Decreasing vitamin premix on chicken carcass composition and blood chemistry in floor and battery cage systems
2012
Mahmood Shivazad | Hossein Moravej | Majid Alahyari-Shahrasb
Two experiments were conducted the to compare the effect of a decreasing amount of vitamin premix in diets inbroilers from 29 to 42 days of age on carcass composition and blood chemistry in floor (Experiment 1) and battery cage (Experiment 2) systems. At 35 and 42 days of ages, one bird of each replicate was slaughtered and carcass composition was measured. Blood concentrations of alkaline phosphatase (ALP) and Ca were used to diagnose vitamin D3 deficiency and enzymes aspartate amino transferase (AST) to identify vitamin E deficiency. Floor raised birds showed that vitamin premix reduction/withdrawal at 29 days of age did not impair body weight (BW), carcass composition, ALP and Ca during the final rearing period. However, diet without vitamin premix (T1) had a higher AST at 42 days of age than the other diets. Birds reared in cages were slightly more sensitive to vitamin premix reduction/withdrawal, probably due to the impracticality of performing coprophagy. Diet without vitamin premix (T1) had a lower BW, carcass breast and thigh yield at 42 days of age; also serum ALP, AST and Ca were impaired. In conclusion, the withdrawal of vitamins is not a reasonable option but it is possible to reduce vitamin premix in finisher broilers’ diets without negative effects on performance and on some metabolic traits during the finisher period with both methods of rearing.
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