Whole blood chemiluminescence response in broiler chickens on different experimental diets and challenged withClostridium perfringens

Impact of Reduced Dietary Crude Protein in the Starter Phase on Immune Development and Response of Broilers Throughout the Growth Period

Crude protein (CP) levels in commercial broiler (Gallus gallus) diets, optimized for maximum yield production vs. feed cost, have only begun to be assessed for impact on immune function. In order to study immune effects of dietary CP levels, different starter phase (day 1–14) diets were fed to 230 Ross 708 male broiler chicks randomly assigned at 1 day of age into two treatment groups. Group 1: Standard diet (STD) contained 3,000 kcal AMEn/kg energy and 23.78% CP; and Group 2: Reduced crude protein diet (RCP) contained 3,000 kcal AMEn/kg energy and 21.23% CP. From day 15–35 a common standard grower/finisher diet (3,150 kcal AMEn/kg energy and 22.18% CP) was allocated to both groups. Zymosan, a glycan derived from yeast cell walls that binds to TLR 2 and Dectin-1, was used for intra-abdominal challenge. Results demonstrated that a reduced crude protein starter diet (21.23 vs. 23.78% CP) between age 1–14, while maintaining the same levels of metabolizable energy and essential amino acids, did not affect broilers growth performance or lymphoid organ weights (P > 0.05). Interestingly, basal leukocyte levels in the RCP group significantly (P < 0.01) increased in the blood compartment at d35 in the unchallenged birds. Significant enhancements to leukocyte infiltration into the abdominal cavity were also detected post-immune challenge with zymosan (day 14 and day 35; P < 0.01). Post-challenge levels of TNF-α, IL-1β, and CXCL8 gene expression cells collected from the abdominal cavity were not affected by the diets (P > 0.05). Moreover, dietary treatments did not influence percentage of ROS producing cells in the abdominal cavity (P > 0.05). To our best knowledge, this is the first study that reports the impacts of reduced crude protein diet on the innate immune response of poultry to an acute inflammation model in the abdominal cavity. Overall, our results highlight that reduced crude protein diets can be used without negatively impacting broiler performance and may enhance the capacity of broilers to recruit leukocytes upon infection.

Measuring the Asian seabass (Lates calcarifer) neutrophil respiratory burst activity by the dihydrorhodamine-123 reduction flow cytometry assay in whole blood

The neutrophil oxidative respiratory burst response is a key component of the innate immune system responsible for killing microbial pathogens. Since fish rely on the innate immune system for health, monitoring the respiratory burst activity may be an effective means of gauging fish health status. Here we report that the respiratory burst of Asian seabass neutrophils can be measured in whole blood by the dihydrorhodamine (DHR)-123 reduction assay and flow cytometry. Neutrophils responded to phorbol myristate acetate (PMA) in a concentration dependent manner with significant respiratory burst activity at 100-1000 nM. Other known neutrophil agonists, such as bacterial lipopolysaccharide, tumor necrosis factor, the tripeptide f-met-leu-phe and zymosan, did not induce a significant DHR reduction. Thus, the findings enable us to propose that the DHR-123 flow cytometry whole blood assay, incorporating PMA as a stimulator, would not only facilitate future studies into fish blood neutrophil research but provides a simple, rapid and reliable assay for gauging fish natural immunity status and health.

Aspergillus awamori-fermented mung bean seed coats enhance the antioxidant and immune responses of weaned pigs

The potential benefits of Aspergillus-fermented mung bean seed coats (FMSC) for weaned pigs remain unexplored. Both in vitro and in vivo experiments were employed to evaluate the potential of FMSC supplement on the growth, antioxidant and immune responses of weaned pigs. The total polyphenols and DPPH scavenging capability of ethanol extract of FMSC exhibited a greater (p < 0.01) increase than those of pre-fermentation. With the addition of the polyphenol of FMSC extract, an increase in phagocytosis by neutrophils and proliferation of peripheral blood mononuclear cells (PBMC) were found. However, these observations were significantly inhibited (p < 0.05) in those activated cells. Next, 96 weaned pigs were allotted with a randomized complete block design into four dietary treatments, including 0 (control), 600, 1200 or 1800 mg/kg FMSC in a corn-soya bean meal basal diet for a 35-day trial. The pigs were injected with swine enzootic pneumonia (SEP) vaccines at day 3 and day 21 respectively. The results showed that dietary treatment failed to affect growth performance or serum SEP titre. The diet supplemented with 600-1800 mg/kg FMSC decreased faecal lactoferrin on day 21 and increased plasma trolox equivalent antioxidant capacity (TEAC) and erythrocytes catalase activity, as well as decreased (p < 0.01) plasma malondialdehyde (MDA) concentration on day 35. Diet supplementation of 1800 mg/kg FMSC increased phagocytosis by neutrophils and PBMC proliferation induced by pokeweed mitogen (PWM). However, the polymorphonuclear leucocytes (PMN)-positive respiratory burst cells were decreased in the supplementation of 1200 or 1800 mg/kg FMSC respectively. In addition, the serum haptoglobin concentration was decreased in the supplementation with 1200 mg/kg FMSC. Taken together, FMSC enriches polyphenols with antioxidative and immune modulated properties. After feeding FMSC, an improvement in antioxidative capability and immunocompetence was found, implying that FMSC could provide as a feed additive at optimal level 1200 mg/kg for weaned pigs.