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Potential applications of chicken meat with the woody breast (WB) condition in further processed products could provide processors with alternatives to deal with this meat quality problem. The objective of this study was to evaluate the effect of the use of broiler breast fillets at varying degrees of WB severity and proportions on instrumental texture characteristics of chicken patties. A total of 54 breast fillets were collected from broilers processed as per commercial practices, previously classified based on tactile evaluation in 3 WB categories (normal [NOR]; mild [MIL], and severe [SEV]). Instrumental compression analysis was performed to validate subjective scores. Nine treatments with 6 replicates of chicken patties were prepared: 100% NOR (T1), 67% NOR + 33% MIL (T2), 67% NOR + 33% SEV (T3), 33% NOR + 67% MIL (T4), 33% NOR + 67% SEV (T5), 100% MIL (T6), 67% MIL + 33% SEV (T7), 33% MIL + 67% SEV (T8), and 100% SEV (T9). Instrumental texture profile analysis along with cook loss, color, and dimensional changes was evaluated in cooked patties. Compared with normal samples and excluding treatments T2 and T4, hardness, springiness, and chewiness values of chicken patties decreased (P 26%, P 16%, P 2) than normal patties. These data suggest that the potential use of WB meat in chicken patties is associated with the degree of WB severity and the incorporation rate. The inclusion of WB fillets at high levels into this product is not recommended owing to their poor functionality. However, feasible mixtures of normal breast fillets with those affected by WB myopathy at relatively low proportions could be considered by processors as an alternative in commercial chicken patty formulations.

Consumer concern for broiler welfare has increased interest in chicken from slower growing (SG) broiler strains. Broilers from SG strains take longer to reach market weight, which may necessitate differences in management practices, such as stocking density. This study evaluated the effects of 2 stocking densities on production performance, body conformation, and welfare of broilers from 2 strains. Broilers from strains that reach market weight at age 42 D (CONV; N = 284) and at 63 D (SG; N = 284) were exclusively stocked into pens at a density of either 29 kg/m2 or 37 kg/m2. Birds were provided the same starter, grower, and finisher diets with diet phase changes occurring when SG bird body weight (BW) matched CONV. Live BW, body length, pelvic width, shank length, shank width, keel length, breast width, and breast depth were collected at 4 phases: Phase 1—chick placement, Phase 2—starter, Phase 3—grower, and Phase 4—finisher. At Phase 4, footpad dermatitis (FPD), hock burn (HB), and toe damage (TD) were scored. Feed conversion ratio (FCR) and mortality for each pen were recorded throughout the study. Final BW was similar (2.68 kg) for both strains and stocking densities of birds (P > 0.05). CONV bird FCR was 35% more efficient than SG (P

Stress and leg weakness are detrimental to broiler production, health, and welfare. Traditional methods to evaluate stress may be stressful to the bird because they are invasive and require handling and restraint. Two studies examined the effects of light intensity and flooring on the following in broilers: 1) traditional methods for assessing stress using heterophil-to-lymphocyte ratios and serum corticosterone (CORT) concentrations, 2) noninvasive measures of stress from infrared thermography (IRT) eye and beak surface temperatures, and 3) latency-to-lie (LTL) test times of birds tested individually and in groups of 5. Day-of-hatch male broiler chicks were placed into 6 pens (N = 120 chicks/pen). At 1 wk, pens were allocated to 3 light intensity treatments (2, 5, or 10 lux). At 4 wk, half of the birds from each pen were moved to a pen with wire flooring and the same light intensity. At 1, 4, 5, and 8 wk, blood samples were collected and IRT images of the heads of 5 clinically healthy broilers from each pen were captured. In study 2, IRT images of the heads of birds that became lame in the wire flooring pens were taken. There were no treatment effects on the LTL times of birds tested in groups or individually (P > 0.05). On day 56 in study 1, birds on wire flooring had elevated heterophil-to-lymphocyte ratios and CORT concentrations (P ≤ 0.002) and depressed IRT eye and beak temperatures (P

Summary: The Cobb MV × Cobb 700 male broiler was evaluated for BW and feed conversion ratio (FCR) when fed diets of increasing levels of digestible lysine (Lys) and ME within each growing phase (0–12 D, 12–26 D, 26–35 D, and 35–55 D). Male BW was highest (P < 0.0001) at 12 D of age for birds fed 1.24% digestible Lys and 3,194 ME vs. birds fed 1.20% digestible Lys and 3,084 ME. Male BW were also highest (P < 0.0001) at 26 D of age for birds fed 1.23% digestible Lys and 3,194 ME. However, birds were able to compensate with increased FCR (P < 0.0001) when fed diets with lower levels of digestible Lys and ME from 26 to 55 D to achieve similar BW (P > 0.05) compared with the birds on the highest level and duration of digestible Lys and ME. The control group, that is, industry standard digestible Lys and ME levels, had the lowest levels of digestible Lys and ME for the duration of the experiment and had the highest (P < 0.0001) FCR and the lowest (P < 0.0001) BW. The results for BW and FCR suggest that the digestible Lys needs are higher than previously established. More investigations within each growing phase should be performed to better define the requirements of the Cobb MV × Cobb 700 broiler for digestible Lys.

Summary The percentage of broiler complex processing plants slaughtering big birds (e.g., those greater than 3.5 kg) has steadily increased in the United States the past 15 yr. Precision amino acids in dietary formulation is key as the growing cycle for these birds is extended, as well as total feed consumed. Furthermore, broilers reared for big-bird slaughter plants are destined for specialty breast meat yield portioning, making digestible Lys one of the key nutrients in feed formulation. This work assesses dietary Lys levels in graduations across feed phases to 53 D in Cobb MV × Cobb 700 female and male broilers. Optimizing digestible Lys in the starter phase (to 14 D) occurred between 1.26 and 1.31%. On average, dietary Lys intake per bird needed to optimize live performance, and white meat yield was higher in male birds (64 g) than in female birds (58 g). Optimization of Lys amino acid density in the Cobb MV × Cobb 700 broilers resulted in increased white meat yields in larger broilers, resulting in increased fillet weights per bird with white striping and woody breast being unaffected.

The use of broiler breast fillets affected by the woody breast (WB) condition in processed poultry products couldbe a feasible solution to this meat quality problem. This study assessed the impact of utilizing broiler breast fillets at differ-ent degrees of WB severity and percentages on instrumental texture characteristics of deli loaves. Breast fillets (n = 270) were collected from broiler carcasses and sorted based on palpation assessment in 3 WB categories (normal [NOR], mild [MIL], and severe [SEV]). Nine treatments of deli loaves were prepared from cubed portions in each of 3 replications: 100% NOR (T1), 67% NOR + 33% MIL (T2), 67% NOR + 33% SEV (T3), 33% NOR + 67% MIL (T4), 33% NOR + 67% SEV (T5), 100% MIL (T6), 67% MIL + 33% SEV (T7), 33% MIL + 67% SEV (T8), and 100% SEV (T9). Cooked deli loaves were subjected to texture profile analysis, cook loss, instrumental color, and dimensional modifications. Hardness of deli loaves increased (P < 0.05), whereas cohesiveness values decreased (P < 0.05), as WB severity increased in the meat added into the product formulation when compared with NOR samples and excluding treatments T2 through T4. The use of SEV fillets at 100% (T9) or mixtures of MIL and SEV fillets (T7 and T8) yielded nonuniform deli loaves with different color parameters and higher levels of cook loss (>13%), coupled with reductions in diameter (>8%) and length (>5%), comparedto NOR samples (P < 0.05). These results suggest that the negative effects of WB on quality and yield characteristics are not minimized by the preparation of this formed product when using high proportions of WB meat. Thus, broiler breast fillets affected by the WB condition may be used at relatively low percentages combined with NOR fillets as an option in commercial chicken deli loaf formulations.

Woody breast (WB) is a major myopathy in broilers characterized by hardness of the breast fillet and can be evaluated by human palpation with a severity scale of 0 (normal) to 3 (severe). The objective of this study was to determine fillet dimensions and meat quality factors that are associated with WB scores that may potentially be used for sorting purposes. A total of 206 broiler breast fillets (deboned at 3 h postmortem) were collected and scored for WB.Thickness and length (overall, cranial, caudal, and keel regions) of the Pectoralis major (whole butterfly) were measured with a caliper. Compression force (CF), pH, and color were measured. The right side of the butterfly fillet was frozen at −20°C for 48 h and thawed for 24 h, and then CF was measured along with cook loss, Meullenet-Owens Razor Shear, and blunt Meullenet-Owens Razor Shear. Pearson correlation coefficients and nominal logistic regression were determined.Measurement responses were compared for 4 categories of WB. The keel length measurement on the breast showed no difference (P > 0.05). However, the thickness was moderately correlated with WB score (r = 0.67) and could differentiate between the scores. In addition, CF of right side was higher than left side of fillets (P < 0.05). Freezing/storage significantly decreased (P < 0.05) CF of thawed fillets compared to chilled (nonfrozen) fillets. Cook loss increased (P < 0.05) as severity for WB increased. Peak counts for Meullenet-Owens Razor Shear and blunt Meullenet-Owens Razor Shear were higher (P < 0.05) for the severe compared to the lower levels of WB severity. In conclusion, meat quality differences were evident among the WB categories, differences in CF were observed between right and left fillets, and freezing/storage decreased hardness of fillets. Breast fillet dimensions along with L* value may potentially be used to identify WB, and this model of prediction of WB could be used in the industry to select the different WB categories in the development of sorting methods.

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.

There are potential advantages for using noninvasive methods instead of conventional approaches for measuring corticosterone (CORT) as a metric of stress. Two studies compared blood heterophil: lymphocyte (H:L) ratios, serum CORT, cecal content CORT (Study 1), colon content CORT (Study 2), and feather CORT concentrations for broiler chicks receiving drinking water with or without added CORT. On day 28, male broilers (N = 140) were provided tap water (Control group) or water containing 20 mg/L of CORT (CORT group) for up to 72 h. Body weight (BW), blood, feather, cecal, and colon content samples were collected from 10 birds from each treatment group at 0, 6, 12, 24, 30, 48, and 72 h. Data were analyzed with a JMP Pro ANOVA. Mean comparisons were analyzed on significant treatment effects using post hoc t-tests to compare control and CORT measures within each sampling time point. Pearson's pairwise correlations for all data were performed. A treatment by time interaction affected all measures in both studies. In both studies, CORT treatment reduced body weight and increased H:L ratios at later time points. In study 1 cecal content CORT concentrations were elevated with CORT treatment after 24 h, whereas in study 2 colon content CORT concentrations were elevated after 6 h. CORT treatment increased body and primary feather CORT and primary feather CORT increased with time in control groups in both studies. Serum CORT exhibited the lowest variability compared with all other sample sources used for determining CORT. Estimates of CORT by different methods were positively correlated. These results indicate that serum CORT concentrations most reliably reflect the CORT status of broilers, and that feather CORT concentrations demonstrated potential for estimating stress in broilers.

Changes in heat production (HP) and body composition (BC) in modern broiler breeders can provide means to understand nutrient utilization. Twelve Cobb 500 breeders were evaluated 10 times from 26 to 59 wk of age. The same wired caged breeders were moved to respiratory chambers connected to an indirect calorimetry to obtain oxygen consumption (VO2) and carbon dioxide production (VCO2), HP, and respiratory exchange ratio (RER). The same hens were evaluated for BC using a dual X-ray absorptiometry (DEXA). Data were analyzed during light (16 h) and dark (8 h) period using a mixed model to evaluate calorimetry parameters, a factorial design 2 × 10 for normalized calorimetry parameters, and Complete Randomized Design (CRD)-one way ANOVA for BC. Means were separated by Tukey-Honest Significant difference (HSD). HP increased with age (d) in 0.152 kcal/d, VO2 and VCO2 were 0.031 and 0.024 L/d per each increase in age (d), respectively. In the light period, hens consumed +17.4 L/d VO2 and produced +18.9 L/d VCO2 (P < 0.01). HP during the dark period was 84 kcal/kg0.75 and during the light period was 115 kcal/kg0.75. RER decreased with age until 43 wk and remained the same until 59 wk suggesting more fat and/or protein being oxidized at later periods of production. Lean body mass ranged from 642 to 783 g/kg during the whole study reaching the lowest at 37 and 50 wk and the highest at 26 to 33 wk (P < 0.01). Body fat ranged from 168 to 261 g/kg with the lowest at 26 to 33 wk and the highest at 50 wk of age (P < 0.01). Broiler breeder females may be catabolizing fat energy reserves from 50 wk onwards when the egg production is reduced, and HP increased at 54 and 59 wk (P < 0.01) due to higher energy required for maintenance of a higher lean mass structure. Broiler breeders change nutrient fuel use during egg production. Indirect calorimetry and DEXA can be used to pursue further feed strategies to maximize egg production and maintain a healthy breeder.

Woody breast (WB) condition causes significant economic losses to the global poultry industry, and the lack of an objective and fast tool to identify this myopathy is a contributing factor. The aim of this study was to determine if there are broiler carcass conformation changes that can be used to identify WB characteristics using image analysis. Images of 8-wk-old male broiler carcasses (n = 544) of high breast-yielding strains were captured before evisceration, which were processed and analyzed using ImageJ software. Measurements were as follows: M0, breast length; M1, breast width in the cranial region; M2, one-fifth of the breast length starting at the tip of keel; 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; and M7, M6 minus M5. Ratios of these measurements were also considered. Whole breast fillets were scored for WB severity based on tactile assessment and compression analysis to correlate them. Spearman's correlation coefficient (rs) between WB scores and compression force was highly significant (rs = 0.83, P

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

Bacterial chondronecrosis with osteomyelitis (BCO) is a leading cause of lameness in broilers. Infrared thermography (IRT) is a noninvasive technique for measuring infrared radiation from an object and can be used to evaluate clinical health. Two replicated studies compared the effect of light intensity on broilers grown on a wire flooring model that experimentally increased their susceptibility to and incidence of BCO lameness. Day-of-hatch male broiler chickens were placed into 6 pens on wood shavings litter, and at 1 wk one of 3 light intensity treatments (2, 5, or 10 lux) was allotted. At 4 wk half of the population from each pen was moved to a pen with wire flooring and the same light intensity. At 1, 4, 5, and 8 wk, an IRT image of the legs of 5 clinically healthy broilers from each pen was taken. The right and left proximal femora and tibiae of sound and lame broilers were scored for femoral head necrosis (FHN) and tibial head necrosis (THN) lesion severity. There were minimal effects of light intensity and flooring. In Study 1, but not Study 2, broilers on wire flooring weighed less on day 38 (P = 0.007) and days 57 to 58 (P = 0.003) compared to those on litter. The proportion of broilers that became lame on wire flooring was 52% in Study 1 and 14% in Study 2. The proportion of sound broilers from litter and wire flooring pens with subclinical signs of BCO in their right or left proximal growth plates was over 45% for FHN and 92% for THN, and lame broilers had more severe (P < 0.0001) FHN and THN compared to sound broilers. IRT surface temperatures of the hock joint, shank, and foot were consistently lower (P < 0.0001) in broilers that became lame when compared to sound. Therefore, IRT surface temperatures of broiler leg regions may be useful for detecting lesions attributed to BCO.

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 (P0.05) 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 (P0.05) 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.

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).

The effects of supplementation of broiler diets with organic acids on live performance and microbiological parameters were evaluated in a series of experiments. In three trials lactic acid (LA) (0.25 to 2.00%) or fumaric acid (PA) (0.5 to 2.00%), and in two trials a formic/propionic acid blend (PP) (.125 to 1.00%) or citric acid (CA) (0.25 to 2.00%) was continually fed to broilers that were inoculated via the drinking water with 10 8 to 10 9 CPU/ml nalidixic acid-resistant Salmonella typhimurium (NAL-SAL) on days 2, 7, and 14. Cecal pH, weight and percentage (on a live-weight basis) were measured at 41 days of age. Performance variables were measured at 21 and 42 days. At 42 days birds were processed and the ceca and prechill carcasses were evaluated for incidence and levels of NAL-SAL. LA, FA, and CA had no adverse effects on live bird performance. The PP blend gave inconsistent results on body weight and feed consumption; the blend did not alter feed conversion or mortality. Neither LA nor FA affected cecal pH; however, the pH was altered when the PP blend or CA was fed. None of the acids affected cecal weight or percentage. None of the acids consistently reduced levels of NAL-SAL in the ceca or on the prechill carcasses. The results from this study and numerous others suggest that feeding organic acids to broilers is not a reliable means of controlling cecal colonization or carcass contamination by Salmonella. The results also suggest that reductions in cecal colonization by pathogens such as Salmonella do not necessarily result in processed carcasses that are contaminated to a lesser degree

White striping could be a potential reason for the rejection of raw breast fillets in the market. The condition is characterized grossly by the white striations occurring on the fillets showing myopathic changes on microscopic examination. Early research has shown similar lesions in the case of nutritional muscular dystrophy, which is a condition caused mainly by the deficiency of vitamin E in the diet. The present study was intended to evaluate the effect of different levels of dietary vitamin E ( dl -α-tocopherol acetate) on the incidence of normal, moderate, and severe degrees of white striping, by modern description, on broiler breast fillets. Basal diets adequate for starter (0 to 18 d), grower (19 to 32 d), and finisher (33 to 49 d) age periods supplemented with 15, 50, 100, 200, and 400 IU of vitamin E/kg of feed were used in the study. Each of the 5 diet treatments were fed to 8 pens (53 birds each) of male broilers from a commercial strain. At 49 d, 5 birds were randomly selected from each pen (n = 40 birds/diet treatment) and were processed. Live weight, ready-to-cook weight, weight of the fillets, wings, tenders, legs, and the racks were obtained. The fillets were scored for the 3 degrees of white striping. There were no significant differences among the diet treatments with respect to the weight and carcass yield parameters. Furthermore, the diet treatments did not show any significant effect on the occurrence of normal, moderate, and severe degrees of white striping. However, fillet weight was the only parameter that had a significant effect on the occurrence of white striping. Higher degrees of white striping were seen associated with heavier fillets, which is in accordance with previous studies. Different levels of vitamin E levels used in the present study did not show any significant effect on the occurrence of 3 degrees of white striping. These results suggest that dietary vitamin E level is not associated with the modern condition of white striping in broiler breast meat.

Contamination and penetration of salmonellae into hatching eggs may comprise an important link in the transmission of these bacteria to growing birds, processed carcasses, and eventually to the consumer. In this study, a predictive model for Salmonella typhimurium as a function of initial cell number and storage or incubation time at a nearly constant temperature and humidity was developed and evaluated to compute the bacterial load after 1 d (holding), 10 d (candling), 17 d (incubation), and 21 d (chick processing). Experiments were conducted for S. typhimurium with both high initial bacterial load (HIBL) and low initial bacterial load (LIBL) of 6.0 and 3.5 log cfu/egg, respectively. Eggs with HIBL experienced 2.0 log reduction in the bacterial load after holding at 4 degrees C for 24 h and 3.0 log increase in the bacterial load during incubation and hatch at approximately 37 degrees C between 17 d and 21 d. Experimental data showed that bacterial load of S. typhimurium from holding to chick processing changed from 3.7 to 6.6 log cfu/egg and from 3.7 to 2.7 log cfu/egg in HIBL and LIBL eggs, respectively. The developed model was able to predict bacterial load of S. typhimurium from 3.6 to 6.6 log cfu/egg in HIBL eggs and from 3.4 to 2.7 log cfu/egg in LIBL eggs from holding to chick processing. Root mean square errors and plot of predicted compared with observed bacterial load of S. typhimurium in contaminated eggs yielded a good fit and prediction. The predicted and experimental results indicated that incubated broiler eggs have an increase in internal bacterial loads between incubation and hatch. This model can be used as a tool to predict bacterial load of S. typhimurium in contaminated eggs as well as help predict the behavior of S. typhimurium during hatch.

Two similar trials were conducted in order to compare the variability in the number of salmonellae between the right and left sides of individual broiler carcasses with the variability among carcasses. In both trials, the variation between carcass sides was equal and was significantly less than the variation among carcasses. For trials involving bactericidal treatment, the authors would suggest that the utilization of carcass halves (one side for control, the other for treatment) would allow for a more-sensitive evaluation of treatment effects.

Subcutaneous administration of naloxone at 1 to 10 mg/kg produced a dose-related decrease in feed intake of broiler chicks. Food deprivation for 3, 6, 12, and 24 hours produced a significant increase in feed intake compared to non-food deprived birds. Subcutaneous administration of naloxone at 1 to 10 mg/kg failed to attenuate hyperphagia of broiler chicks, deprived of food for 12 hrs. These data suggest that opiate receptors are involved in the regulation of spontaneous feeding behavior in broiler chicks. However, in contrast to other mammals and pigeons, a mechanism, other than endorphinergic system, not sensitive to naloxone blockade, might be involved in food deprivation induced hyperphagia in broiler chicks.