Initial observations on the effect of corticosterone and inbred antibody competency in chickens on population development of the northern fowl mite

Topical application of garlic reduces northern fowl mite infestation in laying hens

Northern fowl mites (NFM) are external parasites that can lower egg production and cause anemia and even death in laying hens. An experiment was conducted with New Hampshire Red and Single Comb White Leghorn laying hens. Hens were individually caged and provided a complete laying diet and water ad libitum. Hens were assigned to groups in a way that assured that treatments, within each breed, would be applied to comparable numbers of birds with light and heavy mite infestations. Each hen was sprayed around the vent with either water or 10% garlic juice in water. Spraying continued each week for 3 wk. During the fourth week, each bird was scored for the presence of NFM on its skin and feathers. A small snippet of feathers was removed from below the vent of each hen and placed in a labeled petri dish with a round, white filter paper insert. The NFM content of each dish was scored by two individuals approximately 1 h after sampling. There was no significant difference in the NFM scores for hens based on breed or future treatment. After the birds were treated for 3 wk, there was no significant difference in external NFM scores based on breed. There were significantly fewer NFM on the birds treated with garlic juice compared with controls, based on external and petri dish scoring (P < 0.002 and P < 0.04, respectively). The reduction in external NFM score was also significant (P < 0.004), with controls declining approximately 0.2 units, whereas garlic-treated hens had a 1.8-unit decrease in external NFM score. Topical application of garlic juice may be an effective way to decrease NFM in laying hens.

Gordon Memorial Lecture. Stress, strains and resistance

1. Stress describes the bird's defence mechanisms and a stressor is the situation that elicits the defence response. 2. As the environment can be viewed as a composite of interacting stressors, the bird's success in coping with its environment depends on the severity of the stressors and the physiological ability to respond properly and thus maintain homeostasis. 3. The neural, endocrine and more recently immune systems are considered to be integrators of the stress response. Although stress responses may be necessary for survival in wild bird populations, they are often detrimental to efficient growth, skeletal integrity and disease resistance in domesticated fowl. 4. Stress responses are modified by the genetic components.

Comparative analysis of precipitating antibodies in White Rock and Fayoumi hens injected with bovine serum albumin or crude mite extract with resulting effects on northern fowl mite, Ornithonyssus sylviarum (Acari: Macronyssidae) population densities

Precipitating antibody concentration responses to crude northern fowl mite extract (CME) and bovine serum albumin (BSA) injections were compared in White Rock and Fayoumi hens with two-dimensional immunoelectrophoresis and rocket electrophoresis. The effect of CME injections on northern fowl mite population development was also determined. White Rock and Fayoumi hens developed similar antibody concentrations in response to intramuscular injections of BSA according to serum samples analyzed with two-dimensional immunoelectrophoresis. Rocket electrophoresis analyses of pooled serum samples showed significant differences between slopes of White Rock and Fayoumi pools for CME and BSA injections, suggesting differences in antibody-antigen interactions. Fayoumi hens injected with CME, 78, 50, and 14 days prior to experimental infestation with 2,000 northern fowl mites/bird supported significantly fewer mites than BSA-injected hens, although mite populations were low on both treatment groups. Injections of CME had no effect on mite population development on White Rock hens, even though CME-specific antibodies were detected. Although White Rock hens supported significantly greater mite numbers than Fayoumi hens, the difference was not attributed to anti-CME antibody activity alone.

Production and persistence of antibodies in chickens to sheep erythrocytes. 2. Resistance to infectious diseases

A line of chickens selected for ability to product high antibody titers to sheep red blood cells exhibited stronger antibody to Newcastle disease, was more resistant to Mycoplasma gallisepticum, Eimeria necatrix, a splenomeglia virus, and feather mites and less resistant to Escherichia coli and Staphylococcus aureus infection than a line selected for a lack of ability to produce antibody titers. A line of chickens selected for a nonpersistance of antibody titers to sheep red blood cells was relatively more susceptible to all infectious agents tested than a line selected for a persistence of atibody titers.