Effects of Induced Moisture Loss in Chicken Embryos at Embryonic Day 18 and Post-hatch Immune Response During Salmonella enteritidis Lipopolysaccharide Challenge in Broilers.

Two experiments were conducted to investigate the effects of induced moisture loss on embryonic development and the immune response following an inflammatory challenge immediately post-hatch. In Experiment I, fertile leghorn eggs (n = 100) and commercial broiler eggs (n = 300) were set at 37.5°C and moisture loss was induced in one-half of the Leghorn and broiler eggs by drilling two, 1.5 mm diameter holes. The Control eggs had 0 holes. At embryonic day (ED)18, layer and broiler eggs in the 2-holes treatment had a significant (P < 0.01) increase in moisture loss compared to the control treatment (10.1% vs. 8.2%). Similarly, at ED18, the broiler eggs with 2-holes had a significant increase (P < 0.01) in moisture loss compared with control eggs (9.9% vs. 8.4%). Thymocytes from both the leghorn (104%) and broiler (62%) embryos in the 2-holes treatment had significantly increased in vitro proliferation compared with the control embryos (P ≤ 0.05). At ED18, layer and broiler embryos in the 2-holes treatment had an approximate twofold increase in the splenic CD8+/CD4+ ratio (P ≤ 0.05) and CD4+CD25+ cells percentage in both the thymus and spleen (P ≤ 0.05). At ED18, both layer and broiler embryos from the 2-holes treatment had a significant increase in splenic IL1-ß, IL-6, IL-10, and TLR-4 mRNA transcription compared to the control group (P ≤ 0.05). Experiment II was repeated with 300 fertile broiler eggs. On the day of hatch, chicks were randomly distributed into one of four treatments in a 2 (0, 2 holes) × 2 (0, 500 µg lipopolysaccharide, LPS) factorial arrangement of treatments. Chicks in the LPS groups were injected intraperitoneally with 500 µg/kg BW LPS. At 24 and 48 h post-hatch, chicks hatched from eggs with 2-holes and challenged with LPS had a significant increase (P ≤ 0.05) in thymocyte proliferation at 24 h (42%) and 48 h (37%) when compared with chicks hatched from the control (0-hole; 0 µg LPS) treatment. Chicks hatched from the 2-holes treatment and challenged with the LPS had an approximately twofold higher splenic CD8+/CD4+ ratio and 1.5 fold increase in CD4+CD25+ percentage compared to control chicks (P ≤ 0.05). In chicks hatched from the 2-holes treatment, MUC2 mRNA transcription was comparable to control chicks at 24 and 48 h in response to the LPS challenge. Our data suggest that the 2-holes treatment reprograms gene transcription to facilitate cell survival via proliferation and differentiation during an LPS inflammatory challenge.

Centennial Review: Trace mineral research with an emphasis on manganeseDedicated to Dr. Roland M. Leach, Jr.

A century of publications in the Poultry Science journal is celebrated with Centennial papers. It is relevant, therefore, to explore trace mineral (TM) research with an emphasis on manganese and selected aspects of skeletal development. Some of the initial observations on the topic appeared in the earliest volumes of our journal. Published studies in the late 1920's and 1930's confirmed the importance of the diet and unidentified organic (i.e., vitamins) and inorganic nutrients (i.e., TM) relative to skeletal development. The early nutrition research emphasized requirement studies, the search for unknown factors to alleviate recognized deficiencies, and lastly important nutrient interactions, especially in the gut. This review will discuss TM research with an emphasis on manganese (Mn). Some of the fundamental discoveries on the mechanisms underlying embryonic and post-hatch skeletal development led directly to research directed at the role of Mn in the synthesis of the epiphyseal matrix. The TM research agenda today is considerably different with respect to all trace nutrients and is largely driven by gut health, antibiotic free production, food safety and environmental outcomes. A significant proportion of the published research over the last 2 decades has focused on the form (i.e., organic, inorganic) of a given TM relative to a given physiologic or production response under the pretext that modern commercial genotypes and production realities have changed considerably since the last NRC publication (NRC, 1994). If one closely reviews the more recent scientific literature, however, it could be argued that the term "trace mineral requirement" is often a misnomer. Many of the TM levels recommended or in use today are not the result of quantifiable requirement studies but are often based on efficacy comparisons with the different organic and inorganic forms of commercially available TM.

Interrelations between the microbiotas in the litter and in the intestines of commercial broiler chickens.

The intestinal microbiota of broiler chickens and the microbiota in the litter have been well studied, but the interactions between these two microbiotas remain to be determined. Therefore, we examined their reciprocal effects by analyzing the intestinal microbiotas of broilers reared on fresh pine shavings versus reused litter, as well as the litter microbiota over a 6-week cycle. Composite ileal mucosal and cecal luminal samples from birds (n = 10) reared with both litter conditions (fresh versus reused) were collected at 7, 14, 21, and 42 days of age. Litter samples were also collected at days 7, 14, 21, and 42. The microbiotas were profiled and compared within sample types based on litter condition using PCR and denaturing gradient gel electrophoresis (PCR-DGGE). The microbiotas were further analyzed using 16S rRNA gene clone libraries constructed from microbiota DNA extracted from both chick intestinal and litter samples collected at day 7. Results showed significant reciprocal effects between the microbiotas present in the litter and those in the intestines of broilers. Fresh litter had more environmental bacteria, while reused litter contained more bacteria of intestinal origin. Lactobacillus spp. dominated the ileal mucosal microbiota of fresh-litter chicks, while a group of bacteria yet to be classified within Clostridiales dominated in the ileal mucosal microbiota in the reused-litter chicks. The Litter condition (fresh versus reused) seemed to have a more profound impact on the ileal microbiota than on the cecal microbiota. The data suggest that the influence of fresh litter on ileal microbiota decreased as broilers grew, compared with temporal changes observed under reused-litter rearing conditions.

Effect of embryonic thermal manipulation on heat shock protein 70 expression and immune system development in Pekin duck embryos.

Two experiments were conducted to study the effects of thermal manipulation on heat shock protein 70 (HSP70) transcription and immune cell characteristics' in Pekin duck embryos. In experiments I and II, fertile duck eggs were incubated at either a standard (S; 37°C) or high (H; 38.0°C) temperature from embryonic day (ED) 1 to 10. At ED11, half the eggs incubated at 37.5°C or 38.0°C were either kept at 37.5°C (SS) or 38.0°C (HH) respectively, or moved to the opposite incubator/temperature of either 38.0°C (SH) or 37.5°C (HS). Beginning on ED 21, all eggs (embryos) were incubated at 37.5°C. In experiments I and II, the mean egg shell temperature (EST) of eggs incubated at 38.0°C was higher than that from 37.5°C at ED10 (P < 0.01). In both experiments, the yolk free wet embryo body weight (YFWEBW) of embryos from the HS treatment was increased while that in the HH treatments was decreased compared with the SS treatment at ED25 (P < 0.01). In experiment II, embryos from the HH treatment had increased HSP70 mRNA compared with the SS treatment in the liver, thymus, and bursa (P < 0.05). The thymus and bursa from embryos in the SH treatment had increased MHCI mRNA when compared with the SS treatment (P < 0.05). The thymus from HH and SH treatments had increased MHCII mRNA while the bursa from the HH and SH treatments had decreased MHCII mRNA when compared with the SS treatment (P < 0.05). The spleen and bursa from the HH treatment had increased IL-6, IFNγ, and IL-10 mRNA when compared with the SS treatment (P < 0.05). The thymus and spleen from embryos in the HH treatment had increased CD8+/CD4+ ratios and CD4+CD25+ cell percentages compared with the SS treatment (P < 0.05). In conclusion, embryos incubated at 0.5°C higher than the standard incubation temperature from ED1 to 21 had increased HSP70 mRNA, MHCI, and inflammatory cytokines, and the immune response was skewed toward cell-mediated immunity.

Degenerative primer design and gene sequencing validation for select turkey genes.

We successfully designed and validated degenerative primers for turkey genes MUC2, RPS13, TBP and TFF2 based on chicken sequences in order to use gene transcription analysis to evaluate (quantify) the mucin transcription to probiotic supplementation in turkeys. Primers were designed for the genes MUC2, TFF2, RPS13 and TBP using a degenerative primer design method based on the available Gallus gallus sequences. All primer sets, which produced a single PCR amplicon of the expected sizes, were cloned into the TOPO(®) vector and then transformed into TOP 10(®) competent cells. Plasmid DNA isolation was performed on the TOP10(®) cell culture and sent for sequencing. Sequences were analyzed using NCBI BLAST. All genes sequenced had over 90% homology with both the chicken and predicted turkey sequences. The sequences were used to design new 100% homologous primer sets for the genes of interest.