LAYING PERFORMANCE, FAT DIGESTIBILITY AND LIVER CONDITION OF LAYING HENS SUPPLEMENTED WITH VITAMIN B12 OR BIOTIN AND/ OR BILE ACIDS IN DIET

For 8 weeks feeding trial, two hundred and seventy, 53 weeks old laying hens were used to investigate the effects of dietary supplementation of vitamin B-12 or biotin and/or bile acids on performance, egg quality, fat digestibility and liver composition and histopathology. Birds were randomly divided into 6 groups (three replicates) and fed the experimental diets; group1 (G1) fed on the basal diet without additives as control while G2 and G3 supplemented with 0.02 ppm vitamin B-12 and 0.3 mg biotin/kg diet respectively, groups 4-6 fed as the previous detailed design of G1 - G3 with the addition of 400 g of dried bile acid (DBA) /tone feed. Biotin supplementation significantly (P<0.05) increased body weight losses of laying hens, both vitamins significantly (P<0.05) decreased daily feed intake (FI) and improved FCR. DBA addition alone or with biotin reduced these weight losses along with significant (P<0.05) increase in daily FI. Vitamin B-12 supplementation alone or with DBA increased average egg production (P<0.05) while was reduced with biotin supplementation. Fat digestibility was non-significantly improved (P >= 0.05) with both vitamins supplementation without or with DBA. Biotin significantly (P<0.05) reduced the average yolk relative weight, which was increased when mixed with DBA, while significantly increased average egg albumin relative weight. Vitamin B-12 or biotin addition without or with DBA non-significantly increased blood serum GOT and GPT activities, non-significantly reduced (P >= 0.05) fat content of liver tissue (on dry matter or fresh basis) and serum lipid profile parameters except serum HDL concentration, was increased, with no histopathological changes in hepatic tissue. It could be summarized that vitamin B-12 supplementation without or with DBA is recommended in layer diet as it gave the best performance, reduced serum lipid profile and improved fat digestibility and the hepatic health.