Can fermented soybean meal and squid by‐product blend be used as fishmeal replacements for Japanese flounder (Paralichthys olivaceus)?

An experiment was carried out to evaluate fermented soybean meal and squid by‐product blend (1:1) (FP) as replacement of fishmeal (FM) for Japanese flounder, Paralichthys olivaceus. Five isocaloric (19 kJ g^?1) diets were prepared by replacing 0 (FP0), 12 (FP12), 24 (FP24), 36 (FP36) and 48% (FP48) FM protein with FP. Triplicate groups of juveniles (mean weight of 3.9 g) were delivered the test diets for 8 weeks in a flow‐through sea water system. The results showed that there were no significant differences (P > 0.05) among the growth rates of fish fed FP0, FP12, FP24 and FP36 diets. Growth and nutrient utilization parameters were significantly reduced in fish fed FP48 diet. Although, whole body proximate composition of fish were not significantly affected by the dietary treatments compared to the control; methionine and phenylalanine contents were significantly decreased in FP48 group. Protein retention was also significantly decreased in the similar group of fish. Dietary treatments did not alter most of the plasma metabolites, while some of the health parameters were improved in the replacement groups. Results suggested that FP is a potential candidate for alternative protein ingredient in aquafeed and can replace 36% FM protein in the diet of Japanese flounder.     

IL-1β在鱼类皮肤免疫应答中的作用机制

正白细胞介素1(interleukin 1,IL-1)是一种重要的促炎性细胞因子,是体内调节免疫和炎症反应的中心介质,在哺乳动物中已发现11种IL-1家族成员,包括IL-1α、IL-1β、IL-1ra、IL-18、IL-1F5和IL-33等[1],目前在鱼类中只发现了IL-1β和IL-18。研究表明,IL-1β在鱼类皮肤免疫应答中起重要作     

基于最大熵模型分析西南大西洋阿根廷滑柔鱼栖息地分布

根据2008—2010年中国鱿钓船在西南大西洋海域得到的生产数据及海洋环境数据(海表面温度,sea surface temperature,SST;海面高度sea surface height,SSH;叶绿素-a浓度,chlorophyll-a,chl.a),利用最大熵模型(Max Ent)分析捕捞主渔汛期间(1—4月)阿根廷滑柔鱼的潜在栖息地分布,同时与实际作业位置相比较,结合海洋环境因子分析不同年份分布差异的原因。模型运算结果显示:阿根廷滑柔鱼潜在分布区域的变化与实际作业位置变动基本一致;南北方向上,2008年和2009年的潜在分布区域较为广泛,而2010年的潜在分布区域较为狭窄,且主要分布在45°S以南的区域。Jackknife检验表明,SST是影响阿根廷滑柔鱼分布的首要环境因子,SST等温线分布可用来表征海流的强弱进而影响阿根廷滑柔鱼的分布,其中12°C等温线可以作为寻找渔场的一个指标。SSH等高线分布及其涡的变化也会影响到阿根廷滑柔鱼分布。chl.a只能间接地反映阿根廷滑柔鱼渔场的分布,不能很好地作为表征其分布的环境因子。研究表明,分析阿根廷滑柔鱼栖息地分布及其差异原因应主要观察SST和SSH的变化。     

Varietal differences in phenolic content and astringency in skin and flesh of hardy kiwifruit resources in Japan

Varietal differences in the total phenolic content and astringency in the skin and flesh were determined among the cultivars and local collections of hardy kiwifruit with a ploidy variance found in Japan. The average values of the total phenolic content in the skin and flesh were 2.66 and 0.18 g 100 g⁻¹ FW, respectively. There were large varietal differences in the total phenolic content in the skin in the range of 1.3–5.0 g 100 g⁻¹ FW. Kochi (tetraploid), while Gassan and ‘Mitsuko’ (hexaploid) contained a larger amount of total phenolics. High astringency was found in Gassan, ‘Mitsuko’ and ‘Hoko’ (hexaploids) and Kochi. HPLC analysis showed that the major components of phenolics in the flesh were (+)-catechin, chlorogenic acid, rutin, (−)-epicatechin and quercetin.     

Effects of cage netting colour and density on the skin pigmentation and stress response of Australian snapper Pagrus auratus (Bloch & Schneider, 1801)

The unnaturally dark pigmentation of cultured Australian snapper Pagrus auratus can be improved through dietary astaxanthin supplementation and by holding fish in tanks with a white background. The practical application of these laboratory‐based findings was examined with two experiments to establish if the advantages of transferring fish to light coloured tanks before harvest could be achieved on‐farm using white cages and to determine the effects of fish density on skin colour. For the first experiment, snapper (mean TL=29.7 cm) were transferred from a commercial snapper sea cage to black or white netted cages and fed diets supplemented with unesterified astaxanthin (supplied as Lucantin^® Pink, BASF) at 0 or 39 mg kg^?1 for 42 days. Skin colour was measured using the CIE (black–white), (green–red), (blue–yellow) colour scale. Snapper held in white netting cages became significantly lighter (higher ) than snapper held in black cages; however, values were not as high as previous laboratory‐based studies in which snapper were held in white plastic‐lined cages. Snapper fed astaxanthin displayed significantly greater and values, and total carotenoid concentrations after 42 days. In addition, total carotenoids were higher in fish from black than white cages. The second experiment was designed to investigate whether density reduced the improvements in skin colour achieved by holding fish in white coloured cages and whether cage colour affected stress. Snapper (mean weight=435 g) were acclimated to black cages and fed 39 mg kg^?1 astaxanthin for 44 days before transferring to black or white plastic‐lined cages at 14 (low), 29 (mid) or 45 (high) kg m^?3 for 7 days after which time skin colour, plasma cortisol and plasma glucose concentrations were measured. Skin lightness () was greater in snapper transferred to white plastic‐lined cages with the lightest coloured fish obtained from the lowest density after 7 days. Density had no effect on plasma cortisol or glucose levels after 7 days, although plasma cortisol was elevated in snapper from black cages. For improved skin colouration we recommend feeding unesterified astaxanthin at 39 mg kg^?1 for approximately 6 weeks and transferring snapper to white plastic‐lined cages or similar at low densities for short periods before harvest rather than producing fish in white netting sea cages subject to biofouling.     

Effects of dietary astaxanthin concentration and feeding period on the skin pigmentation of Australian snapper Pagrus auratus (Bloch & Schneider, 1801)

A single‐factor experiment was conducted to investigate the effects of dietary astaxanthin concentration on the skin colour of snapper. Snapper (mean weight=129 g) were held in white cages and fed one of seven dietary levels of unesterified astaxanthin (0, 13, 26, 39, 52, 65 or 78 mg astaxanthin kg^?1) for 63 days. Treatments comprised four replicate cages, each containing five fish. The skin colour of all fish was quantified using the CIE L^*, a^*, b^* colour scale after 21, 42 and 63 days. In addition, total carotenoid concentrations of the skin of two fish cage^?1 were determined after 63 days. Supplementing diets with astaxanthin strongly affected redness (a^*) and yellowness (b^*) values of the skin at all sampling times. After 21 days, the a^* values increased linearly as the dietary astaxanthin concentration was increased before a plateau was attained between 39 and 78 mg kg^?1. The b^* values similarly increased above basal levels in all astaxanthin diets. By 42 days, a^* and b^* values increased in magnitude while a plateau remained between 39 and 78 mg kg^?1. After 63 days, there were no further increases in measured colour values, suggesting that maximum pigmentation was imparted in the skin of snapper fed diets >39 mg kg^?1 after 42 days. Similarly, there were no differences in total carotenoid concentrations of the skin of snapper fed diets >39 mg kg^?1 after 63 days. The plateaus that occurred in a^* and b^* values, while still increasing in magnitude between 21 and 42 days, indicate that the rate of astaxanthin deposition in snapper is limited and astaxanthin in diets containing >39 mg astaxanthin kg^?1 is not efficiently utilized. Astaxanthin retention after 63 days was greatest from the 13 mg kg^?1 diet; however, skin pigmentation was not adequate. An astaxanthin concentration of 39 mg kg^?1 provided the second greatest retention in the skin while obtaining maximum pigmentation. To efficiently maximize skin pigmentation, snapper growers should commence feeding diets containing a minimum of 39 mg unesterified astaxanthin kg^?1 at least 42 days before sale.     

冰衣结合保鲜剂处理对冻藏鱿鱼品质的影响

为研究冰衣对鱿鱼品质的影响,在鱿鱼冻藏过程中,以未镀冰衣的样品为对照组,对比纯水冰衣组及冰衣中分别添加聚丙烯酸钠、迷迭香酸、异抗坏血酸钠及其复配组,分析鱿鱼在-18℃下冻藏6个月的持水力、色泽、pH、质构、丙二醛、巯基含量、水分含量和游离氨基酸的变化。结果显示:鱿鱼冻藏过程中品质显著下降,镀冰衣处理能明显延缓质量损失、脂质氧化和蛋白质降解;含有聚丙烯酸钠的冰衣不易破裂,可有效维持鱿鱼的品质;冰衣中加入异抗坏血酸钠的比加入迷迭香酸有更好的保鲜效果;异抗坏血酸钠/聚丙烯酸钠复配冰衣可有效延缓冻藏期间鱿鱼品质下降,且能延长货架期。     

罗非鱼鱼皮提取明胶的酶法脱脂工艺研究

用脂肪酶对罗非鱼鱼皮进行酶法脱脂工艺研究。通过单因素与正交试验确定最适的酶法脱脂工艺为:pH值9,脱脂时间3h,酶添加量2%,料液比1:4,温度40℃,该工艺的脱脂率可达67.5%。通过超声波辅助脱脂研究表明其脱脂率并无明显的提高。     

番茄裂果与果皮结构的关系及其杂种优势表现

以4份抗裂番茄为母本,3份易裂番茄和1份抗裂番茄为父本,按照不完全双列杂交设计配制4×4的杂交组合,研究8个亲本和16个F1的裂果特性与果皮结构的关系,分析它们的杂种优势表现.结果表明,易裂基因型的果皮较薄,抗裂基因型的果皮普遍较厚,但也有果皮薄而抗裂能力强的基因型.裂果特性有明显的杂种优势,优势的方向在不同组合间有很大的差异.亲本的一般配合力对杂种后代的抗裂时间发挥了决定性作用.对利用结构特征改良番茄抗裂能力的潜力进行了讨论.