Nutritional Characteristics of a Peruvian Anchovy (Engraulis ringens) Protein Concentrate

ABSTRACT

The aim of the present study is to present a new anchovy protein concentrate and compare it to other similar fishery products. A 76.4% protein concentrate was prepared from fresh Peruvian anchoveta (Engraulis ringens) (APC) by means of acid treatment with 1% citric acid, solubilization with 1% sodium chloride, and isoelectric precipitation processes. Remaining fat was 5.2%, and 0.51 A_w indicates good stability. When APC was rehydrated for 10 minutes, it had a 3.5 initial weight increase. It provided 17.8% protein of very high nutritional quality, with only histidine content deficient for children 1–2 years old. Fat content in APC offered 33.4% EPA+DHA. No changes in the essential/non-essential amino acids (EAA/non-EAA), polyunsaturated/saturated fatty acids (PUFA/SFA), or w6/w3 ratios were observed as a result of the process in the raw material. Because of the high sodium content, a 25 g portion is recommended to fulfill nutritional FAO recommendations. APC can be considered as an important source of calcium (30% adults and 35% children requirements), phosphorous (30% adults and 52% children requirements), and iron content (approximately 20% adults and children needs). APC is an important high-quality protein, providing w-3 fatty acids, calcium, phosphorous, and iron.     

正常和白化褐牙鲆皮肤和肌肉中DHA和EPA含量的比较

利用气相色谱法对相同养殖条件下生长的正常和白化褐牙鲆(Paralichthys olivaceus)的皮肤和肌肉组织中的DHA和EPA含量进行了比较分析。结果显示，正常和白化褐牙鲆的皮肤和肌肉中EPA含量相近，但白化个体皮肤中DHA含量显著低于正常个体，约为后者的1／2。而两者肌肉中的DHA含量则没有显著差异。同时，白化个体皮肤和肌肉组织中的DHA／EPA比值略低于正常个体。这一结果证明白化褐牙鲆皮肤蓄积或利用DHA的能力要低于正常褐牙鲆。关于鲆鳔类白化现象同鱼体对饵料中脂肪酸类物质的利用率之间的关系有待深入研究。     

Lipid composition of malpigmented and normally pigmented newly settled yellowtail flounder, Limanda ferruginea (Storer)

The lipid composition of malpigmented (MP) and normally pigmented (NP), newly settled yellowtail flounder (Limanda ferruginea, Storer) was compared in order to elucidate a possible connection between lipids and pigmentation development. Larvae were fed commercially enriched live food for 12 weeks post hatch and then differences in lipid composition and size were analysed. NP fish were found to be significantly larger (standard length 35 mm) than MP fish (32 mm) at 100% settlement. There were higher proportions of triacylglycerols in NP fish (P = 0.01), whereas MP fish had an increased percentage of phospholipids (P = 0.01). NP fish had a higher percentage of docosahexaenoic acid (DHA) in the polar lipids of their body (P = 0.03) and total lipids of their eyes (P = 0.04). These data support previously proposed theories for the importance of DHA in pigmentation development. Principal components analysis (PCA) described the majority of the variance (77%) within the data set using just two principal components axes. PCA demonstrated that differences between body zones were greater than those between NP and MP fish within a given zone.     

Vitamin B6 supplementation increases the docosahexaenoic acid concentration of muscle lipids of rainbow trout (Oncorhynchus mykiss)

Fish fillet quality is influenced by feed quality. In particular, vitamin B₆ availability improves growth rate and nutritional value, because it is related to protein and lipid metabolism. The present study investigates the effect of increasing amounts of vitamin B₆ on growth, fatty acid composition and lipid peroxidation of muscle tissue of rainbow trout (Oncorhynchus mykiss). Quadruplicate groups of trout of a mean initial weight of 110 g were fed commercial diets supplemented with four different quantities of vitamin B₆ (0, 10, 25 and 50 mg kg^?1 diet). Over the experimental period, there were no significant differences in weight gain and feed intake, while vitamin B₆ concentration of muscle was affected by dietary intake, even though its increase was not proportional to the concentrations in the feed. The fatty acid composition of muscle lipid showed differences between the four groups. The percentage of long‐chain unsaturated fatty acids, in particular docosahexaenoic acid, increased significantly in vitamin B₆‐supplemented groups. However, despite the increased fatty acid unsaturation index, lipid peroxidation parameters such as vitamin E content, malondialdehyde production, glutathione reductase and glutathione peroxidase activities did not show significant differences, meaning that the higher level of long‐chain unsaturated fatty acid did not increase the muscle susceptibility to oxidative stress.     

牙鲆幼鱼对EPA和DHA的营养需求

研究了EPA和DHA水平对牙鲆生长的影响,饲料中含0.5%EPA和1.0%～1.5%DHA能保证牙鲆幼鱼最适生长,鱼体水分最低,肝体指数最小,脂肪含量有较大幅度提高,肝脏极性脂中EPA和DHA达到最大积累;在肝脏和肌肉的非极性脂部分,各组间的脂肪酸组成没有显著变化,而极性脂部分能体现出饲料中n-3 HUFA含量对鱼体脂肪酸组成的影响,极性脂中的EPA和DHA含量远高于非极性脂;在肌肉和肝脏的极性脂和非极性脂中都含有较高的16:0和18:1n-9; 18:1n-9/n-3HUFA可以作为必需脂肪酸满足程度的一个判据,18:1n-9值的升高往往是缺乏必需脂肪酸的表现,在生长最佳时18:1n-9/n-3HUFA比值下降,为0.62和0.74.     

Influence of Dietary Lipids and Environmental Salinity on the n-3 Long-Chain Polyunsaturated Fatty Acids Biosynthesis Capacity of the Marine Teleost Solea senegalensis

Fish vary in their ability to biosynthesise long-chain polyunsaturated fatty acids (LC-PUFA) depending upon the complement and function of key enzymes commonly known as fatty acyl desaturases and elongases. It has been reported in Solea senegalensis the existence of a Δ4 desaturase, enabling the biosynthesis of docosahexaenoic acid (DHA) from eicosapentaenoic acid (EPA), which can be modulated by the diet. The present study aims to evaluate the combined effects of the partial replacement of fish oil (FO) with vegetable oils and reduced environmental salinity in the fatty acid composition of relevant body compartments (muscle, hepatocytes and enterocytes), the enzymatic activity over α-linolenic acid (ALA) to form n-3 LC-PUFA through the incubation of isolated hepatocytes and enterocytes with [1-¹⁴C] 18:3 n-3, and the regulation of the S. senegalensis fads2 and elovl5 in the liver and intestine. The presence of radiolabelled products, including 18:4n-3, 20:4n-3 and EPA, provided compelling evidence that a complete pathway enabling the biosynthesis of EPA from ALA, establishing S. senegalensis, has at least one Fads2 with ∆6 activity. Dietary composition prevailed over salinity in regulating the expression of fads2, while salinity did so over dietary composition for elovl5. FO replacement enhanced the proportion of DHA in S. senegalensis muscle and the combination with 20 ppt salinity increased the amount of n-3 LC-PUFA in hepatocytes.     

Evaluation of macroalgal detritus as food source for juvenile Manila clam,Ruditapes philippinarum: Effects on growth,amino acid content and fatty acid composition

Sufficient high‐quality microalgae are required for indoor nursery of juvenile Ruditapes philippinarum. However, culturing numerous microalgae to support clam feeding is a heavy burden on many hatcheries. The effects of detritus from the macroalgae Ulva pertusa, Chondrus ocellatus and Undaria pinnatifida on the growth, amino acid content and fatty acid profile of R. philippinarum were assessed as potential substitute diets. The green microalga Tetraselmis cordiformis served as comparative diet. Results revealed that the clams ingesting distinct diets presented no significant differences in growth of soft tissues, but the nutritional component of these clams differed dramatically. The clams fed with Undaria + Tetraselmis had the highest content of essential amino acids and proteins. In addition, the clams fed with single macroalgal diets and mixed macroalgal detritus and Tetraselmis showed significantly higher or statistically equal levels in n‐3/n‐6 ratio and docosahexaenoic acid (DHA)/eicosapentaenoic acid (EPA) ratio with respect to Tetraselmis diets. The relative percentages of EPA and DHA in clams fed with Undaria were 28% and 63% higher than those fed with Tetraselmis, and the arachidonic acid abundances in clams ingesting Undaria + Tetraselmis and Tetraselmis were significantly higher than those in clams ingesting other diets. Together, the diets containing single Undaria or mixed Undaria + Tetraselmis produced Manila clams with nutritional advantages in terms of essential amino acids and polyunsaturated fatty acids. Thus, the detritus of macroalgae, especially Undaria, is an appropriate substitute diet, at least partially, for culture of nutrition‐improved R. philippinarum.     

Effect of dietary DHA/EPA ratio on the early development,antioxidant response and lipid metabolism in larvae of Siberia sturgeon (Acipenser baerii,Brandt)

A 30‐day growth study was conducted to evaluate the impacts of the dietary DHA/EPA ratios on growth performance, antioxidant and lipid metabolism of Siberian sturgeon larvae. Four isonitrogenous and isoenergetic microcapsuled diets were formulated with various DHA/EPA ratios as 0.73 (R_0.73), 1.25 (R_1.25), 1.75 (R_1.75) and 2.33 (R_2.33). The results showed that the final body length, final body weight, specific growth rate and survival in the group R_2.33 were highest (p < 0.05), while there were no significant differences on viscerosomatic index and condition factor among all groups. Visceral catalase activity of groups R_2.33 and R_1.75 was significantly higher than that of groups R_0.73 and R_1.25, but superoxide dismutase, total antioxidant capacity, malondialdehyde, total cholesterol, triglycerides and high‐density cholesterol were not different among groups. The gene expression of PPARα and lipoprotein lipase had no difference among groups, but the expression of hepatic lipase gene in groups R_1.75 and R_2.33 was significantly lower than that in group R_0.73 as a negative feedback of high dietary DHA intake. In conclusion, growth performance was improved but kept stable antioxidant response in visceral mass with increased levels of DHA/EPA ratios from 0.73 to 2.33 for Siberian sturgeon larvae. Improving DHA/EPA ratios is a benefit for larvae to selectively deposit more DHA, then EPA and ARA than MUFA in the body to meet the requirement for early development.     

Use of commercial fermentation products as a highly unsaturated fatty acid source in practical diets for the Pacific white shrimp Litopenaeus vannamei

Removal or reduction of marine ingredients (MI) from feed formulations is critical to the sustainability of the aquaculture industry. By removing MI, diets may become limiting in several nutrients including highly unsaturated fatty acids (HUFA) such as docosahexaenoic acid (DHA) and arachidonic acid (ArA). To reduce reliance on MI in shrimp diets, two trials were conducted with Litopenaeus vannamei juveniles to determine the feasibility of using fermentation meals rich in DHA and ArA as the primary source for HUFA. A practical diet with no MI was formulated with/without DHA and ArA supplements and fed in the first trial. A diet with menhaden fish oil or a combination of plant oil with/without DHA and ArA supplements was used in the second trial. To determine whether HUFA is only needed in the early growth stages, we also fed one group a HUFA‐supplemented diet to 5 g and then switched them to a HUFA‐supplement‐free diet. In both trials, the weights were reduced when HUFA supplements were not provided either throughout the trial or from 5 g to harvest (<16 g). These results suggest that supplementation of plant oils with DHA‐ and ArA‐rich oils from fermented products is a viable option to replace marine fish oil for L. vannamei.