FLUORESCEIN LABELLED ANNEXIN V STAINING LIMITATIONS FOR DETERMINATION OF BLASTODERMAL CELLS APOPTOSIS

It is known that blastoderm contains not only blastodermal cells (BCs) but also cellular “debris”. These particles include yolk granules and lipid droplets. Some authors used AnnexinV (AnV) staining technique for determination of cell apoptosis. However, AnV is a protein with high affinity to lipids. So the aim of our study was to demonstrate the AnV binding in the blastoderm and yolk cell suspensions. Cell populations were obtained from fertilized chicken eggs. The blastoderms were isolated using filter paper ring method and mechanically fragmented. After that, samples were stained with AnV-FITC and analyzed by fluorescent microscopy (FM) and flow cytometry (FC). FM showed non-specific binding of AnV-FITC on the yolk and lipid particles. Therefore, the FC method using specific nuclear dye DRAQ5 was used to separate BCs from cellular debris. Only 1.82 ± 0.27 % cells were DRAQ5 positive. On the other hand, increase of total events (21 ± 3.30 %) of AnV positive cells without DRAQ5 dye was recorded. Moreover, the affinity of yolk to AnV by FC was also observed (10.45 ± 2.59 %). Significant differences among the groups (P < 0.001) were recorded. This trend was caused by non-specific binding of AnV to the lipid and yolk particles. So it is necessary to stain suspension with nuclear dye to separate BCs than co-stained with some marker of apoptosis. Based on the results we can summarized that AnV staining is inappropriate technique for apoptosis of BCs, however, using nuclear dye we can prevent of non-specific binding.

Research Note: Effects of preincubation and higher initiating incubation temperature of long-term stored hatching eggs on hatchability and day-old chick and yolk sac weight

We studied the effect of increased initial incubation temperature and repeated preincubation of 35-d stored eggs from 46-week-old Ross 308 parental stock on the hatchability and day-old chick and yolk sac weight. Two different temperatures were applied during the first 36 h and they were combined with 4 preincubation treatments during storage. One half of the hatching eggs (2,400) were incubated for the first 36 h at an incubation temperature of 38.3°C, and the second half were incubated at a higher temperature of 39.2°C. Four different preincubations were applied; none, once at the 7th d of hatching egg storage, twice at the 7th and 12th d of storage and 3 times at the 7th, 12th and 19th d of storage. Both preincubation and increased temperature had negative effects on hatchability (P < 0.001). The interaction between these 2 factors was also significant (P < 0.05). These 2 factors also negatively affected early and late embryonic mortality (P < 0.001). However, middle embryonic mortality was not influenced. Live weight, weight of residual yolk sac, and yolk sac proportion were not affected by repeated preincubation nor by increased temperature over the first 36 h of incubation (P > 0.05). A higher initial temperature decreased chick yolk free body mass (P < 0.05). Although neither increased initial temperature in the setter nor repeated preincubation affected one-day-old chick weights, these treatments were not suitable for long-term stored eggs because of decreased hatchability and impairment of one day chick yolk free body mass.

Active components of essential oils as acaricides against Dermanyssus gallinae

1. The aim was to evaluate the acaricidal effects of pure active components of essential oils against poultry red mite (Dermanyssus gallinae) as an alternative to chemical acaricides (organophosphates and pyrethroids).2. The toxicities of five pure active components of essential oils (eugenol from clove bud, eucalyptol from rosemary, limonene from citrus fruits, linalool from lavender and cinnamaldehyde from cinnamon) were tested on D. gallinae females in an impregnated paper assay.3. The active substances were dissolved in water and Tween 20 and applied at concentrations ranging from 0.002 to 0.06 µl/cm². Toxicity was expressed as a lethal dose (LD₅₀ or LD₉₀).4. The highest mortality was observed with eugenol. The LD₉₀ was estimated to be 5.1 µg/cm² for this substance, followed by cinnamaldehyde, the LD₉₀ of which was estimated to be 11.0 µg/cm². Limonene and eucalyptol were generally less effective in controlling D. gallinae.

Development and reactivity of the immune system of Japanese quail lines divergently selected for the shape of the growth curve

1. Selection strategies for broilers must balance rapid growth with the welfare and health of animals, strategies must deal with the trade-off with other vital functions.2. Divergent selection of Japanese quail for high (HG) and low (LG) relative body weight gain between 11 and 28 days of age has been conducted to accelerate linear phase growth without influencing the final adult body weight. Higher body growth rate is often connected with a weakened immune system. Therefore, the present study explored the immunological characterisation of quail from HG and LG lines, which differ substantially in their growth rate.3. The trial evaluated the maternal investment to immunologically active substances, cell-mediated immunity stimulated by phytohaemagglutinin (PHA) injection and the acute phase of the immune response to lipopolysaccharide (LPS) administration in three different phases of early postnatal growth.4. Except for higher lysozyme activity in the LG group when compared to the HG line, the maternal investment did not differ between the two lines. Plasma antibody concentrations responded quickly to any change in growth rate in both lines. Overall, it seems that initial rapid growth of the LG line had long-lasting effects on immune responsiveness, even after the growth rate of the HG line escalated during the linear phase of growth.5. The study indicated that changes in the growth rate caused by the selection for growth in meat-type Japanese quail can influence the acute phase of the immune response and development of the immune system.

Comparison of Microbiomes between Red Poultry Mite Populations (Dermanyssus gallinae): Predominance of Bartonella-like Bacteria

Blood feeding red poultry mites (RPM) serve as vectors of pathogenic bacteria and viruses among vertebrate hosts including wild birds, poultry hens, mammals, and humans. The microbiome of RPM has not yet been studied by high-throughput sequencing. RPM eggs, larvae, and engorged adult/nymph samples obtained in four poultry houses in Czechia were used for microbiome analyses by Illumina amplicon sequencing of the 16S ribosomal RNA (rRNA) gene V4 region. A laboratory RPM population was used as positive control for transcriptome analysis by pyrosequencing with identification of sequences originating from bacteria. The samples of engorged adult/nymph stages had 100-fold more copies of 16S rRNA gene copies than the samples of eggs and larvae. The microbiome composition showed differences among the four poultry houses and among observed developmental stadia. In the adults' microbiome 10 OTUs comprised 90 to 99% of all sequences. Bartonella-like bacteria covered between 30 and 70% of sequences in RPM microbiome and 25% bacterial sequences in transcriptome. The phylogenetic analyses of 16S rRNA gene sequences revealed two distinct groups of Bartonella-like bacteria forming sister groups: (i) symbionts of ants; (ii) Bartonella genus. Cardinium, Wolbachia, and Rickettsiella sp. were found in the microbiomes of all tested stadia, while Spiroplasma eriocheiris and Wolbachia were identified in the laboratory RPM transcriptome. The microbiomes from eggs, larvae, and engorged adults/nymphs differed. Bartonella-like symbionts were found in all stadia and sampling sites. Bartonella-like bacteria was the most diversified group within the RPM microbiome. The presence of identified putative pathogenic bacteria is relevant with respect to human and animal health issues while the identification of symbiontic bacteria can lead to new control methods targeting them to destabilize the arthropod host.

The effect of dietary calcium source, concentration and particle size on calcium retention, eggshell quality and overall calcium requirement in laying hens

1. Four different sources of calcium in isonitrogenous and isoenergeric diets were fed to laying hens for 2 weeks when they were 56 and 57 weeks old. The calcium source blends were as follows: 29% fine limestone (LF)+71% large limestone (LG), 32% LF+68% eggshell, 32% LF+68% oyster shell, 50% LF+50% LG. The contents of these blends of calcium in the diets were as follows: 103.3, 93.3, 93.3 and 93.3 g/kg, respectively. 2. The coefficients of calcium retention were significantly higher in 50:50 LF:LG (0.578) and 32:68 LF:eggshell (0.576). The midnight feeding significantly improved the coefficient of calcium retention in all mixtures except 50:50 LF:LG. 3. In the mixtures 29:71 LF:LG and 32:68 LF:oyster shell, there were significantly greater eggshell quality, eggshell weight, eggshell thickness and eggshell strength. Midnight feeding had no significant effect on eggshell quality. 4. In the ration with oyster shells, 96.5% of the retained calcium was deposited in the eggshell, but in rations 32:68 LF:eggshell and 50:50 LF:LG the utilisation was only 73.9 and 78.6%, respectively. 5. To ensure good quality eggshells in the last third of production, the recommendation for calcium is 4.1 g/kg (900 g/kg dry matter, feed intake 110 g/d). As a source of calcium in this stage of production, a feed mixture containing two-thirds large particles should be used (limestone grit or oyster shell).

The long-term effects of using a higher amount of iodine supplement on the efficiency of laying hens

1. Two different levels of dietary iodine supplement (K + 0, 3.57 mg/kg; K + I, 6.07 mg/kg) were used in a 52-week experiment using 32 ISA Brown laying hens. 2. The greater iodine content in the diet impaired the egg production (K + 0, 319.9 +/- 1.31 eggs/hen; K + I, 312.4 +/- 4.19 eggs/hen), the egg weight (K + 0, 64.4 + 0.66 g; K + I, 63.1 +/- 0.61 g) and the food to egg mass ratio (K + 0, 2.13 +/- 0.023 kg/kg; K + I, 2.22 +/- 0.030 kg/kg). 3. The greater dietary iodine content had significant (P<0.05) negative effects on Haugh units, yolk index and eggshell weight.