A Process-Based Nutrient Model for the Bedded Manure Pack of Confined Beef Systems

Manure management is of growing concern for beef cattle producers and the general public. The overall objective of this research was to develop a process-based model that predicts concentration and gaseous emission from the bedded manure pack of a confined beef cattle system, with respect to different bedding material, manure storage time, and ambient temperature. The model incorporated the data collected in three experiments designed to understand transformations and processes occurring in the bedded pack. The first study evaluated the source of volatilized ammonia nitrogen from beef cattle manure. Isotope ratio mass spectrometry was used to determine the origin of aerial ammonia nitrogen losses (urine or fecal material) from the relative isotopic abundance of nitrogen in the 15N -labeled slurry mixture. On average 84% of total ammonia nitrogen losses originated from the urine portion and were highest during the first two to four days, when fresh material was added. The second and third experiments were conducted to determine differences in ammonia, carbon dioxide, nitrous oxide, and methane concentrations and moisture content, nutrient concentrations (ammonium nitrogen, total nitrogen, total phosphorus, total potassium), short-term nitrification activity potential, and denitrification enzyme activity from simulated beef cattle bedded manure packs related to storage length (0 to 3, 3 to 6, and 6 to 9 weeks), bedding material (corn stover or soybean stubble), and temperature (10°C or 40°C). Temperature impacted all nutrient concentrations, while most variables differed with age and sample depth. A strong relationship between water and nutrient movement existed. Nitrous oxide concentrations occurred as high pulses right after material addition which was most likely caused by incomplete denitrification from pulse nitrate concentrations available in the dried bedding material. Ammonia concentrations were three times higher above bedded packs at 40°C assumedly because major ammonia losses occur through urea hydrolysis which is temperature-dependent and completed faster at higher temperatures. A model was developed based on the Integrated Farm Systems Model (IFSM). The main process for water movement was considered evaporation. Ammonia emissions were simulated based on the urea degradation process in the urine, while nitrous oxide emissions were predicted as denitrification losses. Compared to data from the bedded pack experiments, the model did not adequately capture observed hourly conditions for ammonia and nitrous oxide conditions which did not affect total nitrogen concentration. Ammonia emission at times of material addition were realistically predicted which is important for real-life barns. Depending on bedded manure pack age, the bias in model prediction for moisture content, nitrogen, phosphorus and potassium concentrations were on average 3%, 20%, 0% and -25% , respectively. Overall, the simulations showed that the model can be used to predict N-P-K fertilizer concentration for bedded manure packs

Modeling Single-Screw Extrusion Processing Parameters and Resulting Extrudate Properties of DDGS-Based Nile Tilapia (Oreochromis niloticus) Feeds

A single-screw laboratory extruder was used to conduct an L18 (22´ 36) Taguchi fractional factorial study of aquafeed processing. The ingredients were based on a formulation for nutritionally-balanced Nile tilapia diets containing distillers dried grains with solubles (DDGS) and soybean meal as the main protein sources, in addition to constant amounts of corn flour, whey, and fishmeal. The effects of three levels of DDGS (20, 30 and 40%), soybean meal (30, 40 and 50%), ingredient moisture content (20, 30 and 40% db), screw speed (100, 150 and 200 rpm), die dimension (L/D ratios of 5, 9 and 13), barrel temperature (80-100-100°C, 80-120-120°C and 80-140-140°C) and two levels of screw configuration (compression ratios of 2:1 and 3:1) on extrudate physical properties (moisture content, water activity, bulk density, unit density, expansion ratio, pellet durability index, water absorption and solubility indices, water stability, color) and extruder processing parameters (resulting temperatures, die pressure, extruder torque, mass flow rate, apparent viscosity, and specific mechanical energy) were determined. Data from raw materials, processing conditions, and extrudate properties were used to develop surface response curves and equations. However, predominantly low R2values (\u3c 0.5) only permitted linear relationships between some independent parameters and response variables. Regarding main effects, die pressure significantly decreased with higher DDGS levels, moisture content, temperature, lower die L/D, and higher screw compression. Expansion ratio decreased significantly with higher moisture content and lower die L/D. Significant differences in color were caused by changes in DDGS levels and moisture content. In summary, DDGS, moisture content, die dimension, and extrusion conditions had the biggest impact on most of the extrudate physical properties and processing conditions. Different combinations of these independent factors can be used to achieve desired extrudate physical properties and processing conditions

Effects of Amylose-To-Amylopectin Ratios on Binding Capacity of DDGS/Soy-Based Aquafeed Blends

Demands for seafood products are steadily increasing. Alternative protein sources are required to compensate for enormous amounts of fishmeal that is needed for global seafood production. Starch is a food polymer that can be added to fish feed formulations to enhance binding and expanding capabilities of extrudates. Floatability, a key factor for most aqua feeds, can be optimized by the addition of certain starch sources. Six ingredient blends with a similar protein content (~32.5%) containing two starch sources, Hylon VII (containing 70% amylose, 30% amylopectin) or Waxy I (containing 0% amylose, 100% amylopectin), 20% distillers dried grain with solubles (DDGS), and 15, 25, and 35% moisture content were used along with appropriate amounts of soybean meal, menhaden fishmeal, whey, vitamin and mineral mix to investigate nutritionally-balanced feeds for Nile tilapia (Oreochromis niloticus L.). The blends were processed using a laboratory single-screw extruder with varying temperature settings (90-90-90°C, 100-120-120°C, and 100-120-140°C), screw speeds (100, 120, and 140 rpm), and length/diameter ratio (3.4, 6.6, 9.2) of the die. Extensive analyses of expansion ratio (ER), unit density (UD), sinking velocity (SV), and pellet durability indices (PDI), water absorption (WAI) and water solubility indices (WSI) were conducted to evaluate the effects of the two starch sources on extrudate binding and floating capacity. By varying process conditions, significant differences (P\u3e0.05) among the blends were detected for all extrudate physical properties. Significantly higher values for ER, UD, and PDI were achieved by using the Waxy I starch source, while values for SV and WAI decreased. For WSI no significant differences were detected. Increasing the moisture content from 15-35% resulted in a significant increase in ER, WAI, and PDI and a significant decrease in UD. WSI showed no clear pattern in changes. The impact of different amylopectin to amylose ratio, temperature and moisture content on extrudate stability, cohesion and physical properties was demonstrated in this study. All formulations yielded viable extrudates while the blends with the amylopectin as the sole source of starch resulted in higher quality extrudates

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

Increases in global aquaculture production, compounded with limited availabilities of fish meal for fish feed, has created the need for alternative protein sources. Twinscrew extrusion studies were performed to investigate the production of nutritionally balanced feeds for juvenile yellow perch (Perca flavescens). Five isocaloric (~3.06 kcal/g) ingredient blends, adjusted to a target protein content of 36.7% db, were formulated with 0%, 10%, 20%, 30%, and 40% distillers dried grains with solubles (DDGS) at an initial moisture content of 5–7%db, with appropriate amounts of fish meal, fish oil, whole wheat flour, corn gluten meal, and vitamin and mineral premixes. During processing, varying amounts of steam (6.9–9.7 kg/h) were injected into the conditioner and water (6.7–13.1 kg/h) into the extruder to modulate the cohesiveness of the final extrudates. Extrusion cooking was performed at 226–298 rpm using a 1.9 mm die. Mass flow rate and processing temperatures generally decreased with progressively higher DDGS content. Moisture content, water activity, unit density, bulk density, expansion ratio, compressive strength and modulus, pellet durability index, water stability, angle of repose, and color were extensively analyzed to quantify the effects of varying DDGS content on the physical properties of the final extrudates. Significant differences (P\u3c0.05) among the blends were observed for color and bulk density for both the raw and extruded material, respectively, and for the unit density of the extruded product. There were also 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 extruded diets resulted in very good water stability properties and nearly all blends achieved high pellet durability indices. In summary, each of the ingredient blends resulted in viable extrudates

Isotope Ratio Mass Spectrometry Monitoring of Nitrogen Volatilization from Beef Cattle Feces and 15N-Labeled Synthetic Urine

A 15-day bench-scale manure storage experiment with a slurry mixture comprising beef cattle feces and synthetic urine with 15N-labeled urea was conducted to evaluate the source of volatilized ammonia nitrogen (NH3-N). Beef cattle feces was mixed daily in a 1:2.2 mass ratio with 15N-labeled urine and added for four consecutive days to 2-L storage containers and then left undisturbed for eleven days. Isotope ratio mass spectrometry was used to determine the origin of aerial NH3-N losses from the relative isotopic abundance of N in the 15N-labeled slurry mixture. On average 84% of total NH3-N losses originated from the urine portion and were highest during the first two to four days, when fresh material was added. After fresh material addition ceased, daily NH3-N emission from the urine decreased gradually, whereas emission from the feces remained relatively constant. Calculations showed that over 34% of aerial N was not captured, suggesting that other N gas emission is significant from slurry mixtures. Likely all uncaptured N losses were from urinary urea. The study verified the applicability of 15N-labeled synthetic urine for beef slurry mixtures. However, the results suggest further research to explain and model the NH3 and N release from fecal material is warranted and to determine the identity of the uncaptured N losses

Extrusion processing of selected fish feed blends containing distillers dried grains with solubles (DDGS)

Rising demands for seafood products have made aquaculture to one of the fastest growing sectors in the food industry, but have increasingly depleted wild fish stocks through capture fisheries. Commonly, fish meal has been used as the primary source to supply fish with essential proteins, but it is expensive. Feed represents over half of the operating costs for aquaculture operations. This study investigated using distillers dried grains with solubles (DDGS) as a sustainable, less expensive alternative protein source for fish feeds. Two extrusion studies using a single-screw extruder and two studies using a twin-screw extruder were conducted to prepare nutritionally-balanced diets for yellow perch (Perca flavescens), rainbow trout (Oncorhynchus mykiss), and Nile Tilapia (Oreochromis niloticus L.). The ingredient blends included combinations of DDGS, soybean meal, fish meal, fish oil, corn starch, whole wheat flour, corn gluten meal, whey, vitamins and minerals, respectively. DDGS levels were adjusted between 10 and 50% and the net protein content varied between 30 and 53% db. Various extruder settings were used, including screw speed (100-298 rpm) and processing temperatures (15°C to 140°C). For the twin-screw extruder, varying amounts of steam (6.9-9.7 kg/h) were injected into the conditioner and water (4.3-13.1 kg/h) into the extruder to modulate the cooking and resulting cohesiveness of the final extrudates. The effects of varying formulations and extruder settings on extruder processing parameters and on the resulting physical properties of the extrudates were examined. During processing, mass flow rate (g/min), moisture content at the die and at the conditioner exit (% db), respectively, and barrel temperatures (°C) were measured. The analyses of the extrudates included moisture content (% db), water activity (-), unit density (kg/m3), bulk density (kg/ m3), expansion ratio (-), compressive strength (MPa), compressive modulus (MPa), pellet durability index (%), water stability (min), angle of repose (°), color (-), sinking velocity (SV), water absorption (WAI) and water solubility indices (WSI), respectively. The first study was performed using a laboratory-scale single-screw extruder for the production of nutritionally-balanced diets for juvenile yellow perch. The effects of increasing DDGS levels (0-50%) on the extruder processing parameters and physical properties of the resulting extrudates were investigated. The mass flow rate generally increased with higher amounts of DDGS. Expansion ratio and compressive strength of the extrudates were low. On the other hand, all blends showed very high pellet durability and water stability. Each of the ingredient blends resulted in viable, high quality extrudates. In the second study, a twin-screw extruder was used to investigate the production of balanced diets for juvenile yellow perch. Compared to the first study, the ingredient composition of the blends for yellow perch varied. The effects of DDGS levels (0-40%) on the extruder processing parameters and on the resulting physical properties of the extrudates were analyzed. With increasing DDGS levels; significant differences (P For the third study, twin-screw extrusion trials were performed to investigate the inclusion of DDGS (0-50%) on the production of rainbow trout feeds. The experimental conditions were the same as for the second study. The compressive strength was low for all extrudates and increased significantly with higher DDGS amounts. The expansion ratio was low for all extrudates, while the water stability was very high. Pellet durability index of the final product was high for all formulations. Ail ingredient blends containing DDGS up to 50% yielded viable extrudates. The fourth study examined the effects of two starch sources Hylon VII (containing 70% amylose and 30% amyiopectin) and Waxy I (containing 0% amylose and 100% amylopectin), respectively, on DDGS-based Nile tilapia feeds. The effect of different amylose to amylopectin ratio of the starch sources, varying feed moisture (15, 25, and 35% db); temperature setting (90- 90-90°C, 100-120-120°C, and 100-120-140°C), screw speed (100,120, and 140 rpm) and length/diameter ratio of the die (3.4, 6.6, 9.2) on extrudate binding and floating capacities were investigated. All formulations yielded viable extrudates while the blends with Waxy I resulted in higher quality extrudates. Significant differences with varying processing conditions were detected for ail extrudate physical properties among the different blends. Expansion ratio, water absorption and pellet durability index increased significantly with higher feed moisture, whereas unit density decreased. Expansion ratio, unit density, and pellet durability index significantly increased when using Waxy I as a starch source. For WSI, no significant differences were detected. Increasing the moisture content from 15-35% resulted in a significant increase in ER, WAI, and PDI and a significant decrease in UD. WSI showed no clear pattern in changes. The impact of different amylopectin to amylose ratio, temperature and moisture content on extrudate stability, cohesion and physical properties was demonstrated in this study. Blends containing Waxy I as the starch source yielded the best results for the majority of all tested physical properties. These studies demonstrated that DDGS could be included up to 40% and 50%, respectively, to produce viable fish feed extrudates that were highly water stable and durable using a single-screw and twin-screw extruder. Adding a starch source with a 100% amylopectin can enhance extrudate stability and cohesiveness. Additionally, the effects of the temperature setting and feed moisture on extrudate physical properties were examined

Effects of Amylose-To-Amylopectin Ratios on Binding Capacity of DDGS/Soy-Based Aquafeed Blends

Demands for seafood products are steadily increasing. Alternative protein sources are required to compensate for enormous amounts of fishmeal that is needed for global seafood production. Starch is a food polymer that can be added to fish feed formulations to enhance binding and expanding capabilities of extrudates. Floatability, a key factor for most aqua feeds, can be optimized by the addition of certain starch sources. Six ingredient blends with a similar protein content (~32.5%) containing two starch sources, Hylon VII (containing 70% amylose, 30% amylopectin) or Waxy I (containing 0% amylose, 100% amylopectin), 20% distillers dried grain with solubles (DDGS), and 15, 25, and 35% moisture content were used along with appropriate amounts of soybean meal, menhaden fishmeal, whey, vitamin and mineral mix to investigate nutritionally-balanced feeds for Nile tilapia (Oreochromis niloticus L.). The blends were processed using a laboratory single-screw extruder with varying temperature settings (90-90-90°C, 100-120-120°C, and 100-120-140°C), screw speeds (100, 120, and 140 rpm), and length/diameter ratio (3.4, 6.6, 9.2) of the die. Extensive analyses of expansion ratio (ER), unit density (UD), sinking velocity (SV), and pellet durability indices (PDI), water absorption (WAI) and water solubility indices (WSI) were conducted to evaluate the effects of the two starch sources on extrudate binding and floating capacity. By varying process conditions, significant differences (P>0.05) among the blends were detected for all extrudate physical properties. Significantly higher values for ER, UD, and PDI were achieved by using the Waxy I starch source, while values for SV and WAI decreased. For WSI no significant differences were detected. Increasing the moisture content from 15-35% resulted in a significant increase in ER, WAI, and PDI and a significant decrease in UD. WSI showed no clear pattern in changes. The impact of different amylopectin to amylose ratio, temperature and moisture content on extrudate stability, cohesion and physical properties was demonstrated in this study. All formulations yielded viable extrudates while the blends with the amylopectin as the sole source of starch resulted in higher quality extrudates.This article is from Journal of Food Research 5 (2016): 43–56, doi:10.5539/jfr.v5n5p43. Posted with permission.</p

Modeling Single-Screw Extrusion Processing Parameters and Resulting Extrudate Properties of DDGS-Based Nile Tilapia (Oreochromis niloticus) Feeds

A single-screw laboratory extruder was used to conduct an L18 (22´ 36) Taguchi fractional factorial study of aquafeed processing. The ingredients were based on a formulation for nutritionally-balanced Nile tilapia diets containing distillers dried grains with solubles (DDGS) and soybean meal as the main protein sources, in addition to constant amounts of corn flour, whey, and fishmeal. The effects of three levels of DDGS (20, 30 and 40%), soybean meal (30, 40 and 50%), ingredient moisture content (20, 30 and 40% db), screw speed (100, 150 and 200 rpm), die dimension (L/D ratios of 5, 9 and 13), barrel temperature (80-100-100°C, 80-120-120°C and 80-140-140°C) and two levels of screw configuration (compression ratios of 2:1 and 3:1) on extrudate physical properties (moisture content, water activity, bulk density, unit density, expansion ratio, pellet durability index, water absorption and solubility indices, water stability, color) and extruder processing parameters (resulting temperatures, die pressure, extruder torque, mass flow rate, apparent viscosity, and specific mechanical energy) were determined. Data from raw materials, processing conditions, and extrudate properties were used to develop surface response curves and equations. However, predominantly low R2values (This article is from Journal of Food Research 2, no. 2 (2013): 11–28, doi:10.5539/jfr.v2n2p11.</p

Isotope Ratio Mass Spectrometry Monitoring of Nitrogen Volatilization from Beef Cattle Feces and 15N-Labeled Synthetic Urine

A 15-day bench-scale manure storage experiment with a slurry mixture comprising beef cattle feces and synthetic urine with 15N-labeled urea was conducted to evaluate the source of volatilized ammonia nitrogen (NH3-N). Beef cattle feces was mixed daily in a 1:2.2 mass ratio with 15N-labeled urine and added for four consecutive days to 2-L storage containers and then left undisturbed for eleven days. Isotope ratio mass spectrometry was used to determine the origin of aerial NH3-N losses from the relative isotopic abundance of N in the 15N-labeled slurry mixture. On average 84% of total NH3-N losses originated from the urine portion and were highest during the first two to four days, when fresh material was added. After fresh material addition ceased, daily NH3-N emission from the urine decreased gradually, whereas emission from the feces remained relatively constant. Calculations showed that over 34% of aerial N was not captured, suggesting that other N gas emission is significant from slurry mixtures. Likely all uncaptured N losses were from urinary urea. The study verified the applicability of 15N-labeled synthetic urine for beef slurry mixtures. However, the results suggest further research to explain and model the NH3 and N release from fecal material is warranted and to determine the identity of the uncaptured N losses