Effect of Feeding a Postbiotic Derived from Saccharomyces cerevisiae Fermentation as a Preharvest Food Safety Hurdle for Reducing Salmonella Enteritidis in the Ceca of Layer Pullets.

ABSTRACT: Salmonella Enteritidis is responsible for a significant proportion of foodborne salmonellosis in the United States and continues to be attributable to table eggs despite increased federal oversight. Technologies, including feed additives, continue to be evaluated for preharvest application and their potential food safety benefits. Diamond V Original XPC, a Saccharomyces cerevisiae fermentation-based postbiotic (SCFP), was evaluated for its effectiveness in reducing Salmonella Enteritidis (SE) colonization in young layer pullets. A total of 40 day-old Hy-Line W-36 layer pullets were equally divided and randomly assigned to one of two dietary treatments, with SCFP or without SCFP (PCON), and orally gavaged on day 28 with SE at 106 CFU/mL. Another 20 day-old pullets were fed the same control feed without SCFP and blank inoculated on day 28 with 1 mL of sterile phosphate-buffered saline to serve as a negative control. Qualitative and quantitative analyses of cecal contents for Salmonella were performed for all birds on day 32. The prevalence of SE in the ceca of all directly challenged birds was 100%; however, the SE concentration in birds fed SCFP diet (3.35 log CFU/g) was significantly lower (P < 0.0001) than that of the PCON birds not fed SCFP (4.49 log CFU/g). The proportion of birds with enumerable SE concentrations was lower in SCFP-fed pullets (57.9%) than in the PCON pullets (95.0%). These data suggest that inclusion of SCFP in the diet may aid in the reduction of SE within the ceca of commercial laying hens and could serve as an additional preharvest food safety hurdle.

Effects of dietary Original XPC on selected blood variables in layer pullets challenged with Mycoplasma gallisepticum,.

Effects of dietary Original XPC (XPC) on 17 selected blood variables in commercial layer pullets challenged with the virulent, low-passage R strain of Mycoplasma gallisepticum (RlowMG) were investigated. Hy-Line W-36 pullets sourced from M. gallisepticum-clean layer breeders were fed a basal diet with XPC (1.25 kg/metric ton) or without from hatch until 12 wk of age (woa). At 8 and 10 woa, half of the birds in each dietary treatment were challenged with RlowMG. Blood samples were taken immediately before the initial RlowMG challenge at 8 woa and again at 12 woa (4 wk after challenge). At 8 woa, blood pH was lower and glucose concentration was higher in the preassigned challenge treatment groups. At 12 woa, the concentration of oxygen dissolved in the blood was significantly lower in the RlowMG-challenged group than the unchallenged group of birds regardless of dietary treatment. The RlowMG challenge significantly increased blood carbon dioxide partial pressure, calcium, sodium, anion gap, osmolality, glucose, and corticosterone levels but significantly decreased blood oxygen partial pressure, oxyhemoglobin concentration, concentration of oxygen dissolved in the blood, chloride, and pH levels. Because blood pH and glucose concentration at 8 woa were examined before challenge, their baseline values were biased with respect to challenge treatment before treatment was applied. However, the lack of a significant main effect due to diet at 8 woa for blood pH and glucose concentration, along with the other 15 blood variables, indicate that the baseline data with respect to dietary treatment were unbiased, allowing for real dietary effects to be accurately assessed. In conclusion, layer pullets challenged with RlowMG undergo a stress response associated with changes in various physiological blood variables, and a decrease in pH and increase in carbon dioxide partial pressure, in association with a lack of change in bicarbonate, indicates that the stress response caused by the RlowMG challenge was associated with respiratory acidosis. Nevertheless, feeding XPC did not influence the effects of challenge treatment on these postchallenge physiological blood values.

Growth and humoral immune effects of dietary Original XPC in layer pullets challenged with Mycoplasma gallisepticum.

Effects of dietary Original XPC (XPC) in commercial layer pullets challenged with the virulent, low passage R strain of Mycoplasma gallisepticum (Rlow MG) were investigated. Hy-Line W-36 pullets sourced from MG-clean breeders were fed a basal diet with or without (CON) XPC (1.25 kg/metric ton) from hatch until 12 wk of age (woa). At 8 and 10 woa, half of the birds in each dietary treatment were challenged with Rlow MG. Body weight was recorded at 3, 8, and 12 woa, and ovary, ceca, and bursa weights were recorded at 3 and 12 woa. Blood samples were taken immediately before the initial Rlow MG challenge at 8 woa and again at 12 woa to test for IgM and IgG antibody production against MG. All birds were evaluated for MG lesion scores at 12 woa. Regardless of challenge, inclusion of XPC in the diet did not significantly alter BW at 3 or 8 woa or relative organ weights at 3 or 12 woa. However, at 12 woa, BW of XPC-fed birds, regardless of challenge was significantly (P = 0.0038) heavier than CON by 25.7 g. All birds tested negative for MG antibodies before the 8 woa challenge. Respective percentage serum plate agglutination and ELISA positive birds at 12 woa were 0 and 0% (CON, nonchallenged), 1.4 and 0% (XPC, nonchallenged), 100 and 47.2% (CON, challenged), and 100 and 50.0% (XPC, challenged). Diet did not significantly affect ELISA titers, but they were significantly (P < 0.0001) increased due to challenge. Furthermore, lesion scores were significantly higher for Rlow MG-challenged birds (P = 0.0012), and dietary treatment with XPC in challenged birds numerically reduced MG lesion scores from 0.278 to 0.194. In conclusion, although dietary XPC did not significantly alter the humoral immune response, antibody titer levels, or severity of MG lesions in layer pullets that were or were not challenged with Rlow MG, it led to an increase in their rate of growth through 12 woa.

Utilizing original XPC™ in feed to reduce stress susceptibility of broilers.

Reduction of stress is an important factor in improving poultry welfare, especially during periods of heat stress. A study was conducted to evaluate the effects of feeding the functional metabolites of Diamond V Original XPCTM to broilers reared under ambient or heat stress temperatures. Dietary treatments included: control feed (CON) and Original XPC fed continuously at 1.25 kg/MT (XPC). Half the birds in each dietary treatment were subjected to either no heat stress (24°C constant) or heat stress (35°C:24°C for 18:6 h daily) from 28 to 42 d. At the end of the heat stress period, blood was collected from 40 birds/treatment. Blood was analyzed for plasma corticosterone (CORT), plasma HSP70 (HSP70), and heterophil/lymphocyte ratios (H/L). At 42 d, bilateral metatarsal traits were also measured in 40 birds/treatment to assess physical asymmetry. Birds fed XPC had significantly lower CORT levels than CON (P < 0.001; 5,129 ± 617 vs. 8,433 ± 730, respectively). Physical asymmetry scores were also significantly higher in CON compared to XPC fed broilers (P < 0.001; 1.50 ± 0.13 vs. 0.54 ± 0.05, respectively). H/L ratios were significantly greater in CON than for XPC birds (P = 0.01; 0.81 ± 0.05 mm vs. 0.62 ± 0.05 mm, respectively). No differences were observed between CON and XPC fed broilers in HSP70. However, heat stress did increase (P < 0.0001) HSP70 compared to no heat stress birds (5.65 ± 0.12 vs. 4.78 ± 0.11 pg/mL, for heat stress and no heat stress, respectively). Feeding XPC to broiler chickens improved animal welfare via reduced stress indicators while under heat stress or no heat stress conditions. These results indicate that feeding XPC may improve poultry welfare by reducing heat stress susceptibility.

Effects of feeding Original XPC™ to broilers with a live coccidiosis-vaccine under industry conditions: Part 1. Growth performance and Salmonella inhibition.

Supplementation of poultry diets with Diamond V Original XPC™ (XPC) has been proposed as a means to ameliorate the commonly observed loss of appetite and depression of growth in birds given a live coccidiosis vaccine. A study was conducted to compare the effects on bird performance of a live coccidiosis vaccine in broilers, with and without the dietary inclusion of XPC (1.25 g/kg). Ross 708 male broilers (n = 1,280) were allocated to one of 4 feed treatments: cocci-vaccine (T1), cocci-vaccine + XPC (T2), cocci-vaccine + salinomycin in the grower diet only, (T3), and cocci-vaccine + salinomycin in the grower diet + XPC (T4). Birds consuming diets containing XPC (T2 and T4) and salinomycin (T3) exhibited increased (P < 0.05) feed intake and significantly heavier body weights at 28 d (1.70, 1.74, and 1.67 kg, respectively) and 42 d (3.29, 3.31, and 3.26 kg, respectively). Feed conversion ratio at 28 d was improved (P < 0.05) by adding XPC to diets (T2: 1.47 and T4: 1.44) compared to control diets (T1: 1.50 and T3: 1.47). Salmonella prevalence determined via selective media indicated the inclusion of XPC in the diet resulted in a significant reduction of Salmonella when compared to treatments lacking XPC. Molecular confirmation of Salmonella species indicated S. Kentucky to be present in 38 of the 39 positive samples. Results revealed the ability of XPC in reducing the prevalence of Salmonella. Results from this study also suggest that XPC could be used in conjunction with a live coccidiosis-vaccine to increase growth rate and improve feed conversion of broilers. However, further work is needed to delineate more specific effects directly attributable to XPC.

Divergent selection for muscle color in broilers.

One consumer-related physiological abnormality that is a recent concern for the poultry industry is atypical meat quality. Currently in the processing plant, meat is characterized on appearance such as tears, bruises, discoloration, or missing parts. Unfortunately, this method ignores physical properties such as palatability, texture, tenderness, taste, color, pH, and water-holding capacity (WHC). The growing demand for a convenient, economical, and palatable product has shifted the market toward value-added poultry products. The effect of a meat's physical properties on its marketability and versatility has become apparent to processors attempting to utilize poor quality meat. After 8 generations of divergent selection for muscle color or lightness (L*) in broilers, muscle quality parameters were investigated. The 2 broiler lines divergently selected for high (HMC) and low (LMC) muscle color along with their randombred control line (RBC) were included in the study. Heritability estimates for L* were 0.47 ± 0.05 and 0.51 ± 0.05 in the HMC and LMC lines, respectively. For generation 8, the mean L* for the HMC, RBC, and LMC lines were 53.91, 49.70, and 46.86, respectively. Selection for increased L* was found to result in increased breast fillet yellowness (b*), whereas selection for decreased L* resulted in an increase in breast fillet redness (a*). Selection for increased L* has resulted in increased rate of pH decline over time, whereas selection for decreased L* has resulted in a decreased rate of pH decline. The HMC line exhibited a higher percentage fillet drip loss than both the LMC and RBC lines, which did not differ from each other. Overall selection for L* was effective in modifying breast muscle color as well as correlated responses associated with atypical poultry meat such as drip loss and postmortem muscle pH. These selected lines can serve as resource populations for the study of PSE and DFD-like meat in poultry and demonstrate that L* selection could be applied to primary breeding programs as a way to improve or manage muscle quality in pedigree elite lines.

Divergent selection for ascites incidence in chickens.

Chicken lines that were either resistant or susceptible to ascites syndrome were developed by using a hypobaric chamber to induce the disease. Birds were reared in a hypobaric chamber that simulated high altitude by operating under a partial vacuum, which thereby lowered the partial pressure of oxygen. Ascites mortality data from birds reared under hypobaric chamber conditions were used to select siblings to be used for breeding. The response to selection for the susceptible (SUS) and resistant (RES) lines of chickens was very rapid from the base population, which exhibited an incidence of ascites of 75.3%. Extremes in the incidence of ascites were observed in generation 8, with line SUS exhibited an average incidence of ascites of 95.1%, and in generation 9, with line RES exhibited an average incidence of ascites of 7.1%. The incidence of ascites in the relaxed line remained relatively stable and currently has a general incidence of ascites of 60%. The heritability estimates +/- SE for ascites were estimated to be 0.30 +/- 0.05 and 0.55 +/- 0.05 for lines SUS and RES, respectively. Changes in the incidence of ascites appeared to be associated with livability. By generation 10, selection for ascites in line RES increased livability by 11.5 d, whereas in line SUS, livability was decreased by 8 d. Although divergent selection for ascites resulted in a reduction in d 42 BW for both the SUS and RES lines, the SUS line was approximately 163 g heavier than the RES line. Negative genetic correlations between ascites and the right ventricle:total ventricle (RV:TV) ratio were observed in both the SUS and RES lines; however, no significant change in the RV:TV ratio was observed for birds reared under normal conditions in either line. The current data raise questions about the validity of using the RV:TV ratio as an indicator trait in a selection program designed to reduce the incidence of ascites. Overall, direct selection for resistance to ascites by using sire family performance appeared to be an effective means of reducing the incidence of ascites. However, simultaneous selection for BW should be applied to counterbalance the losses in correlated BW.

Hypobaric hypoxia in ascites resistant and susceptible broiler genetic lines influences gut morphology.

Genetic selection based on rapid growth rates, improved feed conversion, and increased body weights has led to a predisposition to ascites in broiler populations. Sire-family selection was applied to a commercial elite line to produce divergent lines of ascites-resistant (RES) and ascites-susceptible (SUS) broilers by the 8th generation. One objective of this research was to determine the effects of hypobaric hypoxia on gut morphology in these genetic lines. In two separate trials, pedigree broiler chickens were randomly assigned to cages in a hypobaric chamber (simulated 2,900 m above sea level) or a matching local altitude chamber (390 m above sea level). Ascites incidence was characterized by heart enlargement and fluid accumulation in the abdominal cavity. At the end of the study on d 42, all surviving birds were killed and evaluated for the presence of ascites and 2-cm sections from the duodenum and lower ileum were collected from 5 chickens per line, per altitude for each trial for morphometric analysis. At a high altitude, ascites incidence was lower in the RES line (20.9 and 3.7%) than in the SUS line (86.4 and 66.9%, Trials 1 and 2, respectively). No ascites was observed at a local altitude. Under hypoxic conditions, duodenum villus surface area was higher (P < 0.05) in the RES line (181.3 +/- 16.8 and 219 +/- 10.9 microm) compared with the SUS line (130.1 +/- 10.5 and 134.3 +/- 9.3 microm; Trials 1 and 2, respectively). No differences in ileum villus morphology were observed for any of the parameters measured. The reduced surface area in the duodenum of birds selected for ascites susceptibility suggests reduced enteric function and may provide clues as to why these birds have increased incidence of ascites.