The utilization of calcium soaps from animal fat by laying hens.
Ground wheat was employed as a carrier to evaluate the utilization by laying hens of animal fat, calcium soaps of fatty acids from animal fat (CS), and animal fat in the presence of 3.8% added calcium. Birds trained to consume their daily feed in two 1-h periods were fed ground wheat with 0, 3, 6, and 9% animal fat, CS, or 10% ground limestone and animal fat to provide 11 experimental diets. Animal fat and preformed CS were highly available to laying hens with total fatty acid availabilities of 100.2 +/- 1.2 (SE) and 99.2 +/- 3.6%, respectively, estimated by the regression of added fat on determined fat retentions. However, 3.8% calcium reduced animal-fat fatty acid availability to 86.3 +/- .7%. The true metabolizable energy of animal fat, as determined by regression from bomb-calorimetry data, was 9.63 +/- .58 kcal per g; a value of 9.36 kcal per g was obtained from fat-retention data [100.2% of the gross energy (GE) of 9.34 +/- .78 kcal per g]. With added limestone, the respective TME values were 9.36 +/- 1.30 kcal per g (regression) and 8.06 kcal per g (retention). The TME of the CS fatty acids was 7.20 +/- 1.05 kcal per g, estimated by regression; and the value calculated from CS fat retentions was 8.14 kcal per g, representing 99.2% of the GE (8.20 +/- .58 kcal per g). Discrepancies between calorimetric and fat-retention TME estimates represented animal-fat effects on wheat starch, fat, and amino-acid retentions.
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Department of Animal Sciences, University of Arizona, Tucson 85721.
Maiorino
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Mitchell
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Reid
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BL
D000042:Absorption; D000821:Animal Feed; D000818:Animals; D002118:Calcium / Q000008:administration & dosage / Q000378:metabolism*; D002151:Calorimetry; D002645:Chickens / Q000378:metabolism*; D004041:Dietary Fats / Q000008:administration & dosage / Q000378:metabolism*; D004063:Digestion; D004435:Eating; D004734:Energy Metabolism; D005227:Fatty Acids / Q000008:administration & dosage / Q000378:metabolism*; D005260:Female; D012044:Regression Analysis; D014908:Triticum
D004041:Dietary Fats; D005227:Fatty Acids; D002118:Calcium