Abstract in English:Feed is responsible for about 70% of broilers production costs, leading to an increasing number of studies on alternative dietary products that benefit bird performance and lower production costs. Since the 1950s, antimicrobial additives are the most frequently used performance enhancers in animal production and their positive results are observed even in high-challenge conditions. Since the 1990s, due to the ban of the use of some antibiotics as growth promoters and the growing trend of the public to consume natural products, plant extracts have been researched as alternatives to antibiotic growth promoters. The first study that evaluated the antibacterial activities of plant extracts was carried out in 1881; however, they started to be used as flavor enhancers only during the next decades. With the emergence of antibiotics in the 1950s, the use of plant extracts as antimicrobial agents almost disappeared. There are several studies in literature assessing the use of plant extracts, individually or in combination, as antimicrobials, antioxidants, or digestibility enhancers in animal feeds. Research results on the factors affecting their action, such as plant variety, harvest time, processing, extraction, as well as the technology employed to manufacture the commercial product and dietary inclusion levels show controversial results, warranting the need of further research and standardization for the effective use of plant extracts as performance enhancers, when added to animal feeds. This article aims at presenting plant extracts as alternatives to antibiotics, explaining their main modes of action as performance enhancers in broiler production.
Abstract in English:The aim of this experiment was to determine the productive performance and egg quality of Japanese quails fed different types of processed rations (mash, extruded, or pelleted). One hundred and forty-four 18-w-old quails (Coturnix coturnix japonica) were housed in galvanized wire cages and fed a 21.50% CP and 2850 kcal ME/kg basal feed supplied in mash, extruded, or pelleted form. Experimental data were analyzed by ANOVA as a complete randomized design, with three treatments (ration forms) and six replicates of eight quails each. When necessary, means were compared by Tukey's test at 5% significance. Quails fed pelleted feed presented higher egg production, feed intake, and egg mass weight as compared to mash- and extruded-diet-fed birds. Under the conditions of the present experiment, it was possible to conclude that the feed physical form did not affect egg quality, except for pelleted diets, which promoted good production performance and high egg mass. However, the use of feed pelleting should be economically analyzed considering the final cost of egg production.
Abstract in English:Health status, feed conversion ratio, and mortality are long known broiler chicken production indicators. However, further parameters are required by today's demanding meat markets, as these indicators are not sufficiently accurate to determine flock overall welfare. Morphological asymmetry has been pointed as an alternative welfare indicator as it reflects the ability of the bird to cope with the challenges that rearing conditions may impose. This study aimed at evaluating the possibility of using morphological asymmetry as a welfare indicator. Broilers from 28 to 42 days of age were used in the trial. Birds were randomly selected in a commercial poultry farm and transported to the laboratory. They walked over the force measurement platform in order to determined their feet force as a percentage of body weight. The following body parts of the live birds were measured by two different operators using a digital caliper: tarsometatarsus length, outertoe length, midtoe length, and backtoe length. In the corresponding carcasses, the following traits were measured: wattle width, eye length, and first secondary feather length. Data were submitted to statistical analyses and no correlation was found between specific feet trait measurements and walking ability. Considering the time budget involved in measuring morphological asymmetry, this procedure did not appear to be a practically feasible welfare indicator.
Abstract in English:Hatching results are directly related to environmental and biological surroundings. This research study aimed at evaluating the influence of incubation environmental conditions on hatchability and one-day-old chickling quality of five production flocks using multivariable analysis tool. The experiment was carried out in a commercial hatchery located in the state of São Paulo, Brazil. Environmental variables such as dry bulb temperature, relative humidity, carbon dioxide concentration, and number of colony forming units of fungi were recorded inside a broiler multi-stage setter, a hatcher after eggs transference, and a chick-processing room. The homogeneity of parameter distribution among quadrants inside the setter, the hatcher, and the chick room was tested using the non-parametric test of Kruskal-Wallis, and the fit analysis was applied. The multivariate analysis was applied using the Main Component Technique in order to identify possible correlations between environmental and production parameters. Three different groups were identified: the first group is represented by temperature, which was positively correlated both with good hatchability and good chick quality; the second group indicates that poor chick quality was positively correlated with air velocity and relative humidity increase. The third group, represented by carbon dioxide concentration and fungi colonies forming units, presented strong positive association with embryo mortality increase.
Abstract in English:In the present study, 35 farmers contracted by an integration company were selected. Each farmer owned an average of seven poultry houses, and housed six flocks per year, with a total of 4.0 million housed broilers. Birds were grouped into 5 market ages (MA1=<43, 43<MA2=<44, 44<MA3=<45, 45<MA4=<46, MA5>46 days), and the following parameters were measured: average flock body weight (AFW), feed conversion ratio (FCR), livability (L), production efficiency index (PEI), production cost, and farmer's gross margin. MA significantly influenced all parameters, except production cost/kg broiler. The effects of farm and farm*MA interaction were not significant. Each day of MA increase resulted in increases of 68.43g and 0.039 units in AFW and FCR, respectively. PEI was 4.0% lower in MA5 as compared to MA1, thereby reducing farmer's compensation in 11.89% per reared broilers. Production costs were not different among market ages, partially due to a reduction from 16.86 (MA1) to 14.62% (MA5) in the farmer's participation in the total cost. The results show that a new farmer's compensation index that included MA is necessary to calculate farmer's margin.
Abstract in English:The objective of this study was to evaluate the effects of different additives on broiler performance and meat quality. A total of 1620 one-day-old male Cobb broilers were distributed by a completely randomized experimental design into 5 treatments: positive control - zinc bacitracin (PC); negative control - without additives (NC); probiotic 1 - 10.000 g/ton (PR-I); probiotic 2 - 500 g/ton (PR-II); and probiotic 3 - 50 g/ton (PR-III). The PC treatment promoted better weight gain (WG) than PR-II (1-28 days) and PR-III (1-14; 1-28 days), better feed conversion (1-40 days period), and the highest WG among all treatments (p<0.05). The performance of broilers fed probiotics was not different than those in the negative control group in any rearing phase, but there were performance differences among probiotic-treated birds. Hot and cold carcass yields and breast pH were not influenced by the different additives as compared to the negative control treatment. The only observed differences were in breast color (a*) and carcass yield between PR-III and the negative control group. Probiotics increased water holding capacity (except for PR-II) (p<0.05). The treatment with antibiotic promoted the highest WG. Meat quality suffered little influence from the different additives.
Abstract in English:Two experiments were carried out to evaluate the effects of the dietary inclusion of different dietary sunflower meal (SFM) levels (0% and 20%), with or without the supplementation of an enzyme complex (EC) (cellulase, β-glucanase, xylanase, and phytase) on broiler performance, carcass and cuts yields, economics, and dietary AMEn values. A randomized block experimental design, with a 2x2 factorial arrangement of eight replicates of 20 birds each, was used to test performance. A completely randomized experimental design with a 2x2 factorial arrangement of eight replicates of four birds each was used to test metabolism. No interaction effects between SFM and EC were observed on performance. Although SFM significantly reduced feed intake in the starter phase and total period, weight gain was not different in these phases. Feed: gain ratio improved with the use of SFM in all phases, probably due to the dietary inclusion of oil, which may have improved digestibility. There was a significant increase in weight gain with the use of EC in the starter phase, which is possibly explained by the immature digestive system of birds at this age. There were no SFM or EC significant effects on carcass or cuts yields. There was no significant effect of the addition of EC on dietary AMEn values; however, EC significantly improved the apparent metabolizability coefficients of phosphorus and calcium.
Abstract in English:Two experiments were carried out to evaluate the performance, abdominal fat yield, and bone parameters of broiler chickens fed diets containing different lipid feedstuffs as energy source. During the starter phase (1 to 21 days) of Experiment 1, a completely randomized design with four treatments with eight replicates of 49 birds each one was applied. Broilers were fed starter diets formulated with different lipid sources: soybean oil (SO), cottonseed oil (CO), poultry offal oil (PO), and beef tallow (BT). During the finisher phase (21 to 42 days) of Experiment 1, each initial treatment was divided in two experimental groups: one fed the same fat ingredient as the previous period, and the other fed SO as energy source. Thus, during this period, a completely randomized design with seven treatments, four replicates, and 43 broilers per experimental unit was tested. During the starter phase (1 to 21 days) of Experiment 2, all broilers were fed with the same soybean oil-supplemented diet. The experimental groups were divided during the finisher phase (21 to 42 d) in a completely randomized design with five treatments groups with six replicates of 30 birds each. During this period, treatments consisted of diets formulated with SO, rapeseed oil (RO), sunflower oils (SFO), PO, or BT as lipid sources. No effects (P>0.05) of the treatments on any of the studied parameters were observed in either experiment. Results suggest that there is no influence of animal or vegetable dietary lipid sources on performance, abdominal fat deposition, or tibia density and strength in broilers.
Abstract in English:The addition of antioxidants to broiler diets has been shown to enhance their antioxidant status. Since boldo (Peumus boldus Mol.) leaves contain highly antioxidant molecules, a dried extract of boldo (DEB) was added to broiler diets to improve "in vivo" antioxidant tissue status and to favor animal growth. A DEB standardized for antioxidant content was prepared and added to poultry diets at three different levels (low-DELB, medium-DEMB, and high-DEHB) for a period of 6 weeks. A single negative control (no added antioxidant) and one positive control (supplementation with 200 mg/kg vitamin E) were used. Plasma antioxidant capacity (PAC), thiol content (GHS), and basal and induced lipoperoxidation of liver, leg and breast tissues were determined in birds at 2, 4, and 6 weeks of age. PAC increased with chicken age until week 6, but was unaffected by DEB addition at any level. However, DEB increased hepatic GSH content. No data indicated that DEB improved the resistance against induced lipoperoxidation in the assayed tissues. DEB contains compounds exhibiting high antioxidant activity "in vivo", as evidenced by the increase in liver thiol content. Regarding broiler performance, no differences in poultry body weight and feed consumption were detected during the assay.
Abstract in English:The study was designed to evaluate the productive consequences of fasting neonatal chicks obtained from strains genetically divergent for growing. Four hundred eight chicks from three strains, 160 from breeders selected for high growth rate and excellent feed conversion ratio (Cobb 500), 160 from breeders not selected for fast growth (JA57), and 160 from a white egg layer strain (Hy-Line W98) were allotted in a 3 (strain) x 2 (fasting period - 8 and 36h after hatching) factorial arrangement with 5 replicates of 16 chicks each. Immediately after hatching, all chicks had similar (P>0.05) relative yolk sac weights (14.13%, 14.50%, and 15.49% for Hy-Line, Cobb, and JA57, respectively). The yolk sac retractions were proportionally higher for Cobb and JA57 chicks up to 144 h (6 days) after placement, but were not influenced by 36h of feed fasting. At 7 and 14 days of age only Cobb chicks had their body weight and weight gain significantly (P<0.05) depressed by 36h feed fasting after hatching. Results indicate that broiler chicks with intense initial growth rates (Cobb 500) need an outstanding nutritional supply, either from exogenous (feed) or endogenous (residual yolk) sources, to achieve a final weight compatible with their genetic constitution. For slow-growing chicks (Hy-Line), nutritional supplementation via yolk sac seems to be more important than exogenous supply (feed) of nutrients during the neonatal period.