Karina Márcia Ribeiro de Souza

Métodos alternativos de restrição alimentar na muda forçada de poedeiras comerciais

Alternative methods were assessed of qualitative feed restriction compared to the conventional forced molt technique. Four hundred and eighty Babcock hens were used distributed in three levels of feed restriction (100, 75 and 50%) and three body weight reduction percentages (15, 20 and 25%), with five replications of 32 hens. When the birds reached the body weight reduction percentage the packed cell volume, percentages of ovary, oviduct, gizzard, intestine, abdominal fat and oviduct length were determined. Starting on day 28 and during five 28-day periods the quantitative and qualitative characteristics of production after forced molt were measured. The largest restriction period occurred at 50% of restriction that resulted in the smallest percentages of abdominal fat (0.66%), ovary (0.60%), oviduct (0.77%) and oviduct length (32 cm). The egg production percentage was higher in the first period, for the 75 and 100% restriction methods with up to 15 and 20% body weight reduction, respectively. However, for the birds with 50% restriction and 25% body weight reduction, the highest productions (86.80 and 83.20%) occurred in the 4th and 5th periods. Qualitative feed restriction at 50% of the diet with feed and rice hulls, because it was less aggressive, resulted in better welfare conditions and facilitated farm management.

Farelo da raiz integral de mandioca em dietas de frangos de corte tipo caipira

The aim this work was to evaluate cassava root meal inclusion levels in diets of free-range broiler chickens on performance, carcass yield, parts yield and functional properties of the meat. 384 male chickens of ISA S757-N strain (naked neck) were distributed in a completely randomized design with four treatment and four replicates of 24 birds each. The treatments were 0%, 20%, 40% and 60% of FRIM (cassava root meal) in the total ration. The trial period was divided into three rearing phases: initial (1 to 28 days of age), growth (29 to 56 days of age) and fattening (57 to 84 days of age). Final body weight (PF), weight gain (WG), feed intake, feed conversion and liveability were evaluated. At 84 th day, carcass, breast, thigh + upper thigh, wing, back and abdominal fat yield were obtained. Breast meat was used to determi- ne the pH, water holding capacity (CRA) and cooking loss (PPC) too. The shank and breast skin color scores were determined by visual comparison. The results were submitted to analysis of variance, analysis of regression and averages were compared by Tukey’s test to 5% of probability. The analysis of variance found a significant difference between treatments for BW and WG, only at the phase of 1 to 28 days of age. There was a linear increased in BW and WG when the CRM inclusion level increased in feed. There were no significant differences between the treatments for the variables of carcass yield, cuts yield, pH, CRA and PPC. The use of FRIM in the diets of free- range broiler chickens promoted linear reduction in the shank and breast skin colors with the increase of the inclusion level of this ingredient in the feed. The FRIM can be used in the diets of free- range broiler chickens in the proportion of 60% of total ration without resulting in worst performan- ce, carcass yield, cuts yield and functional properties of the meat, however it promotes shank and breast skin no coloration.

Ractopamina em dietas sem ajustes aminoacídicos para suínos machos castrados em terminação

Este estudo teve o objetivo de avaliar planos de suplementacao com ractopamina, em dietas sem ajustes aminoacidicos, para suinos machos castrados, em terminacao. Foram utilizados 72 suinos machos castrados, com peso inicial de 68,61 ± 3,89 kg, distribuidos em seis planos de suplementacao com duracao de 30 dias (0 ppm; 5 ppm; 10 ppm; 20 ppm; 5 ppm, durante 15 dias, seguidos por 10 ppm durante 15 dias; e 10 ppm durante 15 dias seguidos por 20 ppm durante 15 dias), com seis repeticoes e dois animais por unidade experimental. A suplementacao com ractopamina melhorou a conversao alimentar. A suplementacao com 5 ppm de ractopamina aumentou o ganho de peso diario. Os niveis de 10 e 20 ppm e as suplementacoes graduais reduziram o consumo de racao diario e de nutrientes. Nao houve influencia da suplementacao sobre o peso de carcaca quente e o comprimento de carcaca. A ractopamina reduziu a espessura de toucinho e aumentou a profundidade de musculo, o percentual de carne magra, a quantidade de carne magra e o indice de bonificacao das carcacas. A suplementacao de 5 ppm de ractopamina em dietas sem ajustes aminoacidicos melhora o desempenho e as caracteristicas de carcaca de suinos em terminacao, nos 30 dias pre-abate.

Níveis de lisina digestível para frangos de corte tipo caipira de 28 a 56 dias de idade

The objective of this study was to evaluate digestible lysine levels for free-range broiler hillbilly, from 28 to 56 days old. We used 720 naked neck chickens slow-growing Label Rouge strain males, distributed in a completely randomized design with six digestible lysine levels (0.800, 0.850, 0.900, 0.950, 1.000 and 1.050%), six replicates of 20 birds each. The lysine levels did not influence (P>0.05) broiler performance in accumulated periods 28-35 days, 28-42 days and 28-49 days. There was no effect (P>0.05) of treatments on feed intake and feed conversion in the total periods (28-56 days). Effect was observed (P 0.05) for carcass and breast weights of abdominal fat, thigh + drumstick, back, wing and fat deposition between the levels of lysine. The carcass weight and breast varied (P<0.05) quadratically depending on the levels of dietary lysine. Increased breast weight provided an increase of carcass weight, a fact explained by the increase (P<0.05) in protein deposition according to the level of lysine that can be considered an indication of improved efficiency of utilization of nutrients. It is concluded that the level of 0.910% meets the requirement of digestible lysine for broilers hillbilly type, from 28 to 56 of age.

Níveis de energia líquida e ractopamina na qualidade da carne suína

The greater efficiency of ractopamine is associated with nutritional diet adjustments due to the gradual increased need for nutrients to support the increased deposition of muscle protein. Some research shows that fats improve the use of energy and digestibility of other components of the diet for as yet unknown interactions. The survey was conducted by verifying the qualitative assessment of the flesh of pigs fed diets containing different levels of net energy and supplemented with ractopamine (10ppm). A total of 100 pigs, high genetic potential, with average initial weight of 70kg and average final weight of 100kg were used in the study. The experimental design is a randomized block with a 5x2 (factorial arrangement with five levels of net energy: 2.300; 2.425; 2.550; 2.675; 2.800kcal/kg diet and two levels of dietary ractopamine: 0 e 10 ppm). Samples were taken up to the 12th rib, being subjected to slow freezing and subsequent cooling. Thawing was performed at refrigerator temperature. Not observed interaction between the net energy levels of ractopamine supplementation and dietary variables for shear force, water holding capacity, oxidation, pH and colour. Net energy and levels of ractopamine not change the shear force, holding capacity of water, oxidation, staining and pH of pig meat.

Digestible phosphorus levels for barrows from 50 to 80 kg

This study was carried out to evaluate the levels of digestible phosphorus in diets for barrows with a high potential for lean meat deposition from 50 to 80 kg. Eighty barrows, with an initial weight of 47.93±3.43 kg, were distributed in completely randomized blocks, with each group given five levels of digestible phosphorus (1.86, 2.23, 2.61, 2.99, and 3.36 g kg−1). There were eight replicates, and two animals per experimental unit. Phosphorus levels did not significantly influence feed intake, weight gain, or feed conversion ratio. Daily digestible phosphorus intake increased linearly as levels of phosphorus in the diet were increased. Phosphorus levels did not significantly influence muscle depth, loin eye area, backfat thickness, or the percentage and quantity of lean meat in the carcass. A linear increase was observed for feeding cost as the levels of digestible phosphorus in the diet were increased, and the level of 1.86 g kg−1 cost 29.4% less when compared with the level of 2.61 g kg−1. The dry matter, natural matter, the coefficient of the residue, and volatile solids of the waste were not significantly influenced by phosphorus levels. Conversely, it was possible to observe an increasing linear effect for total solids, total phosphorus, and total nitrogen in the waste of animals receiving diets with increased levels of digestible phosphorus. The level of 1.86 g kg−1, which corresponded to a daily intake of 4.77 g−1 of digestible phosphorus, meets the requirements of barrows weighing 50 to 80 kg.

Metabolizable energy values of diets supplemented with xylanase determined with laying hens

The objective of this study was to evaluate the effect of the supplementation of xylanase in diets with reduced energy level on the apparent metabolizable energy corrected for nitrogen, determined with laying hens at 14, 36, 60 and 80 weeks of age. Four digestibility trials were conducted, using 80 Hy-line W36 laying hens aged 14, 36, 60 and 80 weeks of age. Birds were distributed in a completely randomized design in 2 × 2 factorial arrangement (energy level × inclusion of xylanase), totaling four treatments with 10 replicates of two birds each. Treatments were: positive control (balanced diet for their age); positive control + xylanase; negative control (diet with reduction of 100 kcal/kg in the level of metabolizable energy); and negative control + xylanase. Xylanase, produced by microorganism Trichoderma reesei, was added to the diets at 100 g/t (16,000 BXU/kg) for diets fed at 14 weeks and 75 g/t for diets of 36, 60 and 80 weeks (12,000 BXU/kg). The data obtained were subjected to analysis of variance at 5% probability. Supplementation of xylanase promoted higher values for AME (apparent metabolizable energy) and AMEn (apparent metabolizable energy corrected for nitrogen) determined with 80-week-old laying hens, subjected to diet with energy level according to the nutritional requirements for their age. Supplementation of xylanase increases the matabolizability coefficient of the dietary crude protein and improves the nitrogen retention of laying hens at 14 weeks. In addition, xylanase associated with adequate levels of dietary energy promotes higher values for AME and AMEn determined with laying hens at 80 weeks of age.