Assessment of meat quality attributes of four commercial broiler strains processed at various market weights.

As the demand for poultry meat continues to rise, industry production is constantly challenged with obtaining consumer needs. Integrators have answered this increasing demand by improving the growth rate of broilers allowing for increased production efficiently. The resulting broiler produces higher yields and a larger quantity of fresh poultry to satisfy consumer needs. However, this increase in efficiency has cost integrators as new quality issues continue to manifest through global production. Therefore, the objective of the current experiment was to evaluate the effect of genetic strain (standard and high yielding) and target weight on meat quality attributes such as pH, water holding capacity (WHC), and tenderness, alongside meat quality defects such as breast and tender myopathies. In the current study, 1,800 broilers from 4 commercial strains (2 high breast yielding (HY) and 2 standard yielding (SY) were raised sex separate to evaluate meat quality trends over time at 6 previously defined market weights. Birds were processed at weights ranging from 2,043 to 4,313 g in 454 g increments. HY strains produced higher breast and tender yields than those of SY strains (P < 0.05). There was an increase in breast and tender yield as target weight increased (P < 0.05) for both HY and SY strains. Differences were observed between strains for all fillet dimensions (P < 0.05); however, these measurements increased as target weight increased as expected. Woody breast (WB) had a higher severity (P < 0.05) in HY strains over SY strains, for both males and females. Differences were observed in white striping (WS; P < 0.05) for females in both strains, but no differences were observed in males. A main effect of target was noticed for both WB and WS (P < 0.05), expressing increased severity as target weight increased. Shear values were influenced more by target weight (P < 0.05), but inconsistent differences were observed between HY and SY groups. Meullenet-Owens Razor Shear (MORS) energy values increased slightly as target weights increased (P < 0.05) from 2,951 to 4,313 g in both males and females, but differences were minor and inconsistent with the smaller carcass weights. The MORS peak counts generally increased as target weight increased for both sexes. While strain had minimal effects on meat quality attributes, processing weight had a greater influence on quality, specifically muscle myopathies, WHC, and shear properties.

Meat quality attributes of male and female broilers from 4 commercial strains processed for 2 market programs.

In recent times, meat quality has become a key aspect of poultry production. In the current study, 2,400 sex separate broilers from 4 commercial strains were placed in 6 replications to evaluate various meat quality characteristics when grown to 2 market weights. Broilers were fed 1 of 2 diets with varying degrees of amino acid inclusion to evaluate meat quality of broiler raised on varying planes of nutrition. Birds were processed to meet 2 specified target weights (2.5 and 3.8 kg) representing small bird and big bird debone markets in the United States, respectively. Birds were processed using commercial methods, deboned at 3-h postmortem, and meat quality was assessed. Myopathies (woody breast, white striping, spaghetti meat, along with tenderloin quality), fillet dimensions, color, water-holding capacity (e.g., drip loss, cook loss), and Meullenet Owens Razor Shear was determined. Data were analyzed using the Mixed Model platform of JMP Pro 15.2 (SAS Institute, Cary, NC). Diet had no effect (P > 0.05) on the key quality responses; data were then pooled resulting in main effects of sex, strain, and target weight (noted as carcass size). On the day of processing, high yielding (HY) strains produced higher breast and tender yields (P < 0.05) when compared to standard yielding (SY) strains. In addition, and as expected, females exhibited higher breast and tender yields (P < 0.05) than males. However, males had significantly thicker (P < 0.05) and longer (P < 0.05) fillets, higher incidences (P < 0.05) of white striping, and higher (P < 0.05) cook loss when compared to females. Differences were also observed in tenderness as SY strain A produced the lowest shear values, whereas SY strain B produced the highest shear values across parameters (P < 0.05). SY strains in the small bird (SB) market performed better than SY strains in the big bird (BB) market as indicated by lower incidences of breast and tender myopathies white striping, woody breast, spaghetti meat, woody-like tender, and tender feathering and improved quality attributes (P < 0.05). Similar trends were observed (P < 0.05) in HY strains as SB carcasses produced a better overall product than BB. Differences in carcass size directly impacted quality (P < 0.05) as SB markets showed improvements in most parameters assessed, but broilers representing BB markets had greater breast yield. Although strain had minimal impacts on quality measures, carcass size, and sex had a greater impact on muscle myopathies, water-holding capacity, and shear properties.

Characterization of growth patterns and carcass characteristics of male and female broilers from four commercial strains fed high or low density diets.

Over the last few decades, the poultry industry has seen the emergence of various market segments that are beneficial for rearing various flock sizes. Two concurrent experiments consisting of 1,200 broilers each were conducted to evaluate the effects of broiler size and diet on the performance of four commercially available broiler strains, including 2 standard yielding (SY) and 2 high yielding (HY) strains. Within each experiment (Experiment 1: males, Experiment 2: females), a small bird (38 and 40 d processing) and big bird (47 and 54 d processing) debone market were targeted to give variable carcass size. Two polyphasic diets were fed based on varying of amino acid densities. The low-density diet (L) consisted of 1.20, 1.10, 1.00, and 0.96% digestible Lys and the high-density diet (H) consisted of 1.32, 1.21, 1.10, and 1.06% across the 4-phases, respectively, with similar essential amino acid to digestible Lys ratios between the L and H diets in each phase. Weekly BW, BW gain, feed intake, and feed conversion ratio were assessed, as well as processing yields during both experiments. Broilers fed the H diets responded better than those fed the L diets, regardless of sex, with increased BW and decreased FCR (P < 0.05). Male HY strains provided the highest carcass yields (P < 0.05) compared to SY strains, with no differences observed in females (P > 0.05). High density diets (Diet H) also produced increases in carcass, breast, and tender yield (P < 0.05) for males, but that trend was not present in carcass yield for females (P < 0.05). Overall, strain impacted performance traits and carcass yields. Therefore, the use of specific strains and amino acid density for various market segments is beneficial for integrators to maximize return.

Constant and cyclic chronic heat stress models differentially influence growth performance, carcass traits and meat quality of broilers.

This experiment compared the effects of 2 chronic heat stress (HS) models, constant (coHS), and cyclic (cyHS), on broiler performance, carcass characteristics, and meat quality. A total of 720 male chicks from a Cobb 500 line were placed in 12 environmentally controlled chambers divided into 2 pens of 30 birds. Before the experimental HS models were applied, chamber temperatures were gradually decreased from 32°C at placement to 24°C on d 20. From 20 to 41 d, 4 chambers were set to 35°C (coHS), and 4 chambers were set to 35°C for 12 h and 24°C for the next 12 h (cyHS). Four thermoneutral chambers were maintained at 24°C with half of the birds pair-fed to equalize feed intake (FI) with coHS birds (TN-coPF) and half fed ad-libitum (TN-al). From 20 to 41 d, FI and BW gain (BWG) of cyHS, coHS and TN-coPF birds were decreased (P < 0.001), whereas feed conversion ratio (FCR) was increased (P < 0.001) for coHS and TN-coPF birds compared with TN-al birds. The overall BWG and FCR of coHS birds were lower (P < 0.001) than TN-coPF birds. Both HS models reduced (P < 0.001) carcass weight, pectoralis major yield, total breast meat yield, and increased (P < 0.001) wing yield relative to TN-al birds, with each of these measurements more impacted by coHS than by cyHS. Pair-fed birds had lower (P < 0.001) fat pad and a higher total breast meat yield than coHS birds. They also had the lowest (P < 0.001) pectoralis major ultimate pH and yellowness, and these parameters were lower (P < 0.001) for coHS birds than for TN-al birds. Both HS models reduced (P < 0.001) the incidence of woody breast and white striping. Thus, these data indicate that the detrimental effects of HS cannot be entirely explained by reduced FI and that HS per se affects metabolic pathways associated with muscle and lipid accretion in broilers.

A comparison of formic acid or monoglycerides to formaldehyde on production efficiency, nutrient absorption, and meat yield and quality of Cobb 700 broilers.

After being banned by the European Commission in 2018, the use of formaldehyde as a feed amendment in the United States has come into question. Therefore, this study was conducted to explore alternatives to formaldehyde, such as formic acid and monoglycerides, and their effects on poultry production. In total, 1,728 Cobb 700 broilers were randomly assigned to 96-floor pens on day of hatch (18 birds/pen). Using a randomized complete block design (4 blocks), treatments were assigned to pens with blocking based on location within the barn, with the eastern half of the barn designated for digestibility and the western half designated for production (per experiment: 8 control pens and 10 pens per treatment). All diets were based on a negative control (NC), basal diet. Dietary treatments consisted of: NC, NC + 0.25% formalin (F), NC + 0.25 and 0.50% Amasil NA (AML and AMH; 61% formic acid and 20.5% Na-formate), and NC + SILO Health 104L (SILO; mixture of monoglycerides; 0.5% from 0 to 14 d, 0.4% from 14 to 28 d, and 0.2% from 28 to 42 d). Water and feed were provided ad libitum. Performance data were collected during feed changes on d 0, 14, 28, and 42, with digestibility data collected at d 14 (2 per pen) and carcass quality (6 per pen) assessed at d 46 with a randomly selected group of broilers. A one-way ANOVA followed by Dunnett's multiple comparison, where treatments were evaluated against F were conducted using JMP 14.0 (P ≤ 0.05). Main effect of treatment was significant for performance, nutrient digestibility, and carcass quality. Differences in body weight and ADG were observed from d 14 to d 28, resulting in a trending improvement in lysine digestibility on d 14 and carcass quality on d 46 of birds fed AML and AMH in comparison to those fed F (P < 0.05). Whereas birds fed SILO had reduced digestibility of methionine on d 14 and a decrease in meat quality on d 46 in comparison to those fed F (P < 0.05). Therefore, Amasil NA at 0.25 or 0.50% may be an effective alternative to formaldehyde as a feed amendment for poultry production.

Referral guidelines for medical imaging in children: an ESR-EuroSafe Imaging survey on availability, awareness and use in clinical practice among European radiologists.

OBJECTIVES: Justification of medical exposures from medical imaging is fundamental to radiation protection. Referral guidelines are intended to help physicians decide when an imaging study is justified. For two decades, referral guidelines have been a legally binding requirement for European Union member states. Recently, the European Society of Radiology (ESR) developed iGuide tool, which provides evidence-based referral guidance for imaging inclusive of children. The aim of this survey was to assess the availability, use and familiarity of referral guidelines for medical imaging in children and knowledge about the availability of ESR iGuide among ESR member radiologists. METHODS: Over a 2-month period (15 September-15 November 2019), 33,257 ESR member radiologists were invited to respond to an anonymised web-based questionnaire, which consisted of 12 multiple-choice questions. RESULTS: In total, 2067/33,257 responses (6.3%) were received from 52 countries. A total of 1068 out of 2067 (51.7%) respondents were aware that imaging referral guidelines are a legal requirement. One thousand five (48.6%) of all respondents did not know whether dedicated guidelines for imaging in children were available, and only 653 (31.2%) were aware of the mainstays of the available guidelines. Similarly, just 746 (36.1%) of all respondents were aware of ESR iGuide availability and features. CONCLUSIONS: The information gathered confirms that effective and widespread adoption of imaging referral guidelines is lacking, especially in children. Further work is required to improve uptake and awareness. KEY POINTS: • Justification of medical exposures is fundamental to radiation protection and evidence-based referral guidelines are crucial for practical implementation of this principle. • About half of survey respondents are aware that the availability of imaging referral guidelines is a legal requirement, despite this being mandated since 1997. • The information gathered from this survey confirms that, especially in children, an effective and widespread adoption of imaging referral guidelines is lacking.

Effect of pullet body weight and hen dietary amino acid treatments on their progeny fed high and low amino acid diets.

Four studies were conducted on Cobb 700 broilers to evaluate the dietary protein and any maternal effects on live production and processing parameters. Day-old Cobb 700 broiler breeder pullets were reared to conform to 2 different BW curves (control BW and increased BW) with 8 replicate pens per treatment. Birds were fed common diets from 1 d of age until first egg (24 wk). At 24 wk, 12 pens of each pullet treatment were given different amino acid (AA) diets (low = 14% CP, high = 15% CP). The performance of female and male progeny from 32 and 45 wk hens were evaluated on low AA and high AA density diets. The 4 progeny trial designs were identical factorial 2 × 2 × 2 designs, with 2 pullet BW curves (control BW and increased BW), 2 dam CP diet levels (low and high), and 2 progeny CP diets (low and high), with 6 replicates each containing 18 birds, for a total of 108 broiler progeny per treatment. Broiler chickens on the higher AA density feed exhibited consistent improvement in mid-growth BW and FCR and white meat yield percentage. Some maternal effects were noted, including increased carcass yield in female broilers from 32 wk old hens. There were 3-way interactions of pullet BW × hen dietary AA × progeny dietary AA treatments for female progeny carcass yield (from 32-week-old hens) and male tender yield (from 45-week-old hens). There were 2-way interactions of pullet BW x hen dietary AA treatments effect on female and male progeny drumstick yield from 32-week-old hens, pullet BW × progeny dietary AA treatments effect on male 27 d BW from 32-week-old hens, and hen dietary AA × progeny dietary AA treatments effect on male thigh yield from 45-week-old hen. The epigenetic effects of maternal pullet BW and dietary AA treatments were seen in processing yields suggesting, the need of dietary CP changes of the progeny.

Instrumental compression force and meat attribute changes in woody broiler breast fillets during short-term storage.

Woody breast (WB) is a myopathy of the Pectoralis major muscle in broilers that is characterized by increased hardness of the raw fillet. This defect increases economic losses due to associated decreased meat quality and the addition of training skilled laborers to identify problematic fillets. Therefore, the objectives of this study were to determine if compression force (CF) could be used as a non-invasive method of detecting WB and to assess changes in meat attributes during cold storage. Deboned fillets (n = 121) were collected from 8-wk-old broilers, and categorized as normal (NORM, n = 42), mild (MILD, n = 39), and moderate/severe (SEV, n = 40) for WB. Right fillet weight, drip loss, and CF of the cranial region were measured on the day of processing (day 0) and 1, 2, 3, 4, and 8 d of cold storage (4°C). Left fillets were sampled for sarcomere length (SL) and gravimetric fragmentation index (GFI) analysis following 1, 3, and 8 d of cold storage. Initial breast fillet weight, CF, cumulative drip loss, and SL increased as severity of WB category increased (P < 0.05). Compression force was highly correlated to WB severity (rs = 0.79). Compression force, SL, and GFI declined with storage time (P < 0.05), whereas cumulative drip loss increased (P<0.05). Cumulative drip loss, SL, and GFI had interactions between storage length and WB category (P < 0.05), where SEV generally changed more than NORM over time. The results of this study indicate that increased severity of WB fillets is associated with higher CF compared to normal fillets. Furthermore, there is a softening effect of the meat over time and data suggest that moisture (drip loss) and myofibril proteolysis (fragmentation) contribute to these changes. Using instrumental CF to assess fillet hardness can be used as a reliable tool to identify WB. However, adaptability in the commercial processing require additional studies prior to the incorporation into the processing plant for online grading purposes.

Descriptive sensory and instrumental texture profile analysis of woody breast in marinated chicken.

The broiler industry is currently experiencing a muscle anomaly referred to as "woody breast," and the effect of different cooking methods on the marination properties of severe woody breast (SWB) has not yet been reported. This study compared the texture attributes of marinated (injected) normal (NOR) and SWB using a convection oven and a flat-top grill. The objectives were 1) to develop and validate a descriptive texture attribute panel with 6 trained panelists using a 16-point scale and 2) to evaluate the instrumental texture profile analysis (TPA) using a texture analyzer. Sixty-four NOR and SWB were obtained from a commercial facility. Fillet color (L*, a*, b*) and pH were measured before marination. In each of 2 trials, the breast muscles were injected in bulk with 15% brine (0.48 STPP, 0.55% NaCl, final concentration), and marinade retention was determined after 20 minutes. The meat was vacuum packaged, stored at -20°C (7 d sensory; 29 d TPA) and then thawed (4°C, 24 h). Fillets were cooked to 73°C on a flat-top grill (176°C) or in an oven (176°C), and cook loss % was determined. Panelist samples (2 × 2 cm) and TPA samples (4 × 2 cm) were cut into 3 pieces. Color and pH were higher for SWB than NOR fillets (P < 0.05). Marinade retention was 83.21% for NOR meat and 59.23% for SWB meat. The flat-top grill method resulted in higher cook loss than oven (P < 0.05). SWB had higher cook loss when compared to NOR (P < 0.05). Sensory texture descriptors springiness, hardness, denseness, cohesiveness, fracturability, fibrousness, crunchiness, and chewiness were higher for SWB than NOR fillets (P < 0.05). TPA attributes also showed higher values for SWB compared to NOR (P < 0.05). No differences in texture were found between the grill and oven for sensory and TPA attributes. In summary, marinated SWB has significant texture differences when compared to NOR, regardless of cooking method.

Physical and chemical characteristics of meat from broilers raised in 4 different rearing systems, stored under freezing for up to 12 months.

This study evaluated the effects of freezing (-18°C) for 12 mo on attributes related to the texture of breast, drumstick, and thigh from broilers raised in 4 different rearing systems. Five-hundred carcasses of male broilers raised in 4 rearing systems (Antibiotic-free, Cobb 500, n = 125; Free-range, Hubbard ISA, n = 125; Conventional, Cobb 500, n = 125; Organic, Cobb 500, n = 125) were divided into breast, drumstick, and thigh and stored under freezing (-18°C) for 3, 6, 9, and 12 months. Breast, drumstick, and thigh meat from broilers raised in all studied rearing systems showed reduction (P < 0.001) of water-holding capacity (WHC) during freezing for up 12 months. It was observed an increase (P < 0.001) of cooking loss in breast samples from antibiotic-free, conventional, and organic broilers, and in thigh samples from broilers raised in all rearing systems studied. Breast meat from alternative broilers showed an increase in shear force values, while breast meat from conventional broilers became tenderer during the freezing storage. In general, alternative broilers had harder thigh meat than conventional broilers. A reduction (P < 0.001) in myofibrillar fragmentation index and total collagen concentration was verified in breast, drumstick, and thigh samples throughout the experiment. The freezing for up to 12 mo affects characteristics related to the succulence of chicken meat. Freezing chicken meat cuts for long periods, regardless of the rearing system, may interfere with the meat texture during preparation and consumption and, consequently, influence the consumer decision in a next purchase.

Incidence of broiler breast myopathies at 2 different ages and its impact on selected raw meat quality parameters.

White striping (WS) and woody breast (WB) are 2 poultry meat quality defects that affect the acceptance of raw breast fillets as well as properties of cooked and further processed products. The present study was intended to evaluate the incidence of these conditions in broilers at different ages and to compare the properties of fillets with different degrees of WS and WB. For this study, 1,920 birds were processed, at 6 and 9 wk of age, in a standard commercial inline processing system. After chilling, carcasses were deboned and butterfly fillets were collected and weighed. Individual fillets were scored for normal, moderate, severe, and very severe degrees of WS and WB, and for petechial hemorrhagic lesions (PHEM, 0 - no lesion to 2 - severe lesion). Representative fillets with NORM-WS/WB, SEV-WS, SEV-WB, and SEV-WS/WB were selected and stored at 4°C. After 24 h, fillet length, width, cranial height, and caudal height, as well as pH, color, and drip loss were recorded. There was an increase in incidence of severe and very severe WS and WB conditions at 9 wk compared to 6 wk of age. The relationship between fillet weight and the myopathies plateaued at 9 wk of age with more fillets showing a higher score. Mean PHEM scores were higher (P < 0.05) in SEV-WS, SEV-WB, and SEV-WS/WB compared to NORM-WS/WB birds, both at 6 and 9 weeks. NORM-WS/WB birds had lower (P < 0.05) live and breast weight, breast yield, and cranial and caudal heights, as well as b* value (yellowness) compared to SEV-WS/WB. NORM-WS/WB had lower (P < 0.05) pH while NORM-WS/WB and SEV-WS samples showed lower (P < 0.05) drip loss when compared to SEV-WB and SEV-WS/WB. The results from this study showed that the severe degrees of WS and WB are associated with heavier and older birds, and thicker breast fillets. Occurrence of severe degrees of WS and/or WB can affect various raw meat quality factors, mainly color and water holding capacity.

Current and future approaches to large airways imaging in adults and children.

"Large airways disease" is a catch-all phrase encompassing a wide variety of pathology affecting the trachea, main, lobar, segmental, and proximal sub-segmental bronchi. Relevant pathologies can be divided into focal or diffuse processes and many conditions have classic appearances on computed tomography (CT). We provide a review of the imaging specifics of a wide range of large airway pathologies in adult, childhood, and fetal life with examples of common and rare pathologies ranging from well-known entities such as cystic fibrosis and allergic bronchopulmonary aspergillosis to rarities such as Williams-Campbell, primary ciliary dyskinesia, and congenital high-airway obstruction syndrome (CHAOS). Although the spatial and temporal resolution of modern multidetector CT lends itself well to the depiction of small structures such as the peripheral airways, concerns regarding radiation exposure and increasing interest in the role of functional and quantitative imaging have led to a surge in research into dose reduction in CT and both structural and functional airway imaging via magnetic resonance imaging. We discuss the current literature on these emerging techniques along with some exiting near future directions for large airways imaging.

White striping and woody breast myopathies in the modern poultry industry: a review.

Myopathies are gaining the attention of poultry meat producers globally. White Striping (WS) is a condition characterized by the occurrence of white striations parallel to muscle fibers on breast, thigh, and tender muscles of broilers, while Woody Breast (WB) imparts tougher consistency to raw breast fillets. Histologically, both conditions have been characterized with myodegeneration and necrosis, fibrosis, lipidosis, and regenerative changes. The occurrence of these modern myopathies has been associated with increased growth rate in birds. The severity of the myopathies can adversely affect consumer acceptance of raw cut up parts and/or quality of further processed poultry meat products, resulting in huge economic loss to the industry. Even though gross and/or histologic characteristics of modern myopathies are similar to some of the known conditions, such as hereditary muscular dystrophy, nutritional myopathy, toxic myopathies, and marbling, WS and WB could have a different etiology. As a result, there is a need for future studies to identify markers for WS and WB in live birds and genetic, nutritional, and/or management strategies to alleviate the condition.

Effect of pre- and post-marination aging on meat quality attributes of early deboned (2 h postmortem) broiler breast fillets.

Marination is an effective method that can be used to improve the tenderness of early deboned breast fillets. The present study was designed to evaluate the effect of pre- and post-marination aging of 2 h postmortem (PM) deboned chicken fillets to get optimum meat quality. In this study, a total of 300 broilers (43 to 46 d of age) were processed using an in-line system and deboned at 2 h PM. Fillets were marinated, at either 2.5, 4, 6, 8 or 24 h PM, using vacuum tumbling (20 min) with a 15% marinade (final concentration of 0.5% salt and 0.45% phosphate). A non-marinated control (CON) was included. The left (HOLD) fillets were aged (held at 4°C for 24 h) prior to freezing post-marination while the right (NO HOLD) fillets were frozen immediately after marination to simulate various commercial practices. Marination pickup (MPU), total marinade retained after thawing (TMR), total purge loss after thawing (TPL), cook loss (CL), and Meullenet-Owens Razor Shear energy (MORSE) values were measured. Both in HOLD and NO HOLD fillets, there was an increase (P < 0.05) in MPU and TMR as the time of marination increased from 2.5 to 24 h PM. Furthermore, the HOLD fillets had a higher (P < 0.05) TPL when compared to the NO HOLD group. There was a higher (P < 0.05) CL for the CON fillets when compared to all marinated fillets suggesting that marination resulted in better water holding capacity. However, both in HOLD and NO HOLD groups, the MORSE values for the marinated fillets decreased (P < 0.05) from 4 h PM onwards, with 8 and 24 h PM having lower (P < 0.05) values than all other treatments. The results of this study suggest that pre-marination aging (aging after deboning prior to marination) of early (2 h PM) deboned fillets to 8 h PM can provide better tumble marination pickup and retention as well as tenderness (or lower shear values).

Effect of outdoor structural enrichments on the performance, use of range area, and behavior of organic meat chickens.

Chickens provided with outdoor access often do not fully use the range area. Natural cover, such as trees, can provide shelter and increase range use, but may not be practical for use in all free-range operations. A study was conducted to determine whether constructed enrichments that simulate natural structures increase range use and impact behavior of meat chickens. Slow-growing Delaware chickens were raised in floor pens (17 birds/pen) in a naturally ventilated house, with a pophole in each pen that allowed daily access to a vegetation-covered outdoor area. Feed and water were provided inside and outside. Birds were randomly assigned to one of 2 treatments: no range enrichment (control; NON) or range enrichment (ENR), which had roosts made of plastic pipe or screened shelters placed 7.6 m and 22.9 m from the house and overhead shade panels at 15.2 m. There were 4 replications. The numbers of birds inside and in the 4 quadrants of the range were counted in 7-min intervals 3 times daily (0900 h, 1300 h, and 1600 h) for 3 consecutive d when the birds were 7 and 10 wk of age; the numbers of birds performing various behaviors also were counted. On average, only 12.9% of birds used the range at any given time. The behavior of the birds was strongly affected by location (inside vs. outside), with birds mainly foraging and walking while outside and feeding, standing, and sitting while inside. Time of d impacted the number of birds that ranged (P ≤ 0.0001), with fewest birds outside during mid-day. Overall, birds using the range were most often (71%) observed in the quadrant nearest the house (zero to 7.6 m). However, in the ENR treatment, more birds (13%; P ≤ 0.0001) were observed in the farthest 2 quadrants (15.2 to 30.5 m from the house) than in the NON treatment (6%). This indicates that adding constructed enrichments to the range encouraged meat chickens to use it more fully.

Meat quality of broiler breast fillets with white striping and woody breast muscle myopathies.

The global poultry industry has been faced with emerging broiler breast meat quality issues including conditions known as white striping (WS, white striations parallel to muscle fibers) and woody breast (WB, hardness of raw fillet). Experiments were conducted to evaluate effects of WS and WB hardness on meat quality traits in broiler breast fillets. In Exp. 1, birds were processed at approximately 9 wk of age and deboned at 4 h postmortem (PM); in Exp. 2, birds were processed at approximately 6 and 9 wk of age and deboned at 2 h PM. Fillets were categorized as: normal for both white striping and woody breast (NORM); moderate for white striping and mild for woody breast (MILD); severe for white striping and mild for woody breast (WS); severe for woody breast and moderate for white striping (WB); or severe for both white striping and woody breast (BOTH). Sarcomere length, gravimetric fragmentation index, marination uptake, cook loss, and Meullenet-Owens razor shear energy (MORSE) values on non-marinated and marinated fillets were assessed. Sarcomeres tended to be longer (P = 0.07) with increasing severity of WS and WB in both experiments and gravimetric fragmentation index did not differ (P > 0.05) among categories. Marinade uptake decreased (P < 0.05) with increasing severity of WS and WB. Cook losses of non-marinated and marinated fillets were greatest (P < 0.05) in the BOTH category. Even though MORSE values did not differ (P > 0.05) in non-marinated fillets, the marinated BOTH fillets had greater MORSE values (P < 0.05) than other categories of fillets in Exp. 1. Non-marinated NORM fillets had greater (P < 0.05) MORSE values than the other categories at 6 wk age; however, MORSE values did not differ (P > 0.05) among categories of marinated breasts. At 9 wk, WS and BOTH were higher (P < 0.05) in MORSE compared to NORM for non-marinated fillets, but similar to NORM marinated fillets. Results suggest that severe degrees of white striping and woody breast, individually or in combination, negatively impact meat quality, especially water holding capacity attributes such as marinade uptake and cook loss.

Absorption and deposition of xanthophylls in broilers challenged with three dosages of Eimeria acervulina oocysts.

1. An experiment was designed to evaluate the effect of different doses of oocysts of Eimeria acervulina on intestinal absorption and skin deposition of xanthophylls (XAs) in broilers. 2. A total of 192 broiler chickens were randomly assigned to 4 groups: an uninfected control group and three groups inoculated with either 1 × 10(2), 1 × 10(4) or 1 × 10(5) sporulated oocysts of E. acervulina by gavaging at 21 d. There were 4 replicate pens (2 male and 2 female) per group. 3. Plasma xanthophyll (PX) and skin yellowness (SY) were measured in live birds weekly. At 42 d of age, SY was measured in the breast and abdomen after chilling and in the breast 24 h post-processing on refrigerated carcasses. 4. In general, in all challenged treatments, and for the duration of the study, the average PX decreased by 0.02 µg/ml (R(2) = 61.6%) for every 1000 inoculated oocysts, whereas PX increased by 1.26 µg/ml/d in uninfected birds. 5. The average SY in live birds from 21 to 42 d of age decreased by 0.019 b*/every 1000 oocysts administered, while SY of uninfected controls increased by 0.57 b*/d. It was also noted that in all treatments females had a greater SY (6.17 b*) than males for the duration of the study. The SY of the breast and abdomen was correlated (r = 0.76) in chilled carcasses. Breast SY in 24 h refrigerated carcasses was greater in the control group and for female birds. 6. Oocyst excretion was different between inoculated treatments only on 7 d post-inoculation (PI). Coccidia lesion scores in the duodenum averaged 1+ in infected birds and 2+ in birds given the highest oocyst dose.

Estimation of factors associated with the occurrence of white striping in broiler breast fillets.

Broiler breast fillets are sometimes characterized grossly by white parallel striations in the direction of the muscle fibers, and the condition is referred to as white striping. Depending on the severity of white striping, fillets can be classified as normal (NORM), moderate (MOD), or severe (SEV). The present study was intended to determine the factors associated with the occurrence of white striping in broiler breast fillets. Broiler birds (59 to 63 d) of 4 different commercial high-yielding strains (both males and females) fed with industrial type or phase-feeding regimens, were processed and ready-to-cook carcass weight was recorded. The carcasses were deboned at either 4 or 6 h postmortem. Fillets were scored for the degree of white striping at 24 h postmortem, and dimensions of fillets (length, width, cranial thickness, and caudal thickness), pH, color (L*, a* and b* values), cook loss, and Meullenet-Owens razor shear energy (MORSE) values were determined. About 55.8% of the birds used in the study showed some degree of white striping with MOD and SEV categories as 47.5 and 8.3%, respectively. Higher degrees of white striping were significantly (P < 0.05) related to higher cranial fillet thickness and ready-to-cook weights. The occurrence of SEV degrees of white striping was accompanied with increased b* values or yellowness of the meat. The growth differences in strains could influence the incidence of this condition, but feeding regimens and chill hour during processing did not. In addition, the degree of white striping did not show any significant (P > 0.05) relationship between various meat quality parameters such as pH, L*, a*, cook loss, and MORSE. In conclusion, the results of this study suggest that there is a greater chance of higher degrees of white striping associated with heavier birds, but the condition is not related to any major changes in cooked meat quality.

Pathological changes associated with white striping in broiler breast muscles.

White striping is a condition in broiler chickens characterized grossly by the occurrence of white striations, seen parallel to the direction of muscle fibers, on broiler breast fillets and thighs. Based on visual evaluation of the intensity of white striping, breast fillets can be categorized into normal (NORM), moderate (MOD), and severe (SEV) categories. This study was undertaken to evaluate the details of changes in histology as well as proximate composition occurring in the fillets with respect to the 3 degrees of white striping. In experiment 1, representative breast fillets for each degree of white striping (n = 20) were collected from 45-d-old broilers, approximately 2 h postmortem. From each fillet, 2 skeletal muscle samples were obtained and fixed in 10% neutral buffered formalin. To identify and differentiate the histological changes, slides were prepared and stained using hematoxylin and eosin, Masson's Trichrome, and Oil Red O stains. In experiment 2, samples with 3 degrees of white striping were collected from 57-d-old birds for conducting proximate analysis. Major histopathological changes observed in the MOD and SEV samples consisted of loss of cross striations, variability in fiber size, floccular/vacuolar degeneration and lysis of fibers, mild mineralization, occasional regeneration (nuclear rowing and multinucleated cells), mononuclear cell infiltration, lipidosis, and interstitial inflammation and fibrosis. Microscopic lesions were visually scored for degeneration and necrosis, fibrosis, and lipidosis. The scale used to score the samples ranged from 0 (normal) to 3 (severe). There was an increase (P < 0.05) in mean scores for degenerative or necrotic lesions, fibrosis, and lipidosis as the degree of white striping increased from NORM to SEV. The results from the histopathological study were supported by the findings from proximate analysis confirming that the fat and protein contents of muscle increased (P < 0.05) and decreased (P < 0.05), respectively, as the degree of white striping increased. In conclusion, the histopathological changes occurring in white striping indicate a degenerative myopathy that could be associated with increased growth rate in birds.

Comparison of hematologic and serologic profiles of broiler birds with normal and severe degrees of white striping in breast fillets.

White striping is the white striation occasionally observed parallel to the direction of muscle fibers in broiler breast fillets and thighs at the processing plant. Broiler breast fillets can be categorized as normal (NORM), moderate (MOD), or severe (SEV) based on the degree of white striping. Histologically, SEV fillets are characterized by the highest degree of degeneration of muscle fibers along with fibrosis and lipidosis when compared with NORM. The present study was undertaken to compare the hematologic and serologic profiles of broilers with NORM and SEV degrees of white striping to get more information on the systemic changes associated with the condition. Day-old male broiler chicks of a commercial strain were grown on the same diet in 6 replicate pens (n = 32 birds/pen). Blood samples (5 mL) were collected from the wing vein of each bird on the day before processing for analyzing hematologic and serologic profiles. At 63 d, the birds were weighed and processed in a commercial inline processing system. Weight of the butterfly fillets, liver, and abdominal fat pad were recorded. Left-side fillets were scored to obtain the degree of white striping for each bird. Representative samples for NORM (n = 24) and SEV (n = 17) categories were selected to compare the hematologic and serologic profiles. The SEV birds had greater (P < 0.05) live, fillet, and liver weights, as well as fillet yield, compared with the NORM birds, but the abdominal fat yield was less (P < 0.05) in SEV birds. The NORM and SEV birds did not show any differences in various hematological parameters, including the differential leukocyte count. Conversely, SEV birds had elevated (P < 0.05) serum levels of creatine kinase, alanine transaminase, aspartate aminotransferase, and lactate dehydrogenase. These results suggest that there is no systemic infectious or inflammatory condition associated with a SEV degree of white striping. The elevated serum enzyme levels confirm the muscle damage associated with the degenerative myopathy in SEV birds.