Feeding Grass Hay Before Concentrate Mitigates the Effect of Grain-Based Concentrates on Postprandial Plasma Interleukin-1β

Monoclonal antibodies for equine IL-1β enable the quantification of mature IL-1β in horses

Interleukin-1β (IL-1β) is one of the key mediators of inflammation during innate immune responses. Mature bioactive IL-1β mediates essential host defense mechanisms but also has a mechanistic role in several autoinflammatory and degenerative diseases. In horses, specific and sensitive assays for IL-1β are crucial for immunological research on inflammatory processes and diseases. In this article, we describe the development of four monoclonal antibodies (mAbs) against equine IL-1β. The specificity of the new IL-1β mAbs was confirmed using a panel of equine recombinant cytokines and chemokines. The mAbs were validated for detection of native mature IL-1β in a fluorescent bead-based assay and for staining of IL-1β-producing immune cells by flow cytometry. The bead-based assay for equine IL-1β had a linear quantification range between 60 pg/ml to 960 ng/ml. Horse peripheral blood mononuclear cells (PBMC) secreted IL-1β after lipopolysaccharide (LPS) stimulation in time and dose dependent manner as quantified by the new equine IL-1β bead-based assay. A comparison of two commercial equine IL-1β ELISA kits with the new IL-1β fluorescent bead-based assay revealed that the bead-based assay improved the quantification of native equine IL-1β in LPS stimulated PBMC supernatants by detecting it with high intensity and a broad linear quantification range, while both ELISAs resulted in low signals and poor native IL-1β recognition. Intracellular staining and flow cytometric analysis confirmed that the main cellular source of IL-1β in equine PBMC after LPS stimulation were CD14+ monocytes. IL-1β secretion from PBMC was inhibited by a caspase inhibitor but protein translation within the cells was not, supporting the accumulation of pro-IL-1β within the cells even when proteolytic cleavage for IL-1β activation is missing. This confirmed the importance of specific mAbs for analyzing the biologically active, mature IL-1β in horses.

Chronic Progressive Lymphedema in Belgian Draft Horses: Understanding and Managing a Challenging Disease

Chronic progressive lymphedema (CPL) in draft horses is characterized by increased dermal thickness and fibrosis, with the development of skinfolds and nodules, hyperkeratosis, and ulcerations on the distal limbs of affected horses. Secondary bacterial, fungal, or parasitic infections frequently complicate and aggravate the lesions, as well as the progression of this disease. CPL has a particularly high prevalence of up to 85.86% in the Belgian draft horse breed. Due to the disease's progressive and incurable nature, affected horses are often euthanized prematurely. The treatment options are solely symptomatic, aimed at improving the horse's quality of life. Despite the severity of this condition, many uncertainties about its etiology and pathogenesis still remain to date. The established scientific research on CPL is rather limited, although there is an urgent need for strategies to tackle this disease. This review summarizes the available knowledge, serving as a guideline for practitioners, and provides perspectives for future research programs.

Targeting the Hindgut to Improve Health and Performance in Cattle

An adequate gastrointestinal barrier function is essential to preserve animal health and well-being. Suboptimal gut health results in the translocation of contents from the gastrointestinal lumen across the epithelium, inducing local and systemic inflammatory responses. Inflammation is characterized by high energetic and nutrient requirements, which diverts resources away from production. Further, barrier function defects and inflammation have been both associated with several metabolic diseases in dairy cattle and liver abscesses in feedlots. The gastrointestinal tract is sensitive to several factors intrinsic to the productive cycles of dairy and beef cattle. Among them, high grain diets, commonly fed to support lactation and growth, are potentially detrimental for rumen health due to their increased fermentability, representing the main risk factor for the development of acidosis. Furthermore, the increase in dietary starch associated with such rations frequently results in an increase in the bypass fraction reaching distal sections of the intestine. The effects of high grain diets in the hindgut are comparable to those in the rumen and, thus, hindgut acidosis likely plays a role in grain overload syndrome. However, the relative contribution of the hindgut to this syndrome remains unknown. Nutritional strategies designed to support hindgut health might represent an opportunity to sustain health and performance in bovines.