Performance of brown layers fed reduced dietary protein levels in two rearing systems

An experiment was conducted aiming to evaluate the effect of different levels of crude protein, based on the ideal protein concept and two rearing systems, on productive performance of brown laying hens. A total of 400 Hisex Brown laying hens between 30 and 45 weeks of age were distributed in a completely randomized design and a 2×4 factorial arrangement, with main effects including two rearing systems (cage and floor) and levels of crude protein (140, 150, 160, and 180 g kg−1), totalizing eight treatments. Five replicates with 10 birds each were used per experimental unit. The following parameters were evaluated: egg production, feed intake, body weight gain, feed conversion ratio, and quality traits such as dirty, cracked, or broken eggs. No interaction effect was observed between dietary protein levels and rearing systems for body weight gain, feed intake, egg production, egg weight, and feed conversion ratio. Feed intake and egg production were higher in the floor rearing system. Feed conversion ratio (kg/dz) was improved in birds reared in the cage system. The rate of cracked and broken eggs was higher in the cage system. The layers reared in the floor system produced a higher percentage of dirty eggs. The dietary protein level did not affect the evaluated parameters. Thus, we conclude that a floor rearing system is an option for layers, and the dietary protein level can be reduced up to 140 g kg−1 for Hisex Brown hens from 30 to 45 weeks of age.(AU)

Feather and blood meal at different processing degrees in broiler pre-starter and starter diets

The objective of this study was to evaluate the inclusion of feather and blood meal (FBM) in broiler pre-starter and starter diets according to the processing method used. Performance, digestibility, and intestinal morphometry of broilers fed diets containing FBM were evaluated in two experiments, in the pre-starter (1-7 d) and starter (8-21 d) phases in a randomized block design with four treatments and five replicates of 12 birds, totaling 20 experimental units per trial. The criteria used for block formation was the battery floor. The meal was processed under different degrees of hydrolysis pressure (2.0 kgf/cm2 for 40 min; 2.5 kgf/cm2 for 30 min; and 3.0 kgf/cm2 for 20 min) and added at 9% to the pre-starter (Experiment I) and starter (Experiment II) diets. In each experiment, 480 male Cobb 500® chicks were allocated to batteries. The following variables were measured: live weight, weight gain, feed intake, feed conversion ratio, and digestibility and retention of dry matter, nitrogen, and ether extract. Performance was not influenced by the dietary inclusion of the ingredient. However, FBM subjected to the highest hydrolysis pressure resulted in the worst overall nutritional balances. The chickens were more susceptible to FBM processing in the pre-starter phase, when the hydrolysis pressure of 2.5 kgf/m2 for 30 min provided the best results. In the starter diet, FBM processed at a hydrolysis pressure of 2.0 kgf/m2 for 40 min provided the best performance results up to 14 days of age, without changing nutrient metabolism. Up to 9% feather and blood meal can be included in broiler pre-starter and starter diets as long as the ingredient processing method is well-known.(AU)