Effect of dietary supplementation of inulin and W. cibaria on haemato‐immunological parameters of hybrid surubim (Pseudoplatystoma sp)

The dietary supplementation of prebiotics, probiotics and symbiotic in hybrid surubins (a Pseudoplatystoma corruscans and P. fasciatum cross) was evaluated for the effects on their autochthonous intestinal microbiota and on haematological and immunological parameters. A total of 160 fish were divided into four treatment groups with four replicates each. The treatment groups were fed with the following diets for 15 days: control diet without supplementation; 0.5% inulin (prebiotic) supplementation; Weissella cibaria (CPQBA 001‐10 DRM 02) (7.87 ± 0.2 log CFU g^?1) supplementation; or 0.5% inulin and W. cibaria supplementation (symbiotic group). The midgut intestines of the fish with the symbiotic diet supplementation had higher concentrations of lactic acid bacteria (7.07 ± 1.11 log CFU g^?1) and low levels of Vibrio spp (1.90 ± 0.60 log CFU g^?1) and Pseudomonas spp (2.23 ± 1.48 log CFU g^?1). In addition, increased erythrocytes and reduced circulating neutrophils were observed in this group. No differences in blood glucose, serum protein or lysozyme levels were detected between treatment groups. However, a higher concentration of total immunoglobulin was observed in fish fed with the probiotic and symbiotic diets. The addition of 0.5% inulin (prebiotic) thus W. cibaria (probiotic) to the diet of Pseudoplatystoma hybrid surubins reduce the number of pathogenic bacteria and stimulate the beneficial intestinal microbiota and may possibly alter their immune defence system.     

人工诱导池养3+龄鲥鱼性腺发育的初步试验与探讨

通过模似鲥鱼性腺发育的自然生态条件和埋植 LHRH-A 和 Testosterone 缓释放颗粒激素,诱导池养3~+龄鲥鱼性腺发育季至第1期,成熟系数达0.9%。试验摸索出麻醉操作鲥鱼不死的有效方法。对今后鲥鱼全人工繁殖的前景及有关问题进行了探讨.     

Dietary α‐linolenic acid affects lipid metabolism and tissue fatty acid profile and induces apoptosis in intraperitoneal adipose tissue of juvenile grass carp (Ctenopharyngodon idella)

A 56‐day feeding trial was conducted to elucidate the effects and mechanism action of dietary α‐linolenic acid (ALA, 18:3n‐3) on lipid accumulation and fatty acid profile of muscle, hepatopancreas and intraperitoneal fat (IPF) in juvenile grass carp using three isonitrogenous and isoenergetic semi‐purified diets containing 0.0% (control group), 1.0% and 2.0% ALA, respectively. The lowest intraperitoneal fat (IPF) ratio was found in 2.0% group. In the muscle, hepatopancreas and IPF, docosahexaenoic acid (DHA, 22:6n‐3) and eicosapentaenoic acid (EPA, 20:5n‐3) contents increased with the increase in dietary ALA. In the IPF, caspase 3, caspase 8 and caspase 9 showed the highest activities in 2.0% group, while the value of Bcl‐2/Bax (B‐cell leukaemia 2/Bcl‐2‐associated X protein) reached the lowest. Meanwhile, swelling of the IPF mitochondria was observed in 2.0% group. The gene expressions of fatty acid desaturase (FAD) and fatty acid elongase (ELO) in the hepatopancreas and muscle showed significantly higher levels in the treatment groups, whereas an opposite trend was existed in the IPF. Fatty acid synthase (FAS), sterol regulatory element binding protein‐1c (SREBP‐1c) in the IPF and hepatopancreas reached the lowest in 2.0% group. Overall, dietary ALA could promote n‐3 highly unsaturated fatty acids (HUFAs) synthesis and suppress the accumulation of lipid by decreasing the expression of related genes and promoting the apoptosis in IPF.     

Effects of dietary live or heat‐inactivated autochthonous Bacillus pumilus SE5 on growth performance,immune responses and immune gene expression in grouper Epinephelus coioides

To evaluate the possible dietary application of live and heat‐inactivated probiotic Bacillus pumilus SE5 in grouper Epinephelus coioides, juveniles (14.6 ± 0.2 g) were fed either a basal control diet (without probiotic) or the basal diet supplemented with 1.0 × 10⁸ CFU g^?1 live (T1) and heat‐inactivated B. pumilus SE5 (T2). The heat‐inactivated probiotic significantly improved the final weight, weight gain (WG) and specific growth rate (SGR) at day 60 and significantly decreased the feed conversion ratio (FCR) at day 30 and 60, while the viable probiotic significantly decreased the FCR at day 60 (P < 0.05). Phagocytic activity, serum complement C3 and IgM levels as well as SOD activity elevated significantly in fish fed the heat‐inactivated probiotic for 60 days (P < 0.05). Furthermore, the heat‐inactivated probiotic remarkably up‐regulated expression of TLR2 and pro‐inflammatory cytokines (IL‐8 and IL‐1β) in head kidney (P < 0.05), but the viable probiotic failed to do so. These results indicated that heat‐inactivated B. pumilus SE5 can effectively improve the growth performance and immune responses of E. coioides.     

Effect of dietary supplemental l‐carnitine on growth performance,body composition and antioxidant status in juvenile black sea bream,Sparus macrocephalus

Effects of dietary l ‐carnitine were studied in juvenile black sea bream (Sparus macrocephalus). The semipurified basal diet [crude protein 450 g kg^?1 dry matter (DM); crude lipid 126 g kg^?1 DM] was formulated to choose white fishmeal as the protein source and fish oil plus corn oil (1 : 1) as the lipid source. Six diets (control + diets 1–5) containing 0.1, 0.12, 0.16, 0.24, 0.39 and 1.1 g of l ‐carnitine kg^?1 diet were fed to triplicate groups of black sea bream (initial weight 13.10 ± 0.05 g) for 8 weeks. At the end of the feeding trial, growth performance, body composition and antioxidant status were determined. The results showed that relative growth rate (RGR) was significantly improved by the elevation of dietary l ‐carnitine level from 0.1 to 0.24 g kg^?1, but decreased with further increment (P < 0.05). Lipid content decreased significantly (P < 0.05) in the dorsal muscle whereas increased (P < 0.05) in the liver with the addition of dietary l ‐carnitine. Dietary l ‐carnitine supplements elevated enzymatic antioxidants (superoxide dismutase, SOD; catalase, CAT; glutathione‐S‐transferase, GST) activities (P < 0.05) yet decreased the content of non‐enzymatic factor, total sulphydryl groups (TSH) (P < 0.05). In summary, the optimum dietary l ‐carnitine level was 0.284 g kg^?1 diet by second‐polynomial regression analysis based on RGR (y = ?647.4x² +367.97x + 234.55; R² = 0.977, x = dietary l ‐carnitine levels, y = RGR), and dietary l ‐carnitine addition within the levels adopted in our study could depress lipid peroxidation in tissues of juvenile black sea bream.     

Growth and body composition of juvenile white shrimp,Litopenaeus vannamei,fed different ratios of dietary protein to energy

A 10‐week feeding experiment was conducted to evaluate the effect of different protein to energy ratios on growth and body composition of juvenile Litopenaeus vannamei (initial average weight of 0.09 ± 0.002 g, mean ± SE). Twelve practical test diets were formulated to contain four protein levels (300, 340, 380 and 420 g kg^?1) and three lipid levels (50, 75 and 100 g kg^?1). Each diet was randomly fed to triplicate groups of 30 shrimps per tank (260 L). The water temperature was 28.5 ± 2 °C and the salinity was 28 ± 1 g L^?1 during the experimental period. The results showed that the growth was significantly (P < 0.05) affected by dietary treatments. Shrimps fed the diets containing 300 g kg^?1 protein showed the poorest growth. However, shrimp fed the 75 g kg^?1 lipid diets had only slightly higher growth than that fed 50 g kg^?1 lipid diets at the same dietary protein level, and even a little decline in growth with the further increase of dietary lipid to 100 g kg^?1. Shrimp fed the diet with 420 g kg^?1protein and 75 g kg^?1 lipid had the highest specific growth rate. However, shrimp fed the diet with 340 g kg^?1 protein and 75 g kg^?1 lipid showed comparable growth, and had the highest protein efficiency ratio, energy retention and feed efficiency ratio among dietary treatments. Triglycerides and total cholesterol in the serum of shrimp increased with increasing dietary lipid level at the same dietary protein level. Body lipid and energy increased with increasing dietary lipid level irrespective of dietary protein. Results of the present study showed that the diet containing 340 g kg^?1 protein and 75 g kg^?1 lipid with digestible protein/digestible energy of 21.1 mg kJ^?1 is optimum for L. vannamei, and the increase of dietary lipid level has not efficient protein‐sparing effect.     

Optimal dietary lipid level for large yellow croaker (Pseudosciaena crocea) larvae

A 30‐day feeding experiment was conducted in blue tanks (70 × 50 × 60 cm, water volume 180 L) to determine the effects of dietary lipid levels on the survival, growth and body composition of large yellow croaker (Pseudosciaena crocea) larvae (12 days after hatchery, with initial average weight 1.93 ± 0.11 mg). Five practical microdiets, containing 83 g kg^?1 (Diet 1), 126 g kg^?1 (Diet 2), 164 g kg^?1 (Diet 3), 204 g kg^?1 (Diet 4) and 248 g kg^?1 lipid (Diet 5), were formulated. Live feeds (Artemia sinicia nauplii and live copepods) were used as the control diet (Diet 6). Each diet was randomly assigned to triplicate groups of tanks, and each tank was stocked with 3500 larvae. During the experiment, water temperature was maintained at 23(±1) °C, pH 8.0 (±0.2) and salinity 25 (±2) g L^?1. The results showed that dietary lipid significantly influenced the survival and growth of large yellow croaker larvae. Survival increased with the increase of dietary lipid from 83 to 164 g kg^?1, and then decreased. The survival of larvae fed the diet with 83 g kg^?1 lipid (16.1%) was significantly lower than that of larvae fed other diets. However, the survival in larvae fed the diet with 16.4 g kg^?1 lipid was the highest compared with other artificial microdiets. Specific growth rate (SGR) significantly increased with increasing dietary lipid level from 83 to 164 g kg^?1 (P < 0.05), and then decreased. The SGR in larvae fed the diet with 164 g kg^?1 lipid (10.0% per day) was comparable with 204 g kg^?1 lipid (9.6% per day), but were significantly higher than other microdiets (P < 0.05). On the basis of survival and SGR, the optimum dietary lipid level was estimated to be 172 and 177 g kg^?1 of diet using second‐order polynomial regression analysis respectively.     

FSWM: A hybrid fuzzy-stochastic water-management model for agricultural sustainability under uncertainty

A hybrid fuzzy-stochastic water-management (FSWM) model is developed for agricultural sustainability under uncertainty, based on advancement of a multistage fuzzy-stochastic quadratic programming (MFSQP) approach. In MFSQP, uncertainties presented in terms of fuzziness and randomness can be incorporated within a multilayer scenario tree, such that revised decisions are permitted in each time period based on the realized values of the uncertain events. Moreover, fuzzy quadratic terms are used in the objective function to minimize the variation of satisfaction degrees among the constraints; it allows an increased flexibility in controlling the system risk in the optimization process. Results of the case study indicate that useful solutions for the planning of agricultural water management have been obtained. In the FSWM model, a number of policies for agricultural water supply are conducted. The results obtained can help decision makers to identify desired water-allocation schemes for agricultural sustainability under uncertainty, particularly when limited water resources are available for multiple competing users.     

温室轴流风送药雾靶标沉积试验

为研究药液雾滴在温室靶区内和植株靶标上的沉积量及分布情况,以炮塔式压力雾化轴流风送高压静电喷雾系统为试验平台,在相同风机频率、喷雾压力和喷雾流量条件下,通过改变喷头高度和静电电压对风送药雾进行靶标沉积试验和分析.结果表明:沿风送轴线上距喷头150～200cm靶区内的药雾沉积量都出现一个沉积高峰区;随着静电电压的增大,植株靶标上的药雾沉积量明显增加,荷电后的药液雾滴在风送射程和喷幅内的靶标沉积率显著提高.根据实际喷施作业目标,合理布置喷头高度和调节合适电压,是增加靶标沉积率的重要手段.     

基于单片机的沼气发酵装置增温控制系统设计

北方沼气系统全年产气的关键是冬季加热增温问题.为此,以生物质炉为热源,通过对循环水的加热,用单片机控制加热水泵的增温系统,研究设计了系统的整体功能以及硬件和软件.该系统具有一定的智能性,保证了沼气系统在北方冬季时的正常运行,提高了产气量.