Diet production and utilization of corn fermented protein compared to traditional yeast in healthy adult cats

The inclusion of yeast in pet food can provide health benefits and increase palatability. Corn fermented protein is a co-product from ethanol production which contains approximately 20% to 25% yeast. The objective of this study was to determine the effects of the yeast in CFP on diet production and utilization when fed to healthy adult cats. The four experimental diets included a control with 15% soybean meal (CON) and diets containing either 3.5% brewer's dried yeast (BDY), 2.5% brewer's dried yeast plus 17.5% distillers dried grains with solubles (BDY+DDGS), or 17.5% corn fermented protein (CFP). All treatments except CON were formulated to contain 3.5% yeast. Experimental diets were fed to adult cats (n = 11) in an incomplete 4 × 4 replicated Latin square design. Cats were adapted to diet for 9 d followed by a 5-d total fecal collection. Titanium dioxide (0.4%) was added to all diets as an external marker to estimate digestibility. Data were analyzed using a mixed model in SAS (version 9.4, SAS Institute, Inc., Cary, NC) with treatment as a fixed effect and cat and period as random effects. Preconditioner discharge temperature was greater (P < 0.05) for CON and BDY (average, 96 °C) compared to BDY + DDGS and CFP (average, 91 °C). Extruder screw speed, die temperature, kibble toughness, and kibble hardness were greatest (P < 0.05) for CFP. The bulk density of BDY + DDGS at 392 g/L was greater (P < 0.05) than BDY and CFP (average, 342 g/L). The sectional expansion index of kibble for CFP was greater (P < 0.05) than BDY + DDGS and smaller (P < 0.05) than CON but similar to BDY. Fecal output was greatest (P < 0.05) for cats fed BDY + DDGS. Nutrient digestibility was lowest (P < 0.05) for BDY + DDGS. The concentrations of short-chain and branched-chain fatty acids in fecal samples were not altered (P > 0.05) by dietary treatment. Cats had no preference (P > 0.05) when comparing CON to BDY or BDY + DDGS. However, cats consumed significantly less CFP compared to CON. The significant differences for bulk density, fecal output, and nutrient digestibility among dietary treatments are likely due to a greater fiber effect of DDGS compared to CFP. Therefore, the yeast component in CFP may provide greater kibble expansion and nutrient utilization compared to DDGS when fed to cats.

Physicochemical and nutritional properties of extrudates from food grade distiller's dried grains, garbanzo flour, and corn grits

Distiller's dried grains and garbanzo flour were blended with corn grits for the development of extruded snacks using a single screw extruder. Distiller's dried grains were processed for food application and termed as food grade distiller's dried grains or FDDG. Effects of different level of FDDG addition (0%-20%) and extrusion process parameters such as barrel and die temperature (100-140°C), screw speed (100-200 rpm), and feed moisture content (14%-20% wet basis) on the physical properties (expansion ratio, bulk density, color parameters), functional properties (water absorption and solubility indices), and nutritional properties (total dietary fiber, soluble and insoluble dietary fiber and protein content) of the extrudates were investigated and optimized using response surface methodology. FDDG incorporation had a significant effect (p < 0.05) on the total dietary fiber, color parameters, water solubility, and water absorption indices of the extruded snacks. Desirable expanded extrudates with a high level of total dietary fiber and protein were obtained with blends containing 20% FDDG extruded at 140°C extrusion temperature, 167 rpm screw speed, and 19% feed moisture content. Results indicate garbanzo flour, and FDDG can be successfully blended with corn grits to produce nutritious gluten-free extruded snacks which are high in protein and dietary fiber.

Effect of feed moisture, extrusion temperature and screw speed on properties of soy white flakes based aquafeed: a response surface analysis

BACKGROUND

Soy white flakes (SWF) is an intermediate product during soy bean processing. It is an untoasted inexpensive product and contains around 51% of crude protein. It can be a potential source of protein to replace fish meal for developing aquafeed. The extrusion process is versatile and is used for the development of aquafeed. Our objective was to study the effects of inclusion of SWF (up to 50%) and other extrusion processing parameters such as barrel temperature and screw speed on the properties of aquafeed extrudates using a single-screw extruder.

RESULTS

Extrudate properties, including pellet durability index, bulk density, water absorption and solubility indices and mass flow rate, were significantly (P < 0.05) affected by the process variables. SWF was the most significant variable with quadratic effects on most of the properties. Increasing temperature and screw speed resulted in increase in durability and mass flow rate of extrudates. Response surface regression models were established to correlate the properties of extrudates to the process variables.

CONCLUSION

SWF was used as an alternative protein source of fish meal. Our study shows that aquafeed with high durability, lower bulk density and lower water absorption and higher solubility indices can be obtained by adding SWF up to 40%.

Extruded aquafeeds containing distillers dried grains with solubles: effects on extrudate properties and processing behaviour

BACKGROUND

The tremendous supply and low cost of distillers dried grains with solubles (DDGS) make it an attractive feedstuff for aquaculture diets. Also, several studies have shown that DDGS can be successfully fed to various finfish. The objective of this study was to evaluate the effects of inclusion rate of DDGS (0, 250, 500 g kg(-1) ), feed moisture content (350, 450 g kg(-1) ) and die opening area (die A = 18.85 mm(2) , die B = 3988.45 mm(2) ) on the properties of the extrudates and on processing behaviour using a single-screw extruder.

RESULTS

Increasing the inclusion rate of DDGS resulted in extrudates with lower unit density, bulk density, expansion ratio, water solubility index and brightness (Hunter L) but higher redness (Hunter a) and yellowness (Hunter b). The increase in moisture content affected the extrudate properties in different ways: it increased bulk density, Hunter L, Hunter b and mass flow rate, whereas specific mechanical energy decreased at high moisture content. Increasing the die opening area primarily decreased expansion ratio of extrudates, power consumption and barrel temperatures but increased mass flow rate.

CONCLUSION

Extrudates from all treatments exhibited high durability and floatability, and less energy was required to produce extrudates when DDGS was used compared with soybean meal-based diets. The aquaculture industry can use this information to develop high-quality feeds at low cost.