The effect of Ochratoxin A on antimicrobial polypeptide expression and resistance to water mold infection in channel catfish (Ictalurus punctatus)

Abstract

Mycotoxin contamination of agricultural commodities poses a serious risk to animal health, including aquaculture species. Ochratoxin A (OA) is the most immunotoxic ochratoxin, yet little is known about its effect on immune function in fish. Antimicrobial polypeptides (AMPPs) are one of the most potent, innate, host defense factors, yet very little is known about what types of chronic stressors affect their expression. Among the most prevalent and potent AMPPs in fish are histone-like proteins (HLPs). In this study, fish were fed 2, 4, or 8 mg OA/kg diet. Skin antibacterial activity and HLP-1 levels were measured on Days 0, 28 and 56. Feeding 2, 4 or 8 mg OA/kg diet resulted in significant growth depression, but higher levels (4 or 8 mg OA/kg diet) resulted in lowering feed intake (FI) and impaired feed conversion ratio. In addition, feeding 8 mg OA/kg diet increased susceptibility to experimental water mold (Saprolegnia) challenge, suggesting that OA toxicity might contribute to some saprolegnosis outbreaks. However, there were no changes in AMPP expression in any treatment group. Our data suggests that the increased disease susceptibility of channel catfish due to OA is probably due to mechanisms other than a direct effect on antimicrobial polypeptide expression.

Identification of potentially pathogenic bacteria from tilapia (Oreochromis niloticus) and channel catfish (Clarias batrachus) culture in Samarinda, East Kalimantan, Indonesia

“…is a bacteria that causes high mortality in fish cultured in Asia. Meanwhile, pathogenic bacteria were found in catfish including Escherichia coli (Zahran et al 2016), Staphylococcus aureus, Salmonella typhi, Pseudomonas aeruginosa, Vibrio cholera, and Shigella dysenteriae.…”

Toxicity of Ochratoxin to Early Life Stages of Zebrafish (Danio rerio)

“…Dietary exposure of channel catfish ( Ictalurus punctatus ) and sea bass ( Dicentrarchus labrax ) to OTA led to reduced weight gains, poorer feed conversion rates, lower survival and changes of haematocrit values [ 5 , 18 ] in these fish species but not in Atlantic salmon ( Salmo salar [ 19 ]). In addition, histopathological damage in the liver and posterior kidney and changes of immune parameters were observed in channel catfish [ 5 , 20 , 21 ]. Similar studies on Nile tilapia ( Oreochromis niloticus ) showed that increasing dietary OTA levels resulted in decreased growth, feed utilization and nutrient composition of the carcass [ 22 ].…”

Occurrence of Fungi and Fungal Toxins in Fish Feed during Storage

“…In temperate regions, OTA contamination is often linked to the occurrence of the Penicillium verrucosum infections, but it has been shown in warmer regions where the Aspergillus species, e.g., A. carbonarius, could also account for OTA production [3,18,19]. In addition, the ability of other Penicillium species to produce OTA has been reported in some studies or may have been based on possible incorrect identification of the P. cyclopium, P. viridicatum, and P. chrysogenum species [21,49]. However, P. chrysogenum was identified in sample 9 along with a small increase in OTA contamination after four weeks of treatment, which may indicate that some P. chrysogenum strains are capable of OTA formation.…”

“…Therefore, the OTA concentration in the feed at the start of the experiment was low. Higher OTA concentrations were observed in the feed samples of the 'warm & humid' treatment after four weeks, and the formation of OTA in samples 7 to 9 could be related to the detection of the Aspergillus and Penicillium species, which are generally known to be capable of OTA production [18][19][20][21]. However, the ability of the Aspergillus species to produce mycotoxins has been related to the activity of certain genes [52], and Aspergillus fumigatus is known to produce mycotoxins such as gliotoxin and fumagillin [53] with a currently unknown impact on fish.…”

“…The mycotoxins that are more likely to occur during food storage and in feed ingredients and compounded feeds often include aflatoxins and ochratoxins [11,12]. Ochratoxin A (OTA), which is often produced by Aspergillus and Penicillium species [13][14][15][16], is of major concern because it is known to have a detrimental impact on vertebrates, causing teratogenic, carcinogenic, and immune-modulative effects [3,[17][18][19][20][21]. However, further fungal species are also known to occur in feed ingredients and animal feeds.…”