Digestibility,growth and pigmentation of astaxanthin,canthaxanthin or lutein diets in Lake Kurumoi rainbowfish,Melanotaenia parva (Allen) cultured species

New cultured ornamental fish namely Lake Kurumoi rainbowfish Melanotaenia parva (Allen) run into reduced of colour performances when reared in the aquaria, consequently, fish feed must be added with carotenoids as a pigment source. The aim of this study was to evaluate the digestibility, growth and pigmentation of astaxanthin, canthaxanthin and lutein in diet. Apparent digestibility coefficients (ADC) of dry matter, lipid, protein, carotenoids, growth and pigmentation were studied in twenty fish after 14 and 56 days of observation. The single‐dose supplementation of 100 mg/kg of astaxanthin, canthaxanthin, or lutein diets on fish was fed by apparent satiation. The basal diet without carotenoids was used as control. The result showed that the ADC of carotenoids of test diets was higher compared to control. Fish fed astaxanthin diet had higher survival rate (96.67 ± 2.89%), colour measurements of lightness (57.60 ± 7.46%), a*‐values (4.66 ± 1.20), total carotenoids content in skin (33.75 ± 5.02 mg/kg) and muscle (2.16 ± 0.74 mg/kg). Astaxanthin also increased the growth after 14 days (2.00% ± 0.19%/days) but there was no significantly different at the end of experiment. The yellowish‐orange colour performance was more rapidly achieved by fish fed astaxanthin diet after 28 days experimentation. These values suggested that dietary carotenoids were required and astaxanthin diet was superior to other diets for skin pigmentation of Lake Kurumoi rainbowfish.     

Changes in fatty acids profile,monosaccharide profile and protein content during batch growth of Isochrysis galbana (T.iso)

To investigate the nutritional value of the marine micro‐alga Isochrysis galbana Tahitian Isochrysis strain (T.iso) as an alternative feed for aquaculture during culture age, its biochemical composition was studied under autotrophic and controlled culture conditions at different growth stages: exponential phase, early and late stationary phases and decay phase. Analysis showed that C14:0, C16:0, C16:1, C18:4 (n‐3) and C22:6 (n‐3) were the most abundant fatty acids in this alga at different growth stages. The highest values of monounsaturated fatty acids were recorded at the late stationary and the decay phases. However, the highest levels of polyunsaturated fatty acids were observed at the early stationary phase. At all growth stages, I. galbana (T.iso) contained arabinose, xylose, mannose, galactose and glucose. Glucose represented the main sugar, and its content per dry alga biomass weight increased with increasing age of the culture and reached about fourfold in the decay phase. The maximum protein content was also observed during this last phase.     

Effect of oregano (Origanum onites L.) essential oil on growth,lysozyme and antioxidant activity and resistance against Lactococcus garvieae in rainbow trout,Oncorhynchus mykiss (Walbaum)

The aim of this study was to investigate the effects of different levels of Origanum onites L. essential oil as feed additives on the growth performance, antioxidant activity and disease resistance of rainbow trout. Fish (26.05 ± 0.15 g) were fed the experimental diets supplemented with four different concentrations (0.125, 1.5, 2.5 and 3.0 mL kg^?1) of O. onites essential oil for 90 days. Fish fed diets containing essential oil of O. onites had significantly higher final weight than the control group. Feed conversion ratio in fish fed diets containing 1.5 and 3.0 mL kg^?1 essential oil of O. onites was improved than other treatments (P < 0.05). The lowest feed conversion efficiency ratio was recorded in the 0.125 mL kg^?1 group of O. onites. Antioxidant status of fish was assayed for levels of plasma superoxide dismutase (SOD) and plasma catalase (CAT) activity. Lysozyme activity in plasma was significantly higher in fish fed diet containing 3.0 mL kg^?1 essential oil of O. onites (P < 0.05). After 8 weeks of feeding, fish were challenged with Lactococcus garvieae and cumulative mortality was recorded over 15 days. Dietary administration of 0.125, 1.5 and 2.5 mL kg^?1 O. onites significantly reduced fish mortality (P < 0.05). The 3.0 mL kg^?1 diet showed no mortality after challenged with L. garvieae. These results suggested that the essential oil of O. onites could be applied as growth promoter and also improved disease resistance when added to rainbow trout feed.     

不同密肥条件下通粳981产量构成因子分析

[目的]探明不同生产条件下穗数、粒数、粒重对产量的影响。[方法]对通粳981在不同密度和肥料条件下形成的产量及其构成因子进行回归、相关和通径分析。[结果]穗数、粒数和粒重对产量均有极显著的增产效应,其增产效应从大到小依次为穗数、粒数、粒重,其中穗数对产量起主要作用;但在基本苗较多或施N量较大的情况下,穗数和粒数的增产作用都很重要。[结论]农业生产中可针对不同生产栽培条件,从产量构成因子中明确主攻目标,合理制定栽培技术措施,提高产量。     

Effects of biofloc under different carbon sources and protein levels on water quality,growth performance and immune responses in black tiger shrimp Penaeus monodon (Fabricius, 1978)

A 75‐day 2 × 3 factorial experiment was conducted to evaluate the effect of two levels of dietary protein (32 and 40%) and two different carbon sources (rice flour–R and molasses‐M), and without carbohydrate (control–C) in black tiger shrimp Penaeus monodon juveniles (3.37 ± 0.04 g) at 100 nos. m^?3 in 100 L fibre reinforced plastic tanks. Biofloc volume and total suspended solid were higher in molasses added groups (32 + M and 40 + M) followed by rice flour (32 + R and 40 + R) and controls (32C and 40C). Molasses and rice flour addition significantly reduced (P < 0.01) the total ammonia–N compared to controls. The highest Vibrio, Bacillus and Lactobacillus counts were recorded in 40 + M, 32 + M and 32 + R respectively. Among the treatments, significantly higher (P < 0.01) final body weight was recorded in 40 + R (8.5 ± 0.3 g), 40 + M (7.8 ± 0.3 g) and 32 + R (7.5 ± 0.4 g) compared to control groups, 32C (6.1 ± 0.3 g), 40C (6.4 ± 0.3 g) and molasses added group, 32 + M (5.7 ± 0.4 g). Rice flour supplementation significantly increased (P < 0.01) the total haemocyte count (×10⁶ cells mL^?1) in 32 + R (45.7 ± 3.7) and 40 + R (44.3 ± 3.1) compared to controls, 32C (27.3 ± 3.4) and 40C (25.8 ± 0.9). Similarly, higher superoxide dismutase, catalase, serum protein and glucose were recorded in the rice flour added groups, 40 + R followed by 32 + R. Among the treatments, the highest level of prophenoloxidase (OD 490 nm, 0.3 ± 0.0) and survival after challenge with Vibrio harveyi (55.6%) was observed in 32 + R. The study elucidates that rice flour addition produces optimum level of biofloc with better growth and immune responses compared to molasses and control. Furthermore, rice flour addition at 32% protein level could replace 40% protein feed.     

Influence of nanochitosan/zeolite composite on growth performance,digestive enzymes and serum biochemical parameters in rainbow trout (Oncorhynchus mykiss)

Protective effects of nanochitosan/zeolite composite besides zeolite and chitosan/zeolite composite on rainbow trout growth, digestive enzyme activities and biochemical parameters were studied. Nanochitosan/zeolite hybrid composites with three different ratio of nanochitosan:zeolite (35:100, 3.5:100 and 0.35:100) were synthesized and analysed by X‐ray powder diffraction (XRD), thermal gravim (TG) analysis and scanning electron microscope (SEM) methods. Prepared composites as well as zeolite and control diets were fed to rainbow trout (50 g) for a period of 60 days. The addition of treated diets significantly improved growth performance compared to the control diet. Supplemental zeolite could only enhance the amylase activity in fish intestine, whereas other treatment groups could increase the pepsin activity besides intestinal alkaline phosphatase, trypsin and amylase activities. No differences were observed for intestinal acid phosphatase and lipase activities among the experimental diets. Meanwhile, serum total antioxidant activity and lipid peroxidation product, indicated by malondialdehyde (MDA), significantly increased and decreased, respectively, with some doses of administration, indicating the elevated antioxidant status in treatment groups. Serum‐specific marker enzymes, namely aspartate aminotransferase (AST) and alkaline phosphatase (ALP), were not affected in all groups. Meanwhile serum total protein in most treatment groups was significantly higher than the control group. Results showed that synthesized composites especially nanochitosan/zeolite composite at 5 g/kg had potential to enhance growth performance, digestive enzyme activities and some biochemical parameters in rainbow trout.     

福瑞鲤选育家系不同养殖阶段的生长差异分析

为了进一步观察最佳线性无偏预测(best linear unbiased prediction,BLUP)家系选育方法在福瑞鲤(Cyprinus carpio)继代选育中的潜力,该研究测量了继续选育第2代家系群体不同养殖阶段的体质量和形态性状。结果表明,生长快速家系群福瑞鲤早期(4月龄)生长速度较慢,到后期则生长加快,其体质量增长表现出明显的优势。在体型方面,随着养殖时间的延长,福瑞鲤各选育家系群的体厚/体长增加,体高/体长降低,逐渐呈现其体型修长的特征;同时2个越冬期的成活率均达到了94%以上。结果表明通过BLUP家系选育对福瑞鲤长期选育是可行的。在此基础上,通过主成分分析发现,福瑞鲤生长性状第一主成分是体质量;对不同生长时期的体质量进行相关性分析,发现9月龄、14月龄、21月龄鱼的体质量与24月龄的相关系数均达到极显著水平(P0.01),分别为0.851、0.897和0.957。因此,在福瑞鲤继续选育过程中,进行早期个体选择值得尝试。     

不同养殖密度对紫贻贝和披针形蜈蚣藻生态混养的影响

通过混养生态系统模拟试验研究了紫贻贝(Grateloupia lanceolata)和披针形蜈蚣藻(Mytilus edulis)不同养殖密度组合下的生态混养状况。选取壳长(45.14±3.85)mm的紫贻贝和长度(62.48±7.38)mm的披针形蜈蚣藻,采用5种湿重配比进行混养实验,分别为G1(1∶0)、G2(1∶0.25)、G3(1∶0.5)、G4(1∶1)和G5(1∶2)。每种组合中紫贻贝密度均为0.63 ind·L~(-1),而披针形蜈蚣藻密度分别为0 g·L~(-1)、1.25 g·L~(-1)、2.5 g·L~(-1)、5 g·L~(-1)、10 g·L~(-1)。36 d后,G3组中紫贻贝特定生长率为(0.21±0.03)%·d-1,极显著高于其它混养组[(0.11±0.028)~(0.21±0.03)%·d-1,P0.01],而单养组的紫贻贝特定生长率仅为(0.063±0.022)%·d-1;G3组中披针形蜈蚣藻特定生长率为(0.96±0.20)%·d-1,极显著高于其它混养组[(0.62±0.16)~(0.96±0.20)%·d-1,P0.01]。G3组生态系统对营养盐(NO_3~--N、NO_2~--N、NH_4~+-N、PO3-4-P)的去除率分别达到(91.38±1.40)%、(96.79±1.97)%、(98.38±2.06)%、(96.86±3.16)%,显著高于G2组(P0.05),而与G4和G5组没有显著性差异(P0.05)。本研究结果表明,当紫贻贝与披针形蜈蚣藻湿重比为1∶0.5时,可以取得较好的生态效应。     

Is behaviour in a novel environment associated with bodily state in brown trout Salmo trutta fry?

Energetic status and body size are inconstant bodily states often considered to have feedback effects on behaviour. Feedbacks can be negative, like starvation‐threshold feedbacks (lower state values = increased risk taking due to higher energy need, and vice versa), or positive, like state‐dependent safety feedbacks (higher state values = lower vulnerability when expressing risky behaviours, and vice versa). Few studies have investigated feedback effects during the early‐life survival bottleneck of territorial species, when rapid growth is particularly important to maintain competitive ability. We investigated effects of body size and energetic status on the emergence latency into an unknown environment in highly territorial brown trout fry. We manipulated energetic status using high and low food rations in different combinations over two consecutive periods. In contrast to results from other small‐sized fishes, no general behavioural effects of energetic state were detected, but larger fish had on average shorter emergence latency. Starvation‐threshold feedbacks were not supported, but the size effect favours the presence of a state‐dependent safety feedback. When individuals were split into clusters characterised by long (>34 s) and short (<34 s) emergence latency, a state‐dependent safety feedback, based on energetic status, was found in the short‐latency cluster. Positive state‐dependent feedbacks may reflect the high level of competition among wild trout fry during the first summer, particularly among the more active individuals (i.e., from the short latency cluster). High state levels could be utilised to gain advantages over lesser competitors (e.g., to establish territories), particularly if the overall risk of starvation is higher than the risk of predation.