Pellet Water Stability Research Articles

To Standardise Parameters for Preparation of Extruded Feed Using Various Conventional and Non-Conventional Ingredients

The purpose of this research was to optimise extruder parameters for the preparation of floating fish diets with appropriate physicochemical qualities. The impact of temperature (90-120oC), moisture content (15%-30%), die diameter (2.0-4.0 mm) and pre-conditioning duration (15-30 m) on physical properties of the pellets such as bulk density, floatability, expansion ratio and water stability, were examined. Accordingly, four iso-nitrogenous (crude protein 35%) experimental diets were formulated for GIFT tilapia advance fry by replacing 50% of GNOC protein of the control diet (T0) by sunflower oilcake (SFOC) (T1), by linseed oilcake (LSOC) (T2) and by fish based silage (T3) protein. The pellets extruded using a combination of 120 oC extruder barrel temperature, 25% moisture content of feed mix, 2.0 mm die diameter and 30 minute of pre-conditioning duration gave most required pellet floatability (90-100%), expansion ratio (1.43-1.61), water stability (95-99%) and bulk density (0.8 - 0.9 g/cm3) for T1 and T2. However, fish silage when incorporated in the feed mix, it affected negatively in all the physical characteristics of a floating feed and resulted in higher bulk density and lower floatability, expansion ratio and also water stability.

The Potential of Fish Protein Hydrolysate Supplementation in Nile Tilapia Diets: Effects on Growth and Health Performance, Disease Resistance, and Farm Economic Analysis.

Fish protein hydrolysate (FPH) has shown immense potential as a dietary protein supplement and immunostimulant in aquaculture, especially in Nile tilapia production. Four isoproteic diets (30% crude protein) were prepared by including FPH at varying percentages (0%, 0.5%, 1%, and 2%). Nile tilapia fed with FPH diets for 90 days, and their growth performance, feed utilization, blood biochemistry, liver and gut morphology, and resistance against Streptococcus iniae were investigated. The findings revealed that diets physical attributes such as pellet durability index and water stability were remarkably (p < 0.05) varied between experimental diet groups. Furthermore, the test diets were more palatable when FPH was included at 1% and 2%. Fish that were fed with a 2% FPH-treated diet had significantly (p < 0.05) greater growth indices than other treatments. Additionally, their feed utilization was significantly (p < 0.05) improved. The experimental diets and intestinal total bacteria count (TBC) exhibited a rising trend with FPH levels, where the 2% FPH-treated diet recorded the highest TBC. Neutrophil (109/L), lymphocyte (109/L), eosinophil (109/L), and red blood cell(1012/L) counts were significantly (p < 0.05) higher in the 2% FPH-treated group, while the white blood cell (109/L), and basophil (109/L) counts were not influenced by the FPH inclusion. Moreover, the FPH-treated groups displayed lower creatinine, bilirubin, and urea levels than the control. The histological examination demonstrated that themid-intestine of 2% FPH-fed Nile tilapia had an unbroken epithelial wall, more villi with frequent distribution of goblet cells, wider tunica muscularis, and stronger stratum compactum bonding than other treatments. Additionally, this group exhibited more nuclei and erythrocytes and less vacuolar cytoplasm in liver than their counterparts. Nile tilapia that were given a diet containing 2% FPH had significantly (p < 0.05) higher resistance (83.33%) to S. iniae during the bacterial challenge test. A significant (p < 0.05) enhancement in farm economic efficiency was observed in the higher inclusion of FPH in diets. In summary, 2% FPH supplementation in Nile tilapia diets improved their growth performance, feed utilization, health status, disease resistance, and farm economic efficiency.

Understanding and modelling the aquafeed extrusion process for Atlantic salmon feed with an empirical model

An empirical model was applied to quantitatively model the effects of extrusion variables and recipe compositions on quality of feed pellets. Lab extrusion trials were performed with an Atlantic salmon feed recipe with using a central component design (CCD). Comparing with a coated commercial feed made with the same recipe, the lab extrusion pellets had similar bulk density, hardness, and durability properties. A Response Surface Method (RSM) was also used to regress the extrusion trial data and compared with the empirical model results. The respective Absolute Average Deviation (AAD %) values of the empirical model and RSM regression were 4.1 % and 1.8 % for pellet bulk density, 7.4 % and 4.9 % for pellet hardness, 10.4 % and 10.0 % for pellet oil absorption, 13.7 % and 8.3 % for pellet water stability, and 11.3 % and 5.5 % for pellet durability. Using the model coefficients obtained from the extrusion results, the empirical model can partly extrapolate the pellet qualities of an additional extruded recipe, which has a slightly adjusted wheat gluten and wheat. The model performance was evaluated based on. R2, RSME (root-mean-square deviation), AAD % of the empirical model was better than the RSM model to predict the effects of extrusion variables on pellet quality parameters. The effects of the extrusion process variables and recipe composition on pellet quality parameters are predicted by the empirical model. Its demonstrates that the empirical model is a new method to understand extrusion trial results in different extrusion systems and recipes without changing its mathematical form of expression, which gives a common reference to compare an extruded recipe in different systems and has practical engineering applications.

Effect of Fish Meal Substitution with Black Soldier Fly (Hermetia illucens) on Growth Performance, Feed Stability, Blood Biochemistry, and Liver and Gut Morphology of Siamese Fighting Fish (Betta splendens)

Insects such as black soldier fly larvae (BSFL) are gaining interest among researchers and the aquafeed industry due to the fluctuating price and supply of fish meal (FM). This study evaluated the growth performance, feed stability, blood biochemistry, and liver and gut morphology of Betta splendens using BSFL as an alternative to FM. Five formulated diets were prepared: 0% BSFL, 6.5% BSFL, 13% BSFL, 19.5% BSFL, and 24.5% BSFL. The expansion rate, pellet durability index, floatability, bulk density, and water stability of the prepared feed have been assessed. Except for the diameter of the feed, all the parameters studied differed significantly ( p &lt; 0.05 ) across the experimental diets. After 60 days, the fish fed with 13% BSFL had the highest final length, final weight, net weight gain, specific growth rate, weight gain, and gastrointestinal weight, with mean and standard deviation values of 3.97 ± 0.43 cm, 3.95 ± 0.1 g, 2.78 ± 0.1 g, 4.63 ± 0.17 , 4.65 ± 0.13 , 237.26 ± 7.9 % , and 0.04 ± 0.01 mg, respectively. Similar blood haematology and biochemical properties, including corpuscular volume, lymphocytes, white blood cells, red blood cells, haematocrit, albumin, and alkaline phosphatase, were the highest ( p &lt; 0.05 ) in the 13% BSFL diet group compared to the other treatment groups. In addition, BSFL had a significant impact ( p &lt; 0.05 ) on villus length, width, and crypt depth for the anterior and posterior guts of B. splendens. The 13% BSFL diet group had an intact epithelial barrier in the goblet cell arrangement and a well-organized villus structure and tunica muscularis, compared to the other treatment groups. Furthermore, the liver cell was altered with different BSFL inclusions; the 13% FM group demonstrated better nuclei and cytoplasm structure than the other treatment groups. In conclusion, replacing 13% FM with BSFL could improve the growth performance, blood parameters, and liver and intestine morphology of B. splendens, thus providing a promising alternative diet for ornamental freshwater fish.

Novel animal feed binder from soybean hulls -evaluation of binding properties

The physical properties, especially water stability, of aquatic animal feed are important components of feed quality. Novel feed binders from soybean hulls (SBH) were developed to further improve water stability of the compound feed. Three (SBH) -based binders were evaluated as binding agent (2%) against three natural control binders (carboxymethyl cellulose (CMC), corn starch (CS) and wheat glucan (WG)) with respect to water stability and nutrient leaching after being immersed in water up to 48 h at two water temperatures (22 °C and 28 °C). Pacific white shrimp, Litopenaeus vannamei (mean weight of 6.08 ± 0.04 g) were fed in triplicate aquaria with the experimental diets at a rate of 4% of body weight per day, four times daily, for 6 weeks in a recirculating water system. Diets with SHB had significantly improved pellet water stability compared to the diets with control binders (CS and WG) after being immersed in water for longer than 12 h. CMC had the poorest water stability at 3 h and longer water immersion. Recovery of pellets with soybean hull binders was significantly higher than the pellets with control binders at 24 h of water immersion. After 48 h of water immersion, only diets with SHB were recovered ranging from 30% to 40%. Increasing water temperature resulted in a corresponding decrease in water stability of all pellets. At higher water temperature, however, water stability of pellets with control binders were significantly lower compared to pellets with SHB. The binder that best retained crude protein in all time periods was SHB-3. However, it was not significantly different from other soybean hull binders. Percent lipid remained unchanged in all leached pellets up to 12 h of water immersion and increased afterward. Percent ash of the leached pellets increased at 3 h of immersion and continued to increase with the increasing period of water immersion. Diets with SHB retained higher nutrients than the diets containing control binders after being immersed in water 3 h or longer. Weight gain and survival of shrimp fed diets with control or SHB for 6 weeks were not significantly influenced by binder type. In summary, the SBH-bound pellets were more water stable than the control binders and can produce better and be less expensive natural alternatives to conventional binders.

Insects in Atlantic salmon (Salmo salar) diets – comparison between full-fat, defatted, and de-chitinised meals, and oil and exoskeleton fractions

The present study investigated the effect of meals and fractions of black soldier fly larvae (BSFL; Hermetia illucens) in diets for Atlantic salmon (Salmo salar) on the physical quality of feed pellets, nutrient utilisation, and growth performance. Six extruded diets were produced: control diet (CD); full-fat BSFL meal diet (IM); defatted BSFL meal diet (DFIM); de-chitinised BSFL meal diet (DCIM); BSFL oil diet (IO) and BSFL exoskeleton diet (EX). The full-fat, defatted and de-chitinised meals replaced 15% of protein in the control diet. An eight-week study was conducted using salmon with average 28 g initial weight. The full-fat and de-chitinised meals in the diets numerically reduced pellet hardness, expansion, and water stability. The full-fat and de-chitinised meals improved growth rate of salmon, whilst defatted meal, oil and exoskeleton supported similar growth performance as the control. Feed intake and growth rate of fish fed full-fat meal diet were higher than those fed the other insect diets, but defatted meal gave a better feed conversion ratio than full-fat meal. Defatted meal, de-chitinised meal and exoskeleton reduced protein digestibility in fish, however; defatted meal increased the digested protein retention. In conclusion, use of full-fat BSFL meal improved feed intake and growth rate of salmon when replacing 15% of dietary protein. The present results suggest that less processed fullfat form of BSFL is more optimal in diets for salmon and further processing to remove lipid or exoskeleton fractions would only lead to an additional cost.

Evaluation of Carboxymethyl Cellulose (CMC) Binder and Squid Oil Attractant in the Formulation of Litopenaeus vannamei Diet

Highlight ResearchEffects of carboxymethyl cellulose (CMC) binder on pellet water stability in shrimp diet.Evaluation of squid oil attractant on feed palatability.The quality of water after inclusion of CMC binder and squid oil in pellet.CMC and squid oil improved dry matter retention and feeding responses in shrimp. AbstractPellet water stability and feeding attractant are the crucial factors to be considered in the formulation of shrimp feed to minimize nutrient leaching and improve food palatability, respectively. The aim of this study was to determine the binding effect of supplementation of carboxymethyl cellulose (CMC) during pellet manufacturing, and feeding responses with the inclusion of squid oil in pellet. Both experiments were conducted separately in five feed formulations ranged from 0.00% to 3.00% of CMC and squid oil. All T0 was referred as control with no CMC or squid oil. Experiment was conducted using 30 shrimps/treatment with triplicates. The dry matter retention up to 120 min of immersion and the feeding response test were evaluated in pellet supplemented with CMC and squid oil, respectively. Results showed the percentage of dry matter retentions increased with the increase of CMC, over time. The CMC containing pellets at 2.00% and 3.00% had minimal disintegration in water and possessed high water stability after 120 min immersion. The addition of 3.00% squid oil in feed exhibited a significant result (p&lt;0.05) in the time taken for shrimp to access the pellet, also increased the time starts for ingestion. No significant change was observed in water quality indicated no water contamination occurred throughout the study. Results demonstrated that the addition of CMC binder at 2.00% and 3.00% improved pellet water stability, whilst 3.00% squid oil was recommended to enhance feed palatability. However, future studies on the activity of enzymes in shrimp bodies after treatment would be an advantage.

Effect of the ratio of wheat flour and cassava and process parameters on the pellet qualities in low starch feed recipe extrusion

The purpose of the investigation was to study the effects of the ratio of wheat flour and cassava and extrusion process parameters on the physical qualities of low-starch content floating feed in a pilot extrusion plant in order to transfer the production characteristics to scale manufacture. The results show that with an increase of cassava content in formulations, the feed pellet bulk density decreases. When the cassava content is ≥ 54.3 g/kg (wt), the floatability of feed pellet reaches 100 %. The feed pellet hardness depends significantly on the starch sources (P < 0.05). The ratio of wheat flour and cassava in a recipe has significant but irregular impacts on the feed pellet water stability. A wheat flour/cassava ratio (54.3/54.3) was selected as an optimal formulation. For the optimal recipe, a pilot extrusion trial shows that an increase of moisture content and die temperature gives a decrease in the feed pellet bulk density, then an increase in pellet floating possibility. Based on Response Surface Methodology, the optimal parameters for processing the selected recipe are moisture content 32 % (wt), screw speed 247 rpm and die temperature 135 ℃. A theoretical model was also applied to cross-check the results from Response Surface Methodology.

Different starch sources affect physical characteristics of extruded feeds prepared for the Malaysian mahseer, Tor tambroides

ABSTRACT Starches from three local crops (sago, Metroxylon sagu; cassava, Manihot esculenta; and taro, Colocasia esculenta) were tested as replacements for corn starch in the production of extruded feed for the Malaysian mahseer, Tor tambroides . Four test feeds were formulated to contain 40.00% protein and 23.44% starch, and extruded using a single-screw extruder (120 rpm speed, 2 mm diameter die head). Temperatures at the feeding, mixing, compressing, and die zones were set at 60°C, 100°C, 120°C, and 160°C, respectively. Physical properties used to evaluate the quality of the extrudates were expansion ratio, bulk density, true density, pellet durability index, water stability, floatability index, sinking velocity, and sample microstructure. Results showed that test starches produced extrudates with fairly equal quality to corn starch extrudates for expansion ratio, pellet durability index, pellet durability index, and floatability index. Cassava starch extrudates had the best external appearance observed under electron microscopy. This study shows the potential that these three starches have in aquafeed production especially in producing quality Malaysian mahseer feed.

Full-fat black soldier fly larvae (Hermetia illucens) meal and paste in extruded diets for Atlantic salmon (Salmo salar): Effect on physical pellet quality, nutrient digestibility, nutrient utilization and growth performances

The present study investigated the effect of graded levels of black soldier fly larvae (BSFL) (Hermetia illucens) meal and paste on physical pellet quality, digestibility and utilization of nutrients and growth performances in extruded diets for Atlantic salmon (Salmo salar). A total of 1260 Atlantic salmon with 34 g of mean initial weight were randomly distributed into 21 fiberglass tanks and fed with one of seven isonitrogenous, isolipidic and isoenergetic diets for seven weeks. The experimental diets consisted of a control diet based on fishmeal, soy protein concentrate, corn gluten, faba bean and fish oil (Control-1); three diets with increased levels of full-fat BSFL meal, substituting 6.25% (6.25IM), 12.5% (12.5IM) and 25% (25IM) of the protein content of Control-1; two diets with increased levels of full-fat BSFL paste, substituting 3.7% (3.7IP) and 6.7% (6.7IP) of protein from Control-1 and an extra control diet with 0.88% of formic acid (Control-2). Pellet durability and hardness were overall high for all diets. However, the expansion, sinking velocity and water stability of feed pellets were lower with increased inclusion of BSFL meal and paste. Dietary inclusion of BSFL meal or paste did not affect the feed intake of fish. Further, replacing the protein content of the control diet with up to 12.5% and 6.7% of BSFL meal and paste, respectively, did not compromise fish growth rate or feed conversion ratio, although polynomial contrast analysis showed that increasing BSFL meal level in the diet linearly (p < .05) decreased these parameters. However, apparent digestibility coefficient (ADC) of protein and lipid, protein efficiency ratio and lipid retention were reduced linearly (p < .05) with increasing inclusion level of BSFL meal. Further, increasing dietary levels of BSFL paste linearly (p < .05) reduced ADC of protein, protein efficiency ratio and phosphorous retention. Despite the decreased ADC of protein, protein retention was not compromised by the inclusion of BSFL meal or paste. Replacement of 25% of dietary protein with BSFL meal decreased (p < .05) growth rate, accompanied by lower (p < .05) ADC and utilization of lipids and protein efficiency ratio. The present study showed that BSFL meal and paste could replace up to 12.5% and 6.7% of dietary protein, respectively, without compromising growth performance in Atlantic salmon.

Some engineering properties and nutrient composition of selected pelletized fish feed in Nigeria

This research work is aimed to study the engineering properties (Physical, Thermal and Mechanical), and nutritional qualities of selected pelletized fish feed in Nigeria. This is to provide a database of engineering properties of fish feed pellets in Nigeria, which can be required for further handling and processing operations. Three locally produced feeds in Nigeria (Kwara P1, Ondo P2, and Edo P3) were selected. The engineering properties analysed include unit density, bulk density, expansion ratio, colour, sinking velocity, water stability, water absorption index, water solubility index, pellet durability index, thermal conductivity, resistivity and diffusivity. The extrudates and pellets were subjected to nutritional composition analyses, which include: crude protein, crude fat, total carbohydrate, ash and crude fibre, Potassium, Phosphorus and Calcium. The unit density, bulk density and expansion ratio of the pellets ranges from 407.08 – 518.36 kg.m−3, 267.33 – 271.93 kg.m−3 and 12.73 – 16.40 %, respectively. The pellet durability index and water stability ranges from 41.07 - 68.60 % and 12.40 – 35.96 mins but P2 had the highest expansion rate (25.55%). The Potassium, Zinc, crude fibre and thermal properties had no significant effect on the feeds at p-level of 5%. The data obtained from this study creates a reference line for the design and development of handling machines, and storage facilities.

Effects of Fish Feed Carbohydrate Sources on the Floatation and Water Stability of Fish Feed Pellets

Three feeds were formulated to carry out a study on the floatation test and water stability tests of fish pellets. The feeds were formulated using different sources of carbohydrate (Maize, Guinea corn and Wheat). After 30 minutes of exposure to water, Guinea corn maintained 90% of floating pellets while the other two sources had 80% floating pellets respectively. There were significant differences in the percentage number of pellets floating between 0 and 30 minutes (P&lt;0.05). There were also significant differences in the water stability of the pellets, between 10 and 30 minutes. Wheat had the highest water stability of 87.8% while Maize had 75.4% water stability and Guinea corn had the lowest percentage of 71.6% but after 50 minutes Maize had the highest percentage of 61.8% and Guinea corn had the lowest percentage of 52.4%. Keywords : Carbohydrate sources, Floating ability and Water stability. DOI : 10.7176/JBAH/9-18-06 Publication date :September 30 th 2019

Physical and Mechanical Properties of Fish Feed Pellets

This work presents a useful information about different fish feed pellets, which will be database for the people work in the intensive fish farming which help then in solving many problems concerning the feeding effectiveness and feed handling and storage. The main objective of this work was to study the physical and mechanical properties of fish feed pellets contained different protein ratios and pellets sizes. These properties include: actual diameter, expansion rate, surface area, volume, weight, bulk density, durability, floatability, moisture content, water stability, repose angle and crushing load. The actual diameter of pellets fish feed value ranged from 1.51 to 4.55 mm. The expansion rate of pellets fish feed value ranged from 33.31 to 40.94%. The surface area of pellets fish feed value ranged from 10.57 to 71.13 mm 2. The volume of pellets fish feed 4.04 to 79.09 mm 3. The weight of 100 pellets value ranged from 0.11 to 5.51 g. The bulk density of pellets of fish feed value ranged from 267.11 to 711.35 kg m -3 . The durability of pellets of fish feed value ranged from 70.66 to 92.62%. The floatability of pellets of fish feed value ranged from 79.51 to 96.45%. The moisture content of pellets of fish feed value ranged from 16.68 to 17.82%. The water stability of pellets of fish feed value ranged from 54.15 to 91.78%. The repose angle of pellets fish feed value ranged from 27.00 to 38.00°. The crushing load of pellets fish feed value ranged from 6.13 to 33.28 N.

Effect of Pellets Diameter and Mash Moisture Content in Pellets quality and production for fish feeding

This research included studying some of factorial conditions manufacture of pellets are included pellet diameter by using three holes diameters for the pellets mincer (2 , 4 and 6 mm) and mash moisture content from determining two levels are (500 and 600 ml) for 1 kg from mash and effect this factorial in specific capacity and specific energy and also pellet settling velocity and water stability. The studying carried employment Completely Randomized Design (CRD) with three replications. The results showed with increase pellet diameter from 2 to 4 to 6 mm apparent. Significant effect in increase specific capacity and settling velocity. Also results to decrease specific capacity 37.87 kg / kwh and minimum specific energy 26.43 kwh/ T at pellet diameter 6 mm, and the minimum settling velocity 6.18 cm / s and maximum water stability for pellet it was pellet diameter 2 mm with increases mash moisture from 500 to 600 ml significant effect in increase specific capacity and water stability and settle velocity and was maximum specific capacity 27.39 kg/kwh and maximum water stability and minimum specific energy 40.39 kwh/ T with 600 ml mash moisture and minimum settling velocity 7.65 cm / S at 600 ml mash moisture content .

Manufacturing pellets with different binders: Effect on water stability and feeding response in juvenile Cherax albidus

In this study, we used natural polysaccharides (pectin, alginate and chitosan) as binders to generate pellets for crayfish feeding. Pellets were produced by cold extrusion in order to preserve nutrients from degradation and reduce energy consumption. Thereafter, pellets were submitted to a coating procedure, with the aim of improving pellet stability in water. Pellet water stability was analyzed by monitoring the diameter of the released particles in water over progressive time intervals up to 24 h, employing a Low Angle Laser Light Scattering Technique. Alginate containing pellets released particles with a smaller diameter than chitosan and pectin containing pellets, indicating that alginate containing pellets disaggregated more and therefore were less stable in water than the other pellet types. The effects of the different polysaccharide containing pellets were evaluated on crayfish feeding response employing juvenile Cherax albidus. The feeding experiment was carried out for 12 weeks, at the end of which growth parameters and the activity of amylase, lipases and proteases in the gastric juice, hepatopancreas and intestine were recorded. Crayfish fed pectin containing pellets exhibited a significant weight gain. Digestive enzyme activities did not statistically show significant differences in the digestive tract except for amylase that was significantly higher in the intestine of animals fed pectin containing pellets. Our data indicate that pectin and chitosan pellets showed the best water stability performances, moreover pectin pellets brought about the highest body weight gain and affected the amylase profile in the intestine of juvenile Cherax albidus.

Effects of replacing fish oil with stearine as main lipid source in diet on growth and survival of Pacific White Shrimp, Litopenaeus vannamei (Boone, 1931)

The stearine fraction from raw fish oil refinement has been treated as a waste material. This study was conducted to evaluate effects of replacing prime refined fish oil with stearine as the main lipid source to a control diet on shrimp growth and survival as well as on pellet water stability of diets. Test diets were processed containing three levels (0.7%, 1.3% and 2.7%) of either stearine or refined fish oil in a semi-purified control diet. These diets were each assigned to five or six replicated tanks and each tank was stocked with seventeen juvenile shrimp (ca. 0.50 g) in an indoor seawater recirculating system. At the end of 6 weeks, the survival of shrimp was 89.4–95.3% with no significant difference (P > 0.05) among dietary treatments. The six test diets obtained significantly higher (P < 0.05) shrimp growth rates (1.46–1.83 g week−1) than the control diet (1.38 g week−1). The shrimp that were fed the three stearine-added diets exhibited high growth rates (1.75–1.83 g week−1). Increasing the inclusion level of the stearine improved pellet water stability (91.7–93.9%; P < 0.05). These results suggest that stearine can replace fish oil in shrimp feed based on the growth performance.

Enzyme pretreatment of fibrous ingredients for carnivorous fish: Effects on nutrient utilisation and technical feed quality in rainbow trout ( Oncurhynchus mykiss)

Carnivorous fish have limited ability to utilise fibrous structures as a source of energy. Treatment with exogenous enzymes targeted at degradation of non starch polysaccharides (NSP) could help to improve the nutritive value of these components. Two experiments were conducted. In the first in vitro experiment, three defatted oilseeds; soybean meal (SBM), rapeseed meal (RSM) and sunflower cake (SFC) as well as green field peas were incubated individually at semi-moist conditions (45% water, 45 min, 45 °C) with or without NSP degrading enzymes (RONOZYME® VP). The amount of total NSP was significantly (P < 0.05) reduced after enzyme treatment of SBM and SFC, but no effect was seen for RSM or field peas. A prolonged wet incubation (85% water, 180 min) with SBM and RSM at three different temperatures (30, 45, 60 °C) was also conducted with RONOZYME® VP. An overall significant (P < 0.05) effect on degradation of total NSP was seen for SBM at wet conditions, but there was no significant difference between the three temperatures, and increased incubation time or moisture level did not improve the degree of degradation any more than the semi-moist treatments. In the following fish experiment three diets were made with combinations of SBM, RSM and SFC: Diet A (SBM + RSM), diet B (SBM + SFC) and diet C (RSM + SFC). In addition to a conventional feed production, the plant ingredients in the three diets were pretreated (45 min, 45% moisture, 45 °C) in the presence of RONOZYME® VP, and mixed with the remaining dry ingredients prior to conditioning and extrusion. Diet A was also pretreated without enzyme as a sham treatment. The temperature in the extruder barrel decreased in the feeds that had been pretreated, but there was no negative effect on the pellet durability index (PDI) or water stability index (WSI). Each of the seven dietary treatments was fed to triplicate groups of rainbow trout raised in seawater tanks (average initial weight, 205 g). The fish body weight was more than doubled during the experimental period. The enzyme pretreatment did not improve the nutrient digestibilities, and the overall feed conversion ratio (FCR) increased significantly (P < 0.05) from 1.04 to 1.10. We conclude that treatment with NSP degrading enzymes has significant effects on reductions in total NSP in vitro, but the released substrates did not contribute to an improvement in fish performance under the current experimental conditions.

Twin‐Screw Extrusion Processing of Rainbow Trout (Oncorhynchus mykiss) Feeds Using Various Levels of Corn‐Based Distillers Dried Grains with Solubles (DDGS)

ABSTRACTIncreasing demand for seafood products and rising demand for fish meal for commercial fish feeds is driving the search for effective alternative protein sources. Twin‐screw extrusion trials were conducted to study the production of nutritionally balanced feeds for rainbow trout fingerlings (Oncorhynchus mykiss). Six isocaloric (≈4.61 kcal/g) ingredient blends with a target protein content of &gt;45% db were formulated with 0, 10, 20, 30, 40, and 50% distillers dried grains with solubles (DDGS) and other feed ingredients. The moisture contents of the diets were initially adjusted to 5–7% db, and then extruded at 250 rpm using dual 1.9 mm dies with varying amounts of steam (7.2–7.7 kg/hr) injected into the conditioner and water (4.3–6.5 kg/hr) into the extruder. Mass flow rates, moisture contents, and temperatures were measured during processing and moisture content, water activity, unit density, bulk density, expansion ratio, compressive strength, compressive modulus, pellet durability index, water stability, and color were analyzed to quantify the effects of varying DDGS content on the extrudate physical properties. Significant differences (P &lt; 0.05) among the blends were observed for color and bulk density for both the raw and extruded materials, respectively, and for the unit density and pellet durability index of the extruded products. There were also significant changes in redness and yellowness, but only minor changes in brightness, among the final products with increasing DDGS content. The compressive strength of the extrudates increased significantly with increasing DDGS. Expansion ratio of all pellets was low. All extruded diets achieved very good water stability.

Single‐Screw Extrusion Processing of Distillers Dried Grains with Solubles (DDGS)‐Based Yellow Perch (Perca flavescens) Feeds

ABSTRACTThis study was conducted to investigate the production of balanced diets for juvenile yellow perch (Perca flavescens) feeds. Six isocaloric (≈3.21 kcal/g), isonitrogenous (30.1 ± 0.4% db) ingredient blends were formulated with 0, 10, 20, 30, 40, and 50% distillers dried grains with solubles (DDGS), and appropriate amounts of soybean meal, fish meal, vitamins, and minerals. Extrusion cooking was performed using a laboratory‐scale single‐screw extruder at a constant barrel temperature profile of 40–90–100°C, and a constant screw speed of 230 rpm (24.1 rad/sec). The mass flow rate was determined during processing; it generally increased with progressively higher DDGS content. Additionally, moisture content, water activity, unit density, expansion ratio, compressive strength, compressive modulus, pellet durability index, water stability, and color were extensively analyzed to quantify the effects of DDGS content on the physical properties of the resulting extrudates. Significant differences (P &lt; 0.05) between blends were observed for color and water activity for both the raw material and extrudates, respectively, and for the unit density of the extrudates. There were significant changes in brightness (L), redness (a), and yellowness (b) among the final products when increasing the DDGS content of the blends. Expansion ratio and compressive strength of the extrudates were low. On the other hand, all blends showed high pellet durability (PDI ≥ 96.18%). Overall, it was ascertained that DDGS could be successfully included at rates of &lt;50%, and that each of the ingredient blends resulted in viable, high quality extrudates.

Replacement of LT fish meal with a mixture of partially deshelled krill meal and pea protein concentrates in diets for Atlantic salmon ( Salmo salar)

The aim of the study was to investigate how the replacement of LT-fish meal by a 3.5:1 mixture of an experimentally produced partially deshelled krill meal (PDKM) and a pea protein concentrate (PPC) affected growth rate, digestibility of main nutrients and minerals, fluoride accumulation and histology in Atlantic salmon ( Salmo salar). Five extruded diets were fed to salmon with an average weight of 546 g, distributed into 15 tanks equipped with flow through sea water. During extrusion, increased krill meal resulted in increased lipid content in the feed mash and subsequently decreased pellet expansion and decreased pellet water stability. The salmon had an optimum growth rate with a PDKM/PPC inclusion of 400 g kg − 1 . Starch digestibility decreased and lipid digestibility increased with increasing PDKM/PPC inclusion. Fluoride in faeces increased linearly with increasing dietary fluoride levels. Plasma cholesterol decreased with increased PDKM/PPC inclusion, whereas no major differences were seen for triglycerides, free fatty acids, glucose, or bile acids. Fish fed increased dietary PDKM/PPC showed an increased prevalence of mild to moderate nephrosis.