SFA‐D and MUFA‐D, respectively) compared to a control diet (CTRL‐D) fed for 8 weeks. The diets containing mostly olive oil (dietary MUFA‐D) and mostly refined palm oil (dietary SFA‐D) did not impact the growth performance or feed utilization parameters of the barramundi. The in vivo beta‐oxidation activity was consistent with the dietary fatty acid composition, with the most dominant FA being heavily beta‐oxidized. Together, the in vivo whole‐body mass balance of fatty acids showed that n‐3 long‐chain polyunsaturated fatty acids (LC‐PUFA) were most efficiently utilized in the SFA‐D‐ and MUFA‐D‐fed fish. This study provides evidence that additional dietary MUFA and SFA are suitable lipid classes for juvenile barramundi and they are both equally efficient at sparing LC‐PUFA from an oxidative fate.     

Arginine effects on biochemical composition of sperm in rainbow trout,Oncorhynchus mykiss

The present study investigated the effect of arginine on seminal plasma composition in rainbow trout. Male rainbow trout broodstocks (2500 ± 200 g) were fed five practical diets (each consisting of three triplicates) supplemented with Arginine at 0.50%, 1.50% and 2.00%. The control group were fed without arginine. Broodstock feeding lasted for 90 days, and then fish semen was sampled. Results indicated no significant differences in LDH, ALP, Fe²⁺ and phosphorous content among the different treatments. The lowest levels of AST and ALT and the highest levels of Ca²⁺ and Mg²⁺ ions were observed in the treatment fed with 1.50% arginine, which showed significant differences from other treatments (P < 0.05). Moreover, the amount of Cl^?, Na⁺ and K⁺ ions was significantly increased in the seminal plasma in fish fed diets containing arginine in comparison with the control. As the amount of arginine was increased, the levels of uric acid became significantly greater in contrast to urea and glucose levels. The highest amounts of cholesterol, fructose and total protein were observed in treatments fed on 2.00%, 0.50% and 1.00% arginine, respectively, showing significant differences from other treatments (P < 0.05). The highest pH value was assayed in the 1.50% arginine treatment. Results indicated that arginine had a potential efficacy on semen quality in rainbow trout broodstocks.     

Marine microalgae as dietary supplements in the culture of juvenile Chinese horseshoe crabs,Tachypleus tridentatus (Xiphosura)

Five treatments (short‐neck clam Ruditapes philippinarum and four formulated diets with the green microalgae Dunaliella tertiolecta or the golden‐brown microalgae Isochrysis galbana in the ratio (dw/dw) of 5% or 10% to that of clam meat) were used to investigate the growth performance and haemolymph quality of juvenile Chinese horseshoe crabs Tachypleus tridentatus under laboratory culture. At the end of the 12‐week study, various growth and moulting indicators as well as haemolymph biochemical parameters did not show any significant differences among the treatments. Significantly higher percentages of haemolymph amoebocyte viability and granular‐spherical amoebocyte state were noted in both 5% and 10% I. galbana‐supplemented diets compared to that of clam meat. However, the percentages of these two haemolymph parameters in juveniles fed with D. tertiolecta decreased significantly at the end of the experiment. Such differences were attributed to the presence of polyunsaturated fatty acid (PUFA), notably eicosapentaenoic acid (EPA), in I. galbana that was absent in D. tertiolecta and clam meat. Like many marine invertebrates, juvenile horseshoe crabs do not naturally obtain sufficient PUFAs from their diets to meet developmental and physiological needs; hence, supplementing microalgae with high levels of EPA in a protein‐rich diet boosts immune competence and the health status of juvenile horseshoe crabs while under culture.     

Effects of dietary essential amino acid deficiencies on the growth performance and humoral immune response in silvery‐black porgy (Sparidentex hasta) juveniles

A 6‐week feeding trial was conducted for determining the effects of dietary essential amino acids (EAA) deficiencies on growth performance and non‐specific immune responses in silvery‐black porgy juveniles (4.7 ± 0.1 g initial weight). Eleven isoproteic (ca. 47%) diets were formulated including a control diet containing the optimum quantity of EAA, and ten EAA‐deficient diets. All diets contained 36% fish meal and 18.5% crystalline EAA and non‐essential amino acids (NEAA) as the main source of dietary proteins. All the EAA and NEAA incorporated in the crystalline amino acids mixture of the control diet simulated the amino acids profile of the fish meal. The other 10 EAA‐deficient diets were formulated by the deletion of each of the 10 EAA (crystalline form) from the control diet and replaced by a mixture of NEAA for the adjustment of dietary nitrogen contents. At the end of the experiment, fish fed with threonine‐deficient diet showed the lowest survival rate (p < .05), whereas growth performance decreased in fish fed all EAA‐deficient diets, although the reduction in body growth varied depending on the EAA considered. Plasma total protein decreased in all experimental groups except for fish fed the phenylalanine‐deficient diet. Fish fed with arginine‐ and lysine‐deficient diets had the lowest plasma C3, C4, lysozyme, total immunoglobulin and total superoxide dismutase activity (p < .05). Present results indicated that lysine, methionine and threonine were the most limiting EAA in terms of growth performance; however, arginine, threonine and lysine were the most limiting EAA for innate immunity responses in silvery‐black porgy juveniles.     

Dietary lipid sources affect the performance of Nile tilapia at optimal and cold,suboptimal temperatures

Five sources of dietary fatty acids (fish, linseed, sunflower, olive and coconut oils) were evaluated in juvenile Nile tilapia in two trials: at optimal (28°C) and suboptimal (22°C) temperatures lasting 9 and 12 weeks, respectively. At 28°C, there was no clear effect of dietary source on fish growth, but at 22°C, the highest daily weight gain occurred in fish fed sunflower, linseed and fish oil. Feed efficiency and apparent net protein utilization increased as the amount of unsaturated fatty acids, especially n‐3 polyunsaturated fatty acids (PUFA), in the diet increased. Coconut oil, which is rich in saturated fatty acids (SFA), led to the worst growth results, especially at 22°C, with the lowest weight gain, feed intake and feed utilization by tilapia. The body fatty acid profile, in % of total fatty acids, was dependent on diet composition. However, for all treatments, PUFA body content increased with the decrease in temperature, but SFA and monounsaturated fatty acids remained the primary contributors to the body profile. Either fish oil or vegetable oil may be used as sources of dietary fatty acids for Nile tilapia, but at suboptimal temperatures, a dietary source containing more PUFA and less SFA improves performance.     

Optimum dietary soybean meal level for maximizing growth and nutrient utilization of on-growing gilthead sea bream (Sparus aurata)

Six isonitrogenous [450 g kg⁻¹ crude protein (CP)] and isoenergetic diets (23 kJ g⁻¹) with six levels of defatted soybean meal inclusion (0, 132, 263, 395, 526 and 658 g kg⁻¹) in substitution of fish meal were evaluated in gilthead sea bream of 242 g initial weight for 134 days. Fish fed diets S0, S13, S26 and S39 had a similar live weight (422, 422, 438 and 422 g, respectively) but fish fed diets S53 and S66 obtained the lowest final weight (385 and 333g, respectively), and similar results were presented in specific growth rate (SGR). Fish fed diets S53 and S66 also obtained the highest feed conversion ratio (FCR). Quadratic multiple regression equations were developed for SGR and FCR which were closely related to dietary soybean level. The optimum dietary soybean levels were 205 g kg⁻¹ for maximum SGR and 10 g kg⁻¹ for minimum FCR. Sensorial differences were appreciated by judges between fish fed S0 and S39 soybean level, but after a re-feeding period of 28 days with diet S0, these differences disappeared.