Impact of nutrition on the innate immune response to infection in poultry

Viral and bacterial diseases remain a threat to the poultry industry and countermeasures to prevent and control them are needed due to production losses. With the continued threat of exotic and emerging diseases and concern over the use of antibiotics in animal production, there is a serious and urgent need to find safe and practical alternatives to prevent or control pathogens. Identification of new tools for the design of new immunological interventions or therapeutic antimicrobials to reduce microbial pathogens in poultry is now required more than ever. Immunological interventions to reduce microbial pathogens in poultry would be of great value to the poultry industry and to the consumer. We have been advocating boosting immunity and encouraging the host to utilize its innate immune system to control and clear infections. Our research has addressed the use of innate immune mechanisms and components to develop new immune modulators (prophylactic and therapeutic) and the characterization and production of antimicrobial peptides as potential immune modulators in poultry. Dietary bioactive food components that interact with the immune response have considerable potential to reduce susceptibility to infectious diseases. With this premise, this paper asks and answers a series of pertinent questions on the utilization of avian immunity for increasing resistance to a variety of potential pathogens problematic in today's commercial poultry industry. Using experimental data to provide answers to these questions, we hope to stimulate a dialog between avian immunologists and nutritionists that results in coordinating and integrating their expertise into specific practical solutions that will benefit the industry and improve the well-being of commercial poultry.     

Effects of dietary supplementation with l-arginine on the intestinal barrier function in finishing pigs with heat stress

Previous studies showed heat stress reduces body weight gain and feed intake associated with damaged intestinal barrier function, and l -arginine (L-Arg) enhanced intestinal barrier function in young animals under stress. The aim of this study was to evaluate effects of L-Arg on serum hormones, intestinal morphology, nutrients absorption and epithelial barrier functions in finishing pigs with heat stress. Forty-eight finishing pigs (Landrace) were balanced for sex and then randomly assigned to six groups: TN group, thermal neutral (22°C, ~80% humidity) with a basal diet; HS group, heat stress (cyclical 35°C for 12 hr and 22°C for 12 hr, ~80% humidity) with a basal diet; PF group, thermal neutral (22°C, ~80% humidity) and pair-fed with the HS; the TNA, HSA and PFA groups were the basal diet of TN group, HS group and PF group supplemented with 1% L-Arg. Results showed that HS decreased (p < .05) the thyroxine concentrations and increased (p < .05) the insulin concentrations in serum compared with the TN group, but 1% L-Arg had no significant effects on them. Both HS and PF significantly increased (p < .05) the mRNA expression of cationic amino acid transporters (CAT1 and CAT2) and decreased the mRNA expression of solute carrier family 5 member 10 (SGLT1) in the jejunum compared with the TN group. Compared with the TN group, HS reduced the expression of tight junction (TJ) protein zonula occluden-1 (ZO-1) and occludin, but PF only decreased ZO-1 expression in the jejunum. Results exhibited that dietary supplementation with 1% L-Arg improved the intestinal villous height, the ratio of villous height to crypt depth, and the expression of occludin and porcine beta-defensin 2 (pBD2) in the jejunum of intermittent heat-treated finishing pigs. In conclusion, dietary supplementation with 1% L-Arg could partly attenuate the intermittent heat-induced damages of intestinal morphology and epithelial barrier functions in finishing pigs.     

α-酮戊二酸对免疫应激下断奶仔猪肝损伤的影响

24头体质量为(7.25±1.13)kg的(21±1)日龄(杜×长×大)断奶仔猪随机分为3组,每个组设有8个重复,每个重复1头猪。3个组分别为:饲喂基础日粮,注射生理盐水(对照组);饲喂基础日粮,注射脂多糖(LPS)(LPS组);饲喂基础日粮+1%α-酮戊二酸(AKG),注射LPS(AKG组)。预试期7d,正式试验期16d,探讨AKG对免疫应激下断奶仔猪肝损伤的影响。结果显示:(1)LPS刺激导致血清腺苷脱氨酶(ADA)的活性显著升高了15.29%(P0.05),日粮添加1%AKG血清ADA活性较LPS组降低了7.85%(P0.05);(2)LPS刺激导致肝脏丙二醛(MDA)活性显著升高了59.61%(P0.05)以及谷胱甘肽过氧化物酶(GSH-Px)活性显著降低了23.21%(P0.05),而日粮添加1%AKG肝脏MDA活性较LPS组降低了13.70%(P0.05)、GSH-Px活性则升高了17.16%(P0.05);(3)LPS刺激导致肝脏总蛋白质含量和RNA/DNA比值分别显著增加了8.20%(P0.05),10%(P0.05),而日粮添加1%AKG较LPS组肝脏总蛋白质含量和RNA/DNA比值分别降低了3.94%(P0.05),10%(P0.05)。结果表明:AKG能在一定程度上缓解LPS刺激对断奶仔猪肝脏的损伤。     

脂多糖诱导奶牛乳腺上皮细胞先天性免疫反应

采取荷斯坦奶牛乳腺,进行体外分离培养,并纯化细胞。用不同质量浓度(0、1、10、100mg/L)的脂多糖刺激乳腺上皮细胞,采用MTT法检测脂多糖对细胞增殖的影响,半定量PCR检测10mg/L的LPS对乳腺上皮细胞TLR4、TLR2、CD14、MD-2四个基因在不同时间(0、2、6h)mRNA表达水平的差异。结果表明,高剂量(100mg/L)的LPS对乳腺上皮细胞的增殖产生明显影响;LPS刺激乳腺上皮细胞后,导致TLR4、CD14、MD-2mRNA表达迅速升高,而TLR2mRNA弱表达。说明TLR4、CD14、MD-2参与LPS的识别,同时也说明脂多糖刺激乳腺上皮细胞后,乳腺上皮细胞能够产生先天性免疫反应。     

Effect of arginine supplementation on the morphology and function of intestinal epithelia and serum concentrations of amino acids in pigs exposed to heat stress

The exposure of pigs to heat stress (HS) appears to damage their intestinal epithelia, affecting the absorption of amino acids (AAs). Arg is involved in the restoration of intestinal epithelial cells but HS reduces Arg intake. The effect of dietary supplementation with Arg on the morphology of intestinal epithelia, AA transporter gene expression, and serum concentration (SC) of free AAs in HS pigs was analyzed. Twenty pigs (25.3 ± 2.4 kg body weight) were randomly assigned to two dietary treatments: Control (0.81% Arg), wheat–soybean meal diet supplemented with l-Lys, l-Thr, dl-Met, and l-Trp, and the experimental diet where 0.16% free l-Arg was supplemented to a similar Control diet (+Arg). All pigs were individually housed and exposed to HS, fed ad libitum with full access to water. The ambient temperature (AT), recorded at 15-min intervals during the 21-d trial, ranged on average from 29.6 to 39.4 °C within the same day. Blood samples were collected on day 18 at 1600 hours (AT peak); serum was separated by centrifugation. At the end of the trial, five pigs per treatment were sacrificed to collect samples of mucosa scratched from each small intestine segment. The expression of AA transporters in intestinal mucosa and the SC of AAs were analyzed. Villi height (VH) was higher (P < 0.01) in the duodenum, jejunum, and ileum but the crypt depth did not differ between the Control and the +Arg pigs. Supplementation of l-Arg increased the mRNA coding for the synthesis of the cationic AA transporter b^0,+ (P < 0.01) and the neutral AA transporter B⁰ (P < 0.05) in the duodenum by approximately 5-fold and 3-fold, respectively, but no effect on mRNA abundance was observed in the jejunum and ileum. The supplementation of l-Arg increased serum Arg, His, Met, Thr, Trp, and urea (P < 0.05) and also tended to increase Val (P < 0.10) but did not affect Ile, Lys, Leu, and Phe. These results indicate that supplementing 0.16% l-Arg to the Control diet may help to improve the function of the small intestine epithelium, by increasing the VH, the abundance of AA transporters, and the SC of most indispensable AAs in pigs exposed to HS conditions. However, the lack of effect of supplemental Arg on both Lys SC and weight gain of pigs suggests that increasing the Lys content in the +Arg diet might be needed to improve the performance of HS pigs.     

Viral deubiquitinases and innate antiviral immune response in livestock and poultry

Among many of the pathogens, virus is the main cause of diseases in livestock and poultry. A host infected with the virus triggers a series of innate and adaptive immunity. The realization of innate immune responses involves the participation of a series of protein molecules in host cells, including receptors, signal molecules and antiviral molecules. Post-translational modification of cellular proteins by ubiquitin regulates numerous cellular processes, including innate immune responses. Ubiquitin-mediated control over these processes can be reversed by cellular or viral deubiquitinases (DUBs). DUBs have now been identified in diverse viral lineages, and their characterization is providing valuable insights into virus biology and the role of the ubiquitin system in host antiviral mechanisms. In this review, we briefly introduce the mechanisms of ubiquitination and deubiquitination, present antiviral innate immune response and its regulation by ubiquitin, and summarize the prevalence of DUBs encoded by viruses (Arteriviridae, Asfarviridae, Nairoviridae, Coronaviridae, Herpesviridae, and Picornaviridae) infecting domestic animals and poultry. It is found that these DUBs suppress the innate immune responses mainly by affecting the production of type I interferon (IFN), which causes immune evasion of the viruses and promotes their replication. These findings have important reference significance for understanding the virulence and immune evasion mechanisms of the relevant viruses, and thus for the development of more effective prevention and treatment measures.     

抗应激药物对热应激肉鸡免疫器官的组织学影响

２００只１４日龄健康艾维茵肉仔鸡随机等分为四组,Ａ、Ｂ两组分别在饲料中添加０．２２５％的抗应激Ⅰ号和抗应激Ⅱ号,Ｃ组为热应激对照组,Ｄ组为常温对照组。Ａ、Ｂ、Ｃ三组鸡舍温度为２８,３２～３６℃,４９日龄时称重、杀死、取材作石蜡切片,观察免疫器官的组织学结构。结果表明,Ｃ组体重明显低于Ａ、Ｂ、Ｄ组,Ａ、Ｂ组鸡体重与Ｄ组间差异不显著。热应激对各免疫器官有明显的损伤性和免疫抑制样变化,而抗应激药物对免疫器官有明显的保护作用,从组织学角度看,抗应激药物可明显地对抗热应激所造成的免疫抑制,使免疫器官组织学结构接近正常水平。     

玉米芯源低聚木糖对罗非鱼幼苗生长性能和先天免疫反应的影响

为研究玉米芯源低聚木糖对罗非鱼生长性能和先天免疫反应的影响,试验选取240尾罗非鱼幼苗随机分为4组,即对照组和试验1、2、3组,对照组饲喂基础日粮,试验组在基础日粮中分别添加0.5%、1%、2%的玉米芯源低聚木糖(CDXOS),试验为期8周。结果表明:与对照组相比,试验1、2组平均末重分别增加11.7%、20.4%(P<0.05),试验1、2、3组平均日增重分别增加13.0%、22.8%、11.2%(P<0.05),料肉比(F/U)显著降低9.0%、10.2%、8.4%(P<0.05)。试验1、2组溶菌酶(LSZ)活性较对照组分别增加66.6%、71.4%(P<0.05),超氧化物歧化酶(SOD)活性分别增加40.5%、67.8%(P<0.05),过氧化氢酶(CAT)活性分别增加22.8%、27.3%(P<0.05),丙二醛(MDA)浓度分别下降35.8%、42.6%(P<0.05)。综述,饲粮中添加玉米芯源低聚木糖能改善罗非鱼生长性能、促进先天性免疫反应,当添加量为1%时效果最为显著。     

Tulathromycin enhances humoral but not cellular immune response in pigs vaccinated against swine influenza

The effect of a standard, single dose therapy with tulathromycin was investigated on the postvaccinal humoral and cellular immune response in pigs vaccinated against swine influenza. Forty‐five pigs, divided into 3 groups, were used (control not vaccinated (C, n = 15), control vaccinated (CV, n = 15), and experimentally received tulathromycin (TUL, n = 15)). For vaccination of pigs, an inactivated, commercial vaccine was used. Pigs from TUL group received single dose of tulathromycin intramuscularly, at the recommended dose (2.5 mg/kg body weight). Pigs from TUL and CV groups were vaccinated at 8 and 10 weeks of age. The specific humoral and cellular immune response against swine influenza virus (SIV) was evaluated. The results of present study showed that humoral postvaccinal response after vaccination against SIV can be modulated by treatment with tulathromycin. In pigs from TUL group, the significantly higher titers of anti‐SIV‐specific antibodies were observed 4 and 6 weeks after booster dose of vaccine. Simultaneously, T‐cell‐mediated immune response against SIV was not affected by tulathromycin. Our recent study confirmed the importance of defining the modulatory activity of tulathromycin because of its influence on the immune response to vaccines. Since the antibodies against hemagglutinin are crucial for the protection against SIV, the present observations should prompt further studies on the practical significance of recent results in terms of clinical implications (postvaccinal protection) in the field conditions.     

Effect of the route of administration on the mucosal and systemic immune responses to Lawsonia intracellularis vaccine in pigs

In an on‐farm study, 40 weaned piglets aged 3 weeks were vaccinated with Lawsonia intracellularis vaccine orally, IM or IP while a fourth group remained unvaccinated. All vaccinated animals showed increased serum levels of L. intracellularis‐specific IgG antibodies, but significantly elevated concentrations of specific IgG, IgA and cytokines were generated in ileal mucosal secretions from the orally and IP vaccinated pigs when examined at 17 days after vaccination.     

5个草地早熟禾品种在干热胁迫下的生理响应

高温和干旱是冷季型草坪草的两个重要胁迫因子。试验将5个早熟禾品种进行干热胁迫处理21 d,每隔3 d评定草坪质量(TQ)、叶片萎蔫率(LW)、测定叶片相对电导率(EL)、叶片相对含水量(RWC)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和丙二醛(MDA)含量的变化。结果显示,随着干热胁迫天数的增加,草坪质量、叶片相对含水量、超氧化物歧化酶和过氧化氢酶的活性都明显下降,而叶片萎蔫率、叶片相对电导率和丙二醛的含量却明显上升。     

Daidzein enhances immune function in late lactation cows under heat stress

Heat stress decreases natural immunity making cows more vulnerable to diseases. A previous study reported that daidzein can enhance animal resistance to heat stress and regulate animal immunocompetence. However, it is unclear whether daidzein regulates the immune performance of late lactation cows under heat stress. In this study, late lactation cows in four groups were raised in hot weather and fed with basic diet, basic diet plus 200, 300, 400 mg/day daidzein, respectively, and the experimental period was 60 days. Blood was collected to examine the changes of serum total protein (TP), albumin (ALB), immunoglobulin G (IgG), interferon alpha (IFN‐α), and interleukin‐2 (IL‐2). We found the levels of serum IgG and INF‐α were significantly higher in late lactation cows after 300 and 400 mg/day daidzein treatment compared to those in the control group and 200 mg/day daidzein treatment (P < 0.05 or P < 0.01). Moreover, 300 and 400 mg/day daidzein treatment markedly increased serum IL‐2 (P < 0.01), while the levels of serum TP and ALB were not changed by any concentration of daidzein treatment (P > 0.05). Daidzein can enhance the immunocompetence of late lactation cows and strengthen cow resistance to heat stress.     

热应激牛初乳对新生犊牛血清免疫指标的影响研究

新生犊牛通过初乳获得被动免疫,但是关于热应激对新生犊牛被动免疫的影响程度尚不清楚。本试验旨在研究热应激牛初乳对新生犊牛被动免疫是否有显著影响,并与非热应激生产条件下进行比较。试验动物为对应于采食热应激和非热应激母牛初乳的新生犊牛各4头,在其采食母牛初乳后的不同时间内采血用于免疫指标分析。结果表明:热应激奶牛哺乳犊牛血清中各成分含量在144h内均低于非热应激奶牛哺乳犊牛血清中相对应成分,其中IgG、T3、T(472h内)变化差异显著(P<0.05),INS和IGF-Ⅰ变化差异不显著(P>0.05),热应激在一定程度上影响新生犊牛被动免疫,有关机理有待于进一步研究。     

谷氨酰胺对热应激肉鸡S-IgA、血液内毒素和细胞因子的影响

选用1日龄科宝-500肉鸡240只,随机分为6个处理,每处理4个重复,每重复10只,Ⅰ组饲喂玉米-豆粕型基础日粮,Ⅱ、Ⅲ、Ⅳ、Ⅴ和Ⅵ组分别在基础日粮中添加0.4%、0.8%、1.2%、1.6%和2.0%的谷氨酰胺,试验时间15～42日龄,共28d。试验期间从每天09：00-17：00温度维持在（35±1）℃8h,17：00至次日09：00温度维持在（30±1）℃,鸡舍相对湿度控制在70%～80%。试验测定了热应激条件下21、28、35、42日龄肉鸡小肠黏膜分泌型免疫球蛋白含量A,血浆中血液内毒素含量和白介素-1、肿瘤细胞坏死因子含量。结果表明,日粮中添加谷氨酰胺显著提高了21、28、35、42日龄热应激肉鸡小肠黏膜分泌型免疫球蛋白含量（P〈0.05）,降低血浆中血液内毒素、白介素-1、肿瘤细胞坏死因子的含量（P〈0.05）。因此,在基础日粮中添加一定水平的谷氨酰胺可改善热应激肉鸡的肠道免疫性能。     

Partial inhibition of the humoral immune response of pigs after early postnatal immunization

The ability of young pigs to be immunized during the postnatal period was studied. Eight groups of pigs born on the same day from 3 sows were injected with hen egg-white lysozyme in Freund's incomplete adjuvant at days 0, 1, 2, 3, 4, 5, 7, and 10 after birth. The serum antibody titers were determined each week. Results indicated that pigs injected within the first 3 days of life exhibited a delay of 10 days in the appearance of the humoral antibodies, compared with the antibody response observed in pigs injected later. Serum antibody titers were markedly lower in the early immunized pigs. The secondary immune response was similar in all pigs. This partial inhibition is not directly linked to the corticoids present in the serum at the immunization day. Possible reasons for this impairment of the humoral immune response were reviewed.     

Effect of seasonal thermal stress on oxidative status,immune response and stress hormones of lactating dairy cows

This study aimed to assess the impact of seasonal thermal stress on oxidative stress, immune response, and stress hormones of lactating dairy cows in subtropical regions with different levels of temperature-humidity index (THI). A total of 32 healthy lactating Holstein dairy cows experienced 4 seasons (8 cows/season). The physiological parameters were categorized into low THI (LTHI, THI = 42.97 ± 0.95) in winter, moderate THI (MTHI, THI = 61.84 ± 0.42) in spring and autumn, and high THI period (HTHI, THI = 86.09 ± 0.23) in summer. The blood samples were collected twice in each season to measure oxidative stress, inflammatory and hormonal parameters. Our results showed THI had a positive correlation with the rectal temperature (R² = 0.821, P < 0.001) and respiratory rate (R² = 0.816, P < 0.001). Dry matter intake, milk yield and fat percentage also significantly differed among groups (P < 0.05). Compared with the MTHI group, the LTHI group exhibited a significant increase in malondialdehyde (MDA) level (P < 0.001), and the HTHI group displayed a significant increase in levels of cortisol, interleukin (IL)-10, IL-1β and tumor necrosis factor-α (P < 0.001). Opposite changes in serum endotoxin and immunoglobulin G levels were observed with the increasing THI (P < 0.001). LTHI notably increased the triiodothyronine level, although the thyroxine level was reduced by LTHI and HTHI compared with the MTHI group. In conclusion, LTHI and HTHI conditions may induce different degrees of oxidative stress, inflammation response, and stress hormone imbalances on lactating dairy cows, therefore environmental management is necessary for the health of dairy cows in extreme weather conditions.     

Individual response of growing pigs to lysine intake

Nitrogen (N) balance experiment was carried out to study the individual and group response of growing pigs to lysine (Lys) intake. A series of 15 purified diets limiting in Lys were fed sequentially to nine pigs (initial body weight, 39 kg) during a 15‐day experiment. Lysine concentration ranged from 50% to 140% of its assumed requirement. N retention in individual pigs was related to Lys intake using linear‐plateau (LP) and quadratic‐plateau (QP) models. No difference in the closeness of fit between the models was found (p = 0.72). There were significant differences between the slopes of individual regression lines in the LP model (p = 0.018) and between the individual plateau values in both models (p < 0.0001). The breakpoint values in the QP model were greater than those of the LP model (p = 0.027), while the plateau values estimated by both models were similar (p = 0.32). In the LP model, no relationship was found between the slopes and plateau values (p = 0.67, r = 0.17) or between the slopes and breakpoint values (p = 0.55, r = ?0.23), thus suggesting that pigs with higher protein deposition rate do not utilize lysine more efficiently. However, there was a close positive correlation between breakpoint and plateau values (p = 0.0005, r = 0.92). Based on LP and QP models, the mean daily requirement of Lys for a 47‐kg gilt was estimated to be 20.8 and 24.2 g (0.79 and 0.92 g/MJ metabolizable energy), respectively, with coefficients of variation of approximately 10%. Marginal efficiency of Lys utilization derived from the LP model was 0.67 and was dependent on the range of input data selected. Lysine disappearance was a curvilinear function of Lys intake, indicating that Lys catabolism is not directly related to Lys intake. The closeness of fit of exponential, saturation kinetics or four‐parameter logistic models applied to data set of all pigs was similar to that of LP or QP models.     

高温胁迫下冷季型草坪草的耐热性评价

对5个典型冷季型草坪草品种在海南进行耐热性试验.在大田高温胁迫环境下,草坪草热害症状最初表现为叶片发生萎蔫,生长率减缓或停滞,但其是否受害却最先反映在叶片灼伤率上,受害最终表现为草坪盖度和根系生长量的下降.叶片灼伤率是判断草坪草早期是否受到热伤害最敏感的指标.耐热性评价结果:Pacer高羊茅Festuc atundincea cv.Pacer＞Houndog高羊茅F.arundinacea cv.Houndog＞Merit草地早熟禾Poa pratensis cv.Merit＞Derby黑麦草Lolium pernne cv.Derby＞Cobra匍匐翦股颖Agrostis palustris cv.Cobra.28～36 ℃可认为是冷季型草坪草的临界受害温度区间,28～32 ℃为初始受害温度区间,32～36 ℃为致死温度区间.     

Effect of δ-aminolevulinic acid on growth performance, nutrient digestibility, blood parameters and the immune response of weanling pigs challenged with Escherichia coli lipopolysaccharide

This study investigated the effects of dietary δ-aminolevulinic acid (ALA) on growth performance, nutrient digestibility, blood parameters and whether ALA improved the immune response of weanling pigs challenged with Escherichia coli lipopolysaccharide (LPS). Eighty pigs (body weight = 7.21 ± 0.51 kg) were allotted to four dietary treatments, with four pens per treatment and five pigs per pen. Basal diets were supplemented with 0, 5, 10, and 15 mg/kg ALA (as-fed basis) and fed for 35 days. At the end of the feeding period, 10 pigs were selected from both the 0- and 10-mg/kg ALA treatment groups; five were injected i.p. with LPS (50 μg/kg BW) and the other five pigs with an equivalent amount of sterile saline, resulting a 2 × 2 factorial arrangement. Blood sample and rectal temperature data were collected at 0, 2, 4 and 12 h after challenge. Growth performance was not affected by dietary treatments over the total experimental period. However, dry matter (DM) and nitrogen (N) digestibility was improved in the 15-mg/kg ALA treatment group at day 35 (P < 0.05). Serum hemoglobin (Hb) and iron levels were also increased, with the 10-mg/kg ALA treatment showing the highest concentration (P < 0.05). On day 35, red (RBC) and white blood cell (WBC) counts were elevated, with the 5- and 10-mg/kg ALA treatments having the highest counts (P < 0.05). During challenge, LPS injection elevated rectal temperature at 2 and 4 h postchallenge (P < 0.05). Plasma cortisol concentration was also increased by LPS injection at 2 and 4 h postchallenge and an ALA-alleviating effect was evident at 2 h postchallenge (P < 0.01). Concentration of plasma insulin-like growth factor-I (IGF-I) was increased in the ALA-supplemented treatments at 2 h postchallenge (P < 0.05). LPS injection increased plasma tumor necrosis factor-α (TNF-α) concentrations at 2, 4 and 12 h (P < 0.01), while an ALA-alleviating effect was observed at 2 and 4 h postchallenge (P < 0.05 and P < 0.10, respectively). Challenge with LPS decreased WBC counts at 2 and 4 h postchallenge (P < 0.01). At 12 h postchallenge, RBC, WBC and lymphocyte counts were affected by LPS challenge, while an ALA effect was only observed on WBC count (P < 0.05). In conclusion, dietary supplementation of ALA in weanling pigs can improve DM and N digestibilities, and iron status and have a beneficial effect on the immune response during inflammatory challenge.