G. T. Pharr

Valine requirements for immune and growth responses in broilers from 3 to 6 weeks of age.

1. Four experiments were conducted to evaluate valine (Val) requirements in Ross 508 broilers from 3 to 6 weeks of age. Common diets were fed to broilers until 3 weeks of age. 2. Growth and carcass measurements were taken in all experiments. Immune responsiveness measurements were taken in Experiments 1 and 2. 3. Birds given 7·2 g Val/kg of diet in Experiment 1 had more abdominal fat than birds given 8·2 g Val/kg of diet, but there were no differences in growth or other carcass measurements. Because growth performance was not reduced in birds given 7·2 g Val/kg of diet, Val concentration was reduced to 6·4 g Val/kg of diet in Experiments 2 and 3. 4. Increasing Val from 6·4 to 8·7 g Val/kg of diet resulted in linear increases for BW gain, feed efficiency and Val intake in male birds, and Val intake in female birds. Quadratic responses to increasing dietary Val were not observed in any experiment. There were no effects of Val on innate or adaptive immunity. 5. A nonessential amino acid mixture containing the same nitrogen content as the L-Val additions in Experiment 4 was added and tends to support the idea that the responses to Val were specific and not due to increases in total nitrogen. 6. Dose responses to Val resulted in male, but not female, birds given 7·3 g Val/kg of diet having improved BW gain and feed efficiency compared with birds receiving 6·4 g Val/kg of diet.

Mycoplasma gallisepticum transmission: Comparison of commercial F-strain vaccine versus layer complex-derived field strains in a tunnel ventilated house

Two simultaneous trials were conducted using a commercially available, live, F strain Mycoplasma gallisepticum (FMG) vaccine (trial 1) or 2 inocula of layer complex-derived MG strains (LCD-MG; trial 2). In each of the 2 trials, 4 commercial turkeys were housed in each of 2 adjoining pens immediately adjacent to air inlets. The turkeys (8/trial) were inoculated in the right eye with either a 1× dose of FMG (trial 1) or with 0.02 mL of 1 of 2 actively growing LCD-MG inocula (4 turkeys/inoculum; trial 2). In each of the 2 trials, one pen housing 4 inoculated turkeys was maintained without the addition of other poultry, whereas 16 MG-free broilers and 4 MG-free layers were added to the other pen of 4 inoculated turkeys. Within each of the trials and at increasing intervals, either 4 layers (3 pens) or 4 turkeys (3 pens) were placed down-airstream from the inoculated pens. The distance of the first pen from the inoculated turkeys was separated by the width of one pen that was empty. Succeeding down-airstream pens were situated such that the empty distance (absence of any poultry) between pens that contained poultry doubled from one pen to the next such that the final pen that contained poultry had 4 empty pens between it and the next up-airstream pen that also contained poultry. At 106 d postinoculation, all poultry were bled, swabbed for MG from the choanal cleft, and then euthanized and necropsied. No commingled poultry in trial 1 (FMG), whether inoculated (turkeys) or commingled (layers and broilers), died during the course of the trial, and 5 of the 8 FMG-vaccinated turkeys exhibited serological but not cultural evidence of mycoplasmosis. In trial 2 (LCD-MG), 2 commingled broilers died and no inoculated turkeys exhibited either serological or cultural evidence of mycoplasmosis. In both trials, no poultry housed down-airstream from the inoculated poultry showed evidence of clinical signs of mycocplasmosis and none showed either serological or cultural evidence of mycoplasmosis.

Identification of the gene product recognized by monoclonal antibody GIIF3

&NA; The chicken as a research model has a disadvantage compared with the mouse and the human because of the low number of available antibodies against gene products of interest. The goal of this study was to identify the antigen recognized by monoclonal antibody (mAb) GIIF3, which is a 42 kDa protein that appears in follicle‐associated epithelium of the guinea hen as well as in different muscle types during chicken embryonic development. The 42 kDa protein, immunoprecipitated from chicken gizzard protein lysates, was evaluated by mass spectrometry. Mass spectrometry analysis revealed peptides specific for the chicken &bgr;‐ or &ggr;‐actin isoforms. The mAb GIIF3 can be used as a new research tool for smooth muscle cell and bursa of Fabricius developmental studies.