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Description:
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Four experiments were conducted to evaluate guar meal as a source of prebiotic galactomannans for laying hens . In the 1st experiment , late phase laying hens were fed diets with 0 , 5 , 10 % guar meal (GM ) for 56 days or 15 % GM for 28 days then switched to the 0 % GM diet for the final 28 days . In the 2nd experiment , young pullets were fed guar germ (GG ) or GM at 0 , 2 .5 or 5 % for 20 weeks . In the 1st and 2nd experiments , egg production and feed consumption were not affected by feeding up to 5 % guar by -products whereas feed efficiency was decreased by guar feeding . Feeding of GG or GM did not affect egg weight or shell quality , but decreased the egg yolk color and Haugh units . Guar increased absolute and relative liver weight , but did not affect the weights of the pancreas , spleen , or the incidence of fatty liver or liver hemorrhage . Feeding 10 % GM depressed feed consumption and increased body weight loss . Feeding 15 % GM severely depressed egg production followed by a recovery of production after returning to 0 % GM feeding . In the 3rd and 4th experiments , late phase laying hens were induced to molt by feed withdrawal (FW ) or feeding 15 or 20 % GM with or without & #946 ; -mannanase (Hemicell ? ? ) . All hens except those fed 15 % GM with enzyme obtained a complete cessation of lay in 10 days . Compared to FW birds , hens fed GM had lower body weight reduction and mortality , while hens fed 20 % GM with enzyme had higher post -molt egg production . Salmonella enteritidis (SE ) present in 6 organs (crop , liver , spleen , ovary , oviduct and cecum ) , and SE in cecal contents were significantly reduced by 20 % GM feeding with and without enzyme . The results showed that GG or GM can be safely fed to laying hens up to 5 % without adverse effects on performance . An alternative molting method employing 20 % GM with or without & #946 ; -mannanase is preferable to FW because GM feeding results in a complete molt and decreases mortality , as well as enhances the resistance to SE of molted hens . |