Influence of gossypol from dietary cottonseed meal on haematology, reproductive steroids and tissue gossypol enantiomer concentrations in male rainbow trout (Oncorhynchus mykiss )

Abstract

Rainbow trout (Oncorhynchus mykiss) males were fed, during a 9‐month period, five experimental diets where fishmeal proteins were gradually replaced with cottonseed meal (CS) proteins (0, 25, 50, 75 and 100%; diets 1–5, respectively). This study was carried out to evaluate the action and tissue concentrations of gossypol. Growth performance of fish was not affected with the increasing levels of CS in the diets. Haemoglobin concentration and haematocrit significantly decreased in fish fed 100% CS compared with other dietary treatments. Gonadosomatic index, plasma sex steroids (testosterone, 11‐ketotestosterone and 17,20β‐dihydroxy‐4‐pregnen‐3‐one) and sperm characteristics (concentration, motility, protein concentration and lactate dehydrogenase activity) were not negatively affected by increasing levels of CS. For the first time, a comprehensive study of gossypol concentrations, total and (+) and (−)‐enantiomers, in several tissues (liver, blood plasma, spermatozoa and seminal plasma) was performed. The concentrations of both (+) and (−)‐enantiomers significantly increased with increasing levels of CS in the diet. The highest concentrations were found in the liver of fish fed diet 5 (185 ± 18 μg g−1). In blood plasma, the concentrations of total gossypol were 10 times lower than the one found in the liver, but 10 and 100 times higher than the concentrations in the spermatozoa and seminal plasma, respectively. In all tissues studied, the concentration of (+)‐enantiomer was higher than the (−)‐enantiomer. The ratio (−)‐enantiomer/total gossypol did not change significantly with the increasing levels of CS in the diet. The results of the present study indicate that CS can be used over a period of 9 months to replace fishmeal proteins completely without compromising growth and reproduction of rainbow trout males.

Effect of dietary cottonseed meal on growth performance, physiological response, and gossypol accumulation in pre-adult grass carp, Ctenopharyngodon idellus

“…The same growth performance and feed utilization were observed under these conditions as fi sh fed a complete FM diet during outdoor culture. Large rainbow trout (1.5 year old adults and broodstock) fed CM-containing feed for more than 9 months do not show depressed growth (Dabrowski et al, 2000;Blom et al, 2001;Rinchard et al, 2003;Lee et al, 2006). In contrast, lower growth was observed in both sexes of mature tilapia ( Oreochromis sp.)…”

“…The anti-nutritional eff ect of gossypol is not only determined by its toxicity but by its interaction with other nutrients. The ε-amino group of lysine combines with the reactive aldehyde group of gossypol to form a Schiff base, which lowers lysine bioavailability (Rinchard et al, 2003). Depressed growth was reported in juvenile and broodstock rainbow trout fed CM containing >300 μg/g and 463 μg/g free gossypol, respectively (Lee Herman, 1970;Blom et al, 2001;Rinchard et al, 2002).…”

Application of low-gossypol cottonseed meal in laying hens’ diet

“…We measured serum BUN and UA levels to evaluate kidney function and AST, ALT, ALB, and TP levels for liver function (Travlos et al, 1996). The liver is a main organ of FG metabolism (Rinchard et al, 2003) while the egg white proteins are continuously synthesized in the oviduct. We also assessed the kidney, liver, and oviduct structure by histopathological analysis.…”

Growth performance, haematological and serum biochemical profiles in rainbow trout (Oncorhynchus mykiss ) fed diets with varying levels of lupin (Lupinus albus ) meal

“…Rinchard et al. () fed rainbow trout for 9 months with feeds prepared using cottonseed pulp as replacement of fishmeal at increasing ratios of 0%, 25%, 50%, 75%, and 100%. At the end of the experiment, they found that the levels of haemoglobin and hematocrit significantly decreased as the proportion of plant protein in the diet increased.…”