Response of common carp fry fed diets containing a pea seed meal (Pisum sativum) subjected to different thermal processing methods

Three forms of pea seed meal (native - NAT Diet, autoclaved - AC Diet and dry cooked - DC Diet) were evaluated in balanced diets for common carp fry (Cyprinus carpio L.) replacing solvent extracted soybean meal protein in a fish meal / soybean meal based control diet (CTR Diet).After a 49- day growth trial, weight gain, feed conversion ratio, protein efficiency ratio and apparent net nitrogen utilization of fish fed the fish meal / soybean meal diet (CTR Diet) and of that fed the pea seed meal subjected to different thermal treatments were determined. Significant differences (P < 0.05) were found in the mean final weight (MFW) and specific growth rates (SGR) between fish fed the CTR and NAT Diets (i.e., mean final weight: 30.69 and 25.70 g, respectively; SGR: 2.84 and 2.51 g, respectively). The mean final weight of carp fed the autoclaved pea seed meal diet (MFW 28.40 g, AC Diet) and the group fed the dry cooked pea seed meal diet (MFW 29.34 g, DC Diet) were not deemed significantly (P > 0.05) different to those of carp fed the fish meal / soybean meal control diet.A sequential digestibility study was also undertaken to complement the growth trial. Apparent nutrient and energy digestibility coefficients (ADCs) reflected a similar trend as results in the first trial. Apparent nutrient and energy digestibility coefficients were found to be highest when fish were fed the CTR Diet. Apparent digestibility coefficients of carp fed the AC and DC Diets were generally higher than that of the NAT Diet. Overall, ADC's of fish fed the DC Diet were generally higher than that of the AC Diet.It can be concluded that thermal treatment can nutritionally modify pea seed meal to some extent: the dry heating treatment proved to be slightly more effective than the moist heat treatment in terms of growth performance, feed utilization efficiency and apparent digestibility in common carp.