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Effects of different amounts of thermal energy added in the conditioner on starch cooking, the macrostructure kibbles, digestibility and palatability of extruded diets for cats

Grant number: 18/23864-4
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): April 01, 2019
Effective date (End): August 31, 2020
Field of knowledge:Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
Principal researcher:Aulus Cavalieri Carciofi
Grantee:Mayara Aline Baller
Home Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil


Extrusion of feed for cats, due to their composition rich in protein, requires application of thermal energy in the form of direct steam, at the preconditioned equipment. Thermal energy is the main source of energy, quantitatively greater than the application of mechanical energy in the extruder barrel or tube in the processing of foods. However, although the information available on the effect of thermal energy application on energy efficiency and reduction of mechanical wear in the extrusion system, little is known about its implications to the macrostructure of kibbles, nutrient digestibility and palatability of food. The aim of this study will be evaluate the effects of the addition of six amounts of thermal energy in extruded diets for dogs on starch cooking, digestibility, fermentation products in the colon, palatability and macrostructure of kibbles. The same standard formulation for cats and production batch will be used, based on flour of corn and chicken viscera After mixing and grinding of the ingredients, diets will be produced adding six amounts of steam in the conditioner. Water input during extrusion will compensate the greater or lesser injection of steam, however the total moisture of the process will be kept the same for all treatments (28% of in-barrel moisture). The extruder parameters feed rate, screw speed, matrix open area and the knife speed will not change. The study will follow a randomized block design with three blocks of 12 experimental units, six treatments and two animals per diet in each block. The experiment will last 18 days: diet adaptation from day 1 to day 10 and digestibility trial from day 11 to 18. Dogs will be housed in individually metabolic cages. The palatability will be compared by two-pan method in which at least 40 individually housed cats will be tested on two consecutive days. Process evaluation and macrostructure of kibbles include the determination of thermal energy application (kJ/kg), specific mechanical energy (kW-t/ton), starch gelatinization degree, specific density, radial expansion, specific length and cutting force (kgf). Data will be submitted to analysis of variance (ANOVA) and means compared by polynomial contrasts (P <0.05). (AU)

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Academic Publications
(References retrieved automatically from State of São Paulo Research Institutions)
BALLER, Mayara Aline. Application of thermomechanical energy in the formation of kibbles, palatability, digestibility and nutrient retention in extruded food for dogs and cats.. 2020. Doctoral Thesis - Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal Jaboticabal.

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