Processed feed pea and canola meal for blue shrimp diets

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98 Table 6 Apparent dry matter, protein and NFE digestibility in diets and ingredients, adjusted for losses by leaching before ingestion, and corresponding energy contents in pea and canola meals Ž mean of four replicate values"standard deviation. 1 WRA 2 WEX 3 DRA 4 DEX 5 WMI 6 CEX 8 Ref. pea 9 Ref. Canola ANOV Prob. Diet digestibility (%), adjusted ADMD 76.6"2.1 b 77.7"1.3 b 76.1"2.2 ab 77.8"1.0 b 73.8"3.0 ab 74.1"3.6 ab 72.5"2.5 a 73.9"2.3 ab 0.027 APD 87.3"1.1 ab 89.3"1.2 b 89.1"1.5 b 88.2"0.8 ab 87.7"2.7 ab 89.5"2.4 b 85.5"2.8 a 88.8"1.3 b 0.09 ANFED 73.9"3.8 cd 77.8"2.2 d 70.4"4.0 bc 74.9"2.0 cd 69.4"4.6 bc 71.1"6.6 bcd 62.1"4.5 a 67.0"4.3 ab 0.09 Ingredient digestibility (%), adjusted IADMD 86.5"6.9 ab 90.1"4.4 b 84.7"7.4 ab 90.4"3.3 b 77.0"10.0 a 74.4"12.1 a 0.045 IAPD 77.1"5.7 87.2"6.1 86.3"7.0 82.2"3.9 79.0"13.8 79.0"6.5 0.371 IANFED 99.1"8.6 101.4"5.0 87.4"8.9 96.8"4.5 85.5"10.5 100.5"26.9 0.671 Ingredient energy content ( kJr g) 1 ME 15.6"1.2 2 16.2"0.8 15.4"1.3 16.4"0.6 14.0"1.8 2 14.2"2.2 0.307 3 DE 15.9"1.3 2 16.6"0.8 15.8"1.3 16.8"0.6 14.3"1.9 2 14.8"2.2 0.383 Different letters in same raw indicate different homogeneous subsets Ž Duncan 0.05% .. 1 Metabolizable energy was calculated as described in material and methods by assigning average productive values Ž Cuzon and Guillaume, 1997. to the digestible nutrient contents as calculated with adjusted digestibility coefficients for protein and NFE. 2 Although IANFEDadj. was calculated at 101.2% for WEX and 100.5 for CEX, we used a 100% value for the calculations of metabolizable and digestible energy contents. 3 Digestible energy was calculated by assigning gross energy values Ž Tacon, 1987. to the digestible nutrient contents, adjusted for leaching: DE kJrgsŽ23.4= wprotein x =IAPDadj. . qŽ39.7= wlipid x =0.90. qŽ17.2= wNFE x =IANFEDadj. .. L.E. Cruz-Suarez et al.rAquaculture 196 ( 2001 ) 87–104
( ) L.E. Cruz-Suarez et al.rAquaculture 196 2001 87–104 99 3.4. Analysis of the effects of dehulling and extrusion Factorial ANOVA of the results for diets 1, 2, 3 and 4 showed that the effects from extrusion were generally higher than from dehulling. No significant effects on performance were observed as a result of dehulling, although a higher feed consumption and lower PER approached significance Ž Ps0.121 and Ps0.073, respectively .. Extrusion reduced feed intake Ž P-0.001 ., improved feed conversion Ž Ps0.009 ., increased PER Ž Ps0.006. and tended to improve dry matter digestibility of peas Ž Ps0.192 .. Extrusion had no effect on growth Ž Ps0.44 ., survival Ž Ps1. and protein digestibility Ž Ps0.751 .. These results again can be explained by improved digestibility of gelatinized over native starch. 4. Discussion The impact of dry matter and protein losses due to leaching before ingestion has been evaluated through the calculation of corrected values, which take into account the losses that occurred in the diets after 1 h. This simple correction seems justified by considering that most of the losses occur during the first hour of immersion ŽRomero-Alvarez, 1995 ., and that the average interval time of feed consumed was generally noted to be approximately 1 h after offering the feed. Corrected values showed the same relative positions as standard values, even in the case of the WEX treatment, which stability in water was significantly better than that of other diets. The corrected values are of interest because they indicate the true biological values of feed intake, conversion ratio and PER as a more accurate measurement of the crustacean’s metabolic response to the dietary treatments. They also allowed a truer estimation of the carbohydrate digestibility of the experimental ingredients. The uncorrected values on the other hand reflect the results of a practical significance, which can be compared with other studies using standard calculations. The results of this study show that raw peas, and peas processed by dehulling, extruding and micronizing, have a nutritional value similar to that of a mixture Ž 1:3. of soybean meal and wheat flour Ž 80% hard–20% soft varieties, Table 2. in shrimp diets. Also, substituting a portion of the soybean meal, fish meal and wheat Ž1:2:3 parts, respectively. with extruded canola meal did not affect shrimp performance. Our results corroborate the reports by other authors cited in the introduction that pea seed meal and canola meal can be successfully included in practical aquaculture feeds. When alternate plant origin ingredients are used in diets containing the same concentration of digestible energy and digestible protein, and meeting nutrient requirements, similar performance can be expected. However, Gomes et al. Ž 1995. found that voluntary food intake of trout fed diets including coextruded peas and canola was depressed due to inherent factors present in the plant ingredients Ž Novoa and Castillo, 1998 .. Therefore, similar growth was not obtained. In the present study, no adverse response to raw whole peas was observed. Studies with trout Ž Kaushik et al., 1993. and European sea bass ŽGouveia and Davies, 2000. have emphasized the requirement for dehulling and extrusion cooking under conditions that would be more severe than they would during complete feed
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Page 9 and 10: Table 4 Growth experiment results
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Processed feed pea and canola meal for blue shrimp diets

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