Layer Pullets Research Articles

Interaction between energy level and starch: fat ratio on intestinal energy metabolism of layer pullets

During the growing period, the gastrointestinal tract of layer pullets is not yet well developed and may be susceptible to dietary energy level. The energy level and composition might impact the intestinal energy metabolism of layer pullets. To test this hypothesis, a total of 480 “Jing Tint 6” layer pullets were used in an 8-week study and allocated to 4 groups, each consisting of 8 replicates, with 15 birds per replicate. Pullets were treated with low or high starch: fat ratios (LS, 10:1; HS, 20:1) in a 2 × 2 factorial arrangement with regular energy (RE, 11.85 and 11.68 MJ/kg for birds from 6 to 10 weeks of age and 11 to 14 weeks of age, respectively) or low energy (LE, 0.55 MJ/kg lower than RE) levels. A significant interaction (P < 0.05) showed that HS increased glandular stomach weight and the jejunal villus length to crypt depth ratio (VCR) in LE diets, but decreased these parameters in RE diets. Dietary energy reduction impaired energy metabolism in the ileum (P < 0.05) mainly via decreasing the gene expression of enzymes involved in the tricarboxylic acid (TCA) cycle (α-ketoglutarate dehydrogenase complex [α-KGDH]; isocitrate dehydrogenase (NAD (+)) [IDH] catalytic; citrate synthase [CS]) and adenosine triphosphate (ATP) synthesis, reducing contents of phosphoenolpyruvate (PEP) and adenylate energy charges (AEC) and down-regulating the adenosine monophosphate-activated protein kinase (AMPK) pathway. HS stimulated AMPKα phosphorylation, increased protein abundance of peroxisome proliferator activated-receptor gamma coactivator 1α (PGC1α) and improved contents of amino acids (aspartate, glutamate, glutamine, alanine and threonine) and malate in the ileum regardless of energy levels (P < 0.05). By an interaction (P < 0.05), the transition from LS to HS diets up-regulated ileal gene expression of AMPKα1 and decreased content of adenosine monophosphate (AMP), accompanied by higher AEC but only in birds fed with LE diets. Collectively, these results suggest that low energy feeding may not be enough for maintaining intestinal energy homeostasis in layer pullets and emphasizes the importance of a relatively high starch: fat ratio in restoring energy metabolism in the ileum.

Evaluation of Growth Performance and Economic Efficiency of Immature Lohmann Brown Layers Fed Graded Levels of Undeshelled Defatted Moringa oleifera Seed Cake

In a 22-weeks experiment, the impact and economic efficiency of feeding undeshelled defatted Moringa oleifera seed cake (UDMOSC) to Lohmann Brown layer chicks and pullets were investigated. The study had two phases, focusing on chicks (0-8 weeks) and pullets (9-22 weeks). A total of 150-day-old chicks were randomly assigned to five dietary treatments (0%, 5%, 10%, 15% and 15% with Burgazyme inclusion), each replicated three times, and each replicate containing ten (10) birds in a completely randomised design. Data collected was subjected to analysis of variance (ANOVA) using the GenStat statistical package (2008). In the initial phase, chicks fed dietary UDMOSC consumed less feed but had similar (p ˃ 0.05) final body weight compared to the control group. Chicks fed the control, and 5% UDMOSC gained more weight with better feed conversion. Chicks fed 10% UDMOSC had higher mortality. In the second phase, pullets fed the control diet and 15% UDMOSC with the enzyme (UDMOSC15E) showed significantly higher (p = 0.01) feed intake. Final body weight and body weight gain were notably higher (p = 0.001) in pullets fed the control diet. Feed conversion ratio and mortality rate did not significantly differ (P ˃ 0.05) among treatments. Dietary UDMOSC reduced feed cost per kilogram of body weight gain for starters and pullets. While dietary UDMOSC did not significantly affect starter growth, it lowered total feed cost per bird for starters and pullets except for UDMOSC15E, accruing 20.54 – 27.81%. and 25.39 – 40.19% percentage profit range, respectively. Dietary UDMOSC depressed the growth of starters and pullets, but it was economically advantageous by reducing the cost per kilogram of body weight gain for both groups. The negative impact of dietary UDMOSC on the growth of starters and pullets suggests that including UDMOSC in the immature layer diets should be cautiously approached for economic gain and, therefore, recommended for the pullet stage at an inclusion level not exceeding 10%.

Yeast cell wall supplementation affects the Salmonella enteretidis load in the ceca and ovaries of layer pullets

Salmonella enteretidis (SE) has a great propensity to translocate from the cecum into internal organs such as the spleen and liver. However, a major concern is the ability of SE to colonize the ovaries. This study aimed to evaluate the efficacy of cell walls from Saccharomyces cerevisiae to control the Salmonella load in the ceca and ovaries of commercial layer pullets. Ten-week-old layer pullets were divided into 2 groups: one group was fed a control diet with commercial feed without additives, and another group was fed the same diet supplemented with 0.5 kg/metric ton of yeast cell walls (YCWs). At 16 wk of age, the birds in both groups were challenged with 3.0 × 109 CFU/mL SE by oral gavage. The birds were euthanized on d 7 and 14 postchallenge to collect the ceca and ovaries for Salmonella load determination. The results demonstrated that there were no statistical differences in ovary SE infection rates. The trend in the prevalence of SE positivity in the ovaries was similar at 14 d, with 2.1% (YCW pullets) to 4.2% positive for the ovaries of the nontreated pullets. There was also no significant difference in the SE log10 MPN/gram between the YCW and the control groups. In the ceca, the high level of SE (3.0 × 109 cfu/pullet), which results in ovarian transmission, causes high intestinal tract inflammation. There was a significant difference in the prevalence of SE in the ceca at 7 d postchallenge but not at 14 d postchallenge. In conclusion, the reduction in Salmonella load observed in the ceca on d 7 in this study shows the potential of YCW supplementation for reducing Salmonella colonization in poultry.

Heterologous maternal antibodies derived from infectious bronchitis vaccines prevent the development of lesions associated with false layer syndrome

Infectious bronchitis virus (IBV) strains of the Delmarva (DMV)/1639 genotype have been causing false layer syndrome (FLS) in the Eastern Canadian layer operations since the end of 2015. FLS is characterized by the development of cystic oviducts in layer pullets infected at an early age. Currently, there are no homologous vaccines for the control of this IBV genotype. Our previous research showed that a heterologous vaccination regimen incorporating Massachusetts (Mass) and Connecticut (Conn) IBV types protects layers against DMV/1639 genotype IBV. The aim of this study was to investigate the role of maternal antibodies conferred by breeders received the same vaccination regimen in the protection against the development of DMV/1639-induced FLS in pullets. Maternal antibody-positive (MA+) and maternal antibody-negative (MA−) female progeny chicks were challenged at 1 day of age and kept under observation for 16 weeks. Oviductal cystic formations were observed in 3 of 14 birds (21.4 %) in the MA− pullets, while the lesions were notably absent in the MA+ pullets. Milder histopathological lesions were observed in the examined tissues of the MA+ pullets. However, the maternal derived immunity failed to demonstrate protection against the damage to the tracheal ciliary activity, viral shedding, and viral tissue distribution. Overall, this study underscores the limitations of maternal derived immunity in preventing certain aspects of viral pathogenesis, emphasizing the need for comprehensive strategies to address different aspects of IBV infection.

Short communication: Effects of a commercial triple-strain Bacillus-based probiotic on cecal colonization with Salmonella Enteritidis in commercial layer pullets

A commercial triple-strain Bacillus-based probiotic was tested to determine its effect on the colonization of the ceca by Salmonella Enteritidis (SE) in commercial layer pullets. Two treatments were tested, each with containing 128 day-of-hatch LSL layer chicks. On top of a standard diet: 1) no supplement (Control, CON), and 2) Probiotic (GalliPro® Fit, 500 g/MT, 1.6 × 106 CFU/g of finished feed, PRO). Environmental swabs were collected from each treatment group and tested to ensure freedom from SE prior to challenge. At 21 days of age, the SE challenge strain was administered orally at a dose of 3.3 × 108 CFU/bird. Pullets from each treatment group (n=32) were euthanized at 6-, 10-, 14-, and 18-days post infection (dpi). Contents from the ceca were aseptically collected and assessed for presence and abundance of SE. No differences in the prevalence of SE positive ceca following oral inoculation (P>0.05) were observed between treatment groups at 6-, 10-, 14-, or 18-dpi. Counts of SE in the ceca of the PRO group were not significantly different (P>0.05) from those of CON at 6- or 10-dpi. However, significantly lower counts of SE in the ceca of the PRO group were observed at 14-dpi (P<0.05) and 18-dpi (P<0.05) compared with CON. SE counts were 1.24 and 1.34 logs lower than CON at 14- and 18-dpi, respectively. In conclusion, supplementation of the triple-strain Bacillus-based probiotic resulted in lower cecal counts of SE compared to those that did not receive an effective probiotic, thereby reducing the risk of foodborne pathogens prior to harvest through sustainable, natural methods.

Development and Evaluation of Mycoplasma gallisepticum Challenge Model in Layer Pullets.

Manufacturers of Mycoplasma gallisepticum (MG) modified live vaccines usually recommend a single application at 8 wk of age. This makes 12-16-wk-old layer pullets suitable for challenge studies intended to evaluate these vaccines. Numerous challenge models in different poultry species and ages have been reported. However, there is not an established layer pullet challenge model for this age. The aim of this study is to develop a suitable challenge model in 12-wk-old layer pullets. MG Rlow strain was used as the challenge strain, and its ability to induce clinical signs and lesions in 12-wk-old Hy-Line W-36 layer pullets was evaluated. Three different doses (low, 7.95 × 104 color-changing units [CCU]/bird; medium, 7.95 × 106 CCU/bird; and high, 7.95 × 108 CCU/bird) via three different routes (eye drop, fine spray, and contact infection) were compared and evaluated using different parameters. At 14 days post-challenge, there were no mortalities in any of the groups throughout the study. Layer pullets directly challenged with the high dose via the fine spray route showed the clearest and most consistent results (clinical signs, positive quantitative real-time PCR [qPCR], seroconversion, air sac scoring, and histopathological changes of the tracheal mucosa). Medium and low challenge doses applied via fine spray or eye drop did not show consistent results. Rlow strain was able to spread to the contact infection birds, as confirmed by the positive qPCR results; however, none of the contact-infected birds showed any clinical signs or gross or microscopic lesions. Our results suggest that a high dose (7.95 × 108 CCU/bird) administered through a fine spray route is the model of choice in any future MG vaccine evaluation trials in 12-wk-old layer pullets.

Internal Organ Colonization by Salmonella Enteritidis in Layer Pullets Infected at Two Different Ages During Rearing in Cage-Free Housing.

The poultry-housing environment plays a significant role in the transmission and persistence of the egg-associated pathogen Salmonella Enteritidis in laying flocks. The commercial egg industry is in the midst of a transition toward cage-free housing, but the food safety ramifications of this shift are not yet certain. The present study assessed internal organ colonization by Salmonella Enteritidis in layer pullets reared in cage-free housing and infected at two different ages. Groups of 280 pullets were transferred from the rearing facility (at 9 wk of age in one trial and 15 wk in another) to a containment facility with four isolation rooms simulating commercial cage-free barns with perches and nest boxes (70 birds/room). Twenty-four pullets in each room were orally inoculated with Salmonella Enteritidis immediately after placement in the containment facility. At 1-2 wk postinoculation in each trial, samples of liver, spleen, and intestinal tract were collected from all birds in two rooms for bacteriologic culturing to detect Salmonella Enteritidis. At 21-22 wk of age, samples of spleen, ovary, and intestinal tract were similarly collected and tested from all birds in the remaining two rooms. Among samples collected at 1-2 wk postinoculation, Salmonella Enteritidis was isolated significantly more often from groups of pullets infected initially at 15 wk of age than from those infected at 9 wk (61% vs. 38% of livers, 59% vs. 31% of spleens, and 84% vs. 57% of intestines). Among samples collected at 21-22 wk of age, the frequency of recovery of Salmonella Enteritidis was again significantly greater in birds infected at 15 wk of age than in those infected at 9 wk (16% vs. 6% of spleens, 9% vs. 1% of ovaries, and 26% vs. 10% of intestines). These data suggest that Salmonella Enteritidis infections introduced into flocks during the later stages of pullet rearing have greater potential to persist into the early phase of egg production.

Early vaccination of laying hens with the live bivalent Salmonella vaccine AviPro™ Salmonella DUO results in successful vaccine uptake and increased gut colonization.

Salmonella Enteritidis and S. Typhimurium are the two most clinically important zoonotic Salmonella serovars and vaccination of breeding and laying hens affords effective Salmonella control. The use of live vaccines has proven beneficial for a number of reasons, including ease of application, protection from the first day of life onwards and initiation of a strong local immune response. Live vaccines can be applied in the drinking water from the first day of life onwards, but some rearers choose to wait until the end of the first week to ensure sufficient water consumption. However, this practice leaves the birds unprotected during the crucial first week of life, where they are most susceptible to colonization by field strains. The aim of this study was to determine if successful vaccine uptake is achieved when layer pullets are vaccinated as early as day one. Three pullet flocks were vaccinated at 1, 2, 3 or 5 days-of-age with AviPro™ Salmonella DUO, a live vaccine containing attenuated strains of S. Enteritidis and S. Typhimurium (Elanco Animal Health, Cuxhaven, Germany). The vaccine was administered via the drinking water following manufacturer's instructions. Two days post-vaccination, 10 birds per flock were culled and caecal and liver samples taken, along with two pools of faeces per flock. Levels of vaccine strains were determined by quantitative and qualitative bacteriology. Vaccine strains were detected in all birds from all age groups indicating successful uptake of the vaccine. Levels of the S. Enteritidis vaccine were higher than levels of the S. Typhimurium vaccine, with the latter frequently only detectable following enrichment. There was an inverse correlation between age and caecal levels of vaccines, with the highest numbers seen in birds vaccinated at 1-day-of-age. Interestingly, S. Enteritidis vaccine strain levels in liver samples were highest when birds were vaccinated at 5 days-of-age. These results show that successful uptake of both vaccine strains was evident in all age groups. The earlier the chicks were vaccinated, the higher the vaccine levels in caecal contents. We therefore recommend vaccination of pullets as early as practicably possible to ensure protection against exposure to field strains.

Microbiome Changes in Layer Pullets Reared in Floor Pens along the Growth Period.

The gastrointestinal tract microbiome is essential for regulating nutrient absorption, gut immune function, and host growth and development. In the present study, we characterized the development of ileum and cecum microbiota in pullets throughout the rearing period, encompassing a period from the day of hatching to 18 weeks of age. The growth performance and intestinal microbiome (ileum and cecum) of pullets were analyzed at 1, 5, 11, and 18 weeks of age. The richness of the ileum and cecum bacterial communities (alpha diversity) was higher in pullets at 18 weeks of age than in those at 1 and 5 weeks of age. Microbiota from weeks 1, 5, 11, and 18 were distinctly grouped in a NMDS plot, representing beta diversity within the ileum. However, the results for cecum microbiota did not reveal evident separation among the different age groups in the weighted UniFrac. In conclusion, our findings demonstrate variations and diversification in ileum and cecum microbiota across different rearing stages in pullets. These insights have the potential to inform the development of nutritional strategies that promote gut health and contribute to the improved development of pullets.

Effects of Metabolizable Energy Intake and Body-Weight Restriction on Layer Pullets: 1-Growth, Uniformity, and Efficiency

This study aimed to determine the effects of dietary energy and body-weight (BW) restriction on layer pullets’ growth, uniformity, and feed efficiency. Two experiments were conducted using a precision feeding (PF) system (Experiment 1) and a conventional feeding (CON) system (Experiment 2). Experiment 1 consisted of a 2 × 4 factorial arrangement (eight treatments) with two feed allocation (FA) levels: meal every visit (MEV) or restricted to the lower boundary of Lohmann Brown-Lite pullets; and three dietary metabolizable energy (ME) levels: Low, Standard (Std), and High (2600, 2800, and 3000 kcal/kg, respectively); the fourth treatment enabled birds to choose from the three diets (Choice). Experiment 2 consisted of a 2 × 3 factorial arrangement (six treatments): two FA levels (ad libitum or restricted) and three dietary ME levels (Low, Std, and High). In each experiment, BW, coefficient of variation (CV), average daily feed intake (ADFI), average daily metabolizable energy intake (MEI), and feed conversion ratio (FCR) were recorded. Diet ADFI preferences and feeding motivation were determined only in the PF experiment. ANOVA was conducted on each experiment with the two main effects as fixed factors (FA and dietary ME), and age or period as the sources of variation. Differences were reported at p ≤ 0.05. MEV (PF experiment) and ad libitum-fed (CON experiment) pullets had greater BW compared to restricted-fed pullets (p &lt; 0.05). The lowest CV was observed in the restricted-fed pullets from the PF experiment (p &lt; 0.05). ADFI was greater in pullets fed the Low ME diet in the PF experiment compared to all the other groups, and the lower the dietary ME, the greater the ADFI in the CON experiment (p &lt; 0.05). Choice-feeding pullets preferred feed with greater ME content in the PF experiment (p &lt; 0.05). The lower the dietary ME, the greater the FCR in the CON experiment (p &lt; 0.05). Restricted-fed pullets had greater daily visits, and lower daily meals, meal size, and successful visits to the PF system (p &lt; 0.05). In conclusion, the results of this trial indicated that lower dietary ME increased FCR and ADFI, whereas feed restriction decreased BW and increased feeding motivation. Future steps after this trial will include examining the effects of dietary energy and feed restriction on carcass composition and sexual maturation.

Brown and white layer pullet hybrids show different fear responses towards humans, but what role does light during incubation play in that?

Good early life conditions are increasingly recognized as essential to animal welfare later in life. The use of light during incubation might improve coping capacities and welfare in later life in poultry, by more closely approximating chicken natural environments compared to the current conventional incubation in darkness. Previous studies showed that lighted incubation resulted in more lateralized chicks, a more pronounced daily behavior rhythm, earlier onset of melatonin rhythms, and lower stress reactions to various stressors after hatching. Most existing research, however, has been conducted on broilers, and little information on lighted incubation is available for laying hens. In the current research, Dekalb White and ISA Brown eggs were incubated in complete darkness or in a cycle of green 12 L:12D throughout incubation, and five fear of human tests were performed on the 387 chickens during the rearing phase. We expected dark-incubated chickens to show stronger fear responses than light-incubated chickens. That was only the case for one of 15 behavior measurements taken during the tests (p < 0.05). In addition, white layer hybrids are known to be flightier and more fearful than brown hybrids. In this study, white chickens indeed showed stronger fear responses than brown chickens in 12 of the 15 behavior measurements (p ≤ 0.002). Furthermore, we expected light during incubation to have stronger effects on white chickens than on brown chickens, because of the stronger transmission of light through white eggshells. However, the interaction between hybrid and incubation was never significant (p ≥ 0.18). Finally, contrary to our expectations, there was no effect of the incubation treatments or the hybrid on plasma corticosterone responses to a manual restraint test (p ≥ 0.36). Since there was a hybrid effect on behavior in this test, it is reasonable to think that behavior reflected coping style, rather than fear level. To conclude, the light regime used in this study does not seem as promising as expected to improve laying hen welfare. Finally, the brown hybrid was usually less fearful than the white hybrid, though there were some exceptions depending on the stressor, and that should be taken into account in research and in laying hen management.

PROTECTION ACTIVITY OF T CELL LYMPHOKINES AGAINST INFECTIOUS BURSAL DISEASE IN LAYER PULLETS

The present study was aimed to administering hyperimmunized avian salmonella-immune lymphokines (S-ILK) to 200 one-day-old layer pullets to improve the immunological response against Gumboro (IBDV) divided into four groups. On the first day, the following was applied to all groups: G1: intraperitoneal injection of 0.50 mL S-ILK followed by a 30-minute challenge with 0.1 mL IBDV (ELD50 103.2); G2: intraperitoneal injection of 0.5 mL of S-NILK followed by a 30-minute challenge by 0.1 mL IBDV. G3: challenged with 0.1 mL of IBDV only, G4: uninfected, unchallenged group consider as a negative control. The results of the findings indicated the greatest a statistically significant rise (p≤ 0.05) in IgG and IFN-γ titres in that group and the viral load test revealed that at 7 and 14 days after infection, The largest number of IBDV RNA copies were found in G2 and G3. in the bursa of Fabricius. The first group had the lowest mortality rate compared to the other groups. Early S-ILK administration improves maternal resistance to IBDV infection and inhibits viral replication in the fabricius bursa following IBDV challenge. Thus, we may reduce the amount of time, effort, and money spent on immunization procedures that do not completely protect against diseases.

Impact of growth trajectory on sexual maturation in layer chickens.

Recent studies showed that apart from photostimulation, metabolic triggers may independently activate sexual maturation and egg production in chickens. However, the origin, mode of action, and specific target(s) of this metabolic control remain unknown. Beyond body weight (BW), we hypothesize that body composition (BC) and associated specific metabolic signals are involved. Thus, this study was conducted to determine the BW and BC thresholds triggering spontaneous sexual maturation in layer pullets under different growth trajectories. Day-old Lohman LSL lite and Lohman brown lite chicks (n = 210 each) raised in brooding cages under ad libitum (AL) feeding until 8weeks of age were randomly allocated into individual cages and assigned to one of 3 experimental growth profiles; AL, breeder's target (T), restricted 20% below target (R), (n = 70 birds/profile/strain). Birds had free access to water throughout the trial. All hens were maintained on 10h of light (10lux) throughout the rest of the study. Blood and tissue samples were collected throughout the study to measure plasma estradiol (E2) concentrations and organ weights, respectively. Furthermore, carcasses were subjected to Dual-energy X-ray absorptiometry (DEXA) analyses. All analyses were completed with SAS using the MIXED procedure. Results show that R treatment slowed (p < 0.001) growth, delayed age at first egg (FE) and egg production (p < 0.001) and resulted in lower BW at FE (p < 0.001), lower ovary weight and number of follicles (p < 0.001) compared to AL in both strains, whereas, the strain significantly impacted body weight (p < 0.0001), ovary weight (p < 0.001), BW at FE (p < 0.001), age at FE (p < 0.001), egg production (p < 0.0001), E2 (p < 0.0001) and body composition (p < 0.05). For DEXA, AL feeding (p < 0.001) increased fat deposition compared to R. Furthermore, there was a positive correlation between plasma E2 and bone mineral content (p < 0.01) and bone mineral density (p < 0.01). In conclusion, feed allocation impacted growth and BC in a strain dependent manner which resulted in differing age at sexual maturation and egg production. Furthermore, a body fat threshold between 10% to 15% appears to be required for the occurrence of spontaneously sexual maturation in laying hens.

Effect of a Saccharomyces cerevisiae Postbiotic Feed Additive on Salmonella Enteritidis Colonization of Cecal and Ovarian Tissues in Directly Challenged and Horizontally Exposed Layer Pullets.

Determining the efficacy of feed-additive technologies utilized as pre-harvest food-safety interventions against Salmonella enterica may be influenced by factors including, but not limited to, mechanism of action, experimental design variables, Salmonella serovar(s), exposure dose, route, or duration in both controlled research and real-world field observations. The purpose of this study was to evaluate the dietary inclusion of a Saccharomyces cerevisiae fermentation-derived postbiotic (SCFP) additive (Diamond V, Original XPC®) on the colonization of cecal and ovarian tissues of commercial pullets directly and indirectly exposed to Salmonella Enteritidis (SE). Four hundred and eighty commercial, day-of-age W-36 chicks were randomly allotted to 60 cages per treatment in two identical BSL-2 isolation rooms (Iowa State University) with four birds per cage and fed control (CON) or treatment (TRT) diets for the duration of study. At 16 weeks, two birds per cage were directly challenged via oral gavage with 1.1 × 109 CFU of a nalidixic-acid-resistant SE strain. The remaining two birds in each cage were thus horizontally exposed to the SE challenge. At 3, 7, and 14 days post-challenge (DPC), 20 cages per group were harvested and sampled for SE prevalence and load. No significant differences were observed between groups for SE prevalence in the ceca or ovary tissues of directly challenged birds. For the indirectly exposed cohort, SE cecal prevalence at 7 DPC was significantly lower for TRT (50.0%) vs. CON (72.5%) (p = 0.037) and, likewise, demonstrated significantly lower mean SE cecal load (1.69 Log10) vs. CON (2.83 Log10) (p = 0.005). At 14 DPC, no significant differences were detected but ~10% fewer birds remained positive in the TRT group vs. CON (p > 0.05). These findings suggest that diets supplemented with SCFP postbiotic may be a useful tool for mitigating SE colonization in horizontally exposed pullets and may support pre-harvest food-safety strategies.

Applied Research Note: Internal organ colonization by Salmonella Enteritidis in experimentally infected layer pullets after rearing in conventional cage or cage-free housing

Applied Research Note: Internal organ colonization by Salmonella Enteritidis in experimentally infected layer pullets after rearing in conventional cage or cage-free housing

Clostridium butyricum Can Promote Bone Development by Regulating Lymphocyte Function in Layer Pullets.

Bone health problems are a serious threat to laying hens; microbiome-based therapies, which are harmless and inexpensive, may be an effective solution for bone health problems. Here, we examined the impacts of supplementation with Clostridium butyricum (CB) on bone and immune homeostasis in pullets. The results of in vivo experiments showed that feeding the pullets CB was beneficial to the development of the tibia and upregulated the levels of the bone formation marker alkaline phosphatase and the marker gene runt-related transcription factor 2 (RUNX2). For the immune system, CB treatment significantly upregulated IL-10 expression and significantly increased the proportion of T regulatory (Treg) cells in the spleen and peripheral blood lymphocytes. In the in vitro test, adding CB culture supernatant or butyrate to the osteoblast culture system showed no significant effects on osteoblast bone formation, while adding lymphocyte culture supernatant significantly promoted bone formation. In addition, culture supernatants supplemented with treated lymphocytes (pretreated with CB culture supernatants) stimulated higher levels of bone formation. In sum, the addition of CB improved bone health by modulating cytokine expression and the ratio of Treg cells in the immune systems of layer pullets. Additionally, in vitro CB could promote the bone formation of laying hen osteoblasts through the mediation of lymphocytes.

The impact of avian IgY antibodies and probiotics supplementation via drinking water on growth and laying performance of 16-week-old layer pullets

Antibiotics raise an issue concerning the development of antibiotic resistance of some pathogenic bacteria. The use of probiotics and Avian IgY in layer pullet farming is a better way of protecting against pathogenic bacteria and increasing production performance. Supplementation of Avian IgY antibodies and probiotics(Lactobacillus acidophilus, Streptococcus faecium, Bifido bacterium longghum, Bacillus thermophilum) were conducted on 5,724 healthy layer pullets to determine its effect on their growth and laying performance. The supplement was in powder form with a dosage of 100 mg per liter of water for 6 hours. The effect of the supplementation was evaluated by measuring production parameters on growth and laying performance of the layer pullets; there were 3 treatment groups, the control group, Treatment 2 which received 5 days initial supplementation for the first week and then twice every week for 9 weeks and Treatment 3 which received 5 days initial supplementation for the first week and then twice every 2 weeks for 9 weeks. Results showed that the supplementation had significant effects in the age in days when 50% of the total population per treatment laid their first eggs, average number of eggs produced, % Hen day production, % Hen house production, total weight of eggs, and feed conversion efficiency. It also showed that the supplementation is economical and yielded higher profit. On the other hand, the supplementation had no significant effect on the average body weight and mortality count of the layer pullets. The supplementation of Avian IgY antibodies and probiotics in water soluble powder via drinking water with 5 days initial supplementation of Avian IgY antibodies and probiotics for the first week; then twice every 2 weeks for 9 weeks has the greatest effects to increase the production performance and profitability of layers.Keywords: Avian IgY antibodies, Growth performance, Laying performance, Layer pullets, Probiotics

Gut microbiota shift in layer pullets fed on black soldier fly larvae-based feeds towards enhancing healthy gut microbial community

Globally, most gut microbiota-related studies have focused on broilers due to their diverse microbial communities compared to that of layer chicken. However, in Africa few studies have been undertaken despite the increasing benefits to the poultry industry. The utilization of Insect-Based diets to improve the gastrointestinal function and gut health in poultry is increasingly gaining global attention. Here, we evaluated the potential roles of commercial black soldier fly larvae-based feeds (BSFLF) in reshaping the abundance, composition and diversity of the gut microbiota of layer chickens using high throughput Oxford nanopore Minion sequencing of the full length bacterial 16S rRNA gene. Two hundred and fifty ISA Brown layer chicks were reared in pens for a period of 20 weeks. The layer pullets were allotted 5 dietary treatments that were formulated as follows: control diet (T1): 100% FM + 0% BSFL, T2: 25% BSFL + 75% FM; T3: 50% BSFL + 50% FM; T4: 75% BSFL + 25% FM, and T5: 100% BSFL + 0% FM. Sampling was done from the eight major regions including oesophagus, crop, proventriculus, gizzard, duodenum, ileum, large intestines and ceca. Out of the 400,064 classified reads analyzed, the most dominant phyla identified across the feed treatments were Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria. The diet treatment with 100% inclusion levels of BSFL showed the highest intra-species alpha diversity and richness according to Chao1 and Shannon index. Intra-species beta diversity assessment revealed that the diet types significantly influenced the abundance of the microbiota, but differences between most abundant taxa were similar. There was increase in abundance of potentially beneficial bacteria (Lactobacillus, Bacteroides and Enterococcus) with increased inclusion levels of BSFLF in layer pullets diets. Across the different gut segments, Lactobacillus dominated all the eight regions and the ceca was the most diverse segment. Our findings unravel complex gut microbial shift in laying hen fed BSFLF and therefore underpins the potential roles of beneficial bacteria as promising prebiotics and probiotics in reshaping of the gut microbiota to maintain good gut health.

Farm Environmental Enrichments Improve the Welfare of Layer Chicks and Pullets: A Comprehensive Review.

Simple SummaryLayer industries that are still using cage housing systems should encourage the provision of appropriate farm enrichments, especially at an early stage. Farm environmental enrichments such as litter, sand, alfalfa bales, chick papers, pecking stones, pecking strings, perches, slopes, elevated platforms, aviaries and outdoor access reduce feather and skin damage, as well as abdominal fat content. Additionally, they promote the development of the brain and musculoskeletal systems and improve biological function, productivity and product quality with lifelong benefits for hens by continuously exposing them to free access to forage, dust baths and free locomotion. In this review, we summarize several common and effective methods of farm environmental enrichments, including different manipulable materials, structural equipment, and outdoor access, moreover, the competence of the farm staff is a requirement to achieve useful utilization of these farm environmental enrichments that aim to reduce stress and improve the welfare and productivity of layers. Proper farm environmental enrichments benefit the wellbeing of caged birds.Currently, cage housing is regarded as a global mainstream production system for laying hens. However, limited living space and confinement of birds in cages cause welfare and health problems, such as feather pecking, osteoporosis, obesity, and premature aging. Many studies have been conducted to alleviate layer welfare problems by providing farm environmental enrichments such as litter, sand, alfalfa bales, chick papers, pecking stones, pecking strings, perches, slopes, elevated platforms, aviaries and outdoor access with a trend towards complex enrichments. The provision of appropriate enrichments continuously attracts layers towards pecking, foraging, dust bathing, and locomotion, thereby giving lifelong benefits to laying hens. Hence, raising chicks and pullets under such conditions may reduce feather and skin damage, as well as accumulation of abdominal fat, and improve several biological features such as health, productivity, quality products, and docility of laying hens. Therefore, providing enrichment during the first few days of the layer’s life without any interruption is crucial. In addition, due to different farm conditions, environmental enrichment should be managed by well-trained farm staff. For example, in preventing feather pecking among the birds, litter materials for foraging are superior to dust bath materials or new items. However, a limited supply of litter creates competition and challenges among birds. Therefore, providing farm environmental enrichment for layers requires proper handling, especially in commercial layer farms. Hence, improving the welfare of chicks and pullets through optimizing on-farm environmental enrichments is essential for production systems practicing cage housing.

PSXI-19 Evaluation of Salmonella Enteritidis (S.E.) Cecal Excretion and Ovary Infection Rates After SE Challenge in Commercial Layer Pullets fed with Feed Energy Company Product R2

Abstract Salmonella enteritidis is one of the leading bacterial causative agents of acute human gastroenteritis from poultry. The objective of this study was to determine the efficacy of the patent pending low pKa, lipid-based natural R2 product of Feed Energy on commercial layer pullets using a Salmonella enteritidis challenge model. One-day-old HyLine W-36 layer pullets were placed in two separate rooms (116 sq.ft.) at 48 birds per pen. At 10 weeks of age, pullets were placed in individual cages of an A-Frame layer cage with a plastic wall between the R2 treatments (48 cages) and 48 cages for the challenge control. All birds were orally gavaged S.E. at 17 weeks with 5.2x108 CFU/bird. The dietary treatments from day 1: Control: Basal Diet + Distiller corn Oil (DCO), Treatment: Basal Diet + R2 product. The birds were fed a starter feed from day 1 to 12 weeks of age with 2.5% added fat and grower diet from 12 to 20 weeks with 1% added fat. Salmonella prevalences in ceca, ovaries, and cloacal swabs were compared between treatments and weeks using logistic regression. Salmonella CFUs in culture-positive samples were compared using linear regression. All statistical testing assumed a two-sided alternative hypothesis, and P &amp;lt; 0.05 was considered significant. Ceca and ovary samples were evaluated from one-half of the birds at 1 week and 3 weeks post challenge. At both sample times, the birds fed the R2 product had numerically less S.E. prevalence in ceca, ovaries, and cloacal swabs. Although there was not a statistical difference for each individual tissue tested, there was an obvious trend in reduction over time that would indicate the R2 product may be helping hens to more rapidly clear S.E. colonization and long-term benefits in preventing and/or reducing S.E. colonization of the ceca and ovaries.