K C Klasing

University of California, Davis, Davis, California, United States

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Publications (137)323.89 Total impact

  • V J Iseri, K C Klasing
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    ABSTRACT: The nutritional demands of the immune system may result in tradeoffs with competing processes such as growth and reproduction. The magnitude of the nutritional costs of immunity is largely unknown. Thus, we examine the lysine content of the systemic components of the immune system in adult male chickens (Gallus gallus domesticus) in a healthy condition (maintenance) and following a robust Escherichia coli-specific immune response. Lysine was used as a metric, because it is found both in leukocytes and in protective proteins. The dynamics of subsets of leukocytes were monitored in primary and secondary immune tissues (thymus, bone marrow, and spleen) that would be expected to be involved in the response following iv injection of E. coli. The systemic immune system at maintenance has the same lysine content as 332 average-sized feathers, 16% of an egg, or 5.4% of a pectoralis muscle from an adult chicken. During the acute-phase response to E. coli, the additional lysine needed would equal 355 feathers, 17% of an egg, or 5.5% of a pectoralis muscle. The acute-phase proteins accounted for the greatest proportion of lysine in the immune system at maintenance and the proportion increased substantially during an acute-phase response. Hypertrophy of the liver required more lysine than all of the leukocytes and protective proteins that were produced during the acute-phase response. Size of the liver and levels of protein during the acute phase returned to normal during the time when the adaptive response began to utilize significant quantities of lysine. The catabolism would release a surfeit of lysine to provision the anabolic processes of the adaptive response, thus making proliferation of lymphocytes and production of immunoglobulins very cheap.
    Integrative and Comparative Biology 09/2014; · 3.02 Impact Factor
  • Maxine Zylberberg, Kirk C. Klasing, Thomas P. Hahn
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    ABSTRACT: Consistent, stable behavioural differences in how individuals respond to novel situations can lead to variation in exposure to pathogens. To minimize the costs associated with pathogen infection, animals have evolved behavioural and immunological strategies to avoid infection. However, because both behavioural and immunological defences are costly, host individuals should benefit from balancing investment in these defence strategies. It has been suggested that one such behavioural defence strategy is hesitancy to engage with novel objects and environments. In particular, exploratory individuals appear more likely to be exposed to novel pathogens than less exploratory individuals. Here, we tested the hypothesis that immune function is inversely related to behaviours with the potential to decrease exposure to pathogens (i.e. forgoing exploratory behaviours). We found an inverse association between aspects of innate immune function and exploratory behaviours. These observations suggest that individuals that engage in low-risk behaviours when experiencing a novel situation may invest less in some aspects of innate immune function than individuals that engage in high-risk behaviours. This individual variation in pathogen defence strategy is expected to affect the dynamics of pathogen spread through populations, and ultimately the course of epidemics.
    Animal Behaviour. 01/2014; 89:115–122.
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    K D Matson, J R Millam, K C Klasing
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    ABSTRACT: High doses of Zn are widely used for prevention and treatment of diarrhoea in weaning piglets; however, the mechanism of action of Zn against diarrhoea is still not well understood. The objective of this study was to evaluate whether weaning induces Zn deficiency in piglets. Eight litters of primiparous sows were selected for the experiment, and 3 piglets presenting similar weights were selected within each litter. Two of the three selected piglets from each litter were weaned at 21d of age and fed two different diets: a commercial control diet (WCt) and the same diet plus 2000 ppm of Zn as ZnO (WZn). The third selected pig from each litter was kept unweaned (Uw) with the sow and the rest of the litter. All 24 selected animals were killed at 28 d of age, and blood, gastrointestinal content, liver, pancreas and spleen were sampled for Zn, Fe and Cu analysis (mg/kg or L of sample). Data were analysed using anova including treatment as a fixed factor. Weaned pigs fed WCt diet presented a lower Zn concentration in plasma than Uw animals (0.76 ± 0.091 vs. 1.10 ± 0.099 mg/L, p = 0.05). Zinc levels in liver, pancreas and spleen were not affected by weaning. Total concentration of Zn was higher in gastrointestinal contents of weaned animals fed WCt diet than in Uw pigs (p ≤ 0.001 for stomach, jejunum, ileum, caecum and colon). Supplementation with high doses of ZnO increased levels of Zn in gastrointestinal content (p < 0.001), liver (p < 0.001) and pancreas (p < 0.001) compared to WCt diet. It also increased plasma Zn to non-deficient levels (1.32 ± 0.086), but the increase was not as marked as in other locations and final concentration was not different than that in Uw animals (p = 0.231). Weaning creates a Zn deficiency situation in weaned pigs as observed by plasma Zn concentrations. ZnO supplementation counteracts Zn deficiency.
    J Anim Physiol a Anim Nutr 05/2013; 97:6-12. · 1.25 Impact Factor
  • E. Roura, M.W. Baldwin, K.C. Klasing
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    ABSTRACT: Taste has evolved largely as a mechanism to identify nutritious foods and is important for detecting nutritionally relevant carbohydrates, amino acids, lipids, salts and toxic compounds. Species differences in the taste system are intimately related to ecological niche and food availability. It has been argued that birds have a lower taste acuity compared to mammals due to their low taste bud numbers. In addition, chickens seem to have fewer taste receptor genes: the sweet taste receptor is missing and their bitter taste receptor repertoire is very small, consisting of only three members. Furthermore, chickens compared to pigs show a lower sensitivity to glucosinolates. However, chickens are able to quickly adapt their feeding behaviour based on taste cues and the ratio of the number of taste buds/oral cavity volume is higher than in most mammals. Compared to ruminants, chickens show higher aversion to glucosinolates and compared to humans a similar avoidance to quinine chloride. Moreover, many birds (including commercial chicken breeds) seem to have high acuity for dietary calcium. Emerging knowledge mostly derived from genome sequencing, shows that birds have a well-developed taste system. Predicted taste genes for umami, sour, salt, bitter, calcium and lipids are present in the chicken, turkey and zebra finch genomes. Preliminary data indicate that the umami taste receptor may be intact in chickens and that the bitter taste receptor repertoire is small in chickens, but in some bird species it is as large as in mammals. Some of the novel findings outlined in the review have the potential to bring important innovations to the practice of poultry nutrition such as reduction in phosphorus excretion, optimize the use of amino acids and fats, use of alternative feedstuffs or the short and long term manipulation of feed intake. In conclusion, the avian taste system is well developed but differs significantly with different species. Behavioural and genetic evidence show that birds have an accurate capacity to detect different taste modalities challenging the broad consensus that birds have lower taste acuity than mammals. Finally, avian taste is intimately related to nutrient sensing and, consequently, to poultry nutrition practices.
    Animal Feed Science and Technology 03/2013; 180(s 1–4):1–9. · 1.61 Impact Factor
  • V J Iseri, K C Klasing
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    ABSTRACT: The immune response is thought to be costly and deters from growth and reproduction, but the magnitude and sources of these costs are unknown. Thus, we quantified the changes in mass of leukocytes (CD4(+) and CD8(+) T cells, Bu1(+) IgM(+) and Bu1(+) IgG(+) B cells, monocytes/macrophages, heterophils and thrombocytes) and protective plasma proteins in systemic (non-mucosal) components of adult chickens injected intravenously with dead E. coli. During the first day after E. coli injection most types of blood leukocytes decreased and α-1-acid glycoprotein increased. Specific IgM, specific IgY, total IgM, Bu1(+) lymphocytes in the spleen and bone marrow and thymic CD8(+) lymphocytes increased at 5d post-injection. Quantitatively, the increases in the weight of cells and antibodies due to E. coli were dwarfed by the increase in the weight of the liver and acute phase proteins. Thus the acute phase response was markedly more costly than the subsequent adaptive response. The weight of the cells and proteins of the systemic immune system prior to challenge was 0.14% of body weight. Following E. coli injection, the additional weight of the immune components and the hypertrophy of the liver resulted in a 3.6-fold increase in weight which is equivalent to 18.5% of a large egg.
    Developmental and comparative immunology 03/2013; · 3.29 Impact Factor
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    ABSTRACT: In many oviparous animals, bursting type atresia of ovarian follicles occurs during the reproductive cycle resulting in the escape of yolk into the extracellular compartment. In birds, this ectopic yolk is rapidly cleared by an unknown process that involves the appearance of yolk-engorged macrophage-like cells. To study this unique type of lipid transport, we injected young male chickens intra-abdominally with egg yolk. Absorption of egg yolk from the body cavity markedly increased the triacylglyceride-rich fraction (TRL) of plasma lipoproteins and was coincident with increased levels of plasma triacylglycerides (TAG) but not non-esterified fatty acids (NEFA). Thus, the transport of yolk lipids from the abdominal cavity appears to occur in lipoproteins and be more similar to the transport of hepatic TAG to the periphery via lipoproteins than to transport of adipose TAG to the periphery via NEFA released by the action of lipases. When macrophages were exposed to yolk in vitro, they quickly phagocytized yolk; however, it is unclear if this level of phagocytosis contributes significantly to total yolk clearance. Instead, the chicken macrophage may function more as a facilitator of yolk clearance through modification of yolk lipoproteins and the regulation of the local and systemic immune response to ectopic yolk. Yolk appears to be anti-inflammatory in nature. Yolk did not increase inflammatory cytokines IL-1, IL-6 and IFNγ either in vivo or in vitro; in fact, yolk dampened many inflammatory changes caused by lipopolysaccharide (LPS). Conversely, LPS-induced inflammation retarded yolk clearance from the abdominal cavity and plasma TAG levels.
    Journal of Experimental Biology 01/2013; · 3.24 Impact Factor
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    ABSTRACT: High doses of ZnO are used to treat diarrhea in weaning pigs but are also an environmental concern. The mechanism of action of Zn against diarrhea is still not well understood. The amount of solubilized Zn, the relation of Zn with Fe and Cu, and the concentration of these elements in the gastrointestinal tract (GIT) are key data to understanding its mechanism of action and optimize its use. Therefore, we studied the Zn, Fe, and Cu concentrations in the GIT content of unweaned, weaned, and ZnO-treated pigs. Eight litters were used and 3 piglets were selected within each litter. Two piglets from each litter were weaned at 21 d of age and fed a commercial control diet (WCt) or WCt + 2000 mg/kg of Zn as ZnO (WZn). The third pig was kept unweaned (Uw) with the sow. All 24 pigs were killed at 28 d of age, GIT contents were sampled, soluble and insoluble fractions of the content were separated, and Zn, Fe, and Cu concentrations were analyzed. Concentration of Zn increased 3 to 5 fold along the GIT (2 to 10 fold in the soluble fraction) for weaned pigs on WZn compared to WCt and Uw pigs (P < 0.01 in all cases). The proportion of total Zn that was present in the soluble fraction was 4 to 10 folds higher in jejunum, ileum, and cecum of Uw pigs than in those weaned (P < 0.01 in all cases) but was not affected by ZnO treatment. Concentration of Fe in the soluble fraction was higher for Uw pigs compared to weaned pigs along the GIT (P < 0.05 in all cases) even when concentration in total content was lower for Uw pigs in stomach (P = 0.001) and jejunum (P = 0.029). Concentrations of Cu were lower in Uw pigs than in weaned pigs along the GIT (P < 0.05 in all cases). Surprisingly, animals on WZn showed a 5 to 10 fold increase of Cu solubilized in distal parts of the GIT (cecum and colon; P < 0.001) compared to other groups. Differences in Zn, Fe, and Cu concentrations found among treatments will be useful in future studies for understanding mechanism of action of ZnO and optimizing its use in order to avoid environmental concerns.
    Journal of Animal Science 12/2012; 90(Suppl. 4):248-250. · 2.09 Impact Factor
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    Maxine Zylberberg, Kirk C Klasing, Thomas P Hahn
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    ABSTRACT: Infection with parasites and pathogens is costly for hosts, causing loss of nutritional resources, reproductive potential, tissue integrity and even life. In response, animals have evolved behavioural and immunological strategies to avoid infection by pathogens and infestation by parasites. Scientists generally study these strategies in isolation from each other; however, since these defences entail costs, host individuals should benefit from balancing investment in these strategies, and understanding of infectious disease dynamics would benefit from studying the relationship between them. Here, we show that Carpodacus mexicanus (house finches) avoid sick individuals. Moreover, we show that individuals investing less in behavioural defences invest more in immune defences. Such variation has important implications for the dynamics of pathogen spread through populations, and ultimately the course of epidemics. A deeper understanding of individual- and population-level disease defence strategies will improve our ability to understand, model and predict the outcomes of pathogen spread in wildlife.
    Biology letters 11/2012; · 3.35 Impact Factor
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    ABSTRACT: Introduced disease has been implicated in recent wildlife extinctions and population declines worldwide. Both anthropogenic-induced change and natural environmental features can affect pathogen spread. Furthermore, environmental disturbance can result in changes in stress physiology, nutrition, and social structure, which in turn can suppress immune system function. However, it remains unknown whether landscape variation results in heterogeneity in host resistance to pathogens. Avian pox virus, a pathogen implicated in avian declines and extinctions in Hawaii, was introduced to the Galapagos in the 1890s, and prevalence (total number of current infections) has increased recently in finches. We tested whether prevalence and recovery trends in 7 species of Galapagos finches varied by elevation or human land use. To do so, we used infection data obtained from 545 wild-caught birds. In addition, we determined whether annual changes in 4 aspects of innate immune function (complement protein activity, natural antibody activity, concentration of PIT54 protein, and heterophil:lymphocyte ratio) varied by elevation or land use. Prevalence and recovery rates did not vary by elevation from 2008 to 2009. Avian pox prevalence and proportion of recovered individuals in undeveloped and urban areas did not change from 2008 to 2009. In agricultural areas, avian pox prevalence increased 8-fold (from 2% to 17% of 234 individuals sampled) and proportion of recovered individuals increased (11% to 19%) from 2008 to 2009. These results suggest high disease-related mortality. Variation in immune function across human land-use types correlated with variation in both increased prevalence and susceptibility, which indicates changes in innate immune function may underlie changes in disease susceptibility. Our results suggest anthropogenic disturbance, in particular agricultural practices, may underlie immunological changes in host species that themselves contribute to pathogen emergence. Variación con el Uso de Suelo de la Función Inmune y la Prevalencia de la Varicela Aviar en Pinzones de las Galápagos.
    Conservation Biology 10/2012; · 4.36 Impact Factor
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    ABSTRACT: Many frugivorous avian species kept in captivity develop iron storage disease (ISD) as indicated by high concentrations of hepatic iron and hemosiderin deposits in hepatocytes or phagocytes. In several susceptible species fed diets containing moderate levels of iron, ISD develops because of an inability to match rates of iron absorption to tissue needs. Evidence suggests that the pathophysiologic basis of excess iron absorption is due to high levels of expression of divalent metal transporter-1 that transports iron into enterocytes in the proximal intestine, and ferroportin that exports iron to the circulation. The regulatory basis for this inability to sufficiently down-regulate iron absorption is unknown, but disruptions in the hepcidin-ferroportin axis are likely candidates based on recent research in humans and laboratory rodents. It is likely that ISD-susceptible avian species evolved on foods that were very low in bioavailable iron, so there was strong selection pressure for the efficient capture of the small amount of dietary iron but low selection pressure for preventing iron toxicities. Thus, the transporters and regulatory networks for iron absorption seem to be heavily skewed toward iron storage even when food items that are high in iron are consumed. Infections, trauma and neoplasias that trigger an acute phase response may exacerbate ISD in susceptible species and may be the primary cause in species that are normally resistant to ISD (i.e., those that are normally able to shut down intestinal iron absorption when iron stores are replete). The evolutionary basis that resulted in some avian species to be susceptible to ISD (e.g., dietary cause) seems to differ from many inherited ISD disorders in humans that are thought to have evolved to bolster protection against infectious diseases. However the evolutionary basis of ISD in other mammalian species might be more similar to that in ISD-susceptible avian species.
    Journal of Zoo and Wildlife Medicine 09/2012; 43(3 Suppl):S27-34. · 0.43 Impact Factor
  • Journal of Zoo and Wildlife Medicine 09/2012; 43(3 Suppl):S108-13. · 0.43 Impact Factor
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    Journal of Zoo and Wildlife Medicine 09/2012; 43(3 Suppl):S117-9. · 0.43 Impact Factor
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    ABSTRACT: Although dietary n-3 fatty acids have been extensively studied in poultry, they have not yet been prospectively investigated in psittacines, despite potential benefits for preventing and treating atherosclerosis, osteoarthritis, and other chronic disease processes. The objectives of this study were to investigate the incorporation of dietary n-3 fatty acids into red blood cells (RBC) and to determine the effects of supplementation of psittacine diets with fish or flax oil on plasma lipids and lipoproteins in the cockatiel. Adult cockatiels were fed a custom-formulated diet containing either 4% (wt/wt, as-fed) beef tallow (CON), 3% fish oil + 1% tallow (FSH), or 3.5% flax oil + 0.5% tallow (FLX; n = 20 per diet group). Baseline measurements were obtained for RBC fatty acid composition, triacylglycerides (TAG), and cholesterol. After 8 to 13 wk on the study diets, plasma chemistry profiles, lipoprotein density profiles, and RBC fatty acid composition were determined. At 8 wk, total plasma cholesterol was least in FSH birds (P < 0.05) and TAG concentrations were less in FSH birds than FLX birds (P < 0.05). Total n-3 fatty acids, docosahexaenoic acid, docosapentaenoic acid, and eicosapentaenoic acid were markedly greater in the RBC of FSH birds than FLX or CON birds (P < 0.05). Alpha linolenic acid was greatest in FLX (P < 0.05). Initial and final BW, and nonlipid plasma chemistry values did not differ among diet groups. No adverse effects of dietary supplementation of cockatiels with 3.5% flax oil or 3% fish oil were observed during the 13-wk feeding period. Although fish and flax oils provided similar total n-3 PUFA to the diets, fish oil caused greater reductions in cholesterol and TAG, and greater total RBC n-3 incorporation. Thus, dietary modification of psittacine diets with long chain n-3 PUFA from fish oil appears safe and may be beneficial to these long-lived companion birds.
    Journal of Animal Science 05/2012; 90(9):3068-79. · 2.09 Impact Factor
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    ABSTRACT: Enterotoxigenic Escherichia coli (ETEC) K88 is the main bacterial cause of diarrhea in piglets around weaning and the adhesion of ETEC to the intestinal mucosa is a prerequisite step for its colonization. In this study, the adhesion of a fimbriated ETEC and a non-fimbriated E. coli (NFEC) to the intestinal cells and the activation of the innate immune system were evaluated using a porcine intestinal epithelial cell line (IPEC-J2). The impact of several feedstuffs (wheat bran (WB); casein glycomacropeptide (CGMP); mannan-oligosaccharides (MOS); locust bean extract (LB) and Aspergillus oryzae fermentation extract (AO)) on ETEC attachment and the inflammatory response were also studied. The gene expression of TLR-4; TLR-5; IL-1β; IL-8; IL-10 and TNF-α were quantified using Cyclophilin-A, as a reference gene, and related to a non-challenged treatment. The fimbriated strain was markedly better than the non-fimbriated strain at adherence to intestinal cells and inducing an inflammatory response. All the feedstuffs studied were able to reduce the adhesion of ETEC, with the greatest decrease with CGMP or MOS at highest concentration. Regarding the inflammatory response, the highest dose of WB promoted the lowest relative expression of cytokines and chemokines. All tested feedstuffs were able to reduce the adhesion of ETEC to IPEC-J2 and interfere on the innate inflammatory response; however WB should be further studied according to the beneficial results on the intestinal inflammatory process evidenced in this study.
    Comparative immunology, microbiology and infectious diseases 09/2011; 34(6):479-88. · 2.99 Impact Factor
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    ABSTRACT: Many animals convert β-carotene to retinol to meet their vitamin A (VA) requirement. However, this pathway is inefficient in many carnivores. This study quantified the plasma response to a single oral dose of [(2) H(8)]-β-carotene in adult domestic cats, including measurement of [(2) H(4)]-retinol derived from the dose. Cats were fed with either a control diet containing adequate VA (n = 5) or a VA-devoid diet (n = 5) for 28 days. An oral dose of either 5 mg/kg body weight (BW) (n = 4) or 10 mg/kg BW (n = 6) of [(2) H(8) ]-β-carotene was administered on day 28. Plasma samples were collected prior to dosing and at 6, 12, 24, 32, 48, 72, 120, 168 and 216 h post-dose. Plasma retinoids and β-carotene were measured using HPLC and [(2) H(4)]-retinol by GC-ECNCI-MS (gas chromatography/electron capture negative chemical ionization/mass spectrometry). β-carotene was undetectable in plasma prior to dosing. Post-dose, mean peak plasma β-carotene was 0.37 ± 0.06 nmol/ml at 9.0 ± 1.8 h following the dose, while [(2) H(4) ]-retinol peaked at 3.71 ± 0.69 pmol/ml at 55.2 ± 16.3 h. The ratio per cent of total area under the curve for [(2) H(4)]-retinol compared with the β-carotene response was 4.6 ± 2.6%. There was little effect of diet or dose on the β-carotene or [(2) H(4)]-retinol responses. The appearance of [(2) H(4)]-retinol in plasma indicates that cats are capable of converting β-carotene to active VA. Conversion efficiency was not calculated in this study, but it is likely inadequate to meet cats' VA requirement without the inclusion of preformed VA in the diet.
    J Anim Physiol a Anim Nutr 07/2011; 96(4):681-92. · 1.25 Impact Factor
  • K A Livingston, K C Klasing
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    ABSTRACT: To determine whether supplementing retinyl palmitate (RP) to vitamin A-deficient or -adequate chicks during vaccination increased the antibody response, an experiment was conducted that used a 2-generational model. White Leghorn chicks were hatched from eggs that contained 1.06 ± 0.13, 1.41 ± 0.14, or 1.90 ± 0.13 μg of retinol/g of egg yolk. Upon hatch, chicks were allotted to a diet that contained 70, 100, or 130% of the vitamin A requirement (1,500 IU/kg). At 14 d of age, chicks were challenged with keyhole limpet hemocyanin (KLH), Freund's incomplete adjuvant (FIA), KLH and FIA, KLH and RP administered in the same injection, or KLH and RP administered at different injection sites. The RP dosage was 7,000 IU/kg of BW, and dosage of the KLH was 1 mg/kg of BW. Chicks were bled and rechallenged at 19 d of age, and a final blood draw was taken at 29 d of age. The IgM and IgG antibody responses to KLH were determined by ELISA, and agglutination was used to determine natural antibody titers. When compared with chicks fed diets that contained 70 and 100% of the vitamin A requirement, the chicks fed 130% of the vitamin A requirement had a lower primary IgM and IgG antibody response (P < 0.02) and the secondary IgG response was significantly lower (P = 0.004). However, administering RP together or separate from KLH did not significantly change the secondary IgM or IgG responses compared with chicks challenged with KLH and FIA (P < 0.01). Moreover, natural antibody titers were not different among dietary treatments (P = 0.91). In conclusion, administration of RP with KLH did not improve antibody response in chicks.
    Poultry Science 05/2011; 90(5):965-70. · 1.52 Impact Factor
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    ABSTRACT: Immunosenescence, the aging of the immune system, is well documented in humans and laboratory models and is known to increase infection risk, morbidity, and mortality among the old. Immunosenescence patterns have recently been unveiled in various free-living populations, but their consequences in the wild have not been explored. We investigated the consequences of immunosenescence in free-living Tree Swallows Tachycineta bicolor through a field experiment simulating a bacterial infection (challenge with lipopolysaccharide, LPS) in females of different ages during the nestling rearing period. We assessed behavioral and physiological responses of females, as well as growth and quality of their offspring, to determine the costs associated with the simulated infection. Results of the experiment differed between the two years of study. In the first year, old females challenged with LPS lost more body mass and reduced their nest visitation rates more, and their offspring tended to grow slower compared to similarly challenged younger females. In contrast, in the second year, old females did not appear to suffer larger costs than younger ones. Interestingly, immunosenescence was only detected during the first year of the study, suggesting that it is the dysregulated immune function characteristic of immunosenescent individuals rather than age per se that can lead to higher costs of immune defense in old individuals. These results provide the first evidence of costs of immunosenescence in free-living animals and support the hypothesis that old, immunosenescent individuals pay higher costs than younger ones when faced with a challenge to their immune system. Our results also suggest that these costs are mediated by an exaggerated sickness behavior, as seen in laboratory models, and can be modulated by ecological factors such as weather conditions and food availability.
    Ecology 04/2011; 92(4):952-66. · 5.18 Impact Factor
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    ABSTRACT: The diversity of taste perception across species reflects a dietary adaptation to different ecological niches. Laboratory rodents have been widely used as models for human nutritional studies including the understanding of peripheral chemosensing. Nevertheless the diet type as well as the anatomical and functional features of bigger mammals such as the pig may merit further consideration as models for humans. Recently, the porcine umami taste receptor pTas1r1/pTas1r3 and porcine mGluR4 gene sequences have become available. The aim of this study was to compare the umami sensing biology with emphasis in T1R1 sequences, Venus flytrap (VFT) ligand binding domains and L-amino acid agonists of several mammalian species including human, pig and laboratory rodents. Compared to their corresponding human gene orthologues, receptor homologies where highest for the dog (T1r1 and T1r3) and the pig (mGluR4) and lowest for the mouse (T1r1, T1r3 and mGluR4). Th human T1R1 VFT domain contains 10 different amino acid residues critically involved in ligand binding. All 10 amino acid residues are conserved, both in terms of type and location, within the pig VFT domain. In turn, the arginine and histidine (both charged polar) residues at key positions 307 and 308 appear as threonine and tyrosine (both neutral polar) residues in mouse and rat sequences. Comparison of derived molecular models seems to offer a good explanation regarding the differences of in vivo preference data for L-amino acids in rats, pigs and humans. Overall, the umami sensing in pigs show higher similarity to that in humans than the umami sensing in laboratory rodents. Copyright (C) 2011 John Wiley & Sons, Ltd.
    Flavour and Fragrance Journal 01/2011; 26(4):282-285. · 1.82 Impact Factor
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    ABSTRACT: This study investigated the effects of dietary lutein and polyunsaturated fatty acids (PUFA) on the total lutein and lipid levels, the peroxisome proliferators activated receptors (PPAR) alpha and gamma, retinoic acid X receptor (RXR) alpha and gamma and IL-1 mRNA levels in chicken (Gallus gallus) liver and spleen. In experiment I, chickens were fed either 0, 25 or 50mg lutein in a diet with 3% PUFA fat. In experiment II, chickens were fed either 3 or 6% PUFA fat with 25mg lutein. At 23d of age, chickens were injected with LPS. LPS injection decreased the lutein content and increased the fat content in the liver and spleen in both experiments. Increasing dietary PUFA fat to 6% ameliorated the LPS-induced lutein depletion in experiment II. LPS injection increased IL-1 and decreased splenic PPARalpha, PPARgamma, RXRalpha mRNA in experiment I and II. The LPS-induced PPARalpha and RXRalpha downregulation were partially reversed by increasing the dietary lutein content to 50mg/kg feed in experiment I and by increasing the dietary PUFA fat content to 6% in experiment II. Increasing dietary lutein content to 50mg/kg feed increased PPARgamma mRNA amount only in the LPS untreated groups in experiment I. Increasing dietary PUFA fat or LPS injection in the 6% PUFA fat group upregulated PPARgamma mRNA in experiment II. Increasing dietary PUFA fat to 6% blunted the increase in IL-1 mRNA due to LPS. It is concluded that dietary lutein and PUFA fat were anti-inflammatory due to modification of immune tissue lutein content, PPAR, RXR isomers and IL-1beta mRNA levels in liver and spleen.
    Comparative biochemistry and physiology. Part A, Molecular & integrative physiology 11/2010; 157(3):198-203. · 2.20 Impact Factor

Publication Stats

2k Citations
323.89 Total Impact Points


  • 1987–2014
    • University of California, Davis
      • • Department of Animal Science
      • • School of Veterinary Medicine
      Davis, California, United States
  • 2011
    • Autonomous University of Barcelona
      • Centre de Recerca en Sanitat Animal (CReSA)
      Cerdanyola del Vallès, Catalonia, Spain
  • 2010
    • The Ohio State University
      • Ohio Agricultural Research and Development Center
      Columbus, OH, United States
  • 2009
    • Research Center for Food and Development A.C.
      Hermosillo, Sonora, Mexico
  • 2007
    • University of Bristol
      • School of Biological Sciences
      Bristol, ENG, United Kingdom
    • Massey University
      • Institute of Veterinary, Animal and Biomedical Sciences
      Palmerston North, Manawatu-Wanganui, New Zealand
  • 2005–2007
    • California Polytechnic State University, San Luis Obispo
      • Department of Animal Science
      San Luis Obispo, CA, United States
  • 2005–2006
    • University of Missouri - St. Louis
      • Department of Biology
      Saint Louis, MI, United States
  • 2004
    • Princeton University
      • Department of Ecology and Evolutionary Biology
      Princeton, NJ, United States
  • 2001
    • Wageningen University
      • Department of Adaptation Physiology
      Wageningen, Provincie Gelderland, Netherlands
  • 1982–1984
    • Cornell University
      • Department of Nutritional Sciences
      Ithaca, New York, United States