Effect of dietary protein content on growth rate,survival and body composition of juvenile cauque river prawn,Macrobrachium americanum (Bate 1868)

We determined the effect of four concentrations of dietary crude protein, 30.7, 37.2, 41.8 and 46.8% on growth rate, survival and body composition of the juvenile cauque river prawn (Macrobrachium americanum). The prawns were hatched in the laboratory from the spawn of one wild ovigerous female. Prawns consuming 37.2% crude protein reached a final weight of 0.58 g (feed conversion ratio of 2.15), which was significantly better than the other treatments. Survival was 100% in all treatments. Protein content in the diets had no significant effect on whole body proximate composition and amino acid profile. Juveniles consuming the 37.2% crude protein diet grew faster than those fed the other diets. Specific growth rate was adjusted to the two‐slope broken‐line regression analysis model to estimate the optimal protein requirement. In conclusion, these results demonstrated that the 37.2% protein level diet is optimal for juvenile cauque river prawn M. americanum in the experimental conditions of this study.     

Impact of sampling and storage technique,and duration of storage,on the composition of fresh grass when analysed using near‐infrared reflectance spectroscopy

The objective of this study was to examine the effect of sampling technique (pluck or cut), storage duration (immediate analysis, 24‐h or 48‐h), storage temperature (ambient or chilled) and storage conditions (air present, air excluded or breathable) on the composition of fresh grass sampled from a sward managed to simulate grazing. Treatments were repeated across four sampling dates, with grass samples stored in grip seal bags prior to analysis using near‐infrared reflectance spectroscopy. Grass sampled by ‘pluck’ had a higher crude protein and ME content, and a lower acid detergent fibre (ADF) content, compared to that sampled by ‘cut’. Grass stored for 48 h had a lower water soluble carbohydrate (WSC) and ME content and a higher ADF content than for immediate analysis. Samples stored for 24 h did not differ from immediate analysis. Grass stored at ambient temperature had a lower WSC and ME content compared to immediate analysis. Grass stored under ‘breathable’ conditions had a lower ME content and higher ADF content than immediate analysis or samples stored with air present or air excluded. It is recommended that grass for analysis should be sampled by cutting, stored chilled (4°C) in a sealed bag to minimize exposure to oxygen and analysed within 24 h of harvest.     

Effect of dietary phosphorus levels on growth and body composition of crucian carp,Carassius auratus under indoor and outdoor experiments

Indoor and outdoor experiments were carried out simultaneously to evaluate the effects of dietary phosphorus levels on growth performance and body composition of crucian carp. Monocalcium was used to formulate extruded feed containing available phosphorus (AP) of 1.5 (D1), 4.7 (D2), 6.3 (D3) and 9.0 (D4) g kg^?1. Twelve 500‐L recirculating tanks were assigned to four triplicate groups with each tank stocked with 15 juveniles (39.88 ± 0.14 g) for indoor experiment. Twelve polyethylene enclosures were assigned to four groups with each one stocked with 120 juveniles (44.08 ± 1.36 g). After 8 weeks of feeding, survival ranged from 96% to 100%. Weight gain, special growth rate, protein efficiency ratio and feed conversion rate did not show significant differences among dietary treatments in both experiments. Fish cultured in the enclosures grew better, although D1 and D2 treatments did not reach significant level. Crude protein and phosphorus content of the fish were not significantly affected by dietary phosphorus level. Moisture, crude lipid, crude ash and vertebrae phosphorus were significantly affected by different phosphorus levels. Based on vertebrae phosphorus, crucian carp cultured in the tanks and in the enclosures showed phosphorus deficiency under 4.7 g kg^?1 and 6.3 g kg^?1 AP, respectively.     

Effects of dietary protein and lipid levels with different protein‐to‐energy ratios on growth performance,feed utilization and body composition of juvenile red‐spotted grouper,Epinephelus akaara

An 8‐week feeding trial was conducted to assess dietary protein and lipid levels on growth performance, feed utilization and body composition of juvenile red‐spotted grouper (7.85 ± 0.03 g fish^?1). Nine semi‐purified diets were formulated containing varying protein levels (440–520 g kg^?1, dry matter) and lipid levels (60–120 g kg^?1, dry matter). The weight gain of juvenile Epinephelus akaara was affected by dietary protein (p = .005) and its interaction with dietary lipid (p = .020). Viscerosomatic index, intraperitoneal fat ratio and whole‐body lipid level increased with increasing dietary lipid level (p < .001). Nitrogen retention was not affected by dietary protein and lipid, while lipid retention decreased with increasing dietary lipid level (p < .001). The plasma blood urea nitrogen increased with increasing dietary protein level (p = .003). This study showed that diet with 520 g kg^?1 protein and 60 g kg^?1 lipid with 30.58 mg kJ^?1 P:E provided a maximal growth for this species. Moreover, an increase in dietary lipid levels (from 60 to 90 g kg^?1) could reduce the protein requirement (from 520 to 480 g kg^?1) without affecting the growth performance, while higher fat deposition was observed in fish fed high‐lipid diets.     

全豆豆浆与传统豆浆感官品质和营养成分对比

以大豆为原料,通过感官评定对胶体磨技术自制的全豆豆浆和一般机械磨加工的传统豆浆中的永和豆浆和普通豆浆的感官品质进行了比较,通过营养成分检测对全豆豆浆和永和豆浆的营养成分进行了比较,同时将检测的全豆豆浆营养成分与中国食物成分表中的普通豆浆的营养成分进行比较。结果表明:全豆豆浆口感浓厚,细腻爽滑,豆香味浓郁,无豆腥味,感官评价总得分高于传统豆浆中的永和豆浆和普通豆浆,差异有统计学意义(P0.01);全豆豆浆中蛋白质、脂肪、总膳食纤维、维生素B1、维生素B2、钙、磷脂及大豆异黄酮等营养成分含量均高于永和豆浆,更高于普通豆浆。全豆豆浆的普及不仅可以提高豆浆的营养价值,还可以减少资源的浪费,具有一定的社会和经济效益。     

乳山近海渔业资源种类组成及变化

根据2013—2015年乳山近海拖网渔船的渔捞日志,分析了乳山近海的单位捕捞努力量渔获量、渔获种类组成及生物多样性等特征。结果表明:(1)乳山近海渔获物共有36种,隶属于19目28科33属。其中鱼类有26种,虾蟹类4种,头足类4种,水母类1种,贝类1种。(2)2013—2015年全年优势种差异明显。其中,蓝点马鲛3年均为优势种,鳀鱼是2014年和2015年优势种,网纹狮子鱼为2013年和2015年的优势种。(3)乳山近海渔获物主要集中在休渔期前后的4—5月、9—11月,渔业生产存在明显的春汛和秋汛。2013—2015年乳山近海单位捕捞努力量渔获量逐年增加,但与历史单位捕捞努力量渔获量相比还是存在明显下降;多样性指数和均匀度指数变化趋势一致,多样性指数和丰富度指数较高值出现在秋季;春汛和秋汛期间,渔业资源种属组成及群落结构相似性较高。     

Broodstock conditioning of the Portuguese oyster (Crassostrea angulata,Lamarck, 1819): influence of different diets

The Portuguese oyster Crassostrea angulata shows great potential in oyster farming. The conservation of pure populations of this species is important for production diversification and biodiversity preservation. In this way, the zootechnological development for seed hatchery production is extremely important. Broodstock conditioning is a key step in the process of rearing bivalves in a hatchery. Many factors regulate the reproductive cycle, being food one of the most important ones. To evaluate the effect of different diets on C. angulata reproductive performance, broodstock were conditioned with different food regimes formulated fundamentally by flagellates (Diet 1 – Pavlova lutheri and Isochrysis galbana clone T‐ISO; Diet 2 – P. lutheri, T‐ISO and Skeletonema costatum) and constituted fundamentally by diatoms (Diet 3 – S. costatum and Chaetoceros calcitrans; Diet 4 – P. lutheri, S. costatum and C. calcitrans). During conditioning, samples of oysters were collected to evaluate condition index, gonadal development and biochemical composition. At the end of the conditioning period, oysters were induced to spawn to evaluate reproductive output (fecundity, fertilization rate and D‐larvae development). The diets had an impact on the gametogenesis process, energy storage and reproductive output performance, being the best results those obtained in broodstock fed with the diatoms‐predominant diets. However, those fed with diets majority flagellates had an unsuccessful performance. Holistic approaches incorporating all results in this study reveal and reinforce the idea that the diatom species used presented the nutritional requirements to C. angulata broodstock, being essential in the conditioning phase.     

Growth performance and whole‐body composition of yellow catfish (Pelteobagrus fulvidraco Richardson) under feeding restriction

Fish growth is an important index in aquaculture practice. However, the effect of growth under restricted feeding on quality of fish grown to the same size remains poorly unknown. In this study, yellow catfish were reared by feeding them at three different feeding rates such as low (FR‐L group), medium (FR‐M group) and high (apparent satiation) ration levels for 82, 58 and 34 days to reach the same size, respectively. After this period, the growth performance, whole‐body amino acid composition and fatty acid profile of the fish were evaluated. Feeding restriction led to significant decreases in specific growth rate and feed conversion efficiency. Significant increases in dry matter, protein and energy contents were observed in fish under both restricted feeding treatments. FR‐L‐treated fish had significantly lower whole‐body essential amino acid contents, and significantly higher Ala and non‐essential amino acid contents compared to fish fed to satiation. Fish in restricted feeding treatments had significantly higher n‐3 PUFA and n‐3/n‐6 ratio compared to the fish fed to satiation. The present results indicate that from a quality perspective, there are certain advantages in improvement of whole‐body composition and enrichment of n‐3 PUFA associated with the restricted feeding of yellow catfish at slow growth rate.     

基于UHPLC-Q-TOF/MS的不同产地普洱生茶化学成分差异研究

为了更加全面地了解产地对普洱生茶品质与化学成分的影响,本研究选取来自临沧市、普洱市、西双版纳州三大产区12个茶山(自然村)的普洱生茶样品,采用超高效液相色谱-四级杆-飞行时间质谱(UHPLC-Q-TOF/MS)对不同产地普洱生茶的非挥发性代谢物表型进行了研究。结果表明:不同产地普洱生茶的化学成分在含量上具有较大差异,且具有明显的产地特征。采用主成分分析,可以对来自西双版纳自治州(包括勐腊县、勐海县、景洪市)、普洱市、临沧市3个地级行政区的普洱生茶进行有效区分,也可以对来自普洱茶产区的东南、西南、西北3个区域的普洱生茶进行有效区分。进一步鉴定了普洱生茶中79种主要成分,并对其在12个茶山(自然村)的普洱生茶中的含量分布,以及与不同产地普洱生茶滋味品质的关系进行了分析。本研究表明,基于UHPLC-Q-TOF/MS的茶叶非挥发性化学成分轮廓可以作为普洱生茶产地判别的依据。     

赤眼鳟和麦瑞加拉鲮的化学组成、能量密度及对鳜的营养价值

为评价赤眼鳟(Squaliobarbus curriculus)和麦瑞加拉鲮(Cirrhinus mrigala)对鳜(Siniperca chuatsi)的营养价值,分别测定了体质量为(5.27±1.03)g的赤眼鳟、(5.05±1.21)g的麦瑞加拉鲮和(5.19±0.92)g的鳜的化学组成,估算了这3种鱼的能量密度,以探讨赤眼鳟代替麦瑞加拉鲮养殖鳜的可行性。结果显示,赤眼鳟和麦瑞加拉鲮的全鱼蛋白质含量显著高于鳜,水分显著低于鳜(P0.05),必需氨基酸指数分别高达92.56%±2.31%和93.17%±0.36%,多数必需氨基酸的化学评分≥0.82。而赤眼鳟的脂肪和能量密度更高,显著高于麦瑞加拉鲮和鳜,灰分显著低于麦瑞加拉鲮(P0.05)。研究表明,这两种鱼对鳜都具有较高的营养价值,但赤眼鳟的营养价值更高,以赤眼鳟代替麦瑞加拉鲮养殖鳜是可行的,这为转变鳜的养殖方式提供了参考。