Caitlin E. Older

• PhD
• Research Molecular Biologist at United States Department of Agriculture

Hybrid catfish (Ictalurus punctatus × I. furcatus) is the preferred catfish for United States aquaculture due to heterosis exhibited in many production traits. Improvements in fry production protocols have enabled widespread adoption of these hybrids, with producers using management practices optimized for channel catfish. Research to consider diff...

Background The innovations of the “Omics Era” have ushered in significant advancements in genetic improvement of agriculturally important animal species through transforming genetics, genomics and breeding strategies. These advancements were often coordinated, in part, by support provided over 30 years through the 1993–2023 National Research Suppor...

Piscine lactococcosis is a significant threat to cultured and wild fish populations worldwide. The disease typically presents as a per-acute to acute hemorrhagic septicemia causing high morbidity and mortality, recalcitrant to antimicrobial treatment or management interventions. Historically, the disease was attributed to the gram-positive pathogen...

Objective Bacterial community profiling in aquaculture can be useful for monitoring environmental conditions that may lead to disease outbreaks, understanding the impact of dietary treatments on fish health, and identifying microbes that have potential as probiotics. Microbiota characterization is commonly performed with high‐throughput sequencing...

Edwardsiella piscicida is an emerging bacterial pathogen and the aetiological agent of edwardsiellosis among cultured and wild fish species globally. The increased frequency of outbreaks of this Gram‐negative, facultative intracellular pathogen pose not only a threat to the aquaculture industry but also a possible foodborne/waterborne public health...

This study evaluated the supplementation of iron and copper nanoparticles in channel catfish diets and their influences on growth and health. A comparative feeding trial was carried out for 9 weeks to evaluate combinations of iron and copper nanoparticles: only iron nanoparticles (IronNP), only copper nanoparticles (CopperNP), CopperNP + IronNP, an...

With the emergence of diseases, the U.S. catfish industry is under challenge. Current trends prefer autochthonous bacteria as potential probiotic candidates owing to their adaptability and capacity to effectively colonize the host's intestine, which can enhance production performance and bolster disease resistance. The objective of this study was t...

EFFECTS OF AMMONIA STRESS ON THE GROWTH PERFORMANCE AND FILLET QUALITY OF CHANNEL AND HYBRID CATFISH EFFECTS OF AMMONIA STRESS ON THE GROWTH PERFORMANCE AND FILLET QUALITY OF CHANNEL AND HYBRID CATFISH Objectives: Cultivated catfish is the largest sector of the United States aquaculture industry. High concentration of ammonia in pond water is cau...

The microbiome field has grown significantly in the past decade, and published studies have provided an overview of the microorganisms inhabiting the skin of companion animals. With the continued growth and interest in this field, concerns have been raised regarding sample collection methods, reagent contamination, data processing and environmental...

Alternative protein ingredient Intestinal microbiota Brewers' yeast A B S T R A C T The use of corn fermented protein (CFP) can be a promising alternative ingredient to replace soybean meal (SBM) in aquafeeds, because of its attractive price and constant supply. In this study, the apparent digestibility of CFP was evaluated with channel catfish (Ic...

In the United States, catfish are primarily farmed in earthen ponds, resulting in an aquatic environment influenced both by management practices and natural ecological processes. Profiling pond water microbiota can be useful for understanding what conditions may lead to microbial communities associated with production issues and could inform manage...

Erysipelothrix spp., including E. rhusiopathiae, are zoonotic bacterial pathogens that can cause morbidity and mortality in mammals, fish, reptiles, birds, and humans. The southern sea otter (SSO; Enhydra lutris nereis) is a federally-listed threatened species for which infectious disease is a major cause of mortality. We estimated the frequency of...

Enteric septicemia of catfish (ESC), caused by the gram-negative enteric bacteria Edwardsiella ictaluri, is a significant threat to catfish aquaculture in the southeastern United States. Antibiotic intervention can reduce mortality; however, antibiotic use results in an imbalance, or dysbiosis, of the gut microbiota, which may increase susceptibili...

Practical relevance: As with other species, the skin microbiome of cats has been assessed over the past few years utilizing modern technologies. This has resulted in the identification of many more bacterial and fungal organisms compared with what had been recorded historically on the skin in various states of health and disease using culture-base...

Background Channel catfish and blue catfish are the most important aquacultured species in the USA. The species do not readily intermate naturally but F1 hybrids can be produced through artificial spawning. F1 hybrids produced by mating channel catfish female with blue catfish male exhibit heterosis and provide an ideal system to study reproductive...

In the present study, the potential synergism between beneficial lactic acid bacteria (Pediococcus acidilactici) contained in a probiotic and a mixture of fermentable complex carbohydrates and autolyzed brewer’s yeast (or prebiotic) were explored in red drum. Four experimental diets were formulated from practical ingredients, and the basal diet was...

The skin is the first layer of protection from the environment, preventing pathogens from entering the body. Although the skin is often considered to be a hostile microenvironment for microbes, numerous microbes have adapted and thrived as colonizers of the skin in different animal species. Several intrinsic and extrinsic factors can contribute to...

This study evaluated the production of two black soldier fly larval meals (BSFLMs) when rearing the larvae on brewers’ spent grains (BSFLM-B) or a commercially available substrate (BSFLM-C, Gainesville house fly diet). The resulting nutrient composition of the BSFLMs were significantly impacted by the feeding substrates, and they were evaluated as...

Background The pathogenesis of feline allergic dermatitis (FAD) is unclear, with several differences from allergic dermatitis in dogs and humans. Hypothesis/objectives To survey cytokine expression levels in healthy cats and cats affected with allergic dermatitis or asthma. Animals Formalin‐fixed, paraffin‐embedded skin biopsies from 22 cats with...

The objective of this study was to investigate possible effects of sodium butyrate and sodium propionate individually, and in combination, against common pathogenic bacteria and intestinal microbiota in vitro, and when supplemented in high-plant-protein diets for the carnivorous red drum. These organic acids (OA) presented synergistic effects when...

Background Persian cats are predisposed to chronic and severe dermatophytosis. Alterations to the cutaneous microbiota are one potential contributor to this predisposition. Objectives To characterise the cutaneous and environmental fungal microbiota of Persian cats with chronic, severe dermatophytosis, and to compare the fungal microbiota of cats...

History An 18-month-old 55.5-kg (122.0-lb) Dorper ewe with a 2-week history of dyspnea that progressed to open-mouthed breathing was presented to the Texas A&M University Veterinary Medical Teaching Hospital. The referring veterinarian had previously treated the ewe with ceftiofur sodium and flunixin meglumine without improvement in its condition.

Background Various Staphylococcus species have been demonstrated to play important roles on the skin, including causing disease and protecting the host from pathogens. Although culture‐based studies have isolated various Staphylococcus spp. from feline skin, very little is known regarding the species‐level communities on the host. Hypothesis/objec...

Although Staphylococcus pseudintermedius is considered the major pathogen associated with superficial canine pyoderma, no study has investigated the entire bacterial community in these lesions with molecular techniques. The objectives of this study were to characterize the bacterial microbiota in two forms of superficial canine pyoderma lesions, su...

Feline chronic gingivostomatitis (FCGS) has an unclear pathogenesis with the oral microbiome and viral infections, such as feline immunodeficiency virus (FIV), thought to contribute. Although the relationship between the FIV status and FCGS is not clear, one theory is FIV-induced immune dysregulation could contribute to oral dysbiosis, promoting FC...

Following treatment for pneumonia, a 1-y-old female Nubian goat was presented because of a persistent fever for 3 mo and peripheral lymphadenopathy for 1 mo. Cytology and histology of the superficial cervical and prefemoral lymph nodes demonstrated a moderate-to-marked “left-shifted” lymphoid population, suggestive of lymphoma, and extremely rare e...

Previous research revealed the feline skin bacterial microbiota to be site-specific and the fungal microbiota to be individual-specific. The effect of other factors, such as genotype and environment, have not yet been studied in cats, but have been shown to be potentially important in shaping the cutaneous microbiota of other animals. Therefore, th...

Background: The pathogenesis and treatment of cutaneous malodour in dogs have not been investigated previously. Staphylococcus and Corynebacterium spp. are associated with human axillary malodour. Hypothesis: Staphylococcus and Corynebacterium spp. are associated with cutaneous malodour in dogs, and treatment with a topical essential oil-based p...

Next generation sequencing (NGS) studies are revealing a diverse microbiota on the skin of dogs. The skin microbiota of canine sterile granulomatous and pyogranulomatous dermatitis (SGPD) has yet to be investigated using NGS techniques. NGS targeting the 16S rRNA and ITS-1 region of bacterial and fungal DNA, respectively, were used to investigate i...

This chapter characterizes the mycobiota of feline skin using next generation sequencing (NGS) and to determine whether alterations to the mycobiota exist in feline allergic skin diseases. It also identifies reduced diversity at mucosal sites and a predominance of Dothideomycetes (Cladosporium, Alternaria and Epiccocum) similar to what has been rep...

Background The skin is inhabited by a multitude of microorganisms. An imbalance of these microorganisms is associated with disease, however, the causal relationship between skin microbiota and disease remains unknown. To describe the cutaneous bacterial microbiota of cats and determine whether bacterial dysbiosis occurs on the skin of allergic cats...

Alpha diversity averages at 3100 sequences per sample for healthy cats. Values represent averages with standard deviations in parenthesis. Superscript letters represent sites that were significantly different according to Kruskal-Wallis tests with p<0.05. (DOCX)

R statistics for significant (R≥ 0.200, p≤0.05) pairwise comparisons. Shown R values are averages and p-values are ranges from pairwise comparisons. No significant pairwise comparisons in allergic samples with body site. (DOCX)

Global R statistics for beta diversity analysis. (DOCX)

Alpha diversity plots of the physiologies sampled in healthy cats. P-values are from Kruskal-Wallis tests. Lines indicate pairwise comparisons that resulted in significant p-values. (TIF)

Principal coordinate analysis plot of healthy vs. allergic ear canal. Principal coordinate analysis plot based on Bray-Curtis distance matrix comparing healthy and allergic ear canal samples. Healthy and allergic ear canal samples showed distinct clustering. (TIF)

LEfSe plots and cladograms comparing healthy and allergic samples at each body site. (TIF)

Filtered relative taxa abundances and results from Kruskal-Wallis tests for differential taxa abundance. P-values ≤ 0.05 are in bold. Median (Min-Max). (DOCX)

Hypersensitivity information (type, age of onset, seasonality, clinical signs, lesion distribution, ear problems, and treatments for ten allergic cats. Allergy treatments were concurrent. All cats with a Y in the steroids column had previously received steroids, except for F14 and F15 that were receiving steroids at the time of sampling. F18 was di...

Principal coordinate analysis plots of Weighted UniFrac distance matrices of healthy cat samples by A. individual cat and B. physiology. (TIF)

Average relative taxa abundances in the reproductive samples from healthy cats. (TIF)

LEfSe plots and cladograms from allergic cat samples. (TIF)

Identification of fungal organisms often poses a problem for pathologists because the histomorphology of some fungal organisms is not specific, fresh tissues may not be available, and isolation and identification in culture may take a long time. The purpose of this study was to validate the use of panfungal polymerase chain reaction (PCR) to identi...

Background: Next generation sequencing (NGS) studies have demonstrated a diverse skin-associated microbiota and microbial dysbiosis associated with atopic dermatitis in people and in dogs. The skin of cats has yet to be investigated using NGS techniques. Hypothesis/objectives: We hypothesized that the fungal microbiota of healthy feline skin wou...

To characterize the skin-associated fungal microbiota (mycobiota) in dogs, and to evaluate the influence of body site, individual dog or health status on the distribution of fungi, next-generation sequencing was performed targeting the internal transcribed spacer region. Ten dogs with no history of skin disease were sampled at ten distinct body sit...