Muscovy ducklings, a particularly sensitive avian bioassay for T-2 toxin and diacetoxyscirpenol

Day-old domesticated Muscovy ducklings (Cairina moshata) were given the trichothecene mycotoxins T-2 toxin or diacetoxyscirpenol at 0.25, 0.5, or 1 micrograms/g of feed for 7 days. All concentrations of both toxins caused characteristic dose-related lesions on the roof of the oral cavity of the birds. Muscovy ducklings showed these signs in a shorter time (less than 16 hours in some cases) and at a lower feed concentration of these trichothecenes than did other avian species in similar studies.     

Effects of season on the reproductive organs and steroid hormone profiles in guinea hens (Numida meleagris)

1. The study documented gross anatomical and histological differences in the reproductive organs of 28 breeding and non-breeding female guinea fowls. Peripheral progesterone and 17β-oestradiol concentrations were also compared in breeding and non-breeding hens.

2. In non-breeding females, all ovarian and oviducal gross anatomical features had significantly regressed. Histologically, some of the changes in a regressing oviduct include systematic changes in height and size of all epithelial cells in all regions of the duct, absence/sparse ciliation of portions of surface epithelium in the magnum, isthmian and uterine regions, general loss of cytoplasmic mass, reduction in size and degeneration of tubular glands. Mucosal folds in all regions of the oviduct except the infundibular lip were higher in breeding females.

3. No difference was found between the two groups in plasma progesterone concentrations. Breeding females, however, had higher peripheral oestradiol concentrations than non-breeding females. About 2 h prior to oviposition, plasma oestradiol concentrations peaked at 2.4-fold (230 pg/ml) compared with baseline concentration and plasma progesterone concentrations by nearly 9-fold (5.29 ng/ml) of baseline.

4. Significant regression and changes in the histological structure of the ovary and oviduct had occurred in non-breeding females, and lower peripheral oestrogen concentrations may be responsible for this phenomenon.

     

Genomewide association study of immune traits in chicken F2 resource population

Immune traits play pivotal roles in animal immune capacity development and disease resistance. Single nucleotide polymorphisms (SNPs) are common forms of genetic variations among individuals, which are thought to account for the majority of inherited phenotypic variations. In this study, we performed genomewide association, using the Illumina 60K SNP BeadChip studies to detect molecular markers and candidate genes associated with immune traits in an F2 population. Sixteen immune traits were measured. We identified 85 significant SNPs (p < 2.98 × 10^?6) with 5% as the genomewide significance threshold, 380 SNPs of suggestive significance (p < 5.96 × 10^?5) from simple model (general linear model, GLM) and 15 SNPs of suggestive significance (p < 5.96 × 10^?5) from the compressed mixed linear model (MLM), which were also found in GLM (six significant SNPs and seven suggestive SNPs). Three significant SNPs (GGaluGA151406, Gga_rs14554319 and Gga_rs13593979) and candidate genes (LYRM4 and KTN1) were found to be associated with avian influenza antibody titres, and the first two SNPs are from the results of two‐model analysis. For the immune organs, through the analysis of GLM, 19 SNPs were found to be significantly associated with the thymus weight, 61 SNPs were significantly associated with the bursa of Fabricius weight, six of which were located within a 34‐Mb region (125 846 474–159 649 698 bp) on chicken chromosome 1 (GGA1). A candidate region relevant to haematological traits from GLM was found in GGA4 and 9 loci were located on it. Three loci (GGaluGA348521, Gga_rs16098446 and GGaluGA348518) within 179 kb (16 286 868–16 466 134 bp) on GGAZ from GLM provided evidence that this genomic segment may be relevant to red blood cell volume distribution width (RDW). Our study provides a list of significant SNPs and candidate genes that will be valuable information for unveiling the underlying molecular mechanism of immune regulation.     

Estimation of the standardized ileal digestible lysine requirement for primiparous pregnant sows

This experiment was conducted to determine the optimal standardized ileal digestible lysine (SID Lys) level in diets fed to primiparous sows during gestation. A total of 150 (Landrace × Large White) crossbred gilts (weighing 149.9 ± 3.1 kg) were fed gestation diets (12.55 MJ of ME/kg) containing SID Lys levels of 0.43, 0.52, 0.60, 0.70 or 0.80% respectively. Gilts were fed 2.0 kg/day from day 1 to 80 and 3.0 kg/day from day 80 to 110 of gestation respectively. Gilts were allocated to treatments based on their body weight on the day of breeding. Weight gain from day 80 to 110 increased with increasing dietary SID Lys levels (p = 0.044). Fitted broken‐line (p = 0.031) and quadratic plot (p = 0.047) analysis of body weight gain indicated that the optimal SID Lys level for primiparous sows was 0.70 and 0.69% respectively. During gestation, neither backfat thickness nor loin eye area was affected by dietary SID Lys level. Increasing dietary Lys had no effect on the litter size at birth or pigs born alive per litter. Litter weight at birth was not affected by dietary SID Lys level. The litter weight variation at birth quadratically decreased with increasing dietary SID Lys (p = 0.021) and was minimized at 0.70% dietary SID Lys. Gilts fed the 0.70% SID Lys diet had the highest dry matter (p = 0.031) and protein (p = 0.044) content in colostrum. On day 110 of gestation, gilts fed the 0.70% SID Lys diet tended to have the highest serum prolactin (p = 0.085) and serum insulin (p = 0.074) levels. The data demonstrate that the optimal dietary SID Lys was 0.70% for pregnant gilts, which is similar to the recommendation of 0.69% that was estimated by the NRC (2012).     

Nanoemulsion formulation of florfenicol improves bioavailability in pigs

Nanotechnology applications in medicine have seen a tremendous growth in the past decade and are being employed to enhance the stability and bioavailability of lipophilic substances, such as florfenicol. This study aimed to examine the pharmacokinetic properties of the formulated oil‐in‐water florfenicol‐loaded nanoemulsion (FF‐NE). FF‐NE and florfenicol control (Nuflor^®) were administered to the pigs at a dose of 20 mg/kg. Nanoemulsion formulation of florfenicol was highly influenced in vivo plasma profile. The in vivo absorption study in pigs indicated that C_max (14.54 μg/mL) was significantly higher in FF‐NE, 3.42 times higher than the marketed formulation. In comparison with the control group, the relative bioavailability of formulated nanoemulsion was up to 134.5%. Assessment of bioequivalence using log‐transformed data showed that the 90% confidence intervals (90% CI) of C_max and AUC_0–∞ were 2.48–4.60 and 1.21–1.72, respectively.     

Infectious tenosynovitis in broilers and broiler breeders in Egypt

Two infectious tenosynovitis-producing viruses were isolated from tendon sheaths and synovial fluids of 59 broilers and 15 broiler breeders obtained from different flocks in Egypt during June to October 1983. The viruses grew well on the chorioallantoic membrane of developing chicken embryos, produced small localized white pock lesions with oedematous swellings at the inoculation sites and death of most of the embryos 72 to 96 hours post-inoculation. They also induced cytopathic effect in chicken embryo rough, Vero and MS cell lines. The viruses were neutralized by reovirus S1133 antiserum, both in tissue culture and. on the chorioallantoic membrane. Inoculation of the viruses into 2-day-old broiler chicks via the foot pad, intramuscular and oral routes reproduced the disease with the development of characteristic clinical, pathological and serological responses. The infection was transmitted to in-contact control chicks. This is the first report of the disease and of the isolation and identification of the causative virus in Egypt.     

Production of large quantities of interferon with calf testicular cells and leucocytes.

Interferon (IF) was induced in calf testicle monolayer cultures and leucocycte suspension cultures with Semliki forest virus and Newcastle disease virus to evaluate the potency of those cells for producing IF in large quantities for clinical experiments. Interferon activity was measured by an RNA-inhibition test using Semliki forest virus as challenge. To produce 10(6) units of IF, leucocytes from 67-5 litres of blood or 7-2 X 10(9) testicle cells were needed.     

Effects of IgY antibody on the development of Marek's disease.

The effects of passive immunization with immunoglobulin Y (IgY) on the pathogenesis of Marek's disease (MD) were examined in an experimental line of White Leghorn chickens highly susceptible to MD. Purified IgY with anti-MDV antibody activity, when injected into chicks, delayed the development of MDV viremia and lesions until 9 days postinoculation (PI) with Marek's disease virus (MDV). The blastogenic response of spleen cells to concanavallin-A was depressed at 6 days PI in the birds without passive immunization, whereas it was not totally depressed until 17 days in birds passively immunized with IgY anti-MDV antibody.