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Seaweeds are functional feed ingredients that have antioxidant, antimicrobial, and growth-boosting properties that can improve poultry product quality. This study, therefore, investigated the effect of graded levels of green seaweed meal (Ulva spp.) (SWM) on visceral organ sizes, carcass characteristics, and meat quality and stability of Boschveld indigenous hens. A total of 275, four-week-old female chicks (202.4 ± 6.65 g of live weight) were reared on 5 isocaloric and isonitrogenous diets formulated by adding SWM at a concentration of 0 (SW0), 2 (SW20), 2.5 (SW25), 3 (SW30), and 3.5% (SW35). Birds were humanely slaughtered at 14 wk of age. Cecum weight linearly increased (R2 = 0.366, P = 0.002), whereas proventriculus (R2 = 0.205, P = 0.025) and duodenum (R2 = 0.242, P = 0.010) weights linearly decreased with SWM levels. Neither linear nor quadratic trends (P > 0.05) were observed for carcass traits, meat quality parameters, and shelf life indicators in response to dietary SWM levels. Repeated-measures analysis showed a significant time × diet interaction effect on meat redness (a∗). After 24 h of storage, meat from hens fed with SW35 (2.47) diet had a higher a∗ value than meat from hens fed with SW30 diet (0.48). However, the inclusion of SWM promoted similar (P > 0.05) shelf life indicators as the control diet for the rest of the 7-d storage period at room temperature. In conclusion, dietary inclusion of SWM had no adverse effect on visceral organ size, carcass and meat quality traits, and meat stability of Boschveld indigenous hens.

The aim of the present study was to evaluate the effects of quantitative feed restriction (FR) in fast-, medium-, and slow-growing meat-type male and female chickens on their growth, feed consumption, economic efficiency, carcass composition, and gastrointestinal microbiota. In the experiment, fast-growing Ross 308, medium-growing Hubbard JA 757 and slow-growing ISA Dual chickens of both sexes were exposed to quantitative FR between 14 and 21 d of age. During the FR, restricted chickens received 70% of the amount of feed consumed by the ad libitum (AL) group. Live weight at the end of the experiment was affected by genotype (P

Two broiler lines, Line A and Line B, were fed experimental diets from 22 to 42 d with objectives to determine effects of digestible amino acids (AA) to metabolizable energy ratios on feed intake (FI), performance, and processing yield. Experimental diets were formulated to 3,150 kcal/kg with 5 levels of digestible lysine (dLys)—80, 90, 100, 110, and 120% of recommended AA level giving g dLys/Mcal values of 2.53, 2.85, 3.17, 3.48, and 3.80, respectively. All other AA were formulated to a fixed ratio to dLys. A total of 4,050 chicks were utilized in each trial (9 replicate pens for each AA level and each line; 45 chicks/pen) conducted twice: one in hot environmental temperature (HT) (24 h mean ∼85.3 °F; 80.9% RH) and another in cool environmental temperature (CT) (24 h mean ∼71.6 °F; 61.7% RH). Results showed that FI was not impacted by dietary AA levels in HT for both lines. Higher FI (P

White striping (WS) and woody breast (WB) have been previously associated with older and heavier birds. However, there is limited information supporting the association between these 2 muscle conditions and growth parameters. The objectives of this study were 1) to investigate the relationship between WS and WB using different growth production factors and 2) to propose a predictive model that uses growth production factors to investigate the incidence and severity of WS and WB. A combined database of 4,332 broilers pooled from 7 research experiments conducted from 2016 to 2017 at Texas A&M University was used in this study. Parameters such as sex, age (4 wk, 6 wk, and 8 wk), strain (standard A vs. high-breast-yield [B and C]), live weight categories (500 g increments), and breast weight categories (250 g increments) were included in the model. Results showed that WS was 12% more likely to be present in non-WB fillets. The association between WS and WB suggests a moderate relationship between the ranks of both outcome variables (ρ = 0.57, P < 0.0001). Variables such as age, live weight, and sex were not as important as breast weight and strain in the severity prediction of WS and WB. Butterfly fillets above 750 g and with high-breast-yielding strains were more likely associated with higher severity of WS and WB scores. No post hoc variable selection was performed. Both models show good discrimination. The WS model produced an uncorrected area under the curve (AUC) of 0.739, with a bootstrap corrected estimate of 0.736. The WB model produced an uncorrected AUC of 0.753 and a bootstrap corrected estimate of 0.752. Therefore, the growth production factors analyzed in this study indicated that there is a moderate relationship between WS and WB myopathies and were jointly predictive of the severity of WS and WB. Potentially other factors not included in this study may play a major role in the relationship of these 2 myopathies. More research should be done to investigate this possibility.

Effects of light sources, photoperiods, and strains on growth performance, carcass characteristics, and health indices of broilers grown to heavy weights (>3 kg) were evaluated. The experimental design was a 4 × 2 × 2 factorial treatments consisting of 4 light sources [incandescent (ICD, standard), compact fluorescent light, neutral light emitting diode (Neutral-LED), and cool poultry specific LED (Cool-poultry specific (PS)-LED)], 2 photoperiods (regular/intermittent [2L:2D], and short [8L:16D]), and 2 strains (A, B). In each trial, chicks of 2 different strains from different commercial hatcheries were equally and randomly distributed into 16 environmentally controlled rooms at 1 D of age. Each room was randomly assigned one of 16 treatments from day 1 to 56 D of age. Feed and water were provided ad libitum. Birds were provided a 4 phase-feeding program (starter, grower, finisher, withdrawal). Birds and feed were weighed on 1, 14, 28, 42, and 56 D of age for growth performance. On day 56, a total of 20 (10 males and 10 females) birds from each room were processed to determine weights and yields. The BW, BW gain, live weight, and carcass weight of birds reared under PS-LED were higher (P < 0.05) in comparison with birds reared under ICD, but feed intake, feed conversion ratio, mortality, and carcass characteristics were not affected by treatments. Also, broilers subjected to the short/non-intermittent photoperiod had the lowest (P < 0.05) growth performance and carcass characteristics compared with values obtained for regular/intermittent photoperiods. In addition, strain was significant (P < 0.05) for most of the examined variables. Feed conversion, fat, tender, and yield were not affected by treatments. There was no effect of photoperiod, light sources, or their interactions on mortality. This study shows positive impacts on alternative light sources when compared to ICD along with regular/intermittent photoperiod in commercial poultry facilities rearing the 2 strains used in this study, thereby reducing energy costs and optimizing production efficiency without compromising the welfare of broilers grown to heavy weights.

Made available in DSpace on 2020-12-12T01:39:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-10-01 The aim of this study was to identify the influence of different catching practices during manual upright handling on broiler welfare and behavior. Catching was examined in a total of 4,595 Cobb broilers with average live weight of 3.2 kg and 42 days old. Six catching practices were evaluated: shed curtain position, loading time, catching method, catching team, height of the crates from the floor, and placement of the bird in the crate. Behavioral welfare indicators were defined as follows: 1) broiler agitation in the catcher's hands, measured when the birds flapped their wings, kicked, or wriggled in the hands; 2) broiler striking the crate entrance as it was being placed in the crate, measured when the birds get the head, wings, or legs, hit at the crate entrance; and 3) broiler agitation in the crate, measured when birds flapped the wings or jumped inside the crate for 3 s or more after placement in the crate. A logistic regression model was used to calculate the chance of occurrence of each behavioral welfare indicator due to the handling factors. All catching practices evaluated in the present study influenced the birds' welfare and behavior. Thus, some procedures during broiler catching potentially improved their behavior, making them less prone to accidents, and consequently improved their welfare. The catching process should be performed with the curtains in the closed position, carrying one broiler per catcher in an upright position while containing its wings, carefully placing the birds inside the crates, and with the crates being positioned at a height of at least 21 cm from the ground. Additionally, it was concluded that more attention should be given to the broiler catchers, since the position of the curtain, loading time, and position of the crate during handling can influence the work done by them, affecting the welfare and behavior of both humans and birds. UNESP Universidade Estadual Paulista Faculdade de Ciências Agrárias e Veterinárias Departamento de Zootecnia Programa de Pós-graduação em Zootecnia Grupo ETCO Grupo de Estudos e Pesquisas em Etologia e Ecologia Animal Swine Teaching and Research Center Department of Clinical Studies New Bolton Center School of Veterinary Medicine University of Pennsylvania Royal Veterinary College University of London UNESP Universidade Estadual Paulista Faculdade de Ciências Agrárias e Veterinárias Departamento de Zootecnia Programa de Pós-graduação em Zootecnia

The aim of this study was to evaluate the effects of genotype, sex, dietary protein level, and their interactions on select carcass characteristics and meat quality of fast- (Ross 308), medium- (Hubbard JA757) and slow-growing (ISA Dual) chickens (n = 2,520). The diet of the low-protein group of chickens had 6% lower CP than the commercial diet fed to the control group. When the chickens reached an average live weight of 2 kg, 10 males and 10 females of each genotype and the diet were selected for slaughter and breast meat–quality analysis. The dressing out and breast percentages were lower in the JA757 (−2.0 and −5.9%, respectively) and ISA Dual chickens (−9.9 and −14.3%, respectively) than those in the Ross 308 chickens. The ISA Dual chickens had higher abdominal fat percentage, higher DM and protein contents and lower ether extract content and shear force value in breast meat than the other genotypes. Significant interaction effects of genotype, sex, and diet were found on the color of breast skin. Among the various combinations of genotype, sex, and diet group, Ross 308 females fed the low-protein diet had the highest redness and yellowness of breast skin, highest pH45 value, and largest fibers, whereas ISA Dual females had the lowest color parameters and pH45 value, and ISA Dual males had the smallest muscle fibers. The low-protein diet was associated with decreased abdominal fat percentage and changes in meat quality parameters, including increased darkness, meat color intensity, drip loss, and muscle fiber area, in all genotypes. The results indicated greater differences in meat quality owing to genotype than to sex or dietary protein level.

The following study was conducted to define how multiple nutritional strategies affect broiler performance, meat yield, and the presence and severity of white striping (WS) and woody breast (WB) in high-yielding broilers. Relative to a commercial set of reference broiler diets (Commercial reference diet; Trt 1) that were fed in a 4-phase program, the following nutritional strategies were investigated: increasing the ratio of digestible arginine: digestible lysine (dArg: dLys ranged from 113 to 126; Trt 2), supplementing Trt 1 with 94.4 mg vitamin C/kg feed (Trt 3), doubling the vitamin pack inclusion rate (Trt 4), reducing the digestible amino acid density (dAA) of only the grower phase by 15% and feeding the same Trt 1 starter, finisher, and withdraw diets (Trt 5), and combining the 4 strategies just mentioned (Trt 6). There was no difference in performance at the end of the starter phase (P = 0.066); however, at the end of the grower and finisher phases, feeding lower dAA grower diets suppressed BW (Trts 5 and 6; P < 0.001) and increased FCR. Differences in performance amongst all treatments disappeared at day 49 (P = 0.220). No differences were observed in average breast weight (P = 0.188); however, breast yield (as a % of live weight) was greatest for Trt 1 and least for Trt 6 (P = 0.041). The WB score dropped from 1.83 in Trt 1 to 1.49, 1.27, 1.74, 1.53, and 1.43 in treatments 2 to 6, respectively (P = 0.018). These changes were the result of a shift in WB score, where the WB class that contained scores of 2 and 3 shifted from 61.3% in Trt 1 to 49.3, 35.9, 60.0, 50.8, and 38.7 in treatments 2 to 6, respectively. Given the FCR, breast weight data and the fact that high WB scores result in a devaluation of breast meat, feeding a higher ratio of dArg: dLys, higher vitamin C, or lower dAA in the grower phase results in better breast meat quality and value.

This study aimed to investigate the effect of using breeder parents (434-days-old) and broiler chickens (37 D of age) from Ross 308 on meat quality parameters and carcass characteristics; sex and muscle type were also estimated. Carcass assessment involved hot carcass weight, carcass yield, and cuts (breast, legs, wings, back, and shoulder). A total of 120 birds were divided into 2 groups (60 birds from each stock), each stock contain equal number of sexes (30 males and 30 females), and further divided into 6 replicates, so that there were 5 birds in each replicate. The birds were fed ad libitum. A sample of 30 birds (male, n = 15 and female, n = 15) from each group was slaughtered for assessing carcass and physical characteristics. Sensory analysis was carried out on each group after boiling or roasting the bird. Live weight, carcass weight and yield, breast weight, legs, wings, and back weights and yield were higher (P0.001) for breeder parents when compared to broilers, with the exception of breast percentage. Moreover, better carcass characteristics were observed in males than in females. Parent stock had better water-holding capacity and myofibrillar fragmentation whereas broilers had more tender meat than breeders. Moreover, cooking loss and other sensory characters were not significant between the two groups; however, females had more tender pectoral muscles and more myofibrillar fragmentation than males. We concluded that parent breeders had better carcass characteristics than broiler chickens. The broiler chickens of Ross 308 and female birds had better meat quality than parent breeders.

Image analysis could be an objective and rapid method to identify woody breast (WB) myopathy and benefit the global poultry industry. The objective of this study was to determine if there are conformational changes that can be used to detect WB characteristics in commercial broiler carcasses across strains, gender, and ages using image analysis. A total of 900 images of male and female broiler carcasses from commercial standard and high breast-yielding strains and 5 ages (6 through 10 wk) were captured before evisceration. These images were processed and analyzed using ImageJ software. Conformational measurements were M0: breast length; M1: breast width in the cranial region; M2: vertical line from the tip of keel to 1/5th of breast length; M3: breast width at the end of M2; M4: angle formed at the tip of keel and extending to outer points of M3; M5: area of the triangle formed by M3 and lines generated by M4; M6: area of the breast above M3; M7: M6 minus M5. Ratios of these measurements were also considered. Intact breast fillets were scored for WB severity based on tactile evaluation. Regardless of strain, sex, and age, M11 (M1/M0), M9 (M3/M2), and M4 had the highest correlation to WB score (rs ≥ 0.65; P

Slow-growing broilers offer differentiation in the chicken meat market for consumers who have distinct preferences based on perceived higher welfare indices and willingness to pay a higher price for the product. Although breeding for slow-growing broilers is relatively advanced in Europe and the United States, it is limited in Australia. Crossbreeding is one of the approaches taken to developing slow-growing broiler strains. Thus, the aim of this study was to compare performance, immune response, leg health, carcass characteristics, and meat quality of a novel crossbred slow-growing broiler breed (SGB) with the conventional, fast-growing Cobb 500 broiler (CB) to assess their suitability as an alternative for chicken meat production in Australia. A total of 236 one-day-old broiler chicks (116 SGB and 120 fast-growing CB) were reared on standard commercial diet in an intensive production system. Birds and feed were weighed on a weekly basis and feed intake and feed conversion ratio calculated. At 21 d of age, a 2% suspension of sheep red blood cells was injected subcutaneously into 8 broilers of each breed to compare their antibody response. Birds from both breeds were grown to a final live weight of 2.0–2.2 kg, before a latency-to-lie (LTL) test, carcass analysis and apparent metabolizable energy (AME) assay were performed. The SGB reached the target weight at 55 d of age compared with 32 d in CB. However, SGB stood for longer during LTL, had higher thigh, drumstick, and wing yields (as a percentage of carcass weight) as well as darker and redder meat in comparison with the CB. The CB had better feed conversion efficiency, higher antibody (IgM) production, higher AME, heavier breast yield, and lower meat drip loss than the SGB. Although fast-growing CB outperformed the SGB for traditional performance parameters, the crossbred in this study was comparable with other slow-growing broiler breeds and strains across different countries and is thus a suitable candidate for a slow-growing alternative in Australia.

This study investigated the effects of light sources and light intensity on growth performance, carcass characteristics, and welfare indices of heavy broilers (>3.0 kg) in 4 trials with 2 replications per trial. A total of 960 one-day-old Ross×Ross 708 chicks (30 males/30 females/room) were randomly distributed into 16 environmentally controlled rooms at 50% RH. A 4×2 factorial treatment structure evaluated 4 light sources (incandescent [ICD, standard], compact fluorescent [CFL], neutral light emitting diode [Neutral-LED], and cool poultry specific filtered LED [Cool-PSF-LED]) and 2 levels (5 lx, 20 lx) of light intensities. Each of the 4 light sources was paired with one of the 2 light intensities. Birds were fed the same diet with a 4-phase feeding program (starter, grower, finisher, and withdrawal). Feed and water were provided ad libitum. Birds and feed were weighed on one, 14, 21, 28, 42, and 56 d of age for growth performance. All mortality was recorded daily and feed conversion was adjusted for mortality. Immune response was determined on d 28 to d 35, whereas other welfare indices were performed on d 42 and 49, respectively. At d 56 of each trial, 20 (10 males and 10 females) birds from each room were processed to determine weights and yields. The BW, BW gain, live weight, and carcass weights of birds reared under Cool-PSF-LED were different (P≤0.05) in comparison to birds reared under ICD. However, FI, FCR, and mortality were not affected by treatments. There was no effect of treatments on fat or breast and tender weights and yields. In addition, there was no effect of treatments on ocular development, immune response, and other welfare indices, suggesting that the light sources evaluated did not compromise welfare of heavy broilers. It was concluded that the 3 light sources evaluated in this study may be suitable for replacement of ICD light source in poultry facilities to reduce energy cost and optimize production efficiency.

Due to their importance for the control of meat quality in broiler chickens, the present study aimed at identifying the factors associated with the occurrence of myopathies and characterizing the meat properties when affected by myopathies. To this aim, a total of 768 broiler chickens were reared until slaughter (46 d) to evaluate the effect of genotype, gender, and feeding regime (ad libitum vs. restricted rate, 80% from 13 to 21 d of age) on performance and meat quality. Standard broilers were heavier (3,270 vs. 3,139 g; P < 0.001) and showed lower feed conversion (1.56 vs. 1.61; P < 0.001) than the high-yield broilers. Males showed higher final live weight (3,492 vs. 2,845 g) and lower feed conversion (1.54 vs. 1.63) than females (P < 0.001). Feed restriction decreased final live weight (3,194 vs. 3,142 g; P < 0.01) and feed conversion (1.60 vs. 1.57; P < 0.01) compared to ad libitum feeding. At gross examination, feed restriction tended to increase white-striped breasts (69.5 vs. 79.5%; P < 0.10), whereas females showed less wooden breasts than males (8.0 vs. 16.3%; P < 0.05). White-striped fillets had higher pHu (5.87 vs. 5.83), and lower a* (-0.81 vs. -0.59) and b* color indexes (13.7 vs. 14.5) (P < 0.05), whereas wooden breast fillets exhibited higher cooking losses (25.6 vs. 22.1%) and AK-shear force (4.23 vs. 2.84 kg/g) compared with normal fillets (P < 0.001). At histological examination, 3.1% of pectoralis major were normal, 26.6% mildly degenerated, 45.3% moderately degenerated, and 25.0% severely degenerated. In conclusion, genotype had a moderate effect on growth without modifying myopathy occurrence. In contrast, gender and feed restriction affected performance, meat quality, and breast abnormalities.

Limited data are available for comparing light-emitting diode (LED) bulbs that are currently available in commercial broiler production facilities. We evaluated the effects of color temperatures (kelvin) of LED bulbs on growth performance, carcass characteristics, and ocular development indices of broilers grown to heavy weights (3.0 kg). The experiment had a randomized complete block design. Four treatments consisted of 3 LED light bulbs (2,700 [warm LED]; 5,000 [cool LED 1]; and 5,000 K [cool LED 2]) and incandescent light (2,010 K [ICD], standard) from day zero to 56 d of age. A total of 960 Ross×Ross 708 day-old chicks were equally and randomly distributed into 16 environmentally controlled rooms at 50% RH (30 males and 30 females/room). Thus, each of the 4 treatments was represented by 4 rooms (4 replicates) per trial. Feed and water were provided ad libitum. All birds were fed the same diet. Ocular specimens were collected on d 42 for development and histopathologic examination. Blood samples were collected on d 21, 28, 42, and 56 to determine plasma corticosterone. On d 56, twenty birds from each room (10 males and 10 females) were processed to determine weights and yields. The BW and BW gain (BWG), live weight, and carcass weights of birds reared under cool LED 1 were different in comparison to birds reared under ICD (P0.05). However, feed intake (FI), feed conversion ratio (FCR), and mortality were not affected by treatments. The treatments did not affect fat, breast and tender weights, and yields. In addition, ocular development indices and plasma corticosterone concentrations were not affected by treatments, suggesting the LED light bulbs we evaluated did not compromise the welfare of the birds. It was concluded that cool LED 1 may be a better potential replacement light source in comparison to ICD on performance, but it may be equal when compared to other LED light sources examined in this study.

Effects of light sources and photoperiod on growth performance, carcass characteristics and health indices of broilers were investigated in 4 trials. In each trial, 720 1-day-old Ross × Ross 708 chicks were randomly distributed into 12 environmentally controlled rooms (30 males/30 females/room). The experimental design was a 4 × 3 factorial treatments consisted of 4 light sources [incandescent (ICD, standard), compact fluorescent (CFL), neutral light-emitting diode (Neutral-LED), and cool poultry-specific filtered LED (Cool-PSF-LED)] and 3 photoperiods [long/continuous (23L:1D), regular/intermittent (2L:2D), and short/non-intermittent (8L:16D)] from d8-d56. Birds were fed the same diet, while feed and water were provided ad libitum. Birds and feed were weighed on 1, 14, 28, 42, and 56 d of age for growth performance. Mortality was recorded daily and feed conversion was adjusted for mortality. Immune response was determined on d 28 to 35, whereas other welfare indices were performed on d 42, 43, and 49. At 56 d of age, 10 male and 10 female birds from each room were randomly selected and processed to determine weights and yields. The BW, BW gain, live weight, and carcass weights and yields of birds reared under Cool-PSF-LED were increased (P ≤ 0.05) in comparison to birds reared under ICD, but FI, FCR, and mortality were not affected. Moreover, broilers subjected to the short/non-intermittent photoperiod had the lowest (P ≤ 0.05) BW, BW gain, FI, live weight, carcass weight, and pectoralis major and minor weights compared to other 2 photoperiods. There was no effect of treatments on some carcass characteristics. There was no effect of treatments on welfare indices, suggesting that the light sources evaluated did not compromise welfare of heavy broilers. It was concluded that the 3 light sources evaluated in this study may be suitable for replacement of ICD light source along with regular/intermittent photoperiod instead of long/continuous photoperiod in poultry facilities to save energy utilization, thereby reducing the total cost of production.

The ability to determine the optimal broiler feed nutrient density that maximizes margin over feeding cost (MOFC) has obvious economic value. To determine optimal feed nutrient density, one must consider ingredient prices, meat values, the product mix being marketed, and the projected biological performance. A series of 8 feeding trials was conducted to estimate biological responses to changes in ME and amino acid (AA) density. Eight different genotypes of sex-separate reared broilers were fed diets varying in ME (2,723–3,386 kcal of ME/kg) and AA (0.89–1.65% digestible lysine with all essential AA acids being indexed to lysine) levels. Broilers were processed to determine carcass component yield at many different BW (1.09–4.70 kg). Trial data generated were used in model constructed to discover the dietary levels of ME and AA that maximize MOFC on a per broiler or per broiler annualized basis (bird × number of cycles/year). The model was designed to estimate the effects of dietary nutrient concentration on broiler live weight, feed conversion, mortality, and carcass component yield. Estimated coefficients from the step-wise regression process are subsequently used to predict the optimal ME and AA concentrations that maximize MOFC. The effects of changing feed or meat prices across a wide spectrum on optimal ME and AA levels can be evaluated via parametric analysis. The model can rapidly compare both biological and economic implications of changing from current practice to the simulated optimal solution. The model can be exploited to enhance decision making under volatile market conditions.

Light intensity can influence broiler behavior, but discrepancies in the scientific literature remain. Furthermore, few studies have investigated the welfare implications induced by varying light intensity. We investigated the effects of providing 5 or 20 lux light intensity on broiler behavior, welfare and productivity. A total of 1,872 Ross 308 broilers of mixed sex were studied across 2 replicates. Treatments began on d 8 with one of 2 light intensity levels: 5 lux or 20 lux, using LED lights on a 16L:8D photoperiod with 30 min sunrise and sunset periods. Production data, behavioral activity, and plasma samples for corticosterone concentration analysis were collected weekly from 8 to 46 d of age. Eye weight was collected at 42 d of age. Leg strength was assessed at 35, 42 and 45 d of age using the latency to lie test and leg and foot conditions (foot pad dermatitis, hock burn, leg straightness) were assessed at 46 d. Live weight differed between light treatments, with broilers kept at 20 lux being lighter than broilers kept at 5 lux at 46 d of age (males: -5.1%, females: -2.8%, P 0.0001), despite no significant differences in feed intake. However, broilers kept at 20 lux were more active during the photophase than broilers kept at 5 lux throughout the rearing period (P 0.0001). Eye weight was also on average 5% lighter for broilers kept at 20 lux compared to 5 lux (P = 0.001). Nonetheless, there was no significant effect of light intensity on other measures of broiler welfare: mortality and culls, plasma corticosterone concentrations, or latency to lie reflective of leg strength. Hence, broilers kept at 20 lux compared to 5 lux were found to be more active, had slower growth, and had lighter eye weight, but other welfare measures reflective of biological functioning or leg health did not show significant changes.

A study was conducted to determine the effects of feeding sorghum distiller's dried grains with solubles (SDDGS) on carcasses characteristics (live weight, whole net carcass rate, breast muscle percentage, thigh muscle percentage), muscle quality (meat color, shear stress, cooking loss rate, cooked meat percentage), and meat composition of China Micro Duck (CMD) drakes aged from 4 to 8 wk. A total of 240 CMD drakes (aged 4 wk and initial weight was 496.7 g) were randomly allotted to one of 4 dietary treatments in randomized complete block design. The 4 treatments were S0(the control group, S5, S10, S15, indicating the dietary content of SDDGS (zero, 5,10 and 15%, respectively). Each treatment with 60 drakes was equally divided into 6 repeated test groups, each group with 10 drakes. The results showed that S5, S10, and S15 could decrease the thigh muscle percentage linearly (P 0.01); however, there was no significant (p 0.05) effect on other carcass characteristic and muscle quality indexes of live body weight (BW), whole net carcass yield (WNCY), breast muscle percentage (BMP), breast muscle color (BMC), thigh muscle color (TMC), breast shear strength (BSS), cooking loss (CL), or cooked meat percentage (CMP). For meat composition, the increasing level of SDDGS caused a linear and quadratic decrease (P 0.01) of crude protein and a linear and quadratic (P 0.01) increase of crude fat of thigh and breast muscle, while breast muscle ash was not significantly affected (P 0.05). Overall, this study revealed that in the 3 kinds of diets with SDDGS, S5 had the least negative impact on carcass characteristics, muscle quality, and meat composition.

The aim of the current study was to determine the effects of different eggshell temperatures (EST); low (33.3 to 36.7 degrees C), control (37.8 to 38.2 degrees C), and high (38.9 to 40.0 degrees C) during 10 to 18 days of incubation on welfare status including foot pad dermatitis (FPD), hock dermatitis (HD) and feathering status, and gait score in broilers. Score 2, 4, and 5 of FPD were found to be similar among the treatment groups, whereas a score of 3 was found to be higher in the control and high EST groups (27.7% and 29.2%) compred to the low EST group (16.9%). The eggshell temperature fluctuations were significantly affected the incidence of HD, whereas broiler sex did not. All of the broilers in the high EST group had HD with various scores, while a percentage of 21.1% and 6.9% of broilers had the score 1 of HD in the low and control EST groups, respectively. Feathering status showed a difference between body parts including wing, neck, back, and vent and also a general mean score of broilers from low EST treatment had the highest score for feathering. A higher incidence of gait score was observed in broilers from the control EST treatment than low and high EST groups. This can be attributed to a higher live weight of broilers from the control EST group. On the other hand, the incidence of a gait score of 3 and 4 was found for broilers from control and high EST treatment groups. Male and female broilers from the high EST group had the higher gait score. In conclusion, gait score and welfare status of broilers were affected by fluctuations in EST between 10 and 18 days of incubation.

Airborne microorganism level is an important indoor air quality indicator, yet it has not been well documented for laying-hen houses in the United States. As a part of the Coalition for Sustainable Egg Supply (CSES) environmental monitoring project, this study comparatively monitored the concentrations and emissions of airborne total and Gram-negative (Gram(-)) bacteria in three types of commercial laying-hen houses, i.e., conventional cage (CC), aviary (AV), and enriched colony (EC) houses, over a period of eight months covering the mid and late stages of the flock cycle. It also delineated the relationship between airborne total bacteria and particulate matter smaller than 10 μm in aerodynamic diameter (PM10). The results showed airborne total bacteria concentrations (log CFU/m(3)) of 4.7 ± 0.3 in CC, 6.0 ± 0.8 in AV, and 4.8 ± 0.3 in EC, all being higher than the level recommended for human environment (3.0 log CFU/m(3)). The much higher concentrations in AV arose from the presence of floor litter and hen activities on it, as evidenced by the higher concentrations in the afternoon (with litter access) than in the morning (without litter access). The overall means and standard deviation of airborne total bacteria emission rates, in log CFU/[h-hen] (or log CFU/[h-AU], AU = animal unit or 500 kg live weight) were 4.8 ± 0.4 (or 7.3 ± 0.4) for CC, 6.1 ± 0.7 (or 8.6 ± 0.7) for AV, and 4.8 ± 0.5 (or 7.3 ± 0.5) for EC. Both concentration and emission rate of airborne total bacteria were positively related to PM10 Gram(-) bacteria were present at low concentrations in all houses; and only 2 samples (6%) in CC, 7 (22%) samples in AV, and 2 (6%) samples in EC out of 32 air samples collected in each house were found positive with Gram(-) bacteria. The concentration of airborne Gram(-) bacteria was estimated to be

White striping refers to the occurrence of different degrees of white striations on broiler breast fillets and thighs of larger broilers, yet little is known about its causes. Thus, the objective of the study was to estimate the occurrence of normal (NORM), moderate (MOD), and severe (SEV) degrees of white striping with respect to the growth rate of broilers and to compare their proximate composition without the confounding effect of diet. Straight-run 1-d-old chicks (n = 280) were randomly assigned to either a low- (LED) or high-energy (HED) diet (5 replicates of 28 birds/dietary treatment). Birds were processed at 54 d of age, and live weight, deboned fillet weight, and occurrence of white striping were recorded. As expected, birds fed the HED had lower (P0.05) feed conversion ratios than birds fed LED (2.08 vs. 2.28). Also, HED-fed birds had heavier P0.05) live and fillet weights when compared with the LED-fed birds. A greater (P0.05) percentage of breast fillets from LED-fed birds were scored NORM, whereas HED-fed birds produced a greater (P0.05) percentage of SEV fillets. Fillet weight and yield (percent of live weight) increased (P0.05) as the degree of white striping increased from NORM to SEV. Additionally, NORM fillets had greater (P0.05) lipid and lower (P0.05) protein content when compared with SEV fillets. Also, NORM fillets had greater (P0.05) percentages of SFA than SEV fillets; however, proportions of all monounsaturated fatty acids, as well as linoleic and linolenic acids, were greater (P0.05) in SEV than NORM fillets. These results suggest that an increased growth rate results in increased occurrence of higher degrees of white striping in broiler breast fillets, and the various degrees of white striping are associated with differences in chemical composition of breast fillets.

A radial basis function neural network (RBFN) approach was used to develop a multi-input, multi-output model for the effect of diets varying in the percentage of ME provided by protein (% ME P ), fat (% ME F ), and carbohydrate (% ME C ) on live weight gain, protein gain, and fat gain in growing chickens. Thirty-three data lines representing response of the White Leghorn male chickens during 23 to 33 d of age to the diets varying in the % ME P , % ME F , and % ME C were obtained from literature and used to train the RBFN model. The prediction values of the RBFN model were compared with those obtained by multiple regression models to assess the fitness of these 2 methods. The fitness of the models was tested using R 2 , MS error, mean absolute deviation, residual SD, and bias. The developed RBFN model was used to evaluate the relative importance of each input parameter on chicken growth using a sensitivity analysis method. The calculated statistical values corresponding to the RBFN model showed a higher accuracy of prediction than multiple regression models. The sensitivity analysis on the model indicated that dietary % ME P is the most important variable in the growth of chickens, followed by dietary % ME F and % ME c . It was found that the RBFN model is an appropriate tool to recognize the patterns of input-output data or to predict chicken growth in terms of live weight gain, protein gain, and fat gain given the proportion of dietary percentage of ME intake supplied through protein, fat, or carbohydrates.

A trial was conducted to evaluate the effects of different feeding programs on growth performance and carcass characteristics of Nicholas Large White female turkeys. Three different feeding programs were considered for a 12-wk period: 1) 3 diets fed for 4 wk each (starter 24% CP, grower 20% CP, and finisher diet 16% CP), 2) 2 diets fed for 6 wk each (starter-grower 22% CP and grower-finisher diet 18% CP), and 3) no change of diet for 12 wk (starter-grower-finisher diet 20% CP). From 0 to 4 wk of age, birds were fed an ad libitum common starter diet. Each dietary treatment was replicated 3 times, and feed and water were provided ad libitum. Body weight and feed consumption were measured every 2 wk, whereas carcass characteristics were evaluated at 16 wk of age. Feed intake increased as the frequency of dietary changes decreased, and feed conversion was not different between programs 1 and 3. There were no significant differences in final BW among experimental groups. For a single feeding program, the proportion of neck, bone, and feet decreased, and a greater percentage of edible meat was registered as compared with the other 2 groups. Mean carcass, breast, and thigh weights of turkeys reared under multiple diets were not different compared with other groups. Positive correlations were noted between live weight and weight of carcass, breast, thigh, drumstick, wing, and abdominal fat of turkeys. Thus, a single cycle feeding regimen in Nicholas Large White female turkeys results in similar growth performance and carcass characteristics compared with other conventional feeding programs considered in the present study.

This study examined the effects of dietary energy content on the egg production and egg quality of hens kept in 3-hen conventional cages or 8-hen furnished cages. A total of 1,088 Lohmann Selected Leghorn hens were housed in either furnished or conventional cages and offered low- or high-energy diets (from 2,342 to 2,414 kcal/kg or from 2,581 to 2,629 kcal/kg) during 3 consecutive feeding phases of 20, 16, and 16 wk, respectively. The same dietary energy effects were observed in both cage systems. The hens that received the low-energy diet consumed more feed (P < 0.01) and produced fewer eggs per day (P < 0.05) than the birds fed the high-energy diet. Over the entire experiment, housing had no significant effects on production parameters, but during the third feeding phase, the production rate was smaller in furnished cages than in conventional cages (P < 0.01). Because of the greater live weight of the hens in furnished cages at the beginning of the experiment, these hens consumed more feed during the first feeding phase than the hens in conventional cages. During the third feeding phase, the hens in furnished cages consumed less feed than those in conventional cages (P < 0.01), probably because of their better feather cover. No differences in feed conversion ratio were found between the cage types. The results of this study confirm the results of previous studies providing evidence of equal production rates and feed conversion ratios in furnished and conventional cages.

The mathematical models for describing growth kinetics are important tools to examine biological parameters, such as BW at specific time, maximum growth response, and growth rates. Classical growth models such as Gompertz and Richards have been extensively used in broiler studies. To obtain a more intuitive understanding of growth, a class of flexible growth models containing 3 and 4 parameters were developed as hyperbolastic models. These models provide description of growth behaviors for continuous output in different fields, for instance cancer and stem cell growth. This study was conducted to find out if 3 flexible new hyperbolastic growth models, called type 1, 2, and 3 (H1, H2, and H3), may be used to illustrate relationship between live weight and age in broilers and also how effective such models would be compared with 2 classical growth models, namely Gompertz and Richards. A set of growth data over 70 d, obtained from 18 male broilers, was used to fit growth models. Goodness of fit of the models was determined using mean square error, R2, and residual standard deviation. It was revealed that the 3 new models may be used to fit broiler growth data successfully and could be implanted in SAS PROC NLIN. Goodness of fit criteria refers better fit with H3, presumably due to its greater flexibility, followed by the Richards, Gompertz, H2, and H1. In conclusion, it seems that the H3 can be considered as a more useful tool for modeling broiler growth. However, it is reasonable to compare models for fit before selection of the more accurate one.

Standard commercial practice is to deny poultry access to feed 8 to 12 h prior to slaughter. Occasionally a flock of turkeys is marketed at several ages, and starvation can occur for birds that are not shipped. For this project multiple marketed female turkeys were fed a special diet (nutritive supplement) during the preslaughter feed withdrawal period to reduce live weight loss, bird stress, and grazing on manure. Three trials were conducted at the Nova Scotia Agricultural College using 60 female turkey poults for each of 8 pens for each trial. The birds were separated into 8 pens with 20 birds from half of the pens shipped at 63 d of age and all remaining birds shipped 1 wk later. Prior to shipping, feed was withdrawn, with half the pens receiving the supplement. The pens that had received supplement at 63 d of age received it again a week later along with half the pens not previously marketed. The supplement was only consumed in a significant quantity when it was new to the birds (~10 g/kg of bird). The carcass yield, based on the live weight before the conventional feed withdrawal period, was improved for birds that consumed the supplement. Microbiological profiles of the crops revealed that although the total number aerobic bacteria was not affected, birds ingesting the supplement had fewer Escherichia coli and coliforms present. Breast meat samples collected at 15 min postmortem and 24 h postmortem and measured for pH were not found to be different between the treatments. Because birds would only consume the supplement on the first exposure, this supplement is only effective for reducing live weight loss and microbial load of the crop in an all-in all-out management situation.

The effects of dietary conjugated linoleic acid (CLA) supplementation on growth performance, carcass quality, free fatty acid composition, and accumulation of CLA were investigated in broilers. Four hundred eighty 3-wk-old broilers were assigned to 4 dietary treatments (0, 0.5, 1.0, and 1.5% CLA) with 6 replicates of 20 chickens. Feed consumption and BW were recorded at every 5-d period. On d 42, carcass compositions were determined from 30 birds per treatment. There were no significant differences in average daily feed intake among the treatments. However, feed conversion ratio was highly significantly different (P < 0.01) between treatments, and average daily gain was significantly reduced by a supplement of dietary CLA (P < 0.05). Live weight and percentages of carcass, drumstick, thigh, boneless thigh, pectoralis major, and pectoralis minor were not influenced by the dietary CLA. Abdominal fat was significantly reduced (P < 0.01) with the increased CLA level in the broilers' diets. Percentages of liver weight were significantly increased (P < 0.01) after the CLA treatments. Percentages of drumstick and boneless drumstick were significantly decreased (P < 0.05) by dietary CLA. In terms of free fatty acid composition in broiler meat, CLA addition significantly increased (P < 0.05) saturated fatty acids, especially in thigh muscle, whereas unsaturated fatty acids were unchanged. Accumulations of CLA in meat were significantly increased (P < 0.05) with increasing CLA level in the diet.

A study was conducted to determine the influence of genotype, market live weight, transportation time, holding time, and temperature on broiler breast fillet color under commercial processing in Italy. Color was evaluated using a Minolta Chroma Meter (Minolta Chroma Meter CR-300, Minolta Italia S.p.A., Milano, Italy) on a total of 6,997 broiler breast fillets (Pectoralis major muscle) from 79 different flocks chosen at random during a 6-mo period. The flocks were represented by Ross 508 and Cobb 500 genotypes of both genders, processed at different ages, and subjected to different antemortem conditions during transport and holding. Ross 508 broilers exhibited a lower hue angle (H*) than did Cobb 500 (45.12 vs. 48.52; P < 0.01). With regard to the market live weight of broilers, the heavier birds (>3.3 kg) produced a darker breast meat (L* = 51.67) than did the lighter birds (210 km (a* = 3.28 and 3.04, respectively). The shortest holding time (9 h (L* = 52.12 and 52.04, respectively). Furthermore, an increase of both meat a* and saturation (C*) was observed with the advance in holding time. The holding temperature significantly affected the meat color. Breast fillets from birds held at 18°C (L* = 53.11) (P < 0.001). Moreover, the increase in holding temperature (18°C) also determined a lower breast meat a* (3.77 vs. 3.12 vs. 2.72, respectively; P < 0.001), b* (3.72 vs. 3.41 vs. 3.37, respectively; P < 0.05), C*, and H*. In conclusion, the holding time and temperature exerted the most important effect on broiler breast meat color. However, other factors, such as genotype, live weight, and transportation, may influence breast meat color.

This study was undertaken to assess dietary CP and ME concentrations for optimum growth performance and carcass characteristics of French guinea broilers. In a 3 x 3 factorial arrangement, 396 1-d-old French guinea keets were randomly assigned to experimental diets with 3,050, 3,100, and 3,150 kcal of ME/kg of diet; each contained 21, 23, and 25% CP, respectively, from 0 to 4 wk of age (WOA). From 5 to 8 WOA, experimental diets had 3,100, 3,150, and 3,200 kcal of ME/kg of diet, and each contained 19, 21, and 23% CP, respectively. Each dietary treatment was replicated 3 times, and feed and water were provided ad libitum. Body weight and feed consumption were measured weekly, whereas carcass characteristics were evaluated at 8 WOA. For the most part, birds on 3,100 and 3,150 kcal of ME/kg of diet at 0 to 4 WOA exhibited greater (P0.05) BW gain, greater carcass and breast weights (P0.05), and lower (P0.05) feed consumption and feed conversion ratios (FCR) than those on a diet with 3,050 kcal of ME/kg. Mean feed consumption of birds fed 25% CP diets was higher (P0.05) than those on other dietary CP concentrations. Mean BW gain, FCR, and carcass and breast weights of birds fed 25 and 23% CP diets from 0 to 4 WOA were not different (P0.05), but they were better (P0.05) than those of birds on 21% CP diets. Positive correlations (P0.01) were noted between live weight and weight of carcass, breast, thigh, drumstick, and wing of guinea broilers. Thus, diets with 3,100 kcal of ME/kg and 23% CP or with 3,150 kcal of ME/kg and 21% CP at 0 to 4 WOA and 5 to 8 WOA, respectively, were used more efficiently by French guinea broilers.

This experiment aimed to study the effect of ultimate pH (pH(u)) on the biochemical and physicochemical characteristics of turkey breast muscle with normal rate of postmortem pH fall. Five hundred turkey toms (12 wk old, 10 kg live weight) were randomly chosen from a commercial flock. At 24 h postmortem, 64 birds were randomly selected within the subgroup showing pH higher than 6.0 at 20 min postmortem and pH(u) lower than 6.1. These pH levels were used to exclude pale, soft, and exudative (PSE) meat and dark, firm, and dry (DFD) meat, respectively. The pH(u) was significantly correlated with luminance (L*; r = -0.37) and yellowness (b*; r = -0.36) at 24 h postmortem, drip losses (r = -0.56 to -0.62), thawing loss (r = -0.47), 80% compression (r = -0.29), yield of curing and cooking (r = 0.37), glycolytic potential at slaughter (r = -0.44) and lactate at 24 h postmortem (r = -0.47). Significant correlations were found between drip losses and compression test on cooked meat (r = 0.27 to 0.34). Cooking loss was correlated with WB shear force (r = 0.32). These results show that when PSE defects are excluded, the intensities of the correlations between pH(u) and meat quality traits are lower than those usually reported. The present data also indicate that the level of glycogen at time of slaughter poorly explains the variability in pH(u). Thus, further research is needed to identify the mechanisms explaining pH(u) variation in poultry muscle.

An experiment was conducted using Ross x Ross 308 males to estimate the proportion of dietary valine needed to optimize performance in broilers from 42 to 56 d of age. All birds received common feeds from 0 to 42 d, and then experimental diets were given to 56 d of age. A diet consisting of corn, soybean meal, and corn gluten meal (17% CP, 3.25 kcal of ME/g) having 0.60% valine served as basal feed. All other essential amino acids were above recommended levels. Successive additions of 0.07% of L-valine were isonitrogenously substituted for L-glutamic acid up to a total of 0.81%. Regression analysis (95% of response) indicated that valine at 0.72% of the diet maximized body weight gain, whereas 0.73% optimized feed conversion. Depot fat removed from the abdominal cavity after processing was unaltered, and weights of resultant chilled carcasses maximized at 0.73% valine in parallel with final live weight. The amount of fillets recovered from chilled carcasses optimized at 0.73% valine; however, the incidence of distinctive blood streaks in the meat (splash) progressively increased with valine as did the level of redness apart from streaking, based on light reflectance. Given lysine at 0.85%, a ratio of 0.86 with valine appears to be adequate. The presently determined requirement of 0.73% total valine (0.67% digestible) for broiler males from 42 to 56 d of age is slightly higher than the 0.70% recommended by the NRC.

The effects of triticale and wheat on broiler (mixed sexes) performance and cost of production were compared. In experiment 1, wheat- and triticale-based diets were fed to 3 strains of broilers (Ross x Ross, Hubbard x Hubbard, and Ross x Hubbard). Each of the diets was provided to 5 cages/strain (n = 10 chicks/cage; 1,273 cm2/bird). Weekly BW, gain, feed consumption, and feed conversion ratio (FCR; g of feed/g of gain) were determined. At 42 d, 4 chicks/pen were shipped to a commercial processing plant. The plucked, eviscerated carcasses were evaluated for carcass traits. Overall, the triticale-fed birds had lower final BW and average daily gain and higher FCR. Eviscerated carcass, thigh, and drum weights were lower, but pectoralis minor as a percentage of carcass weight was greater in triticale-fed birds. In experiment 2, a wheat diet and a diet in which triticale was substituted (by weight) for wheat were provided in a 3-phase feeding program. Each diet was provided to 2 identically-equipped commercial barns housing 17,034 broilers each. Individual BW of a sample of birds were recorded in each barn at 0, 19, 34, and 42 d, corresponding to the beginning and end of each dietary phase. Feed consumption and FCR were calculated for each barn. An analysis of each of the diets was calculated using a broiler chicken production cost model. Final BW, feed consumption, carcass weight at processing, flock uniformity, percentage of Grade A carcasses, and percentage of condemned carcasses were not affected by cereal source. Overall FCR (2.165, 2.036; P = 0.0052), feed cost (dollars 0.617, dollars 0.577/kg live weight; P = 0.0260), and total cost of production (dollars 1.019, dollars 0.972/kg live weight; P = 0.0183) were greater for the triticale than wheat diets, respectively. Triticale would be an economically feasible replacement for wheat in broiler diets when its price is less than or equal to 95% of the cost of wheat, less dollars 18 (Canadian). Increased knowledge of the available nutrient profile of triticale, as well as least-cost feed formulation would likely increase the value of triticale relative to wheat for broilers.

A study was conducted to determine the effects of a replacement finisher feed (RF) on carcass yield and carcass bacteria recovery. RF is a commercial formulation of a D-glucose polymer (maltodextrin) with added salts and vitamins. Commercial male broilers (41 d of age) were given either RF or control-feed (traditional starter feed) for 8 h, followed by feed withdrawal for 0, 4, 8, or 12 h before processing. During processing, whole carcass rinses (WCR) of pre-eviscerated (feathers, feet, and heads removed) and eviscerated carcasses were analyzed for recovery of bacteria. Body weight at initiation of feed withdrawal (catch weight) or at slaughter (dock weight) did not differ significantly due to type of feed. Live shrink, as a percentage of live weight, increased significantly with time off feed. Birds fed RF exhibited significantly lower live shrink than the birds fed the control feed at 8 and 12 h after feed withdrawal. This difference between types of feed, RF or control, was approximately 0.1% per hour of feed withdrawal. Type of feed or length of feed withdrawal did not affect Campylobacter, coliform, or Escherichia coli counts recovered from WCR of pre-eviscerated or eviscerated carcasses. These data demonstrate that feeding RF to broilers for 8 h before initiation of feed withdrawal may reduce live shrink without affecting carcass Campylobacter, coliforms, or E. coli recovered.

Genetic and gender-related variations in breast muscle yield of broiler chickens may be attributed to differences in number and size of muscle cells (myofibers). In this study, male and female broilers from eight commercial strain crosses (SC) were compared for body and breast muscle weight with adjustment of the Gompertz function. Additionally, breast fillet dimensions (length, width, and depth) and myofiber density (myofiber number/area; MFD) were assessed. Live weight and breast muscle development was determined to 56 d of age at weekly intervals. MFD was assessed at 8 d of age. As expected, SC differed in BW, breast weight and yield, and breast fillet dimensions and had variations in growth curves. Maximal growth rate for breast weight was reached approximately 4 d after that of BW. Males and females showed different growth curves, with males having slower growth rate maturity parameter and reaching the maximal growth rate later than females for BW and breast weight. Breast depth was the breast measure with highest positive correlation to breast yield. SC differences could not be explained by MFD, but males had higher MFD density than females. The possible relationship of the MFD observations to total myofiber number is discussed.

This study was conducted to investigate the effect of a 12-h feed outage at various times prior to slaughter on subsequent broiler performance, live shrink, and processing yields. Broilers were full-fed or subjected to a 12-h feed outage followed by a refeeding period of 12, 24, or 48 h. Bird live weights or feed consumption was monitored during the outage and recovery periods. Birds were subjected to a 10-h feed withdrawal period and were slaughtered using simulated commercial conditions. Carcass weights were recorded through processing for yield determinations. The 12-h feed outage affected female broilers more than male broilers. Although all birds lost weight during their respective feed outage periods, birds were able to consume enough feed upon refeeding such that no significant differences in final live weight were detected at the initiation of feed withdrawal. Female broilers processed after a 12-h refeeding period had significantly larger gall bladders (by weight) as compared to the gall bladders of birds in the other treatments. Other processing parameters were not significantly affected by treatment. A 12-h feed outage and feed replacement prior to normal preslaughter feed withdrawal does not significantly affect processing yields, provided sufficient feed is replaced for at least 12 h prior to feed withdrawal. Because total feed consumption did not change following feed outage replacement, feed must be sufficient to compensate for that not consumed during the outage.

The effects of energy level, fat type, and fat level in breeder hen diets on subsequent offspring market age live BW, carcass yield, and liver characteristics from breeder hens at 29 and 36 wk of age were evaluated. At 22 wk of age, six dietary treatments were imposed. Dietary treatments contained: 1) 3.0%, added poultry fat (PF) and 467 (high energy) kcal/hen per day at peak production (CPP), 2) no added fat and high energy, 3) 3.0% added PF and 430 (low energy) CPP, 4) no added fat and low energy, 5) 1.5% added PF and 449 (moderate energy) CPP, and 6) 3.0% added corn oil (CO) and moderate energy. Breeder age influenced Day 43 broiler live BW, percentage total carcass and front-half yields, and liver moisture contents. Furthermore, wet and dry liver weights were higher in female broilers compared to those of male broilers from 29-wk-old breeder hens. Live BW was higher in broilers from hens fed low-energy diets compared with moderate-energy diets and 3.0% compared to 1.5% PF diets. Percentage liver DM was higher in females compared to male broilers from hens fed 3.0% CO and moderate energy and was highest in male and female broilers from hens fed 1.5% PF and moderate energy. Percentage wet liver weight and liver DM were higher and liver moisture content was lower in broilers from hens fed 1.5% compared to 3.0% PF diets. Overall, energy and fat levels in breeder diets had subsequent influences on market age weight and liver characteristics of broilers.

The growth simulation program, BPHL (Bromley Park Hatcheries Limited), is a computerized, mechanistic, deterministic and dynamic approach to the evaluation of the effects of diet on broiler carcass composition and growth. Daily growth is simulated with information on the initial age and live weight of the bird, number of days over which the diet is to be fed, protein and amino acid densities of the diet, dietary metabolizable energy, and whether feed intake is to be simulated or data provided. Output provides information on a daily basis with respect to daily and accumulated deposition and current bird status for protein, fat, water, and ash body content. Carcass weight, feather weight, live weight, feed eaten, feed deprivation heat loss, limiting amino acids, food conversion ratio, and percentage carcass fat are also provided. The approach employs empirically derived first-limiting amino acid coefficients relating to accretion efficiency and dietary concentration to define limits of protein retention, uses mathematical expressions describing feed intake and heat loss trajectories as datum patterns prescriptive of the strain, introduces calibration as a device for improving correspondence between simulated and field performance, and relies on an assumption that deviations to the datum patterns of food intake and heat output caused by strain and environmental factors can be duplicated by simple multiplers acting on the expressions. The program may be used as a tool for exploring the predicted effect of specific dietary characteristics and strain parameters on growth, body composition, and performance.

Two experiments were carried out to evaluate the influence of the frequency of a sinusoidal stunning current (150 mA, 4 s) on the physical recovery of turkey hens and toms and on the rate and extent of blood loss. In the first experiment, physical recovery of 72 hens and 78 toms was estimated after stunning with one of five different frequencies. The incidence of cardiac arrest after stunning at 50, 300, 480, 550, and 600 Hz was, respectively, 100, 60, 30, 30, and 0% in hens and 53, 38, 0, 0, and 0% in toms. In hens, time to return of corneal reflex and neck tension and the onset of wing flapping decreased as frequency increased. In contrast to hens, about half of the toms stunned at 50 Hz did not show cardiac arrest. In these animals, recovery after 50 Hz was significantly longer than recovery at the four other frequencies. In the second experiment, 50 hens and 53 toms were bled out by a unilateral neck cut 10 s after stunning with one of four different frequencies (50, 300, 480, and 600 Hz). The rate and extent of blood loss within 3 min, relative to live weight, increased as stunning frequency increased. Large differences in the rate and extent of blood loss were observed between turkeys stunned at 50 or 300 Hz, according to the occurrence of cardiac arrest: cardiac activity was associated with significantly higher rate and extent of blood loss in both sexes. Overall, the results suggest that the duration of unconsciousness decreases as stunning frequency increases.

A trial was conducted to compare muscle traits and meat quality characteristics of the pectoralis muscle in 2 chicken commercial hybrids having standard (SBY) and high breast yield (HBY), respectively. A total of 2,124 one-day-old male chicks, equally divided into 2 experimental groups represented by strains (SBY and HBY), were grown using homogenous conditions and fed the same standard diets until reaching live weight of 4.2 kg at 53 and 55 d for the SBY and HBY groups, respectively. Thirty-six birds per each genotype were randomly selected, and their pectoralis major muscles were used to assess meat quality properties (color attributes, pH, drip loss, cook loss, Allo-Kramer shear values after cooking, moisture, proteins, total lipids, and ashes) as well as histological traits (cross-sectional area, frequency of abnormal fibers, and intramuscular fat infiltration). As expected, HBY genotype had higher breast yield (31.0 vs. 30.0%; P ≤ 0.05). Histological evaluations showed that HBY pectoralis muscles had higher cross-sectional fiber area coupled with a dramatically higher (P ≤ 0.001) incidence of abnormal fibers and more abundant infiltration of intramuscular fat. Moreover, histopathological anomalous features such as central nuclei, proliferation of endomysial and perimysial collagen, inflammatory infiltrate, and necrosis of the fibers were also observed. As for meat quality, SBY hybrid showed lower ultimate pH values (5.97 vs. 6.07; P ≤ 0.01), whereas overall color parameters were not affected by genotype. Breast meat from the HBY genotype also exhibited significantly lower ability to retain liquid during refrigerated storage (drip loss, 2.46 vs. 2.06%; P ≤ 0.05) and cooking (26.2 vs. 21.1%; P ≤ 0.05) as well as higher shear-force values (2.59 vs. 2.11 kg/g; P ≤ 0.001). Finally, with regard to chemical composition, significant differences (P ≤ 0.05) were detected in protein (22.8 vs. 23.5%) and lipid (1.65 vs. 1.82%) contents, which were significantly lower in the HBY hybrid, whereas moisture content tended (P = 0.07) to be inferior in the SBY hybrid.

This study was conducted to investigate the potential of garlic powder (GP) in improving production efficiency, egg quality, and gut health of laying hens. A total of seventy-two 30-wk-old Dekalb white strain hens were used. The live weight of the hens ranged between 1.71 and 2.12 kg. Hens were randomly allotted into 3 dietary treatment groups in a complete randomized design experiment. The 3 dietary treatments were control (no garlic addition) and 3 and 5% GP additions to a basal diet on weight:weight ratio basis. Egg production and feed consumption were recorded daily, and hen BW and internal quality of fresh eggs were assessed weekly. Fecal samples were assessed for total bacterial load. The results from this study revealed significant (P < 0.05) increases of 0.81 mm in albumen height and 2.71 Haugh units of fresh eggs at 3% GP addition. Egg and albumen weights increased significantly (P < 0.05) by 2.06 and 1.84 g, respectively, at 5% GP over the control treatment. Egg production decreased significantly at 5% GP following a decrease in feed consumption. Similarly, log bacterial count in feces showed a dose-dependent reduction as dietary GP increased. Organoleptic evaluation of eggs from treatment birds revealed a strong garlic flavor in eggs from 5% GP group compared with the control and 3% GP groups. Results of this study suggest that dietary GP improved egg weight and albumen quality with a strong garlic flavor at high dietary levels.

Two experiments were conducted to determine the effect of different stunning voltages on the objective texture of the Pectoralis major muscles deboned at various post-mortem times. Broilers were stunned at either 50 or 200 V alternating current (VAC) for 10 s in a brine stunner. The artery and vein on one side of the neck were severed, blood collected for 90 s, and blood loss calculated as percentage of live weight. Carcasses were then processed under simulated commercial conditions. In the first experiment, the right and left Pectoralis major muscles were excised at 1 and 2 h post-mortem respectively, weighed, vacuum-sealed in plastic bags, and held overnight at 2 C. In the second experiment, the Pectoralis major muscles were excised at 4 h post-mortem and held overnight at 2 C. The muscles were then heated at 85 C for 30 min, equilibrated to room temperature, and prepared for Warner-Bratzler shear analysis. The stunning treatments did not significantly affect blood loss, which averaged 2.86 and 2.64% for 50 and 200 VAC, respectively. Birds subjected to the 50 VAC treatment had a mean shear value of 7.3 kg, which was significantly lower (P < .05) than the mean shear value of 10 kg for birds subjected to the 200 VAC treatment for muscles excised 2 h post-mortem. The use of 200 VAC for stunning could be used without any detrimental effect on the cooked meat as long as the standard deboning time of 4 h was maintained.

The appearance of whole carcass and skin-on cut-up products is an important attribute that deeply affects the consumer's choice. Skin pigmentation is affected mainly by genetics, concentration and dietary source of pigments, health status of the birds, and scalding-plucking conditions during slaughtering, although other factors might play an important role. Retailers request batches of broiler chicken carcasses characterized by uniform skin pigmentation to be sold as whole carcass or parts. The aim of this study was to evaluate the variability of skin color of yellow-skinned broilers reared under intensive conditions. For the study, a total of 2,300 medium size broiler chickens (2,300 to 2,500 g of live weight) from 23 flocks (100 birds/flock; n = 12 flocks of males and n = 11 flocks of females; n = 12 flocks of Ross 508 and n = 11 flocks of Ross 308) were randomly selected in a single slaughterhouse. The color measurements were carried out on both breast and thigh pterylae as well as on shank skin adopting the L* a* b* system and using a Minolta colorimeter CR 300. The overall range in measured yellowness (b*) was fairly large for all skin color measurement positions. For breast, a mean value of 22.77 (SD = 5.12) was observed, with values ranging from 7.45 to 39.12. Average values of thigh and shank were 20.23 (SD = 5.02; range 1.99 to 37.82) and 53.99 (SD = 8.13; range 24.22 to 78.65), respectively. A higher skin yellowness was observed in females in all body parts as well as in Ross 308. Yellowness values of breast and thigh were significantly correlated (r = 0.85; P < 0.01), suggesting that the color evaluation may be carried out only on one measurement position of the skin.

Two experiments were conducted to compare conventional hand evisceration and yield-by-difference (YBD) methods of determining broiler processing yield. In each experiment, 192 birds from 24 pens were killed by bleeding for 2 min, scalded at 59 C for 2 min, and picked for 30 s in a rotary batch picker. Yield-by-difference was determined by removing and weighing the nonsalable portion of the carcass (inedible viscera, and nongastrointestinal waste). Conventional processing was performed by hand. Data were analyzed by pen and treatment for means and coefficient of variation. Live weight and New York dressed weights of birds processed by the two methods were not significantly (P

The objective of this study was to determine the effects of various levels of dietary black cumin seed on egg production, egg weight, feed conversion ratio, egg shell quality, and egg yolk cholesterol. In this study, eighty 27-wk-old laying hens (Hyline-5 White) were randomly assigned into 4 groups with 4 replicates of 5 birds each (20 laying hens per group) and fed diets supplemented with 1, 2, or 3% black cumin. Eggs were collected and weighed daily. Laying performance, egg quality, and feed conversion ratio were evaluated. Laying hens fed the diet supplemented with 3% black cumin had greater egg production than the control. Diets supplemented with 2 or 3% black cumin increased egg weight compared with other groups. Yolk weights of the eggs from hens fed diets containing 1, 2, and 3% black cumin were significantly greater than those from the control group. Shell thickness of the eggs from chickens fed 2 or 3% black cumin seed was significantly greater than those from chickens fed diets supplemented with 0 or 1% black cumin seed. Also, shell strength of the eggs from hens fed diets supplemented with 3% black cumin seed was significantly greater than the control. In addition, diets supplemented with 2 or 3% black cumin significantly decreased egg cholesterol per gram of yolk compared. No level of black cumin seed supplementation had any effect on live weight, feed consumption, feed conversion ratio, organ weights, and abdominal adipose tissue. This study showed that black cumin at the level of 2 or 3% would positively influence egg production, egg weight, and shell quality and decrease the concentration of cholesterol in the egg yolk.

WOS: 000247429300014, PubMed: 17575185, A study was conducted to determine the effect of live weight of partridges on egg production and egg quality characteristics. A total of 144 Rock Partridges were divided into control, heavy, middle, and light BW groups at 32 wk of age. Live weights averaged 512.78 g for the control group, 576.18 g for the heavy group, 523.49 g for the middle group, and 473.83 g for the light group. Egg production rates of these groups were 41.44, 45.78, 32.38, and 24.67%, respectively, over an 8-wk period (P < 0.05). Live weight significantly affected egg weight, specific gravity, albumen index, shell weight, shell thickness, Haugh unit, and albumen weight (P < 0.05). Live weight did not affect the shape index, membrane weight, or yolk weight. As a result, the live weights of partridges used for breeding should not be under the average live weights of hens of the stock. On the other hand, other important factors that affect the egg quality of partridges should be investigated.

A study was designed to determine the effects of enzyme supplementation on poults fed commercially based diets that included corn, soybean meal, and ground wheat with meat and bone meal (0 to 21 d) or Pro-Pak (22 to 56 d). Day-old turkey poults (n = 3,850) were divided into 35 pens and fed 1 of 5 dietary treatments for 56 d. Treatments were a positive control, a negative control (corn matrix adjustment of 140 kcal), and negative control diets supplemented with Avizyme 1502 at 250, 500, or 750 g/tonne. Feed intake, live weight gain, feed conversion ratio, and mortality were measured for the periods 0 to 21 d, 21 to 42 d, and 42 to 56 d, as well as for the cumulative 0 to 56 d. The 0- to 21-d period was further divided into subperiods (0 to 4 d, 4 to 8 d, 8 to 12 d, 12 to 16 d, 16 to 21 d) to evaluate early nutritional development. Ileal contents along with duodenal, jejunal, and ileal sections (n = 7/treatment) were sampled to determine apparent digestibility and morphology. In most instances, production response differences between the positive and negative controls were not significant, making definitive interpretation of enzyme addition difficult. Energy and protein ileal digestibilities of the negative control diets were lower than those of the positive control diet at 4, 8, 12, 16, and 42 d. Enzyme supplementation significantly improved energy and protein beyond that of the PC diet on d 42. Villus height and crypt depth did not respond to dietary treatment, although there was a significant interaction of age by treatment on jejunal villus height. The similarity between the controls, as well as the high inclusion of CuSO 4 , may be responsible for the low response with enzyme inclusion.