Submitted to: Aquaculture America Conference
Publication Type: Abstract only
Publication Acceptance Date: 10/6/2004
Publication Date: 1/18/2005
Citation: Pasnik, D.J., Evans, J.J., Lim, C.E., Klesius, P.H., Yildirim, M., Barros, M.M., Peres, H., 2005. Plant-based diets containing anti-nutritional factors can cause tissue changes in channnel catfish ictalurus punctatus. Aquaculture America Conference. January 17-20, 2005. New Orleans, Louisiana. Interpretive Summary:
Technical Abstract: Both cottonseed meal (CSM) and soybean meal (SBM) are useful as protein sources in channel catfish feed. However, both also contain anti-nutritional factors (including free gossypol in CSM and trypsin inhibitors in SBM) that are potentially detrimental to fish if present in sufficient concentrations. We studied the effects of these factors by evaluating histopathologic changes in fingerling channel catfish (Ictalurus punctatus) fed diets containing various levels of CSM or SBM for 10-12 weeks. In one study, channel catfish were fed a basal purified diet supplemented with graded levels of gossypol from 0 to 1500 mg. Mild-to-severe histologic changes were seen in the all of the groups fed diets containing gossypol. Changes included significant hepatic glycogen deposition, pancreatic vacuolization, and pigmentation and congestion of the spleen and anterior kidney. Iron, which has been used successfully to counteract dietary gossypol toxicity in monogastric terrestrial animals, had no effect in reducing gossypol toxicity in channel catfish. Fish diets with 27.5% or 55% CSM with or without iron supplementation generally exhibited increased hepatic glycogen deposition, whereas those fish fed a diet in which all SBM was replaced by CSM had increased liver necrosis and pigment deposition in the liver and anterior kidney. Regardless of dietary CSM levels, supplementation of dietary iron had no effect on liver, spleen, or anterior kidney histology. Many of the harmful components of SBM are heat-labile, and thus the histopathologic effects of feeding heat-treated SBM were also evaluated. Fish were fed a diet containing commercial SBM, diets in which the commercial SBM replaced by non-heat-treated raw SBM, or diets in which commercial SBM replaced by raw SBM heated at 130°C for various amounts of time. Mild necrotic lesions were found in the gastric glands, pancreas, and liver, while moderate hepatic glycogen deposition was also observed in all the groups. Generally, the histologic effects appeared to be equivocal between all of the groups, and no abnormalities were noted in the proximal or distal intestines. These studies indicate that CSM and SBM can cause histologic changes in fingerling channel catfish, but compared to other species of fish, channel catfish appear to tolerate relatively high amounts of dietary anti-nutritional factors.