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This experiment was conducted to evaluate the combined effects of manganese-amino acid complex and arginine supplementation on the immune competence of broilers. On the day of hatch 640 male Cobb 500 broiler chicks assigned to two study groups (immune stimulate and non-stimulated). A 2 × 2 factorial arrangement of treatments was used with two manganese sources (MnSO4 or manganese-amino acid complex - MnAA) and two digestible Arg:Lys ratios (1.12 or 1.20). The treatments are: IM (80 ppm MnSO4); MnAA (40 ppm MnSO4 + 40 ppm MnAA); IM+Arg: 80 ppm MnSO4+ L-Arg (Arg:DigLys 1.20); MnAA+Arg: 40 ppm MnSO4 + 40 ppm MnAA + L-Arg (Arg:Lys 1.20). For treatments 1 and 2, the digestible Arg:Lys ratio was 1.12, considered normal for corn-soybean meal-based diets. Birds in the immune stimulated group received a dose of Salmonella Enteritidis vaccine. For growth performance and lymphoid organ development, no significant results were observed. Non-stimulated birds fed diets with Arg supplementation had higher percentage of mucosal T helper, T helper and T cytotoxic, compared to the normal Arg:Lys ratio (1.12). In the immune stimulated birds, broilers fed exclusive IM diet had a higher amount of T helper, T cytotoxic, activated T cytotoxic, and APC cells compared to broilers fed MnAA. The inorganic Mn diets, resulted in higher humoral antibody level (increased IgM levels) only when associated with supplementation of L-Arg. However, the use of an associated Mn source, could support high levels of IgM in commercial levels of Arg. No differences were observed to macrophage phagocytic activity analyses., (© 2018 Poultry Science Association Inc.)

This experiment was conducted to examine the effect of trace mineral sources on broiler performance, carcass composition, trace mineral digestibility, and tibia bone quality of broiler chickens. A total of 480 Ross 308 male day-old chicks were allocated to 24 pens and assigned to 4 dietary treatments in a completely randomized design. Treatments were as follows: inorganic (I) was basal diet supplemented with 750 g/t inorganic trace mineral premix; organic 1 (O1) and organic 2 (O2) was basal diet supplemented with 375 and 500 g/t organic yeast proteinate trace mineral premix respectively; and hydroxychloride (H) was basal diet supplemented with 1000 g/t salt encrusted trace mineral premix. On day 25, no differences in feed intake (FI), body weight gain (BWG), feed conversion ratio (FCR), or livability (LV) were observed between treatments (P > 0.05). On day 38 birds fed O1 and H had higher weight gain (P < 0.05) and lower FCR (P < 0.001) relative to I. Mineral sources had no impact on FI or LV (P > 0.05) on day 38. Spleen percentage of body weight on day 25 was increased in birds fed O1 and H treatments (P < 0.05) over the I treatment. Mineral sources had no effect on relative weights of thymus or bursa of Fabricius on day 25, or bone quality and carcass composition on day 39 (P > 0.05). Apparent digestibilities of Cu and Zn were greater in birds fed yeast proteinated trace minerals compared to other sources.

The aim of the study was to examine the effects of cage furnishing and social stress on some lymphoid organ weight and innate, cell-mediated, and humoral immune responses in laying hens. Sixty-four chickens were used. The chickens were divided into 2 groups; one of the groups was reared in furnished cages (RFC) and the other was reared in conventional cages (RCC). In wk 17, social stress was applied. Heterophil and lymphocyte percentages; liver, spleen, thymus, and bursa of Fabricius weights; phagocytic activity; oxidative burst and chemotaxic activity of heterophil; CD4+ and CD8+ cell proportions; and antibody production were measured. The effect of rearing methods was significant on heterophil, lymphocyte percentage, heterophil/lymphocyte (H/L) ratio, and antibody production. Heterophil percentage and H/L ratio were lower (P=0.001, P=0.001, respectively), and antibody production was higher (P=0.003) in RFC hens compared to RCC hens. The main effect of social stress was also significant on heterophil, lymphocyte percentages, and H/L ratio. Heterophil percentage was higher (P=0.049); H/L ratio tended to be higher (P=0.068); and lymphocyte percentage tended to be lower (P=0.072) due to stress. In addition, thymus and bursa of Fabricius weights tended to be lower (P=0.073 and P=0.074, respectively) in stressed hens. There were significant interactions between rearing methods and social stress on oxidative burst, chemotaxic activity, and CD4+ and CD8+ proportion (P=0.001, P=0.004, P=0.054, and P=0.001, respectively). These parameters were significantly higher in RFC hens, when they were exposed to stress. On the other hand, they did not differ in RCC or unstressed RFC hens. These results indicated that cage furnishing positively affected heterophil functions, CD4+ and CD8+ cell proportions, and antibody production. Therefore, we suggest that cage furnishing, which is recommended for improving the welfare of animals, is also beneficial for improving the immune response of hens under the stress condition., (© 2015 Poultry Science Association Inc.)

An experiment was conducted to determine the effects of different doses of liquid dl-2-hydroxy-4-methylthio butanoic acid (LMA) on growth performance and immune response in broiler chickens. In an arrangement with 4 graded levels of LMA to meet 80, 100, 120, and 140% of methionine requirements of broilers recommended by Chinese feeding standards for chickens, 256 one-day-old Arbor Acres male broiler chickens were randomly divided into 4 treatments with 8 replicates of 8 birds each. Growth performance, cellular immunity, and humoral immunity were determined. Results from increasing LMA levels were as follows. There were no significant differences (P > 0.05) in body weight gain and feed intake among the treatments, but the ratio of feed to gain was linearly decreased and significantly greatest (P < 0.05) in the group fed at 80% of methionine requirement. Serum globulin levels on d 21 and 42 were linearly increased significantly (P < 0.05); phagocytosis of neutral red of peripheral blood lymphocyte was quadratic and was lowest in the deficient group (P < 0.05). The proliferation of peripheral blood lymphocytes in response to lipopolysaccharide was quadratically influenced, and that of the 120% group on d 21 and the 100% group on d 42 was significantly greater than in the other groups (P < 0.05). Antibody titers to Newcastle disease virus on d 4 after the first inoculation of the vaccine were quadratically increased, anti-bovine serum albumin antibody production on d 13 after the second immunization was quadratic, and antibody titers were greatest in the groups fed at 100 or 120% of methionine requirement. In conclusion, methionine deficiency resulted in decreased feed utilization and decreased humoral and nonspecific immuno-competence of broiler chickens. The use of LMA to correct a methionine deficiency corrected these problems.

A dietary deficiency of Arg may suppress chick immune system functions; however, research evaluating immune function responsiveness of commercial broilers fed dietary Arg levels near NRC (1994) recommendations is sparse. Therefore, three experiments were conducted to evaluate growth and immunity of broilers fed varying Arg levels near NRC (1994) specifications. Because Arg and Lys are similar in structure and are known to compete in intestinal absorption, dietary Lys treatments [near NRC (1994) recommendations] were evaluated to determine if Arg and Lys interact to affect broiler immunity. There were four dietary treatments in Experiment 1 representing a 2 x 2 factorial design of additional Arg (120% of NRC) or additional Lys (120% of NRC) added to a control diet containing 100% of NRC Arg and Lys (six replications per treatment). Experiment 2 contained the following four treatments: the control diet; the control diet plus L-Arg (0.20% Arg of diet); the control diet plus L-Lys HCl (0.20% Lys of diet); and the control diet plus L-Arg-L-Glu (0.10% Arg of diet). Graduations of Arg were fed from 90 to 120% of NRC in 10% increments in Experiment 3. Also, half of the birds were exposed to vaccinations of Newcastle disease virus and infectious bronchitis virus in Experiment 3 to derive a 2 x 4 factorial design. Experiments 1 and 2 were conducted from Days 1 to 18 and Experiment 3 was conducted from Days 1 to 15 in Petersime battery brooders. No interactions occurred between dietary Lys and Arg in Experiment 1. Increasing dietary Arg, but not Lys, from 100 to 120% of the NRC recommendation increased (P < or = 0.05) Day 18 BW gain. Treatment differences in the cutaneous basophil hypersensitivity assay in Experiment 1 did not occur. In Experiment 2, treatment differences in growth responses, lymphoid organ development, and primary antibody titers to SRBC did not occur. Unvaccinated birds in Experiment 3 fed an Arg-deficient diet had lower (P < or = 0.05) feed conversion in comparison with vaccinated birds fed an Arg-deficient diet. Vaccinated birds had lower (P < or = 0.05) Day 15 BW than unvaccinated birds, but higher (P < or = 0.05) titers to Newcastle disease virus. Increasing dietary Arg in Experiment 3 increased plasma Arg (P < or = 0.05), but did not affect plasma Lys. Although increased dietary Arg improved BW gain in Experiment 1, minimal effects were noted in growth and immune system parameters throughtout this study. A dietary Arg level near the NRC (1994) recommendation should support proper immune system functions in healthy chicks.

Continuous adrenocorticotropin (ACTH) delivery by mini-osmotic pumps is a reliable method to induce stress in broilers. The present study was conducted to determine the minimum effective dose of ACTH that will evoke physiological stress. Chicks, which had been reared under floor-pen conditions until 5 wk of age received mini-osmotic pumps by surgical implantation. The mini-osmotic pumps delivered 2, 4, 8, or 16 IU of porcine ACTH/kg BW/d for 7 consecutive d. Controls (CON) were untreated chicks. Continuous infusion of ACTH caused dose-related stress responses. Chicks that received 8 or 16 IU showed the greatest responses, whereas those that received 2 or 4 IU were intermediate to the birds dosed with high ACTH and the CON birds. Responses included decreased BW; decreased relative weights of the bursa of Fabricius, thymus, and spleen; and increased relative liver weight. Concomitantly, increased liver lipid and decreased liver moisture were recorded. Plasma concentrations of corticosterone (CS), glucose (GLU), total protein (TP), cholesterol (CHOL), and triglycerides (TRI) and the ratio of heterophils to lymphocytes were increased during ACTH infusion. ACTH infusion at 8 IU/kg BW/d for 7 d was determined to be the minimum effective dose that caused physiological stress in broilers.

A model was developed to study stress in chickens. Continuous administration of adrenocorticotropic hormone was employed (ACTH) using physiological mini-osmotic pumps. A validation of controls for this procedure showed that nonhandled (NHCON), sham surgical procedure for pump implantation (SMCON) and surgical implantation of a pump delivering saline (SALCON) were all acceptable controls. Continuous delivery of ACTH at 8 IU/kg BW/d for 7 d caused increases in plasma corticosterone (CS), glucose (GLU), cholesterol (CHOL), triglycerides (TRI), high-density lipoprotein (HDL), total protein (TP), and the heterophil/lymphocyte (H/L) ratio. Body weight, as well as relative weights of the major immunobiological organs (i.e., spleen, thymus, and bursa of Fabricius) were decreased. Finally, liver was increased due to lipid and moisture accumulation. This model is the first to show in a single experiment all the major adaptive stress responses of chickens.

In vivo effects of graded dietary levels of arginine on the body and lymphoid organs were investigated using Cornell K strain chickens of the B15/B15 haplotype. Two-week-old birds were fed an arginine-deficient basal diet (0.53% arginine) supplemented with additional arginine (up to 1.0% L-arginine to the diet). At four weeks of age, body weight, lymphoid organ weight, and concentrations of amino acids in plasma were measured. Arginine supplementation produced significant increases in plasma arginine (from 200 nM in chicks fed the basal diet to 2,000 nM in chicks receiving the 1.5% arginine diet) and ornithine concentrations (from 17 nM in chicks fed the basal diet to 500 nM in chicks receiving the 1.5% arginine diet). The arginine-deficient diet reduced body weight gain (P < 0.0001) and thymus, spleen, and bursa of Fabricius weights (P < 0.05). In contrast to the bursa weight, the thymus and spleen weights, as percentages of body weight, were also decreased (P < 0.05). This study suggests that arginine markedly influences lymphoid organ development, with a more pronounced effect on the thymus and spleen than on the bursa of Fabricius.

The purpose of the present study was to measure the effect of dietary fat source on the fatty acid composition of immune cells in chickens. One-day-old female chicks were fed corn and soybean meal-based diets containing 7% of either lard, corn oil, canola oil, linseed oil (LO), or menhaden fish oil (FO). After being fed experimental diets for 3 to 4 wk, samples of serum, thymus glands, bursa of Fabricius glands, and splenocytes were collected. All samples were frozen and stored at -80 C until lipid analysis. Results indicate that the fatty acid composition of the sera and immune tissues of chickens reflected the fat in the diet. The relative content of long-chain polyunsaturated fatty acids varied considerably among immune tissues, with, from greatest to least, spleen, bursa, and thymus. The young chick demonstrated a substantial capacity to elongate and desaturate linoleic (C18:2n-6) and alpha-linolenic acids (C18:3n-3). Feeding chicks fats rich in n-3 fatty acids (e.g., LO or FO) decreased significantly (P less than .05) the level of arachidonic acid (C20:4n-6) present in the serum and immune tissues by 50 to 75%. The levels of eicosapentaenoic acid (EPA, C20:5n-3) and docosahexaenoic acid (DHA, C20:6n-3) were substantially increased (P less than .05) by FO and LO feeding. However, LO, which is rich in C18:3n-3, was generally only one-half to one-quarter as effective as FO in elevating EPA and DHA levels in immune tissues. The implications for these changes in serum and immune tissue fatty acid profiles are discussed briefly.

One-day-old White Leghorn male chicks were fed different levels of Thyrotropin Releasing Hormone (TRH) (1 and 5 ppm) or Triiodothyronine (T3) (.1 and 1 ppm) for an 8-wk period. In a second experiment, chicken growth hormone (cGH) (10 micrograms/kg of BW) was injected (iv) into different birds daily for 7 days starting at 7 wk of age. Different groups of birds received both T3 (.1 and 1 ppm) and cGH. Serum concentrations of thyroxine (T4), T3, and growth hormone (GH), lymphoid organ weights, total circulating white blood cells (WBC), and differential counts were measured following hormone treatments. It was found that T3, cGH, or a combination of both significantly lowered serum T4 concentrations. Triiodothyronine supplementation at 1 ppm, alone or with cGH significantly increased serum T3 concentrations. Chicken GH with T3 (.1 ppm) significantly increased serum GH concentrations. Thyrotropin releasing hormone supplementation did not affect serum concentrations of either T4, T3, or cGH. Relative bursa weights were greater in chicks that received T3 (1 ppm) or TRH (1 or 5 ppm) but not cGH. Relative spleen weights were enhanced in response to cGH alone or with T3 (1 ppm) but not TRH. Total WBC count was significantly increased in response to T3 (1 ppm). Supplementation of T3 (.1 or 1 ppm), TRH (1 ppm), and the combination of cGH and T3 (1 ppm) significantly increased the percentage of lymphocyte cell population. These results demonstrate the impact of feeding hormones on T3, T4, and cGH concentrations in the serum and suggest the involvement of the above hormones in the growth of lymphoid organs as well as the production of lymphocytes.

The light and electron microscopic structure of the germinal center of chicken caecal tonsils were studied. Two kinds of germinal centers were revealed; the first was located deep in the lymphatic tissue close to the muscle layer of the caeca. These germinal centers frequently have an incomplete capsule, and are not, therefore, separated from the diffuse lymphatic tissue. The second kind of germinal center was located closer to the epithelium and had a complete capsule separating it from the diffuse lymphatic tissue. Both germinal centers possessed an outer dark cortical zone which contained smaller lymphoblasts (of less than 10 micron in diameter) and a central medullary area which contained larger lymphoblasts (up to 16 micron). Autoradiographic studies revealed that the small lymphoblasts of the outer cortical zone are concerned with cell generation and that the large lymphoblasts of the medullary area may have derived from the small lymphocytes. Within the medullary area of the germinal center are cells which are embedded in an intercellular substance of high density. We propose that the intercellular substance may be a product of this cell. For discussion purposes we have called this cell a secretory cell. The secretory cell may originate from a small lymphocyte-like cell.