Abstract:
The histopathologic effects of feeding heat-treated soybean
meal to fingerling channel catfish (Ictalurus punctatus) were
studied. Fish were fed one of six diets: a diet containing
450 g kg)1 commercial soybean meal (CSBM), or diets with
the CSBM replaced by non-heat-treated raw soybean meal
(RSBM0), or RSBM heated at 130 C for 5 min (RSBM5),
10 min (RSBM10), 20 min (RSBM20) or 40 min (RSBM40).
After 10 weeks, tissue samples were taken from the stomach,
proximal intestine, distal intestine, liver, pancreas and spleen
from fish in each group for histologic examination. Mild
necrotic lesions were found in the gastric glands, pancreas
and liver of fish in all the groups (treatment and control
groups). Hepatic glycogen deposition was also observed in all
the groups, and the spleen samples exhibited considerable
brownish-black pigment deposition around the splenic corpuscles
and diffuse mild-to-moderate congestion in all of the
groups. Generally, these histologic effects appeared to be
equivocal between all of the groups, and no abnormalities
were noted in the proximal or distal intestine. These findings
suggest that feeding channel catfish a diet containing
450 g kg)1 non-heat-treated RSBM did not cause severe
histologic changes associated with soybean meal anti-nutritional
factors as have been reported in salmonids.