The objective of this study was to evaluate the effects of Bacillus subtillis PB6, chromium propionate or a combination of the two on the performance, egg and eggshell quality, nutrient metabolizability and serum biochemistry of layer breeders. White Plymouth Rock and Red Rhodes Island breeder hens at 55 weeks of age were allocated in individual cages using a completely randomized block design with 16 replicates. Hens were fed control, control + probiotic (500 g/ton of Bacillus subtilis PB6), control + CrProp (50 g/ton of chromium propionate) and control + probiotic + CrProp diets from 55 to 70 weeks of age. Productive parameters and eggshell quality as well as cortisol and blood biochemistry were grouped each 28 d as well as for the overall period. The metabolizability of nutrients and energy was determined at 70 weeks of age. In the overall period, hens fed the control + probiotic or control + probiotic + CrProp diets had significantly higher egg production, egg mass, shell percentage, thickness and shell strength. The metabolizability of dry matter, nitrogen and energy increased in hens that were fed the control + probiotic + CrProp diet. In conclusion, diets supplemented with Bacillus subtillis PB6 and chromium propionate resulted in improved productive performance, eggshell quality and nutrient metabolizability of layer breeders, without modifying serum cortisol, albumin and triglycerides.
ABSTRACT. The high cost of nitrogen fertilizers increases the expenses in pasture-based animal production. The inoculation with plant growth-promoting bacteria is an alternative to reduce the costs. This study evaluated the forage yield of Coastcross-1 pastures inoculated with Azospirillum brasilense, fertilized with different levels of nitrogen and subjected to cuts. The experiment was a factorial randomized block design with three replications. The factors were the inoculation (without inoculation, inoculated only at planting and reinoculated in the second year), levels of nitrogen (0, 100 and 200 kg ha -1 year -1 N) and seasons (spring, summer, fall and winter) when cuts were made. Forage yield, forage accumulation rate, botanical and structural pasture composition were evaluated. Forage yield without nitrogen fertilizer in pastures was in the first year 9.1, 11.7 and 11.7 t ha -1 DM, and in the second year 8.6, 11.2 and 11.5 t ha -1 DM, for the factor inoculation, respectively. The forage yield rises with inoculation at pasture planting, without nitrogen fertilization. Reinoculation is not necessary.
The effects of growing pinto peanut mixed with elephant grass-based pastures are still little known. The aim of the current research was to evaluate the performance of herbage yield, nutritive value of forage and animal responses to levels of pinto peanut forage mass mixed with elephant grass in low-input systems. Three grazing systems were evaluated: (i) elephant grass-based (control); (ii) pinto peanut, low-density forage yield (63 g/kg of dry matter – DM) + elephant grass; and (iii) pinto peanut, high-density dry matter forage yield (206 g/kg DM) + elephant grass. The experimental design was completely randomized with the three treatments (grazing systems) and three replicates (paddocks) in split-plot grazing cycles. Forage samples were collected to evaluate the pasture and animal responses. Leaf blades of elephant grass and the other companion grasses of pinto peanut were collected to analyse the crude protein, in vitro digestible organic matter and total digestible nutrients. The pinto peanut, high-density dry matter forage yield + elephant grass treatment was found to give the best results in terms of herbage yield, forage intake and stocking rate, as well as having higher crude protein contents for both elephant grass and the other grasses, followed by pinto peanut with low-density forage yield + elephant grass and finally elephant grass alone. Better results were found with the grass–legume system for pasture and animal responses.
Alternative ingredients can be adequately used in poultry feeds as long as the energy values and nutrient digestibility have been previously determined. For example, brewer’s grains and olive pomace waste, which are residues of the food industry, are potential ingredients of animal feed. This study was conducted to determine the metabolizable energy (ME), nitrogen-corrected ME (MEn), and ileal digestible energy (IDE) of brewer’s grains and olive pomace waste for broiler chickens using the regression method. From day 14 to 21, 280 Cobb 500 male broilers were fed 5 experimental diets with 8 replicates of 7 birds each. The broilers were fed a corn-soy reference diet (RD) and 4 test diets (TD), where TD consisted of brewer’s grains or olive pomace waste that partly replaced the energy sources in the RD at 10 or 20% and 7.5 or 15%, respectively. The total tract metabolizability and the apparent ileal digestibility of dry matter, N, and energy as well as ME, MEn, and IDE were determined. The ME, MEn, and IDE values (kcal/kg) were 2935, 2785, and 2524 for brewer’s grains, respectively, whereas 1778, 1581, and 1394 (kcal/kg) were obtained for the olive pomace waste, respectively. This knowledge can provide useful information that helps to improve the inclusion of alternative ingredients in broilers diets and to formulate accurate feeds to meet broiler requirements.
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