Papers by Aharon Friedman
One of the key stimulators of intestinal development in the chick is physical exposure to feed, w... more One of the key stimulators of intestinal development in the chick is physical exposure to feed, while feed withholding delays the onset of gut development. A delay of 24-72 hours in onset of feeding is quite common in the poultry industry due to variation in hatching time and hatchery treatments. As intestinal development occurs in concert with the development of the gut associated lymphoid tissue (GALT), we investigated the effects of short term feed withholding on development of GALT in broiler hatchlings. Our findings show that innate immunity was fully functional at hatch, while development of adaptive immunity was delayed. GALT development in the foregut was slightly and temporarily impeded by feed withholding, but activity in the hindgut and bursa was significantly delayed till week two of age. The two week vulnerable period should be seriously considered in circumstances where hatchlings are in transit for extended periods from hatcheries to farms.
Avian Pathology, 1992
One-day-old chicks were vaccinated with one of the commercially used vaccines [herpes virus of tu... more One-day-old chicks were vaccinated with one of the commercially used vaccines [herpes virus of turkeys (HVT), bivalent HVT+SB1 or Rispens] and the immune response and resistance to infection evaluated. A temporary depletion of B-lymphocyte activity of varying intensity was found, as demonstrated by a diminished response to a B-lymphocyte-specific mitogen in vitro, and by decreased antibody production to BSA in vivo. Of the three vaccines tested, the bivalent vaccine (HVT+SB1) and Rispens were the most damaging. A temporary decreased resistance to pathogenic E coli infection in vaccinated chicks was observed.
Clinical and Experimental Immunology, 2008
SUMMARY The increased amounts of agalactosyl IgG (N-linked oligosaccharides terminating with N-ac... more SUMMARY The increased amounts of agalactosyl IgG (N-linked oligosaccharides terminating with N-acetylglucoseamine (GlcNAe) in the serum of patients with rheumatoid arthritis (RA) and other chronic inflammatory diseases have suggested that agalactosyl IgG may be involved in the pathogenesis of RA. We have now evaluated the incidence of agalactosyl IgG in the Lewis rat during the course of adjuvant arthritis (AA). The modification in glycosylation of IgG was measured by means of polyclonal and monoclonal anti GlcNAe antibodies as well as by the lectin concanavalin A (Con A). The results show that Lewis rats undergo a change in serum IgG glycosylation during the course of AA. As in human RA patients, rats with AA lack terminal galactose on igG heavy chain oligosaccharides, and the terminal GlcNAe or mannose residues arc thus exposed. The degree of agalactosyl IgG was positively correlated with the incidence of disease, peaked 20 days after disease induction, and the igG gradually rever...
British Journal of Nutrition, 1989
Vitamin A deficiency results in decreased immune responses; the objective of the present study wa... more Vitamin A deficiency results in decreased immune responses; the objective of the present study was to investigate the involvement of T lymphocytes in the depression of immune responses resulting from vitamin A depletion. This objective was achieved by evaluating antigen-specific T lymphocyte proliferative responses in vitro as vitamin A depletion developed. The evaluation was performed in both rat and chick to examine the generality of immune effects due to vitamin A depletion. Our findings show that vitamin A depletion led to severe impairment of T lymphocyte activity in both animal models, and that this was directly related to the vitamin A status in both species. Immune response impairment was found to precede other manifestations of vitamin A deficiency, and was rapidly corrected by feeding retinyl acetate boluses. This implied a possible regulatory, rather than constitutive, role of vitamin A in immune responsiveness.
The Journal of Experimental Biology, 2019
Interactions between coinfecting parasites1 may take various forms, either direct or indirect, fa... more Interactions between coinfecting parasites1 may take various forms, either direct or indirect, facilitative or competitive, and may be mediated by either bottom-up or top-down mechanisms. While each form of interaction leads to different evolutionary and ecological outcomes, it is challenging to tease them apart throughout the infection period. To establish the first step towards a mechanistic understanding of the interactions between coinfecting limited-term bacterial parasites and lifelong bacterial parasites, we studied the coinfection ofBartonella sp. (limited-term) and Mycoplasma sp. (lifelong), which commonly co-occur in wild rodents. We infected Bartonella and Mycoplasma-free rodents with each species, and simultaneously with both, and quantified the infection dynamics and host responses. Bartonella benefited from the interaction; its infection load decreased more slowly in coinfected rodents than in rodents infected with Bartonella alone. There were no indications for bottom...
World's Poultry Science Journal, 2003
To accommodate the rapid transition to external nutrients, the chick's gastrointestinal tract... more To accommodate the rapid transition to external nutrients, the chick's gastrointestinal tract undergoes dramatic changes within the first few days of life. These include a rapid increase in mass, villi number and length, enterocyte number, crypt depth and proliferating cells. Concomitant with the development of digestive structures and functions a rapid development of the gut associated lymphoid tissue (GALT) occurs. This lymphoid system works within and in concert with digestive tract parenchyma, however, there is little information describing the normal development and immunological function of the avian GALT in the immediate post-hatch period. The purpose of this review is to summarize current knowledge on the structure and function of the avian GALT during the early post-hatch period. At hatch, the gut is poorly populated by both innate immune leukocytes and lymphocytes. The basal numbers of lymphocytes are the result of early waves migrating from the thymus and bursa of Fab...
British Poultry Science, 1995
1. The effect of dietary vitamin A on antibody production and T-cell proliferative response was d... more 1. The effect of dietary vitamin A on antibody production and T-cell proliferative response was determined in poults from 21 to 41 d old. Poults were fed on soyabean meal-sorghum-based diets with concentrations of supplemented vitamin A from 0 to 13.2 micrograms/g retinol equivalents from hatching and were immunised with Newcastle disease virus (NDV) and turkey pox vaccines. T-cell proliferation response to concanavlin A was determined in vitro at 31 d old. Antibodies to NDV and turkey pox in serum were determined at 10 and 20 d after inoculation. 2. Poults receiving the diet with no added dietary vitamin A died by 22 d and had very low concentrations of plasma and liver vitamin A. 3. Increasing dietary concentrations of vitamin A enhanced the proliferative response until the diet contained 6.0 micrograms/g, above which the response began to decrease. The antibody titres to NDV and turkey pox increased as dietary vitamin A increased, with maximal values found 10 d after inoculation with 6.0 micrograms/g. At 20 d after inoculation low antibody titres were found with low vitamin A intake. 4. These data suggest that maximal immune responses in the poult may be achieved at dietary intakes of vitamin A at or higher than those recommended by NRC (1984, 1994).
Developmental & Comparative Immunology, 2014
Veterinary Immunology and …, 1989
In a comparison between male and female broiler chicks, the mortality rate of males was found to ... more In a comparison between male and female broiler chicks, the mortality rate of males was found to be significantly higher than that of females, starting from the second week of age until marketing at 7 or 8 weeks of age. The main causes of death during this period ...
Poultry Science, 2016
Due to increase in awareness of poultry welfare and concomitant legislation, it has become necess... more Due to increase in awareness of poultry welfare and concomitant legislation, it has become necessary to determine poultry's response to stress, with minimal harm and maximum reliability. Several methods to determine the response to physiological stress were developed throughout the years to identify stressors and to measure stress in poultry. The most commonly used are plasma corticosterone levels and peripheral blood heterophil/lymphocyte ratio (H/L ratio). However, the value of these responses to determine a state of stress has been questioned in several instances, as these parameters are increased during the process of bird handling and blood sampling irrespective of the general state of stress. Due to these limitations, it appears that the classic stress markers might be sub-optimal in evaluating stress in poultry, particularly those encountered in high-stress environments. Thus, there is a continuing need for stress indicators, preferably indicators that are quantitative, highly repeatable, not influenced by handling and sampling, determined in peripheral blood, represent an initial response to the stressor, and do not daily fluctuate. As the immune system has been shown to rapidly respond to stress, we assessed pro-inflammatory gene expression in peripheral blood cells as an indicator for stress. We initially show that while corticosterone plasma levels and the H/L ratio were responsive to handling and blood sampling, pro-inflammatory gene expression (lysozyme, IL-1β, IL-6, and HSP-70) was not. We then determined the expression of the same pro-inflammatory genes during acute stress (transit) in layer pullets (hen and turkey) and during chronic stress (different caging densities of layers utilizing 2, 3, and 4 hens/cage). While gene expression was significantly and highly elevated during transit, the effect of differing caging densities on gene expression was minimal; collectively, this might indicate that expression of pro-inflammatory genes is more responsive to acute stress than to chronic stressors. We propose to use pro-inflammatory gene expression in peripheral blood cells to measure responses to stress in poultry.
Parasitology Research, 2016
Evaluating host resistance via parasite fitness helps place host-parasite relationships within ev... more Evaluating host resistance via parasite fitness helps place host-parasite relationships within evolutionary and ecological contexts; however, few studies consider both these processes simultaneously. We investigated how different levels of parasite pressure affect parasite mortality and reproductive success in relationship to host defense efforts, using the rodent Gerbillus nanus and the flea Xenopsylla conformis as a host-parasite system. Fifteen immune-naïve male rodents were infested with 20, 50, or 100 fleas for four weeks. During this time number of new imagoes produced per adult flea (our flea reproductive output metric), flea mortality, and change in circulating anti-flea immunoglobulin G (our measure of adaptive immune defense) were monitored. Three hypotheses guided this work: (1) increasing parasite pressure would heighten host defenses; (2) parasite mortality would increase and parasite reproductive output would decrease with increasing investment in host defense; and (3) hosts under high parasite pressure could invest in behavioral and/or immune responses. We predicted that at high infestation levels (a) parasite mortality would increase; (b) flea reproductive output per individual would decrease; and (c) host circulating anti-flea antibody levels would increase. The hypotheses were partially supported. Flea mortality significantly increased and flea reproductive output significantly decreased as flea pressure increased. Host adaptive immune defense did not significantly change with increasing flea pressure. Therefore, we inferred that investment in host behavioral defense, either alone or in combination with density-dependent effects, may be more efficient at increasing flea mortality and decreasing flea reproductive output than antibody production during initial infestation in this system.
The Israel Medical Association journal : IMAJ, 2002
While the etiology of autoimmune diseases remains largely unknown, several target self-antigens h... more While the etiology of autoimmune diseases remains largely unknown, several target self-antigens have been implicated in the established autoimmune state. Examples include single-or doublestrand DNA in systemic lupus erythematosus, myelin oligodendrocyte ...
Poultry Science, 1995
This study examined the effect of increasing amounts of dietary polyunsaturated fatty acids on an... more This study examined the effect of increasing amounts of dietary polyunsaturated fatty acids on antibody production in vivo and fatty acid composition of plasma and lymphoid tissues in the broiler. Chicks were fed four diets containing 12% added fat made up of different proportions of palm oil and soybean oil and immunized against bovine serum albumin at 14 to 16 d of age. Blood samples were taken every 4 to 5 d for 30 d; then the chicks were killed and liver, spleen, thymus, bursa of Fabricius, and bone marrow were sampled. Fatty acid composition in serum and tissues reflected the composition of the diets, although amounts of saturated fatty acids were tissue-specific. Arachidonic acid concentration was not changed by dietary fatty acid content. Antibody production developed more rapidly, reached a higher level, and was more persistent in the chicks fed lower levels of linoleic acid. A quadratic relationship was found between tissue linoleic acid or total polyunsaturated fatty acid concentrations and antibody production at 11 and 14 d after challenge. No correlation was found with arachidonic acid. It is concluded that dietary fatty acid composition can influence immune response in broilers.
British Poultry Science, 1997
1. An experiment was carried out with male broiler chicks to evaluate the combined effect of two ... more 1. An experiment was carried out with male broiler chicks to evaluate the combined effect of two concentrations of vitamin A (1.032 and 10.32 mg retinyl acetate/kg diet) and two concentrations of vitamin E (0 and 150 mg alpha-tocopheryl acetate/kg diet) on the oxidative stability of the drumstick meat of broiler chickens. The experimental diets were fed from 1 to 42 d of age. The oxidative stability, evaluated by thiobarbituric acid reactive substances (TBARS) values, was determined after 125 d of storage at -18 degrees C. 2. TBARS values were very low and not significantly affected by dietary vitamins A and E or their combinations. However, the TBARS values in the meat of birds fed on the vitamin E-free diets, but not on the vitamin E-supplemented diets, were markedly increased after using an accelerated test of oxidation of the meat lipids by incubation. This resulted in a significant (P<0.001) difference from vitamin E supplementation. Vitamin A, alone or in combination with vitamin E, did not affect TBARS values found after incubation. 3. It is concluded that vitamin A at the concentrations used had no effect on the oxidative stability of the meat, in contrast to the protective effect of vitamin E, and that there is no interaction between the effect of these two vitamins on meat stability.
IL-12 is thought to be involved in the susceptibility to experimental autoimmune encephalomyeliti... more IL-12 is thought to be involved in the susceptibility to experimental autoimmune encephalomyelitis (EAE), a Th1 cell-mediated autoimmune disorder of the CNS. IL-12 signals through a heterodimeric receptor (IL-12R 1/IL-12R 2), whose 2-chain is up-regulated on activated, autoreactive ...
The Journal of Nutrition
ABSTRACT The effects of dietary vitamin A and retinole acid in vitro on the proliferative respons... more ABSTRACT The effects of dietary vitamin A and retinole acid in vitro on the proliferative response and gene expression of retinole acid receptor-a (RAR-a) in chicken T lymphocytes were studied. Antigen-specific proliferative responses of T lymphocytes increased with ...
Poultry science, Jan 3, 2017
The transportation process is one of the most stressful practices in poultry and livestock manage... more The transportation process is one of the most stressful practices in poultry and livestock management. Extensive knowledge is available on the impact of transport on stress and animal welfare; however, little is known on the impact of transport on the physiology of turkey pullets, their welfare and health, and even less on the process of homeostatic recovery in the post-transport new environment. The main focus of this manuscript was to focus on trauma, stress, and recovery following transport of turkey pullets from nurseries to pullet farms. Specifically, we determined the physiological consequences of transport, the temporal restoration of homeostasis and its effects on immune system function. We hypothesized that stress signaling by stress hormones would directly activate circulating turkey blood leukocytes (TBL), thus inducing a pro-inflammatory response directed towards tissue repair and recovery. Extensive blood analyses prior to transit and during the collecting, transit, and...
Http Dx Doi Org 10 1080 00071669708418000, Nov 8, 2007
1. This study examined the effect of increasing amounts of dietary polyunsaturated fatty acids on... more 1. This study examined the effect of increasing amounts of dietary polyunsaturated fatty acids on the fatty acid composition in serum and antibody production following a standard vaccination programme in growing turkeys. Turkey poults were fed on 5 diets containing 75g/kg added fat made up of different proportions of palm and soyabean oils, and were vaccinated against Newcastle disease, infectious bronchitis and necrotic enteritis according to a standard vaccination programme. Blood samples were taken before and one week after each vaccination. 2. Fatty acid composition in serum reflected the composition of the diets although arachidonic acid concentration was not changed by dietary fatty acid content. Growth, erythrocyte and leukocyte parameters were not affected by the respective diets. 3. Specific antibody production was related quadratically to serum linoleic and total n-6 polyunsaturated fatty acid concentrations. No correlation was found with linolenic or arachidonic acids. 4. It is concluded that dietary fatty acid composition can augment the specific anti-vaccine immune response in turkey poults.
Http Dx Doi Org 10 1080 03079459808419377, Nov 12, 2007
Infectious stunting syndrome (SS) in broilers is a multi-symptomatic disease that includes lesion... more Infectious stunting syndrome (SS) in broilers is a multi-symptomatic disease that includes lesions in the intestinal tract. We investigated whether these lesions impeded functions of the intestinal immune system. Two functions were studied: the capacity to generate 1) immune responses to a resident pathogen .(E. coli) of the gut and to a parenterally administered antigen (ss-casein), and 2) tolerance to an orally administered antigen (ss-casein). SS was induced in day-old broilers by an inoculum prepared from SS afflicted broilers. After onset of SS, immune responses (or absence of, in the case of tolerance) were studied by specific antibody production and T lymphocyte proliferation. Immune responses were induced by subcutaneous immunization of broilers against ss-casein or following natural exposure to enteric .E. coli. Oral tolerance was induced by a single feeding of ss-casein in gelatine capsules. Both enterai anti-E. .coli and parenteral anti-ss-casein responses were significantly reduced in SS birds. SS afflicted broilers did not develop ss-casein-specific oral tolerance. These results indicate dysfunction of both the intestinal immune system and that of systemic acquired immune responses in SS.
Immunogenetics, 1983
The immune response of T lymphocytes to avidin was measured by proliferative assays, antibody pro... more The immune response of T lymphocytes to avidin was measured by proliferative assays, antibody production and delayed-type hypersensitivity. Mice of H-2 k haplotypes were found to be low responders, whereas mice of other haplotypes, and particularly of H-2 ~, were high responders. Ir genes controlling this response were mapped to the I subregion of H-2. Helper T cells were found to be responsible for the Ir phenotype of antibody production. These results indicate the feasibility of using the avidin-biotin complex as a tool for studying molecular mechanisms by which antigens under Ir gene control are processed and presented to T lymphocytes.
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Papers by Aharon Friedman