The growth performance of Jade Tiger cultured abalone fed diets supplemented with fish oil and vegetable oils

Background
The effects of fish oil (FO) supplementation and the dietary replacement of FO with flaxseed oil (FlaxO) and canola oil (CO) on the growth of cultured abalone was investigated. The study involved three growth experiments: (E1) diets containing 0.5, 1.0, 1.5, 2.0 and 2.5% of FO, respectively; (E2) diets in which FO was serially replaced by 25, 50, 75 and 100% FlaxO, respectively; and (E3) diets in which FO was serially replaced by 25, 50, 75 and 100% CO, respectively.

Results
In Experiment 1, abalone fed a diet supplemented with 1.5% FO showed a significantly higher (121.2 ± 1.1 mg day−1) daily growth rate of weight (DGRw) compared to control (70.1 ± 1.71 mg day−1). In Experiment 2, abalone fed 1.5% FO diet and diets containing 25–75% FlaxO showed no significant differences in DGRw. The diet containing 100% FlaxO showed significantly lower (63.3 ± 6.7 mg day−1) DGRw. In Experiment 3, abalone fed diets containing 25% and 50% CO showed similar DGRw as those fed a 1.5% FO diet. The diet containing 75% and 100% CO showed significantly lower (63.7 ± 5.0 to 95.4 ± 5.1 mg day−1) DGRw.

Conclusion
Supplementation with 1.5% of dietary FO can improve growth performance in cultured abalone. It is feasible to replace 75% of dietary FO with FlaxO and 50% of dietary FO with CO, without negative effect on growth performance.

Rapid onset of renal sympathetic nerve activation in rabbits fed a high-fat diet

Hypertension and elevated sympathetic drive result from consumption of a high-calorie diet and deposition of abdominal fat, but the etiology and temporal characteristics are unknown. Rabbits instrumented for telemetric recording of arterial pressure and renal sympathetic nerve activity (RSNA) were fed a high-fat diet for 3 weeks then control diet for 1 week or control diet for 4 weeks. Baroreflexes and responses to air-jet stress and hypoxia were determined weekly. After 1 week of high-fat diet, caloric intake increased by 62%, accompanied by elevated body weight, blood glucose, plasma insulin, and leptin (8%, 14%, 134%, and 252%, respectively). Mean arterial pressure, heart rate, and RSNA also increased after 1 week (6%, 11%, and 57%, respectively). Whereas mean arterial pressure and body weight continued to rise over 3 weeks of high-fat diet, heart rate and RSNA did not change further. The RSNA baroreflex was attenuated from the first week of the diet. Excitatory responses to air-jet stress diminished over 3 weeks of high-fat diet, but responses to hypoxia were invariant. Resumption of a normal diet returned glucose, insulin, leptin, and heart rate to control levels, but body weight, mean arterial pressure, and RSNA remained elevated. In conclusion, elevated sympathetic drive and impaired baroreflex function, which occur within 1 week of consumption of a high-fat, high-calorie diet, appear integral to the rapid development of obesity-related hypertension. Increased plasma leptin and insulin may contribute to the initiation of hypertension but are not required for maintenance of mean arterial pressure, which likely lies in alterations in the response of neurons in the hypothalamus.

Investigation of process dynamics and control of polystyrene batch reactor using hybrid model

The effects of operating conditions such as initiator and monomer concentration as well as reactor temperature of polymerization reactors are studied in this work. A recently developed hybrid model for polystyrene batch reactor is utilized in simulation study. The simulation results reveal the sensitivity of polymer properties and monomer conversion to variation of process operating conditions. In the second phase of this study, the optimization problem involving minimum time optimal temperature policy is considered for control study. An advanced neural network-based model predictive controller (NN-MPC) is designed and tested online. The experimental studies reveal that the developed controller is able to track the optimal setpoint with a minor oscillation and overshoot.

Performance analysis of two advanced controllers for polystyrene polymerization in batch reactor

The performance of two advanced model based non-linear controllers is analyzed for the optimal setpoint tracking of free radical polymerization of styrene in batch reactors. Artificial neural network-based model predictive controller (NN-MPC) and generic model controller (GMC) are both applied for controlling the system. The recently developed hybrid model [1] as well as available literature models are utilized in the control study. The optimal minimum temperature profiles are determined based on Hamiltonian maximum principle. Different types of disturbances are artificially generated to examine the stability and robustness of the controllers. The experimental studies reveal that the performance of NN-MPC is superior over that of GMC.

Changes in oil content, lipid class and fatty acid composition of the microalga Chaetoceros calcitrans over different phases of batch culture

 Abstract
The diatom Chaetoceros calcitrans is a microalgal species used as food for larva in aquaculture for many species worldwide. Chaetoceros calcitrans is an important source of omega 3 long chain (C ≥ 20) polyunsaturated fatty acids (n-3 LC PUFA), chiefly eicosapentaenoic acid (EPA, 20:5n-3). This article reports lipid content, lipid class composition and fatty acid profiles of each lipid class during the growth cycle of batch cultures of C. calcitrans. Total lipid content and the concentration of neutral lipid were highest in the late stationary growth phase (day 12). However, the amount of EPA was highest during the logarithmic growth phase (1.24 pg/cell on day 4). EPA was initially concentrated in the glycolipid fraction, but this fraction decreased during logarithmic growth, coinciding with the increase in neutral lipid. Docosahexaenoic acid (22:6n-3, DHA) (0.91 pg/cell) was reported as a major fatty acid (>10 mg/100 g) in all lipid classes on day 1. DHA was depleted quickly from the neutral lipid and glycolipid classes, but at a slower rate from the polar lipid fraction. This work confirms that C. calcitrans is a good source of lipid, in particular EPA, for larval and adult filter feeders in aquaculture.

Reduced preprandial dipping accounts for rapid elevation of blood pressure and renal sympathetic nerve activity in rabbits fed a high-fat diet

Consumption of a high-fat diet (HFD) by rabbits results in increased blood pressure (BP), heart rate (HR), and renal sympathetic nerve activity (RSNA) within 1 wk. Here, we determined how early this activation occurred and whether it was related to changes in cardiovascular and neural 24-h rhythms. Rabbits were meal-fed a HFD for 3 wks, then a normal-fat diet (NFD) for 1 wk. BP, HR, and RSNA were measured daily in the home cage via implanted telemeters. Baseline BP, HR, and RSNA over 24 h were 71 ± 1 mm Hg, 205 ± 4 beats/min and 7 ± 1 normalized units (nu). The 24-h pattern was entrained to the feeding cycle and values increased from preprandial minimum to postprandial maximum by 4 ± 1 mm Hg, 51 ± 6 beats/min, and 1.6 ± .6 nu each day. Feeding of a HFD markedly diminished the preprandial dip after 2 d (79–125% of control; p < 0.05) and this reduction lasted for 3 wks of HFD. Twenty-four-hour BP, HR, and RSNA concurrently increased by 2%, 18%, and 22%, respectively. Loss of preprandial dipping accounted for all of the BP increase and 50% of the RSNA increase over 3 wks and the 24-h rhythm became entrained to the light-dark cycle. Resumption of a NFD did not alter the BP preprandial dip. Thus, elevated BP induced by a HFD and mediated by increased sympathetic nerve activity results from a reduction in preprandial dipping, from the first day. Increased calories, glucose, insulin, and leptin may account for early changes, whereas long-term loss of dipping may be related to increased sensitivity of sympathetic pathways.

Salt loading in canola oil fed SHRSP rats induces endothelial dysfunction

This study aimed to determine if 50 days of canola oil intake in the absence or presence of salt loading affects: (1) antioxidant and oxidative stress markers, (2) aortic mRNA of NADPH oxidase (NOX) subunits and superoxide dismutase (SOD) isoforms and (3) endothelial function in SHRSP rats. SHRSP rats were fed a diet containing 10 wt/wt% soybean oil or 10 wt/wt% canola oil, and given tap water or water containing 1% NaCl for 50 days. Without salt, canola oil significantly increased RBC SOD, plasma cholesterol and triglycerides, aortic p22phox, NOX2 and CuZn-SOD mRNA, and decreased RBC glutathione peroxidase activity. With salt, canola oil reduced RBC SOD and catalase activity, LDL-C, and p22phox mRNA compared with canola oil alone, whereas plasma malondialdehyde (MDA) was reduced and RBC MDA and LDL-C were higher. With salt, the canola oil group had significantly reduced endothelium-dependent vasodilating responses to ACh and contractile responses to norepinephrine compared with the canola oil group without salt and to the WKY rats. These results indicate that ingestion of canola oil increases O2 - generation, and that canola oil ingestion in combination with salt leads to endothelial dysfunction in the SHRSP model.

Control of polystyrene batch reactor using fuzzy logic controller

Control of polymerization reactors is a challenging issue for researchers due to the complex reaction mechanisms. A lot of reactions occur simultaneously during polymerization. This leads to a polymerization system that is highly nonlinear in nature. In this work, a nonlinear advanced controller, named fuzzy logic controller (FLC), is developed for monitoring the batch free radical polymerization of polystyrene (PS) reactor. Temperature is used as an intermediate control variable to control polymer quality, because the products quality and quantity of polymer are directly depends on temperature. Different FLCs are developed through changing the number of fuzzy membership functions (MFs) for inputs and output. The final tuned FLC results are compared with the results of another advanced controller, named neural network based model predictive controller (NN-MPC). The simulation results reveal that the FLC performance is better than NN-MPC in terms of quantitative and qualitative performance criterion.

Grain excretion by goats fed whole or processed cereals with various roughages

Despite cereal grains being grown on 5 continents where goats are kept, there is little information on the excretion of whole cereal grains when fed to goats. We determined the effects of various dietary treatments on whole grain and starch loss in the faeces of Angora goats. In Experiment 1 there were 4 replicates of the factorial design: (a) 2 grain types (barley, oats); (b) whole grain or processing (milled barley or rolled oats); (c) 2 roughage qualities (Persian clover hay, barley straw); and (d) 2 feeding levels (level 1, 150 g/d of grain, 250 g/d of roughage; level 2, 250 g/d of grain, ad libitum roughage). In Experiment 2, which immediately followed Experiment 1, and aimed to detect carry over effects of previous feeding of barley straw and grain processing, feed levels were either 650 g/d grain or 400 g/d grain with 550 g/d Persian clover hay. Data were analysed by ANOVA. In Experiment 1, processing had no effect on digestible dry matter intake. The number of whole grains lost per 100 g of fresh faeces and whole grains loss as the % of grain dry matter intake were affected by an interaction between processing and roughage quality. Whole grain fed with Persian clover hay had greater grain loss than all other diets. Whole grain loss was greater with whole grain than with processed grain. Level of feeding had no effects on grain loss. In Experiment 2, more whole grains were lost in fresh faeces when fed with Persian clover hay than when fed without hay, an effect of previous feeding with barley straw reduced whole grain excretion, and more barley grains were lost than oat grain. Faecal starch was affected, with higher levels when whole barley grain was fed, particularly with Persian clover hay, or when previously fed barley straw at a high level. Feeding grain at 650 g/d did not increase grain or starch excretion. Whole grains represented a small loss of grain dry matter intake in faeces, averaging 0.8% with a maximum recorded of 2.6%. Faecal concentration of the whole grains may be altered by grain size and the digestibility of the roughage component of the diet. In this study an additional cost of 3% for processing grains would not have provided economic benefits.