The effects of replacing fish meal or soy protein concentrate with wheat gluten on growth, whole-body composition, and the retention and apparent digestibility coefficient of amino acids in Japanese seabass (Lateolabrax japonicus).

The aim of this study was to evaluate the effects of replacing fish meal (FM) or soy protein concentrate (SPC) with wheat gluten on growth performance, feed utilization, and nutrient digestibility and retention in Japanese seabass (Lateolabrax japonicus). Seven isonitrogenous (441-456 g kg-1 crude protein) and isocaloric (21.5-22.0 MJ kg-1 gross energy) diets were produced to replace 0%, 33.3%, 66.7% and 100% of FM or SPC with a mixture of wheat gluten, wheat, and taurine (GWT, 77.5% wheat gluten, 20.5% wheat and 2.0% taurine). The gradual replacement of protein in FM with GWT had no significant effects on feed intake, whole-body composition, and the hepatosomatic and viscerosomatic indices, but resulted in a linear decrease in the weight gain rate, feed efficiency, and retention of nitrogen, energy, and essential amino acids (Arg, His, Ile, Leu, Lys, Met, Phe, Thr, and Val). The apparent digestibility of most essential amino acids (Cys, His, Leu, Lys, and Phe) and total amino acids increased linearly. Replacement protein in SPC with GWT had no significant effects on feed intake, growth, the feed conversion ratio, whole-body composition, and the hepatosomatic index, but resulted in a linear decrease in nitrogen, energy, and Met retention; the digestibility of Cys and Met increased linearly. Overall, wheat gluten is a more effective alternative for replacing protein in SPC than FM.

Evaluate of Wheat Gluten as a Protein Alternative for Fish Meal and Soy Protein Concentrate in Red Spotted Grouper Epinephelus akaara.

The aim of this study was to evaluate the effects of wheat gluten as a substitute for fish meal (FM) and soy protein concentrate (SPC) in the low-fishmeal-based extruded diet in red spotted grouper Epinephelus akaara. Eight isonitrogenous (441-456 g kg-1) and isocaloric (21.5-22.0 MJ kg-1) diets were produced, including the control diet (R0), three diets with 33.3, 66.7, and 100% FM being replaced by a mixture of wheat gluten, wheat, and taurine (GWT) (RF1, RF2, RF3), three diets with 33.3, 66.7, and 100% SPC replaced by GWT (RS2, RS2, RS3) and one diet with 50% FM and 50% SPC replaced by GWT (RFS). Results showed that feed intake (FI), weight gain (WG), protein retention efficiency, and liver superoxide dismutase activity increased linearly, while feed conversion ratio (FCR) decreased linearly with the decrease of dietary FM. Additionally, FI, WG, and FCR significantly increased with decreasing dietary SPC. Overall, 100% FM or 61.2% SPC can be safely replaced by wheat gluten in the red-spotted grouper diet containing 20.0% FM and 21.4% SPC.

Evaluation of intervention effects of dietary coenzyme Q10 supplementation on oxidized fish oil-induced stress response in largemouth bass Micropterus salmoides.

The aim of this experiment was to investigate whether dietary coenzyme Q10 could alleviate stress response of Micropterus salmoides caused by oxidized fish oil. Four isonitrogenous and isoenergetic diets were formulated to contain 100% fresh fish oil (FFO), 50% fresh fish oil + 50% oxidized fish oil (BFO), 100% oxidized fish oil (OFO) and 100% oxidized fish oil + 0.1% coenzyme Q10 (QFO) and were fed to Micropterus salmoides (95 ± 0.60 g) for 70 days. Higher weight gain rate was recorded in fish fed diet supplemented with coenzyme Q10 (CoQ10). FFO and BFO significantly increased contents of fat and energy in whole-body, while protein and energy retention significantly decreased in fish fed OFO. Apparent digestibility of energy and fat showed a significant decrease trend with increased the proportion of dietary oxidized fish oil. Fish fed OFO significantly increased activities of superoxide dismutase and catalase, while CoQ10 supplementation significantly reduced activities of alanine aminotransferase and aspartate aminotransferase in plasma. Contents of n-3 polyunsaturated fatty acids and highly unsaturated fatty acids, especially EPA and DHA in liver and muscle significantly decreased in fish fed OFO. Transcriptome analysis indicated that a total of 1238, 1189 and 1773 differentially expressed genes (DEGs, |log2(fold change) | >= 1 and q-value<=0.001) were found in the three comparison groups (FFO vs. OFO, FFO vs. QFO, OFO vs. QFO), respectively. After KEGG enrichment, the main changed pathways in the two comparison groups (FFO vs. OFO, OFO vs. QFO) related to the immune system. Dietary OFO up-regulated the expression of immune-related genes and inflammatory factors, while dietary CoQ10 supplementation reduced these effects.

The effect of feed enzymes phytase, protease and xylanase on pelleting of microalgal biomass.

Lower energy consumption for producing feed pellets is an important part of the economy in the feed mill. The same is if physical pellet quality is degraded. The interest in using of novel ingredients is increasing due to requirements for the sustainable development goals. Defatted microalgae as by-product from biodiesel production is one of many novel ingredients. The purpose of this experiment was to understand how the addition of small amount of enzymes can reduce the flow resistance in the die during pellet discharge, without affecting the physical quality of pellets. Thus, possibly reduce the total consumption of electrical energy during compaction. Three enzymes, phytase, protease, xylanase, and combinations of those were added to defatted Desmodesmus subspicatus microalgae at 3 inclusion levels. Feed enzymes xylanase and phytase helped lowering the flow resistance of the material in the die. Reduction of flow resistance was in average 17 times lover when all three levels of enzyme phytase were used. The same was observed when 0.01% xylanase was added. All feed enzymes and their combination have evidently lowered underwater pellet swelling due to their hydrolytic activity at the surface of the microalgal particles. The hydrolytic activities of the feed enzymes did not affect hardness of the microalgal pellets. Contact angle degree between pellet surface and oil droplet was lowered when xylanase and protease was used at all three dosage levels. However, contact angle degree between pellet surface and water droplets was unaffected by the hydrolytic activity of enzymes.

The Role of Temperature, Ammonia and Nitrite to bioluminescence of Aliivibrio fischeri: towards a new sensor for aquaculture.

Recirculating Aquaculture Systems (RAS) present an innovative, clean and practical way of producing fish intensively. Stress caused by high concentrations of chemical species such as nitrite and un-ionized ammonia, affects fish health and growth and therefore the sustainability of RAS would require an online monitoring for those chemical stressors. This work reveals a study on the suitability of Aliivibrio fischeri as a toxicity sensor for un-ionized ammonia and nitrite. Temperature variation effects were also considered. An EC50 of 0.17 mg/L was found for nitrite and 0.57 mg/L for un-ionized ammonia. It was concluded that Allivibrio fischeri is suitable as an indicator for nitrite in aquaculture at optimal salinity and temperature conditions.

Monitoring Aquaculture Water Quality: Design of an Early Warning Sensor with Aliivibrio fischeri and Predictive Models.

A novel toxicity-warning sensor for water quality monitoring in recirculating aquaculture systems (RAS) is presented. The design of the sensor system mainly comprises a whole-cell biosensor. Aliivibrio fischeri, a luminescent bacterium widely used in toxicity analysis, was tested for a mixture of known fish-health stressors, namely nitrite, un-ionized ammonia, copper, aluminum and zinc. Two toxicity predictive models were constructed. Correlation, root mean squared error, relative error and toxic behavior were analyzed. The linear concentration addition (LCA) model was found suitable to ally with a machine learning algorithm for prediction of toxic events, thanks to additive behavior near the limit concentrations for these stressors, with a root-mean-squared error (RMSE) of 0.0623, and a mean absolute error of 4%. The model was proved to have a smaller relative deviation than other methods described in the literature. Moreover, the design of a novel microfluidic chip for toxicity testing is also proposed, which is to be integrated in a fluidic system that functions as a bypass of the RAS tank to enable near-real time monitoring. This chip was tested with simulated samples of RAS water spiked with zinc, with an EC50 of 6,46E-7 M. Future work will be extended to the analysis of other stressors with the novel chip.

Bacterial protein meal produced on natural gas replacing soybean meal or fish meal in broiler chicken diets.

The effects of replacing soybean meal or fish meal with 2, 4 or 6% bacterial protein meal (BPM) on growth performance, ileal digestibility of amino acids and sensory quality of meat, were examined using 630 broiler chickens. Weight gain from 7-32 days of age did not differ significantly among the treatments. Efficiency of feed conversion was increased when BPM replaced soybean meal, and abdominal fat deposition tended to decline. Feed conversion was not affected when BPM replaced fish meal. Amino acid digestibility was unaffected or improved when BPM replaced soybean meal, whereas replacement of fishmeal with BPM resulted in similar digestibility. Sensory quality of fresh thigh meat was similar among treatments, but for freeze-stored chest meat replacement of fish meal with BPM reduced off-odour and off-flavour and increased juiciness. It was concluded that 6% BPM can replace soybean meal or fish meal protein in broiler chicken diets.

Phytate degradation in a mixture of ground wheat and ground defatted soybeans during feed processing: effects of temperature, moisture level, and retention time in small- and medium-scale incubation systems.

The optimal conditions for degradation of phytate (IP6, myo-inositol hexaphosphate) in a mixture of ground wheat and ground defatted soybeans (1:2, w/w) with added exogenous E. coli phytase were investigated at different temperatures (45, 60, 75, and 95 degrees C), moisture levels (25%, 35%, and 45%), and retention times (2-45 min). All treatment combinations were investigated in a small-scale mixer conditioner (experiment 1). The combined 45 degrees C and 45% moisture treatment was most efficient and reduced the content of IP6 by 86% during 45 min of incubation. This treatment combination was applied in a medium-scale mixer conditioner (experiment 2), and 76% reduction of IP6 at 45 min was obtained. During incubation, the content of lower groups of inositol phosphates, such as IP4 (myo-inositol tetraphosphate) and IP3 (myo-inositol triphosphate), increased significantly as the content of IP6 decreased. The major isomer formed was Ins(1,2,5,6)P(4).

Evaluation of nonstarch polysaccharides and oligosaccharide content of different soybean varieties (Glycine max) by near-infrared spectroscopy and proteomics.

A total of 832 samples of soybeans were screened by near-infrared (NIR) reflectance spectroscopy, to identify soybean samples with a lower content of oligosaccharides and nonstarch polysaccharides (NSP). Of these, 38 samples were identified on the basis of variation in protein content and agronomic value and submitted to high-resolution NIR spectroscopy. On the basis of the NIR data, 12 samples were further selected for chromatographic characterization of carbohydrate composition (mono-, di-, and oligosaccharides and NSP). Their soluble proteins were separated by two-dimensional gel electrophoresis (2DE). Using partial least-squares regression (PLSR), it was possible to predict the content of total NSP from the high-resolution NIR spectra, suggesting that NIR is a suitable and rapid nondestructive method to determine carbohydrate composition in soybeans. The 2DE analyses showed varying intensities of several proteins, including the glycinin G1 precursor. PLSR analysis showed a negative correlation between this protein and insoluble NSP and total uronic acid (UA).

Effect of extrusion on trypsin inhibitor activity and nutrient digestibility of diets based on fish meal, soybean meal and white flakes.

The effects of moist extrusion processing of diets containing fish meal (FM) and conventional defatted soybean meal (SBM) or untoasted defatted soybean meal (white flakes [WF]) on amino acid composition, trypsin inhibitor activity (TIA), and apparent total tract digestibility of nutrients were studied. Three diets with the nutritional characteristics of feeds for salmonid fish were formulated: one control based on FM as protein source and two others where 40% of total amino acids from FM were substituted by either SBM or WF. Each diet was fed to mink either as an unextruded mixture of the ingredients or as extruded pellets in order to determine the effect of extrusion processing. Extrusion did not change the amino acid composition of the diets significantly, but reduced the TIA of both diets containing soy products by approximately 76%. Intake of the unextruded WF diet was only one-third compared with the other diets. The dry matter concentration in faeces from mink fed diets containing soy products was significantly lower than in mink fed the FM diet. Digestibility of crude protein, all amino acids and fat was lower, but starch higher, in the unextruded WF diet than in the FM and SBM diets, whereas no significant differences were found among the extruded diets. Extrusion of the WF diet increased digestibility of protein and all amino acids. The greatest increase in digestibility after extrusion of the WF diet was observed for cysteine followed by tryptophan. Extrusion of the FM and SBM diets had no significant effect on amino acid digestibility. Digestibility of starch was, in general, increased by extrusion. It is concluded that the heat treatment involved in typical moist extrusion processing used for fish feed may be sufficient to inactivate most of the TIA in unheated soybean meal, and to increase digestibility of the protein in WF to approximately the same level as found for SBM and FM. Still, extrusion is a lenient process with minor effects on nutrient digestibility of diets containing fish meal or toasted soybean meal as major protein sources.