Bacterial biofilms are structured communities of bacterial cells enclosed in a self-produced polymer matrix that is attached to a surface. Biofilms protect and allow bacteria to survive and thrive in hostile environments. Bacteria within biofilms can withstand host immune responses, and are much less susceptible to antibiotics and disinfectants when compared to their planktonic counterparts. The ability to form biofilms is now considered an attribute of many microorganisms. Diseases associated with biofilms require novel methods for their prevention, diagnosis and treatment; this is largely due to the properties of biofilms. Furthermore, the presence of biofilms on surfaces found at farms, slaughterhouses or food processing plants will have an impact on the efficacy of disinfection protocols. Surprisingly, biofilm formation by bacterial pathogens of veterinary or zoonotic importance has received relatively little attention. The objective of this brief Review article is to bring awareness about the importance of biofilms to animal health stakeholders.

Objective-To investigate effects of intramammary administration of prednisolone on the immune response of mammary glands in cows. Animals- 5 lactating Red Holsteins. Procedures- Cows received a different intramammary infusion in each mammary gland (10 mg of prednisolone, 100 μg of lipopolysaccharide [LPS], 100 μg of LPS and 10 mg of prednisolone, or saline [0.9% NaCl] solution). Milk samples were collected before (time 0) and 3, 6, 9, 12, 24, and 36 hours after treatment. Somatic cell count (SCC), lactate dehydrogenase (LDH) activity, and concentrations of serum albumin (SA) and tumor necrosis factor (TNF)-α in milk and mRNA expression of TNF-α, interleukin (IL)-8, and IL-1β in milk somatic cells were analyzed. Results-Saline solution or prednisolone did not change SCC, LDH activity, and SA and TNF-α concentrations in milk and mRNA expression of TNF-α, IL-1β, and IL-8 in milk somatic cells. The SCC and TNF-α concentration in milk increased similarly in glands infused with LPS, independent of prednisolone administration. However, the increase of LDH activity and SA concentration in milk after LPS infusion was diminished by prednisolone administration. The mRNA expression of TNF-α, IL-8, and IL-1β in milk somatic cells increased after LPS infusion and was unaffected by prednisolone. Conclusions and Clinical Relevance- Intramammary administration of prednisolone did not induce an immune response and did not change mRNA expression of TNF-α, IL-8, and L-1β during the response to intramammary administration of LPS. However, prednisolone reduced disruption of the blood-milk barrier. This could influence the severity and cure rate of mastitis.

Retinoids play an important role in lung development and immune response. The effects of retinoids are mediated through 2 families of retinoid receptors: retinoic acid receptors (RARs) and retinoid X receptors (RXRs), with alpha (α), beta (β), and gamma (γ) subtypes in each family. To date, no data exist on the expression pattern of retinoid receptors in lungs of cattle, dogs, and pigs. Because of the biomedical importance of retinoid receptors in inflammation and immune responses, Western blot, immunohistology, and immunoelectron microscopy were used to determine the expression of retinoid receptors in normal lungs of cattle, dogs, and pigs (n = 2 for each species). Western blot showed expression of all 6 retinoid receptor subtypes in pig lungs. Immunohistology data indicated differential expression of retinoid receptors in airway epithelium, vascular endothelium, alveolar/septal macrophages, and alveolar septum in all 3 species. Electron microscopy showed nuclear localization of retinoid receptors in neutrophils and pulmonary intravascular macrophages. Retinoic acid receptors (RAR) α subtype were localized in cytoplasmic vacuoles of pig monocytes. These data indicate constitutive expression of retinoid receptors in the lungs of cattle, dogs, and pigs.

Objective—To determine the effects of resveratrol (RES) on growth and immune status in chickens receiving conventional vaccinations. Animals—Two hundred forty 1-day-old layer chickens. Procedures—Chickens received conventional vaccinations throughout the study and were randomly assigned to 1 of 4 treatments in 6 replicate pens/treatment. Treatments included 1 control group (basal diet) and 3 experimental groups fed the basal diet plus 200, 400, and 800 mg of RES/kg of diet. At 40 days of age, 1 bird/pen was randomly selected to have blood and tissues collected to determine serum immunity indices; mRNA relative expression of proinflammatory cytokines in splenocytes; mRNA relative expression of nuclear transcription factor-κB, growth hormone receptor, and insulin-like growth factor-1 in hepatocytes; cell proliferation; and apoptosis. Results—Average daily gain, antibody titers against Newcastle disease virus and avian influenza viruses H5 and H9, and insulin-like growth factor-1 expression were quadratically increased with increasing RES concentration. In hepatocytes, growth hormone receptor gene mRNA relative expression was quadratically increased and nuclear transcription factor-κB gene mRNA relative expression was linearly decreased with increasing RES concentration. In splenocytes, nterleukin-1β and tumor necrosis factor-α mRNA relative expression was linearly decreased with increasing RES concentration. Resveratrol supplementation delayed cell proliferation and reduced apoptosis in immunocytes. With increasing RES concentration, proliferation index and relative weight of the thymus, ratio of CD4+ to CD8+ cells, and CD4+ cell count were quadratically increased, and IgM concentration was linearly increased. Conclusions and Clinical Relevance—Dietary resveratrol supplementation improved growth, protected immunocytes against antigen-induced apoptosis, and upregulated immune response in chickens that received conventional vaccinations.

Macrophages function as phagocytes and antigen-presenting cells in the body. As has been demonstrated in mammals, administration of clodronate [dichloromethylene bisphosphonate (Cl 2MBP)] encapsulated liposomes results in depletion of macrophages. Although this compound has been used in chickens, its effectiveness in depleting macrophages has yet to be fully determined. Here, we show that a single administration of clodronate liposomes to chickens results in a significant depletion of macrophages within the spleen and lungs of chickens up to 4 d post-treatment. This finding suggests that, in order to obtain depletion of macrophages in chickens for greater than 5 d, it is necessary to administer clodronate liposomes 4 d apart. The study also showed that 2 treatments of clodronate liposomes at 4-day intervals resulted in the depletion of macrophages for up to 10 d. The findings of the present study will encourage more precise studies to be done on the potential roles of macrophages in immune responses and in the pathogenesis of microbial infections in chickens.