The aim of the present research was to investigate the potential use of the phototrophic microalgae ( ) as a fish meal replacement in diet for Atlantic salmon, . Two experiments were designed with fish meal based control diets and dried whole cells replacing fishmeal in the ratios 3%, 6% and 12% (experiment one) and 3 and 6% (experiment two). Experiment one was a digestibility study lasting for 21 days, investigating effects of inclining level of on apparent digestibility (ADC) of nutrients and energy. Experiment two was investigating ADC's of nutrients and energy, growth performance and nutrient retention in salmon fed for 82 days. The results from experiment one showed a linear reduction in ADC of dry matter (DM; = 0.02), lipid ( < 0.0001), and protein ( = 0.04) with increasing level of algae biomass in the diet. The ADC of starch increased ( < 0.05) with algae inclusion level in both experiments. For experiment two, no effects were observed on digestibility of DM, lipid, protein, energy or ash, with 3 and 6% algae replacing fish meal. Neither was growth or feed conversion affected by 3 and 6% algae replacing fish meal. Increasing inclusion level of algae biomass caused an increase in whole body lipid. The ADC of saturated fatty acids was higher in fish fed 3% alga biomass compared to the 6% group. There was no difference in ADC or retention of -3 fatty acids. In conclusion, the two experiments showed that can replace up to 6% of the fish meal without adverse effects on nutrient digestibility, utilization of the feed and growth performance. Microalgae are potential omega-3-contributing feed ingredients
The evaluation of feed ingredients is crucial to nutritional research and feed development for aquaculture species. In evaluating ingredients for use in aquaculture feeds, there are several important knowledge components that should be understood to enable the judicious use of a particular ingredient in feed formulation. This includes information on (1) ingredient digestibilities, (2) ingredient palatability and (3) nutrient utilization and interference.Diet design, feeding strategy, faecal collection method and method of calculation all have important implications on the determination of the digestible value of nutrients from any ingredient. There are several ways in which palatability of ingredients can be assessed, usually based on variable inclusion levels of the ingredient in question in a reference diet and feeding of those diets under an apparent satietal or self-regulating feeding regimes. However, the design of the diets, the parameters of assessment and the feeding regime can all be subject to variation depending on subtleties of the experimental design. Clearly, issues relating to feed intake are the key performance criteria in palatability assessments, and it is important that such experiments maintain sufficient stringency to allow some self-discrimination of the test feeds by the fish. The ability of fish to use nutrients from the test ingredient, or defining factors that interfere with that process, is perhaps the most complex and variable part of the ingredient evaluation process. It is crucial to discriminate effects on feed intake from effects on utilization of nutrients from ingredients (for growth and other metabolic processes). To allow an increased focus on nutrient utilization by the animals, there are several experimental strategies that can be adopted, which are based on variations in diet design and feeding regime used. Other issues such as ingredient functionality, influence on immune status and effects on organoleptic qualities are also important consideration in determining the value of ingredients in aquaculture feed formulations. A key aspect to note is the need to design all experiments with sufficient experimental capacity to detect significant effects.
Two experiments were conducted to evaluate the effect of moderate feed restriction on productivity of lambs classified on the basis of phenotypic expression of residual feed intake (RFI). In Exp. 1, 58 fat-tailed Kurdi ram lambs (32.1 ± 4.2 kg BW) were individually fed, ad libitum, a pelleted diet (35% alfalfa hay and 65% concentrate). Feed intake and ADG were determined for a 6-wk period and 3 feed efficiency measures including RFI, G:F, and partial efficiency of maintenance (PEM) were calculated. The lambs were sorted based on RFI and the 16 highest RFI (RFI ≥ mean + 0.5 SD) and 16 lowest RFI (RFI ≤ mean - 0.5 SD) lambs were subjected to body composition (BC) and DM digestibility (DMD) analysis. Feeding behavior traits (FB) were also evaluated for 24 h using a regular 5-min interval observation method. The high- and low-RFI lambs (14 lambs/RFI group) so classified in Exp. 1 were used in Exp. 2. Half of the lambs in each RFI group were randomly selected to be fed ad libitum or 85% of ad libitum (restricted feeding), which resulted in 4 experimental groups: 1) ad libitum high-RFI, 2) feed restricted high-RFI, 3) ad libitum low-RFI, and 4) feed restricted low-RFI. The lambs were fed the same diet as Exp. 1, and growth efficiency during a 6-wk test period as well as BC, DMD, and FB were also determined in Exp. 2. In Exp. 1, the low-RFI lambs consumed 14% ( 0.72), and FB ( > 0.24). In Exp.2, the restriction feeding regime negatively affected ADG ( 0.05) were observed. The lambs fed at the restricted level of intake presented a greater time ( 0.05) was detected between RFI phenotype and feeding regime for FB. In summary, feeding high-RFI lambs at 85% of ad libitum level improved G:F with no effect on ADG, whereas growth performance was reduced by feeding low-RFI lambs at 85% of ad libitum. However, these changes in feed efficiency were not related to DMD, BC, or FB.
► We present a general method to prepare the core–shell magnetic MIPs nanoparticles (Fe O @MIPs) for sulfamethazine. ► The Fe O @MIPs possess a highly improved imprinting factor, fast adsorption kinetics and high adsorption capacity. ► The structure and affinity properties of the resulting Fe O @MIPs were characterized. ► We used Fe O @MIPs for enrichment and determination of SMZ in the poultry feed samples. In this study, we present a general method to prepare the core–shell magnetic molecularly imprinted polymers (MIPs) nanoparticles (NPs) for sulfamethazine (SMZ). The resulting Fe O @MIPs NPs possess a highly improved imprinting effect, fast adsorption kinetics and high adsorption capacity, and can be applied to extract sulfonamide in the poultry feed. In this protocol, the magnetite NPs were synthesized by co-precipitating Fe and Fe in an ammonia solution first. Silica was then coated on the Fe O NPs using a sol–gel method to obtain silica shell magnetic NPs. Subsequently, the vinyl groups were grated onto silica-modified Fe O surface by 3-methacryloyloxypropyltrimethoxysilane. Finally, the MIPs films were formed on the surface of Fe O @SiO by the copolymerization of vinyl end groups with functional monomer, methacrylic acid, cross-linking agent, ethylene glycol dimethacrylate, the initiator azo-bis-isobutyronitrile and template molecule, sulfamethazine. The morphology, magnetic, adsorption and recognition properties of Fe O @MIPs NPs were characterized using transmission electron microscope (TEM), scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectrometer, vibrating sample magnetometer (VSM) and re-binding experiments. The results showed that the binding sites of Fe O @MIPs were good accessibility, fast adsorption rate and the maximum adsorption capacity of Fe O @MIPs to SMZ was 344.8 μg g . The selectivity of the obtained Fe O @MIPs NPs were elucidated by the different rebinding capability of SMZ and structural related sulfonamides in the mixed solution. The results indicated that the Fe O @MIPs had high imprinting factor 9.5 and significant selectivity. A method was developed for enrichment and determination of SMZ in the poultry feed samples with recoveries of duck and chicken feed ranging from 63.3 to 76.5% and 68.7 to 74.7%, respectively and the relative standard deviations (RSD) (<6.7%).
This paper reviews the design and control of feed drive systems used in machine tools. Machine tool guides designed using friction, rolling element, hydrostatic and magnetic levitation principles are reviewed. Mechanical drives based on ball-screw and linear motors are presented along with their compliance models. The electrical motors and sensors used in powering and measuring the motion are discussed. The control of both rigid and flexible drive systems is presented along with active damping strategies. Virtual modeling of feed drives is discussed. The paper presents the engineering principles and current challenges in the design, analysis and control of feed drives.
The salmon feed composition has changed the last decade with a replacement of traditionally use of fish oil and fishmeal diets with vegetable ingredients and the use decontaminated fish oils, causing reduced concentrations of dioxins and dioxin-like PCBs in farmed Norwegian Atlantic salmon. The development of novel salmon feeds has prompted the need for prediction on dioxins and dl-PCB concentrations in future farmed salmon. Prediction on fillet dioxins and dl-PCB concentrations from different feed composition scenarios are made using a simple one-compartmental transfer model based on earlier established dioxin and dl-PCB congener specific uptake and elimination kinetics rates. The model is validated with two independent feeding trials, with a significant linear correlation (r = 0.96, y = 1.0x, p < 0.0001, n = 116) between observed and predicted values. Model fillet predictions are made for the following four scenarios; (1) general feed composition of 1999, (2) feed composition of 2013, (3) future feed composition with high fish oil and meal replacement, (4) future feed composition with high fish oil and meal replacement and decontaminated fish oil. Model predictions of fillet dioxin and dl-PCB concentrations from 1999 (1.05 ng WHO -TEQs kg ww) and 2013 (0.57 ng WHO -TEQs kg ww) are in line with the data observed in national surveillance programs of those years (1.1 and 0.52 ng WHO -TEQs kg ww, respectively). Future use of high replacement and decontaminated oils feeds gave predicted fillet concentrations of 0.27 ng WHO -TEQs kg ww, which is near the limit of quantification.