This study aimed at evaluating total or partial replacement of corn by sorghum in broiler diets and at estimating the effect of the pigment supplementation on broiler performance, carcass and cuts yield, and possible breast and leg pigmentation. We used 1680 one-d-old Ross® 308 broilers. Birds were sexed and distributed according to a completely randomized design (2 x 3 + 1). Treatments consisted of a control diet based on corn and diets with two levels corn replacement by sorghum (50 and 100%) and three pigments levels, with four replicates of 60 birds per treatment. There was no effect (p > 0.05) of the dietary replacement of corn by sorghum on performance, carcass and parts yield, and no changes in breast and leg meat pH (p >0.05). Meat redness (a*), yellowness (b*) and luminosity (L*) increased (p < 0.05) as pigment inclusion levels increased. It was concluded that the use of sorghum instead of corn did not affect broiler performance or carcass and cuts yield. When adequate pigments were used, meat color significantly improved.
The Brazilian Ministry of Agriculture (MAPA) regulations establish 12 hours as the maximum pre-slaughter fasting period for broilers; however, many processing plants have considered this time is not sufficient, and consequently return the birds to the farms, with consequent economic losses and welfare problems. Therefore, it is necessary to investigate the possible effects of longer pre-slaughter fasting times. The objective of the present study was to evaluate the effect of pre-slaughter fasting times longer than those established by MAPA on broiler welfare, breast meat quality, and intestinal integrity. Forty 42-d-old broilers were submitted to different pre-slaughter fasting times: group I: 6 hours, group II 9h, group III 12h, and group IV 15h. Bird welfare was assessed before slaughter. After sacrifice, intestinal samples were collected to assess their morphology and morphometrics, and the Pectoralis major muscle was analyzed for pH and color. There was no influence (p>0.05) of treatments on breast muscle pH or color.There were no significant changes in intestinal morphometrics (p<0.05). Bird behavior was affected (p<0.05), suggesting that welfare was impaired as fasting time increased, but no differences in the analyzed parameters were detected between broilers fasted for 12 or 15 hours. It was concluded that the behavioral differences between birds fasted for 12 and 15 hours are not sufficient to assert that those fasted for 15 hours were in worse welfare conditions.
It is known that PSE meat present important functional defects, such as low water holding capacity and ultimate pH, which may compromise the quality of further-processed meat products. In this study, L* (lightness), a* (redness), and b* (yellowness) values of 500 chicken breast fillets were determined using a portable colorimeter (Minolta, model CR-400) in a commercial processing plant. Fillets were considered pale when their L* was >49. Out of those samples, 30 fillets with normal color and 30 pale fillets were evaluated as to pH, drip loss, cooking loss, water holding capacity, shear force, and submitted to sensorial analysis. An incidence of 10.20% PSE meat was determined. Pale and normal fillets presented significantly different (p<0.05) pH values, L* and a* values, water holding capacity, drip loss, and cooking loss, demonstrating changes in the physical properties of PSE meat. Shear force and sensorial characteristics were not different (p>0.05) between pale and normal fillets. Despite the significant differences in meat physical properties, these were not perceived by consumers in terms of tenderness, aspect, and flavor. The observed incidence of PSE may cause losses due to its low water retention capacity.
An experiment was carried out to establish mean bone quality values of the tibiae and femora of ostriches and to evaluate these bones. The right leg bones of 10 males and 10 female African Black ostriches were evaluated. Birds were radiographed immediately after slaughter (during bleeding), with the aid of a portable X-ray apparatus. The obtained radiographs were scanned and bone mineral density means were obtained using software. Bone strength, Seedor index, and dry matter percentage were evaluated and correlated to weight gain during the finishing period (3-13 months of age). Mean values of the evaluated bone quality traits, not previously found in literature, were established. There were no significant differences between males and females in performance or bone quality parameters. It was concluded that male and female ostriches present similar performance and bone quality at slaughter age.
This study aimed at evaluating the effect of different fasting periods and water spray during lairage on the quality of chicken meat. A number of 300 male Ross broilers were reared up to 42 days of age, and submitted to four pre-slaughter fasting periods (4, 8, 12, and 16 hours) and sprayed with water or not during lairage. Deboned breast meat was submitted to the following analysis: pH, color, drip loss, water retention capacity, cooking loss, and shear force. There was a significant effect (p < 0.05) of fasting period on meat luminosity was significantly different, with the highest value obtained for 4-hour fasting, whereas no difference was found among the other fasting periods. Meat pH values were different among fasting periods when birds received water spray, with birds fasted for 4, 8, and 12 hours of fasting presenting lower meat pH values (5.87, 5.87, and 6.04, respectively). The interaction between fasting period and water spray influenced meat drip loss and cooking loss, with birds fasted for 16h and not receiving water spray presenting higher drip loss (4.88) and higher cooking loss (28.24) as compared to the other birds. Fasting period affects meat quality, and very short periods (4h) impair meat quality.
An experiment was carried out with male and females broilers of two different commercial breeds to evaluate bone mineral density of the right femur head. A number of 600 one-day-old broilers were raised in an experimental poultry house up to 42 days of age at the School of Veterinary Medicine and Animal Science of UNESP, Botucatu, Brazil. After slaughter, three males and three females in each breed in each of the established gross scores were selected. Their femora heads were submitted to gross examination, and subsequently the thighs were submitted to the Veterinary Hospital for radiographic analysis. Femora were also submitted to bone resistance, Seedor index, and dry matter content analyses. All these bone quality characteristics were different between males and females, independent of breed. Breeds presented similar behavior. It was possible to establish correlations between bone quality parameters, and confidence intervals for bone mineral density values, correlating them to femoral degeneration score, which allows characterizing femoral head lesions by radiographic optical densitometry.
The aim of this study was to follow-up the physiological variations in the development of the bone tissue, associating them with the egg production curve. This study was carried out in the facilities of the Faculdade de Medicina Veterinária e Zootecnia of the UNESP, Botucatu, Brazil. Twenty-three families of Ross broiler breeders were used, each family consisting of 13 females and 1 male, distributed in 23 pens of 5.0m² each. The management was that recommended by the genetic company manual (Agroceres Ross, 2003), with daily feeding until 6th week of age; and birds were fed according to a 5:2 schedule (5 days fed, 2 days of fasting) between 7 and 17 weeks of age, returning to daily feeding starting at 18 weeks of age. Birds did not receive afternoon calcium supplementation. On the fourth week of rearing, 84 females were removed for bone analyses of the right tibia and femur, using optical densitometry in radiographic images technique. These analyses were sequentially carried out in 4, 8, 12, 15, 20, 24, 30, 35, 42, 47, and 52 week-old birds. The egg production curve of the birds was followed-up and associated to bone mineral density results. For bone mineral density evaluation (BMD) birds were divided by weight categories as light, intermediate, or heavy within each data age. BMD values of the tibias were not influenced by weight range, but by the age at collection. On the other hand, interactions were found among femur BMD values and weight and age categories. There was no correlation between eggshell quality and femur BMD. A negative correlation (-0.15) was observed between tibia BMD and eggshell percentage. It was possible to conclude that the egg production has little influence on bone mineral density of the birds probably because there was no need of bone mineral mobilization during the production period, since the observed egg production was below that observed under commercial conditions.
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 was carried out at Faculdade de Medicina Veterinária e Zootecnia, Universidade Estadual Paulista, Botucatu, SP, Brazil, and evaluated bone quality in broiler breeders. Twenty-three families of Ross broiler breeders were housed in 5.0-m² pens. The families were comprised of 13 females and one male at the onset of the experimental period. The mean number of females per family was 9.34 at the end of the trial. The feeding program and management followed strain guidelines (Agroceres Ross, 2003). Bone analyses were performed in the right tibia and femur using optical radiographic densitometry at 4, 8, 12, 15, 20, 24, 30, 35, 42, 47 and 52 weeks of rearing. Trap nests were used to collect eggs from the breeders two weeks before and after the evaluation weeks. At each evaluation day, five birds were sacrificed after radiographs were taken and the tibias and femurs were collected to perform the following analyses: fatfree dry matter, ash percentage, bone resistance and Seedor index. Therefore, it was possible to establish correlations between bone quality and eggshell quality. Characteristics of bone quality were highly correlated to each other; on the other hand, there were no correlations between bone quality and external egg quality. In conclusion, there was no effect of egg production on egg quality, possibly because there was no reabsorption of bone minerals.
Two trials were carried out in the present study. Trial I evaluated the performance, carcass yield and breast meat quality, whereas Trial II evaluated the efficacy of utilizing prebiotics + probiotics on the control of Salmonella spp incidence in the carcasses of free-range broilers. In Trial I, 688 one-day-old male chicks of the Naked Neck Label Rouge strain were used, distributed in a randomized block design arranged according to a 2 x 2 factorial: control diet or diet supplemented with probiotics and prebiotics; and two rearing systems (confined or with access to paddocks - 3m²/bird), using four replicates with 35 birds each. The birds were reared until 84 days of age following the recommendations of management and nutrition for free-range strains, and had access to paddocks after 35 days of age. Water and food were given inside the experimental poultry house. Birds fed probiotics and prebiotics in the diet and the confined birds showed better performance, carcass yield and meat quality compared to the birds of the other treatments. In Trial II, 128 one-day-old male chicks of the free-range Naked Neck Label Rouge strain were used. The birds were distributed into four treatments: NCC (non-challenged control), NCS (non-challenged supplemented), CC (challenged control) and CS (challenged supplemented). There were no significant effects of adding probiotics and prebiotics in the diet in regard to Salmonella enteritidis recovery from the carcasses.
This study was carried out at Faculdade de Medicina Veterinária e Zootecnia, Universidade Estadual Paulista, Botucatu, SP, Brazil, with the objective of evaluating the efficacy of four techniques in the assessment of tibial dyschondroplasia lesions in broiler chickens. Four hundred Cobb male chicks were reared from 1 to 39 days of age. At 39 days, forty birds were selected and tibial dyschondroplasia status was assessed by four different techniques: evaluation using the lixiscope, macroscopic examination, histological examination and bone mineral density assessment using optical radiographic densitometry. The efficacy of each technique to assess dyschondroplasia lesions in the tibial growth plate was determined in comparison to histology, which was considered to be 100% efficient. The correlation results between lixiscope analysis and histology were poor. Macroscopic scores and densitometry readings were highly correlated with histology scores, and it is considered that these techniques reliably reproduce the status of the growth plate.
This study aimed to evaluate the effects of probiotics and prebiotics of bacterial and yeast origin on the performance, development of the digestive system, carcass yield and meat quality of free-range broiler chickens. Five hundred and sixty male chicks of the strain ISA S757-N were reared from one to 84 days old. The birds were distributed in four treatments according to a completely randomized block design: T1 = Control, T2 = Probiotics and Prebiotics of bacterial origin, T3 = Probiotics and prebiotics of yeast origin, T4 = Probiotics and prebiotics of bacterial origin + probiotics and prebiotics of yeast origin. There were four repetitions with 35 birds per repetition, and the birds had access to a pasture area after 35 days of age. Characteristics evaluated were performance, development of the digestive system, carcass and parts yield, abdominal fat, breast meat physical measurements (length, width and height) and meat quality parameters (pH from breast and leg meat, cooking loss and shearing force from breast meat). Lower mortality (p<0.05) and higher weight gain from 64 to 77 and 64 to 84 days of age were seen in birds supplemented with probiotics and prebiotics of bacterial origin compared to the non-supplemented birds (control). There were significant differences (p<0.05) among treatments for carcass yield. Birds supplemented with both probiotics and prebiotics of microbial and yeast origin (T4) showed higher carcass yield than control birds. Supplementation with probiotics and prebiotics of bacterial origin (T2) or the supplementation of these together with those of yeast origin (T4) reduced mortality and increased the carcass yield in free-range broiler chickens.
This work aimed to evaluate the effects of probiotic associated to prebiotic on performance, carcass and cut yields, qualitative traits of meat, development and score of lesions due to coccidiosis in digestive tract of broiler chickens raised in a free-range system during 85 days. One thousand, six hundred and ninety-six day-old male broiler chicks from naked-neck ISA S757-N Label Rouge line were used in a randomized block design with factorial scheme of 4x2 and four repetitions. The effect of four additive (1 - biologic promoter + coccidiosis vaccine; 2 - biologic promoter + anti-coccidiosis; 3 - chemical promoter + coccidiosis vaccine; 4 - chemical promoter + anti-coccidiosis) and two breeding systems from 35th day of age (one with no-access to pasture or confined and the other with free-access to pasture or semi-confined) on performance parameters, carcass and cut yields, qualitative meat traits, coccidiosis development and lesions in digestive tract were evaluated. There was effect (p<0.05) of additives only on sensorial analysis (meat quality) and percentage of large intestine. Breeding systems affected (p<0.05) live weight (LW) and LW gains, being the better results observed in semi-confined birds.