This study aimed at verifying the possibility of replacing calcitic limestone by marine calcium in the diet of layers. A total number of 321 Hi-sex hens, with 40 weeks of age at the beginning of the experiment, was used. A completely randomized experimental design was applied, with 5 treatments (0, 15, 30, 45, and 60 % of calcitic limestone replacement by marine calcium source) and eight replicates of eight birds each. Treatments significantly affected specific gravity (p<0.05), with the inclusion of 60% marine calcium (T5) presenting the worst result as compared to T1, which included only calcitic limestone as calcium source. It was concluded that marine calcium can replace up to 45% of calcitic limestone with no effects on performance or egg quality.
This study aimed at evaluating the effect of total replacement of dry corn by wet grain corn silage (WGCS) in the feed of label broilers older than 28 days of age on performance, mortality, carcass, parts, breast meat and thighs meat yields, and meat quality. A mixed-sex flock of 448 ISA S 757-N (naked-neck ISA JA Label) day-old chicks was randomly distributed in to randomized block experimental design with four treatments (T1 - with no WGCS; T2 - WGCS between 28 and 83 days; T3 - WGCS between 42 and 83 days; and T4 - WGCS between 63 and 83 days) and four replicates of 28 birds each. Birds were raised under the same management and feeding conditions until 28 days of age, when they started to have free access to paddock with pasture (at least 3m²/bird) and to be fed the experimental diets. Feed and water were offered ad libitum throughout the rearing period, which was divided in three stages: starter (1 to 28 days), grower (29 to 63 days), and finisher (64 to 83 days) according to the feeding schedule. During the short periods of WGCS use (group T2 during grower stage and T4 during the finisher stage), performance and mortality results were similar as to those of the control group (T1). At the end of the experiment, it was observed that the extended use of WGCS (T2 and T3) determined a negative effect on feed conversion ratio. However, the best results of breast meat yield were observed with birds fed WGCS since 28 days (T2). It was concluded that WGCS can replace dry corn grain for short periods during the grower and finisher stages with no impairment of meat quality and yield in slow growth broilers.
This study evaluated the effects of strain, stocking density and dietary energy level on the feathering of broiler chickens. Four trials were carried out between September 2000 and April 2002. There were 10,685 broiler chicks from the strains Ross 308, Cobb 500, Hybro PG, Hubbard, MPK, and Isa Vedette. The bids were reared at stocking densities varying between 10 and 16 birds/m² and were given diets containing different metabolizable energy levels. Broiler feathering was evaluated either by atrributing scores from 1 to 10 to feather covering along the thigh and back (visual inspection), or by determining the percentage weight of the feathers at 28 and 42 days of age. Increasing rearing densities resulted in poorer feathering, mainly if 12 or 13 birds/m² were compared with 16 birds/m². The strains showed different feathering; it was better in Cobb 500 and MPK birds, whereas Hubbard birds showed poorer feathering, mostly along the back. The energy level in the diet has also affected feathering scores. Medium energy level resulted in better feathering along the back at 28 days, and the low level, in better feathering along the thigh at 35 days of age. Finally, feather scores were better in females than in males.