Processed feed pea and canola meal for blue shrimp diets
Processed feed pea and canola meal for blue shrimp diets
Processed feed pea and canola meal for blue shrimp diets
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Ž .<br />
Aquaculture 196 2001 87–104<br />
www.elsevier.nlrlocateraqua-online<br />
Assessment of differently processed <strong>feed</strong> <strong>pea</strong><br />
ž Pisum satiÕum/ <strong>meal</strong>s <strong>and</strong> <strong>canola</strong> <strong>meal</strong> žBrassica<br />
sp. / in <strong>diets</strong> <strong>for</strong> <strong>blue</strong> <strong>shrimp</strong> žLitopenaeus<br />
stylirostris/<br />
L. Elizabeth Cruz-Suarez a , Denis Ricque-Marie a,) ,<br />
Mireya Tapia-Salazar a , Ian M. McCallum b , David Hickling c<br />
a Programa Maricultura, Facultad de Ciencias Biologicas, ´ UniÕersidad Autonoma ´ de NueÕo Leon, ´<br />
Cd. UniÕersitaria Apdo. Postal F-56, San Nicolas de los Garza, NueÕo Leon ´ 66450, Monterrey, Mexico<br />
b Pulse Canada, 330-360 Main Street, Winnipeg, Manitoba, Canada R3C 3Z3<br />
c Canadian International Grains Institute. 1000-303 Main St., Winnipeg, Manitoba, Canada R3C 3G7<br />
Received 8 June 2000; received in revised <strong>for</strong>m 3 November 2000; accepted 6 November 2000<br />
Abstract<br />
The nutritional value of whole, dehulled, extruded, dehulled–extruded <strong>and</strong> micronized <strong>feed</strong><br />
<strong>pea</strong>s, <strong>and</strong> extruded <strong>canola</strong> <strong>meal</strong>, included at a 30% concentration as ingredients in <strong>diets</strong> <strong>for</strong><br />
juvenile <strong>blue</strong> <strong>shrimp</strong> was assessed. Pea <strong>meal</strong>s replaced a portion of soybean <strong>meal</strong> <strong>and</strong> wheat Ž1:3<br />
parts.<br />
on an isonitrogenous <strong>and</strong> isoenergetic basis, <strong>and</strong> similarly extruded <strong>canola</strong> <strong>meal</strong> replaced a<br />
portion of soybean <strong>meal</strong>, fish <strong>meal</strong> <strong>and</strong> wheat Ž 1:2:3 parts.<br />
of a control diet. After 28 days, the<br />
<strong>shrimp</strong> almost tripled their weight on the experimental <strong>diets</strong>. Per<strong>for</strong>mance was unaffected by<br />
dehulling, except <strong>for</strong> a slight increase in <strong>feed</strong> consumption <strong>and</strong> lower protein efficiency ratio<br />
Ž PER .. Extrusion cooking had no effect on growth <strong>and</strong> survival but significantly improved <strong>feed</strong><br />
conversion <strong>and</strong> PER. The micronized <strong>pea</strong> diet produced the highest <strong>feed</strong> intake <strong>and</strong> growth rate.<br />
Response to the diet containing extruded <strong>canola</strong> <strong>meal</strong> was similar to that of the control diet.<br />
Ingredient apparent dry matter digestibility Ž IADMD.<br />
ranged from 80.7% <strong>for</strong> micronized <strong>pea</strong>s to<br />
92.4% <strong>for</strong> dehulled–extruded <strong>pea</strong>s, <strong>and</strong> was 79.4% <strong>for</strong> extruded <strong>canola</strong> <strong>meal</strong>. Higher IADMD<br />
coefficients were obtained <strong>for</strong> extruded <strong>pea</strong> <strong>meal</strong>s as a result of starch gelatinization. Ingredient<br />
apparent protein digestibility Ž IAPD.<br />
ranged from 79.1% to 85.4% <strong>and</strong> did not differ significantly<br />
amongst the test <strong>meal</strong>s. The test ingredients also conferred differential water stability properties<br />
with the whole-extruded <strong>pea</strong>s ingredient containing diet having the lowest dry matter <strong>and</strong> crude<br />
) Corresponding author. Tel.: q52-8-3526-380; fax: q52-8-3526-380.<br />
Ž .<br />
E-mail address: lucruz@ccr.dsi.uanl.mx D. Ricque-Marie .<br />
0044-8486r01r$ - see front matter q 2001 Elsevier Science B.V. All rights reserved.<br />
Ž .<br />
PII: S0044-8486 00 00572-X
88<br />
( )<br />
L.E. Cruz-Suarez et al.rAquaculture 196 2001 87–104<br />
Ž .<br />
protein CP loss following a 1-h immersion in water. This study showed that whole raw <strong>feed</strong> <strong>pea</strong><br />
is a very acceptable ingredient <strong>for</strong> <strong>blue</strong> <strong>shrimp</strong> <strong>diets</strong>; extrusion cooking improved <strong>feed</strong> conversion<br />
ratio <strong>and</strong> PER, <strong>and</strong> micronizing <strong>pea</strong>s enhanced <strong>feed</strong> intake, while dehulling had no effect. q 2001<br />
Elsevier Science B.V. All rights reserved.<br />
Keywords: Crustacean; Nutrition; Growth; Digestibility; Peas; Canola<br />
1. Introduction<br />
Recent reports have described grain legumes or pulses, such as field <strong>pea</strong>s as potential<br />
ingredients <strong>for</strong> aquaculture <strong>feed</strong>s ŽAllan, 1998; Novoa <strong>and</strong> Castillo, 1998; Allan et al.,<br />
1999a; Booth et al., 1999 .. Some reports have indicated that <strong>pea</strong> <strong>meal</strong> is an acceptable<br />
ingredient in <strong>diets</strong> <strong>for</strong> rainbow trout ŽKaushik et al., 1993; Gomes et al., 1993, 1995;<br />
Burel et al., 1996 ., tilapia Ž Fontainhes-Fern<strong>and</strong>es et al., 1997 ., silver perch ŽAllan, 1997;<br />
Allan et al., 1999b; Booth et al., 1999 ., tiger <strong>shrimp</strong> Ž Smith et al., 1999.<br />
<strong>and</strong> Euro<strong>pea</strong>n<br />
sea bass Ž Santos <strong>and</strong> Gomes, 1997; Gouveia <strong>and</strong> Davies, 1998, 2000 .. Peas offer<br />
flexibility in <strong>feed</strong>stuff selection to the <strong>feed</strong> manufacturer as they may replace both grain<br />
Ž e.g., maize corn, wheat. <strong>and</strong> protein Ž e.g., soybean <strong>meal</strong> <strong>and</strong> fish <strong>meal</strong>.<br />
but their use has<br />
been limited due to concerns about the presence of anti-nutritional factors ŽTacon,<br />
1997 .. Studies with rainbow trout have shown that prior heat treatment was necessary to<br />
improve digestibility <strong>and</strong> possibly inactivate anti-nutritional factors ŽKaushik et al.,<br />
1993; Pfeffer et al., 1995 .. Feed <strong>pea</strong>s, the designation <strong>for</strong> the round shaped, low tannin<br />
varieties of Pisum satiÕum, are a major pulse crop marketed extensively in Europe <strong>and</strong><br />
Canada as a source of carbohydrate, mainly starch, <strong>and</strong> protein <strong>for</strong> livestock <strong>feed</strong>s<br />
Ž UNIP-ITCF, 1995 .. As a result of plant breeding, several anti-nutritional factors in <strong>feed</strong><br />
<strong>pea</strong>s including tannins <strong>and</strong> anti-trypsins, have been eliminated or substantially reduced<br />
Ž Castell et al., 1996 ..<br />
Starches are low cost sources of dietary energy <strong>and</strong> are generally well utilized by<br />
<strong>shrimp</strong> Ž Catacutan, 1991; Shiau <strong>and</strong> Peng, 1992; Cruz-Suarez ´ et al., 1994 .. Thermal<br />
processing to gelatinize starch increased its digestibility in <strong>diets</strong> fed to Litopenaeus<br />
Õannamei Ž Davis <strong>and</strong> Arnold, 1993; Cousin et al., 1996 .. However, extrusion conditions<br />
Ž none, wet or dry.<br />
differentially affected energy digestibility coefficients of cereal grains<br />
Ž Davis <strong>and</strong> Arnold, 1995 .. Dehulled <strong>pea</strong>s had higher apparent digestibility coefficients<br />
<strong>for</strong> energy, crude protein Ž CP.<br />
<strong>and</strong> essential amino acids than whole <strong>pea</strong>s when included<br />
in <strong>for</strong>mulated <strong>diets</strong> fed to silver perch Allan Ž 1997 .. Dehulling has also been shown to<br />
improve the nutritional value of leguminous seeds as ingredients in <strong>diets</strong> <strong>for</strong> Penaeus<br />
monodon Ž Eusebio, 1991 ..<br />
Canola <strong>meal</strong> is a particularly rich plant source of sulphur containing amino acids <strong>for</strong><br />
fish <strong>diets</strong> Ž Higgs et al., 1995.<br />
but its potential value as an ingredient in <strong>shrimp</strong> <strong>feed</strong> has<br />
received little attention Ž Buchanan et al., 1997 .. Extrusion processing has also been<br />
shown to improve the nutritive value of <strong>canola</strong> <strong>meal</strong> Ž Satoh et al., 1998 ..<br />
The objective of the present study was to assess growth, nutrient utilization, survival<br />
<strong>and</strong> digestibility in <strong>blue</strong> <strong>shrimp</strong> fed whole, dehulled, extrusion cooked <strong>and</strong> micronized<br />
<strong>feed</strong> <strong>pea</strong>s, <strong>and</strong> extruded <strong>canola</strong> <strong>meal</strong>, <strong>and</strong> held under laboratory conditions.
2. Material <strong>and</strong> methods<br />
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L.E. Cruz-Suarez et al.rAquaculture 196 2001 87–104 89<br />
2.1. Diets<br />
A lot of commercial dry <strong>pea</strong>s P. satiÕum composed of mixed Canadian prairie<br />
varieties was processed to prepare the respective <strong>meal</strong>s. Whole <strong>and</strong> dehulled <strong>pea</strong>s were<br />
pin-milled to produce raw flours, WRA <strong>and</strong> DRA, respectively. Portions of these flours<br />
were preconditioned Ž Wenger model 2 DDC.<br />
<strong>and</strong> extruded with a co-rotating twin screw<br />
extruder Ž Werner <strong>and</strong> Pfleiderer ZSK-57.<br />
through 1r4 in. round hole dies at a product<br />
temperature reaching 1458C at the die plate, <strong>and</strong> pressure ranging between 620 <strong>and</strong> 740<br />
psi. The extruder screw was 147 cm long with a lengthrdiameter ratio of 24:1. The<br />
material was fed into the conditioner at a rate of 90.9, 93.6 <strong>and</strong> 113.6 kgrh <strong>for</strong> whole<br />
<strong>pea</strong>s, dehulled <strong>pea</strong>s <strong>and</strong> <strong>canola</strong> <strong>meal</strong>, respectively, <strong>and</strong> water was injected at a rate of 4.5<br />
lrh. The material was then dried in a fluid bed dryer at 1108C <strong>and</strong> pin milled to produce<br />
whole <strong>and</strong> dehulled extruded <strong>meal</strong>s Ž WEX <strong>and</strong> DEX, respectively .. Commercial <strong>canola</strong><br />
<strong>meal</strong> was similarly extruded <strong>and</strong> ground Ž CEX .. Another portion of whole <strong>pea</strong>s was<br />
tempered to 14% moisture <strong>and</strong> processed using infrared cooking, reaching a temperature<br />
of 1208C. The heat-treated Ž micronized.<br />
<strong>pea</strong>s were subsequently rolled to produce a<br />
flake <strong>and</strong> then milled into a fine powder Ž WMI .. The proximate composition <strong>and</strong> effects<br />
of heat treatment on starch gelatinization in the <strong>pea</strong> <strong>meal</strong>s are presented in Table 1.<br />
Isonitrogenous <strong>and</strong> isoenergetic Ž gross energy.<br />
experimental <strong>diets</strong> <strong>for</strong> the growth trial<br />
were <strong>for</strong>mulated to contain 30% of the test <strong>meal</strong>s, <strong>and</strong> to meet the nutrient requirements<br />
Ž Akiyama et al., 1991. with proteinrenergy ratios Ž Cruz-Suarez ´ et al., 2000.<br />
recommended<br />
<strong>for</strong> <strong>shrimp</strong> Ž Table 2 .. The test <strong>pea</strong> <strong>meal</strong>s were included in the experimental <strong>diets</strong><br />
1 to 5 to replace a portion of a soybean <strong>meal</strong> <strong>and</strong> wheat flour mix Ž1:3 parts,<br />
respectively.<br />
in the practical control diet 7. In test diet 6, extruded <strong>canola</strong> <strong>meal</strong> replaced<br />
a portion of soybean <strong>meal</strong>, fish <strong>meal</strong> <strong>and</strong> wheat Ž 1:2:3 parts, respectively ..<br />
Table 1<br />
Proximate analysis of the test ingredients, <strong>and</strong> degree of gelatinization in <strong>pea</strong> starch be<strong>for</strong>e <strong>feed</strong> manufacture<br />
Ingredients Whole Whole Dehulled Dehulled Whole Canola<br />
<strong>pea</strong>s <strong>pea</strong>s <strong>pea</strong>s <strong>pea</strong>s <strong>pea</strong>s <strong>meal</strong><br />
Process raw extruded raw extruded micronized extruded<br />
Ž WRA. Ž WEX. Ž DRA. Ž DEX. Ž WMI. Ž CEX.<br />
Moisture 7.5 8.0 7.9 8.3 6.5 5.7<br />
1<br />
Protein 21.3 21.8 23.7 23.3 21.1 39.4<br />
1<br />
Lipid 1.4 1.6 1.4 1.6 1.5 4.1<br />
1<br />
Ash 3.0 3.0 3.1 3.1 3.2 7.8<br />
1<br />
Crude fiber 6.3 6.5 1.5 1.6 7.2 13.3<br />
1<br />
NFE 67.9 67.2 70.3 70.5 67.1 35.5<br />
2<br />
Gelatinisation 52 389 70 437 66 –<br />
Ž mg glurg.<br />
1 % of the dry matter, NFEsnitrogen free extract, calculated by difference.<br />
2 mg glucose released per g sample by digestion with amyloglucosidase.
90<br />
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L.E. Cruz-Suarez et al.rAquaculture 196 2001 87–104<br />
Table 2<br />
Composition of the experimental <strong>diets</strong> Ž % as fed.<br />
Diets 1 WRA 2 WEX 3 DRA 4 DEX 5 WMI 6 CEX 7 Growth 8 9<br />
control Digestibility <strong>diets</strong><br />
Pea Canola<br />
<strong>meal</strong>s <strong>meal</strong><br />
1<br />
Soybean <strong>meal</strong> 7.5 7.5 7.5 7.5 7.5 10 15 10.73 14.35<br />
2<br />
Wheat flour 22.5 22.5 22.5 22.5 22.5 30 45 32.20 43.04<br />
WRA 30<br />
WEX 30<br />
DRA 30<br />
DEX 30<br />
WMI 30<br />
CEX 30<br />
3<br />
Fish<strong>meal</strong> 23.26 23.26 23.26 23.26 23.26 13.26 23.26 33.47 19.00<br />
4<br />
Shrimp <strong>meal</strong> 4 4 4 4 4 4 4 5.74 5.74<br />
Fish oil 1.84 1.84 1.84 1.84 1.84 1.84 1.84 2.65 2.65<br />
Soybean lecithin 4.24 4.24 4.24 4.24 4.24 4.24 4.24 6.08 6.08<br />
Sodium alginate 3 3 3 3 3 3 3 4.31 4.31<br />
Sodium 1 1 1 1 1 1 1 1.43 1.44<br />
hexametaphosphate<br />
5<br />
FP attractant 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.72 0.72<br />
6<br />
Stable vitamin C 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.1 0.1<br />
7<br />
Mineral mix 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.36 0.36<br />
8<br />
Vitamin mix 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.36 0.36<br />
Choline chloride 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.06 0.06<br />
Mold inhibitor 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.07 0.07<br />
Antioxidant 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.07 0.07<br />
Ž ethoxiquin.<br />
Chromic oxide 1 1 1 1 1 1 1 1 1<br />
Methionine 0.14 0.14 0.14 0.14 0.14 0.14 0.14 0.21 0.21<br />
Cholesterol 0.31 0.31 0.31 0.31 0.31 0.31 0.31 0.44 0.44<br />
TOTAL 100 100 100 100 100 100 100 100 100<br />
1<br />
Dehulled soybean <strong>meal</strong>, solvent extracted, 46.3% crude protein as fed Ž CP ..<br />
2<br />
Wheat flour Ž ws330 ., made of 80% hard wheat Ž Canada Western Red Spring principally.<br />
<strong>and</strong> 20% soft<br />
wheat Ž Canada Eastern Red Wheat 60% <strong>and</strong> Canada Prairie Spring Red 40% ., 12.3% CP.<br />
3 Chilean jack-mackerel fish <strong>meal</strong>, 67.6% CP.<br />
4 Chilean pelagic <strong>shrimp</strong> <strong>meal</strong>, 39.3% CP.<br />
5<br />
Flavor Pack Ž INVE, Belgium ..<br />
6<br />
Stay-C Ž L-ascorbyl-2-polyphospate, 35% active C ., Roche Vitamins.<br />
7 Mineral mixture composition: Co, 2000 mgrkg; Mn, 16,000 mgrkg; Zn, 40,000 mgrkg; Cu, 20,000<br />
mgrkg; Fe, 1 mgrkg; Se, 100 mgrkg; I, 2000 mgrkg.<br />
8 Vitamin mixture composition: Vit. A, 4000 IUrg; B1, 24,000 mgrkg; B2, 16,000 mgrkg; DL Ca<br />
pantotenate, 30,000 mgrkg; B6, 30,000 mgrkg; B12, 80 mgrkg; C, 60,000 mgrkg; K3, 16,000 mgrkg; D3,<br />
3200 IUrg; E, 60,000 mgrkg; H, 400 mgrkg; niacin, 20,000 mgrkg; folic acid, 4000 mgrkg.<br />
The main ingredients were ground Ž Pulvex 200.<br />
through a a35 screen. The dry<br />
ingredients were mixed <strong>and</strong> water added to facilitate pelleting through a butchers grinder<br />
Ž Tor-rey.<br />
equipped with 1.6-mm hole diameter die. The pellets were dried in a<br />
convection oven at 1008C <strong>for</strong> 8 min, allowed to cool <strong>and</strong> stored at 48C.
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L.E. Cruz-Suarez et al.rAquaculture 196 2001 87–104 91<br />
2.2. Chemical analysis <strong>and</strong> water stability tests<br />
Proximate analysis of ingredients <strong>and</strong> <strong>diets</strong> were determined according to the<br />
following procedures: crude proteinCP Ž Tecator, 1987 ., moisture ŽA.O.A.C., 1990, No.<br />
929.36 ., ash Ž A.O.A.C., 1990, No. 942.05 ., lipid Ž Tecator, 1983.<br />
<strong>and</strong> crude fiber<br />
Ž A.O.A.C., 1990, No. 962.09 .. The gelatinization of starch that resulted from the<br />
processing of the <strong>pea</strong>s was measured as glucose released by digestion with amyloglucosidase<br />
Ž Bjork et al., 1987 ..<br />
Water stability tests, replicated five times per diet, were per<strong>for</strong>med with synthetic<br />
marine water at a salinity of 34‰ <strong>and</strong> temperature between 288C <strong>and</strong> 298C according to<br />
the method of Aquacop Ž 1978 .. Five-gram samples of the pellets Žspaghetti-like str<strong>and</strong>s,<br />
1.6-mm diameter <strong>and</strong> approximately 1-cm length.<br />
were gently shaken in wire-mesh<br />
baskets submersed in seawater <strong>for</strong> 1 h, in order to simulate the conditions on the bottom<br />
of the experimental tanks. The percent dry matter loss Ž %DML.<br />
was calculated as:<br />
%DMLs100= Ž DWdyDWwid.<br />
rDWd; where DWd <strong>and</strong> DWwid are the dry matter<br />
weights in the diet be<strong>for</strong>e <strong>and</strong> after immersion, respectively. The percent crude protein<br />
loss Ž %CPL. was calculated as follows: %CPLsŽ100=CPdyŽ 100yDML . =<br />
CPwid. rCPd; where CPd <strong>and</strong> CPwid are the crude protein concentrations Ž% of dry<br />
matter.<br />
in the diet <strong>and</strong> water immersed diet, respectively.<br />
2.3. Growth trial<br />
The growth trials <strong>and</strong> digestibility bioassays were conducted at the facilities of the<br />
Programa Maricultura in Monterrey, using a closed recirculating system containing<br />
synthetic marine water with a salinity of 34‰. The <strong>shrimp</strong> were held in 60-l fiberglass<br />
culture tanks equipped with aeration <strong>and</strong> constant water temperature control at 288C.<br />
The <strong>shrimp</strong> <strong>for</strong> the growth study were selected in a weight range between 200 <strong>and</strong><br />
310 mg <strong>and</strong> distributed, 10 per tank, in four replicated blocks of seven dietary<br />
treatments. A similar weight distribution pattern in each tank was achieved by allotting<br />
the <strong>shrimp</strong> according to their individual weight. Treatments were r<strong>and</strong>omly assigned to<br />
the tanks within each block. The <strong>shrimp</strong> were weighed again at 14 <strong>and</strong> 28 days to obtain<br />
mean body weights <strong>for</strong> each tank.<br />
Dry <strong>feed</strong> intake was determined by <strong>feed</strong>ing to satiation. The <strong>shrimp</strong> were initially fed<br />
a ration of 10% of biomassrday in two <strong>feed</strong>ings daily at 10:00 <strong>and</strong> 17:00 h. The<br />
following morning leftover <strong>feed</strong>, which could be readily identified by its swollen pellet<br />
shape, was removed <strong>and</strong> quantified by estimating the amount in its original dry <strong>for</strong>m,<br />
<strong>and</strong> the ration adjusted accordingly to minimize the amount of uneaten <strong>feed</strong>.<br />
The following response variables were determined <strong>for</strong> each experimental tank: mean<br />
body weight; growth rate expressed as percent weight gain Ž %WG. s100= Žinitial<br />
weightyfinal weight. rŽ initial weight .; dry food intake per <strong>shrimp</strong> Ž DFI.<br />
was estimated<br />
Ž .<br />
28<br />
from the sum of average daily food intake <strong>for</strong> each tank DFI sÝ wŽ<br />
is1 intake on ith<br />
day. rŽ number of <strong>shrimp</strong> on ith day .x; food conversion ratio Ž FCR. sŽfood intake per<br />
<strong>shrimp</strong>. rŽ average weight gain per <strong>shrimp</strong> .; protein efficiency ratio Ž PER. sŽweight
92<br />
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L.E. Cruz-Suarez et al.rAquaculture 196 2001 87–104<br />
gain. rŽ protein intake .; survival Ž %S. s100= Ž final count. rŽ initial count.<br />
<strong>and</strong> tank<br />
biomass Ž B. sŽ sum of the individual <strong>shrimp</strong> weights present in the tank ..<br />
Taking into account the loss of dry matter <strong>and</strong> protein due to submersion in seawater,<br />
corrected values were calculated multiplying the st<strong>and</strong>ard DFI <strong>and</strong> FCR expressions by<br />
Ž 1y%DMLr100. <strong>and</strong> dividing the st<strong>and</strong>ard PER expression by Ž 1y%CPLr100 ..<br />
2.4. Digestibility determination<br />
The digestibility study was carried out with a separate lot of <strong>shrimp</strong> obtained from<br />
Aquastrat Ž Sinaloa, Mexico ´ ., which had an average weight of 2.7 g <strong>and</strong> were distributed,<br />
eight per tank, in two blocks of eight dietary treatments Žsix test <strong>diets</strong>qtwo reference<br />
<strong>diets</strong> .. The collection period was re<strong>pea</strong>ted twice to obtain four samples per dietary<br />
treatment, considered as four replicates. The <strong>shrimp</strong> were fed once a day at a fixed daily<br />
ration of 0.5 grtank <strong>for</strong> the first two replicates, <strong>and</strong> 1 grtank <strong>for</strong> the other two<br />
replicates. After removing uneaten <strong>feed</strong>, feces were collected at 90, 120 <strong>and</strong> 150 min<br />
after <strong>feed</strong>ing, <strong>for</strong> a sufficient number of days Ž 4–8. to pool 1 g feces per sample Žwet<br />
weight .. The feces were collected by siphoning, rinsed immediately with distilled water<br />
<strong>and</strong> stored frozen. The samples were analyzed <strong>for</strong> chromic oxide by the method of Bolin<br />
et al. Ž 1952 .. Nitrogen was determined by a modified micro-Kjeldahl method ŽNieto-<br />
Lopez ´ et al., 1997.<br />
in a Tecator equipment using the Bolin reagent. The apparent dry<br />
matter <strong>and</strong> protein digestibility of <strong>diets</strong> Ž %ADMD <strong>and</strong> %APD, respectively.<br />
were<br />
calculated by the equations Ž Maynard et al., 1981 .:<br />
%Crin diet<br />
%ADMDs100y100= %Crin feces<br />
%CPin feces %Crin diet<br />
%APDs100y100= =<br />
%Crin feces %CPin diet<br />
Ž .<br />
where %Cr <strong>and</strong> %CP are chromium <strong>and</strong> protein concentrations % of dry matter .<br />
Additionally, apparent digestibility values were adjusted <strong>for</strong> losses by leaching be<strong>for</strong>e<br />
<strong>feed</strong> ingestion, according to the following equations, in which dry matter or protein<br />
intake is corrected:<br />
%Crin diet 1<br />
%ADMDadj.s100y100= = %Crin feces Ž 1y%DMLr100.<br />
%CPin feces %Crin diet 1<br />
%APDadj.s100y100= = = Ž .<br />
%Crin feces %CPin diet 1y%CPLr100<br />
Apparent digestibility of the ingredient to be tested was determined by the method of<br />
Cho <strong>and</strong> Slinger Ž 1979 ., where the test ingredient Ž TI.<br />
replaced 30% of the complete<br />
<strong>for</strong>mula of the reference diet Ž RD .. Accordingly, the reference <strong>diets</strong> Ž<strong>diets</strong> 8 <strong>and</strong> 9, Table<br />
2.<br />
were used to calculate the digestibility coefficients of <strong>pea</strong> <strong>meal</strong>s <strong>and</strong> <strong>canola</strong> <strong>meal</strong>,<br />
respectively, in the test <strong>diets</strong> Ž TD .. Ingredient’s apparent dry matter <strong>and</strong> crude protein
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L.E. Cruz-Suarez et al.rAquaculture 196 2001 87–104 93<br />
digestibility values Ž %IADMD <strong>and</strong> %IAPD, respectively.<br />
were calculated by the<br />
equations:<br />
Ž 100=%ADMDin TD. yŽŽ 100y%TI . =%ADMDin RD.<br />
%IADMDs<br />
%TI<br />
Ž 100=%APDin TD=%CPin TD. yŽŽ 100y%TI . =%APDin RD=%CPin RD.<br />
%IAPDs<br />
%TI=%CPin TI<br />
where %CP in diet or test ingredient, <strong>and</strong> the inclusion level of the test ingredient Ž %TI.<br />
are expressed on a dry matter basis.<br />
The apparent digestibility of the nitrogen free extract in <strong>diets</strong> or ingredients Ž ANFED.<br />
was calculated from the ADMD <strong>and</strong> APD values, <strong>and</strong> from assigned values of 90% <strong>for</strong><br />
lipids digestibility Ž Cruz-Suarez ´ et al., 1999 ., 50% <strong>for</strong> ash digestibility Ž Bureau, 2000.<br />
<strong>and</strong> 0% <strong>for</strong> crude fiber digestibility:<br />
ANFEDs Ž %drymatter=ADMDy%CP=APDy%lipid=90y%ash=50.<br />
r%NFE<br />
2.5. Metabolizable energy estimation<br />
The metabolizable energy content of the experimental ingredients were calculated by<br />
using the Aaverage productive valuesB proposed by Cuzon <strong>and</strong> Guillaume Ž 1997.<br />
as<br />
energy coefficients assigned to the digestible energy sources, as follows:<br />
MEkJrgsŽ 17.2= wNFE x=IANFEDadj. . qŽ 39.5= wlipid x=IALD.<br />
qŽ 21.3= wprotein x=IAPDadj.<br />
.<br />
where wNFE x, wlipidx <strong>and</strong> wproteinx are nitrogen free extract Žassumed to be available<br />
carbohydrate ., crude lipid <strong>and</strong> crude protein concentrations of the ingredient, <strong>and</strong><br />
IANFEDadj., IALD Ž s0.9 ., IAPDadj. are the respective apparent digestibility coefficients.<br />
2.6. Statistical analysis<br />
The responses calculated <strong>for</strong> each tank Žmean body weight, biomass, growth rate,<br />
survival, food intake, food conversion, protein intake, PER <strong>and</strong> digestibility.<br />
were<br />
subjected to an analysis of variance <strong>and</strong> to the Duncan’s multiple range test ŽSteel <strong>and</strong><br />
Torrie, 1988.<br />
to first determine whether significant differences existed among the<br />
experimental <strong>diets</strong> <strong>and</strong> then to identify where they occurred. In addition, a factorial<br />
analysis of variance was carried out on the raw <strong>and</strong> extruded, <strong>and</strong> whole <strong>and</strong> dehulled<br />
<strong>pea</strong> <strong>meal</strong> dietary treatments Ž statistical program SPSS <strong>for</strong> Windows, release 8.0.0 ..
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L.E. Cruz-Suarez et al.rAquaculture 196 2001 87–104<br />
3. Results<br />
3.1. Stability of the <strong>diets</strong> in seawater<br />
Average loss of a dietary dry matter following 1-h immersion was approximately<br />
11% <strong>for</strong> the <strong>diets</strong> containing <strong>pea</strong> <strong>meal</strong>s Ž Table 3 ., except <strong>for</strong> the whole-extruded <strong>pea</strong> diet<br />
Ž WEX .. This diet <strong>and</strong> the reference <strong>diets</strong> Ž 8 <strong>and</strong> 9.<br />
showed a better water stability. The<br />
extruded <strong>canola</strong> diet Ž CEX.<br />
exhibited significantly lower water stability; however crude<br />
protein loss was comparatively low. The WEX diet showed the lowest crude protein loss<br />
while the protein stability of the remaining <strong>diets</strong> was similar to that of control diet in the<br />
growth trial Ž. 7 . The effects of extrusion on increased starch gelatinization Ž Table 1.<br />
may explain the higher water stability of the diet containing whole-extruded <strong>pea</strong>s.<br />
However, this extrusion effect was not observed <strong>for</strong> dehulled <strong>pea</strong>s: %DML <strong>and</strong> CPL<br />
values submitted to factorial ANOVA showed significant probabilities <strong>for</strong> the rawrextruding<br />
factor Ž Ps0.064 <strong>and</strong> 0.058, respectively ., but not <strong>for</strong> the wholerdehulled one<br />
Ž Ps0.112 <strong>and</strong> 0.254, respectively ..<br />
3.2. Feed intake, growth <strong>and</strong> surÕiÕal<br />
The growth bioassay results <strong>and</strong> ANOVA probabilities <strong>for</strong> the calculated parameters<br />
are presented in Table 4. Highly significant differences Ž P-0.001.<br />
in food intake were<br />
observed. The micronized <strong>pea</strong> <strong>meal</strong> diet WMI showed the highest consumption while<br />
both extruded <strong>pea</strong> <strong>meal</strong> <strong>diets</strong>, WEX <strong>and</strong> DEX showed the lowest intake. The raw <strong>pea</strong><br />
Table 3<br />
Proximate analysis <strong>and</strong> calculated energy content of the experimental <strong>diets</strong>, <strong>and</strong> dry matter loss Ž %DML.<br />
<strong>and</strong><br />
crude protein loss Ž %CPL.<br />
after 1 h immersion in seawater<br />
1 1 1 1 1 3 3<br />
Diet Moisture Crude Lipid Ash Fiber N.F.E Gross %DML %CPL<br />
1<br />
protein<br />
2<br />
energy<br />
1 WRA 7.5 30.6 9.5 8.7 1.4 42.4 4.3 11.2"0.4 b 19.9"3.0 bc<br />
2 WEX 7.5 29.7 8.9 9.0 2.7 42.3 4.2 9.9"1.0 ab 12.6"1.1 a<br />
3 DRA 7.6 30.5 9.6 8.6 0.9 42.8 4.4 11.3"1.0 bc 17.4"3.1 b<br />
4 DEX 7.3 30.8 9.3 8.6 0.9 43.1 4.4 11.1"0.9 b 18.5"1.9 b<br />
5 WMI 7.0 29.6 9.6 8.6 2.4 42.9 4.3 11.2"1.4 b 18.9"1.8 b<br />
6 CEX 7.2 30.2 9.3 8.8 3.8 40.7 4.2 12.6"0.8 c 17.2"1.4 b<br />
7 Control 6.8 31.2 8.9 8.5 1.5 43.2 4.4 11.1"0.5 b 18.9"0.4 b<br />
growth<br />
8 Reference 6.6 35.8 12.8 11.0 1.5 32.3 4.5 9.6"1.0 a 17.3"0.8 b<br />
<strong>pea</strong> <strong>meal</strong><br />
9 Reference 6.7 29.0 11.8 9.1 1.6 41.9 4.5 9.6"0.7 a 19.1"0.6 b<br />
<strong>canola</strong><br />
1 % as fed. NFEsnitrogen free extract, calculated by difference.<br />
2<br />
Proteins5.6 kcalrg, lipids9.5 kcalrg, carbohydratess4.1 kcalrg Ž Tacon, 1987 ..<br />
3 Different letters in same column indicate different homogeneous subsets as determined by Duncan’s<br />
multiple comparisons Ž P s0.05 .. One-way ANOVA probabilities were P s0.001 <strong>and</strong> P s0.006 <strong>for</strong> DML<br />
<strong>and</strong> CPL data, respectively.
Table 4<br />
Growth experiment results Ž means of four replicates values"st<strong>and</strong>ard deviation.<br />
Treatments 1 WRA 2 WEX 3 DRA 4 DEX 5 WMI 6 CEX 7 Control Prob. 1<br />
Mean body weight<br />
Initial Ž mg.<br />
255"3 254"2 257"2 255"1 256"3 255"3 256"2 0.497<br />
14 days Ž. g 0.61"0.03 abc 0.57"0.02 a 0.60"0.03 ab 0.61"0.02 abc 0.65"0.03 c 0.60"0.05 ab 0.62"0.03 bc 0.040<br />
28 days Ž. g 1.03"0.11 a 0.95"0.03 a 0.98"0.06 a 0.99"0.07 a 1.13"0.07 b 0.94"0.05 a 1.01"0.04 a 0.012<br />
Dry <strong>feed</strong> intake Ž. g<br />
28 days 1.18"0.10 b 1.03"0.03 a 1.28"0.07 b 1.07"0.04 a 1.56"0.05 c 1.22"0.04 b 1.29"0.09 b -0.001<br />
Dry <strong>feed</strong> intake, corrected <strong>for</strong> losses by leaching be<strong>for</strong>e ingestion Ž. g<br />
28 days 1.05"0.01 b 0.93"0.02 a 1.13"0.06 b 0.95"0.04 a 1.38"0.04 c 1.07"0.04 b 1.14"0.08 b -0.001<br />
Ž .<br />
Weight gain %WG<br />
28 days 301"40 a 273"10 a 282"23 a 288"25 a 340"29 b 269"18 a 292"14 a 0.011<br />
Feed conversion ratio<br />
28 days 1.6"0.1 ab 1.5"0.1 a 1.8"0.2 c 1.5"0.1 a 1.8"0.2 c 1.8"0.1 c 1.7"0.05 bc -0.001<br />
Feed conversion ratio, corrected <strong>for</strong> losses by leaching be<strong>for</strong>e ingestion<br />
28 days 1.4"0.1 ab 1.3"0.07 a 1.6"0.15 c 1.3"0.07 a 1.6"0.14 c 1.6"0.04 c 1.5"0.04 bc 0.001<br />
Protein efficiency ratio<br />
28 days 2.0"0.2 b 2.1"0.1 b 1.7"0.2 a 2.1"0.1 b 1.8"0.1 a 1.7"0.1 a 1.8"0.05 a -0.001<br />
Protein efficiency ratio, corrected <strong>for</strong> losses by leaching be<strong>for</strong>e ingestion<br />
28 days 2.5"0.2 b 2.4"0.1 b 2.1"0.2 a 2.5"0.1 b 2.2"0.2 a 2.1"0.1 a 2.2"0.06 a 0.001<br />
Survival Ž %.<br />
28 days 93"10 90"8 95"6 98"5 100"0 90"0 100"0 0.061<br />
Biomass Ž. g<br />
28 days 9.5"1.7 ab 8.5"0.7 a 9.3"0.4 ab 9.6"1 ab 11.2"0.7 c 8.4"0.5 a 10.1"0.4 bc 0.003<br />
1 Prob.sProbability by a one-way analysis of variance between treatments. Treatment means within the same row with different letters are significantly different<br />
Ž .<br />
Duncan’s test, P s0.05 .<br />
L.E. Cruz-Suarez et al.rAquaculture 196 ( 2001 ) 87–104 95
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<strong>meal</strong> Ž WRA <strong>and</strong> DRA ., the extruded <strong>canola</strong> <strong>meal</strong> Ž CEX.<br />
<strong>and</strong> control <strong>diets</strong> showed<br />
intermediate consumption. Weight gain of the experimental animals practically tripled<br />
after 28 days <strong>for</strong> each of the dietary treatments. With the exception of the micronized<br />
<strong>pea</strong> Ž WMI dietary treatment ., there were no significant differences in weight gain among<br />
the dietary treatments. A food conversion ratio of less than 2 was obtained <strong>for</strong> each of<br />
the dietary treatments. Significantly lower <strong>feed</strong> conversion ratios were obtained <strong>for</strong> the<br />
extruded <strong>pea</strong> <strong>meal</strong> <strong>diets</strong>, perhaps due to improved starch digestibility. The highest PER<br />
values were also obtained <strong>for</strong> the extruded <strong>pea</strong> <strong>meal</strong> <strong>diets</strong> indicating that protein<br />
utilization was not impaired by the effects of heat treatment. Correction of DFI <strong>for</strong><br />
losses in sea water be<strong>for</strong>e the <strong>feed</strong> ingestion led to improved values of FCR <strong>and</strong> PER,<br />
but relative differences among the means <strong>for</strong> the different treatments were not modified<br />
substantially, since homogeneous subsets as defined by the Duncan’s multiple comparison<br />
test remained the same. Survival <strong>for</strong> all treatments Ž above 90% . was excellent <strong>and</strong><br />
did not differ significantly amongst <strong>diets</strong>. The largest biomass gain was obtained <strong>for</strong><br />
<strong>shrimp</strong> fed the WMI micronized <strong>pea</strong> <strong>and</strong> control diet, due mainly to the weight gains of<br />
these groups.<br />
3.3. Digestibility<br />
The apparent dry matter digestibility Ž ADMD.<br />
<strong>for</strong> the experimental <strong>diets</strong> was<br />
generally higher than that of each of the reference <strong>diets</strong> Ž Tables 5 <strong>and</strong> 6 .. The ADMD<br />
<strong>and</strong> apparent protein digestibility Ž APD.<br />
amongst the experimental growth study <strong>diets</strong><br />
Ž 1–6.<br />
were not significantly different. Apparent dry matter <strong>and</strong> protein digestibility<br />
values <strong>for</strong> the test ingredients calculated using reference <strong>diets</strong> Ž 8 <strong>and</strong> 9.<br />
<strong>and</strong> following<br />
the method of Cho <strong>and</strong> Slinger Ž 1979.<br />
are also presented in Tables 5 <strong>and</strong> 6. The<br />
adjustment of the digestibility coefficients <strong>for</strong> leaching losses Ž Table 6 vs. Table 5.<br />
did<br />
not change the statistical inference to the treatment effects. However, in the subsequent<br />
calculation of the carbohydrate digestibility, it was noted that the adjusted coefficients<br />
supported more realistic values that would indicate the correction to be necessary,<br />
especially <strong>for</strong> the extruded <strong>canola</strong> <strong>meal</strong> Ž Table 5 .. The highest dry matter digestibility<br />
values were obtained with the extruded <strong>pea</strong> flours <strong>and</strong> the lowest with micronized <strong>pea</strong><br />
<strong>meal</strong> <strong>and</strong> extruded <strong>canola</strong> <strong>meal</strong>. Similarly, adjusted digestibility of carbohydrate as<br />
expressed by NFE Ž Table 6.<br />
was close to 100% <strong>for</strong> the <strong>pea</strong> ingredients <strong>and</strong> <strong>canola</strong><br />
except <strong>for</strong> DRA <strong>and</strong> WMI Ž 87.4% <strong>and</strong> 85.5% .. In contrast, there were no significant<br />
differences in IAPD among the differently processed <strong>pea</strong> <strong>meal</strong>s <strong>and</strong> <strong>canola</strong> <strong>meal</strong>.<br />
However, in spite of these relatively uni<strong>for</strong>m protein digestibility values, <strong>and</strong> lower<br />
carbohydrate digestibility <strong>for</strong> the micronized <strong>pea</strong>, the <strong>feed</strong>ing trial results show best<br />
per<strong>for</strong>mance with the WMI treatment. There<strong>for</strong>e, the benefit derived from micronizing<br />
<strong>pea</strong>s is apparently due to enhanced <strong>feed</strong> intake rather than an improvement in nutritional<br />
value.<br />
Metabolizable energy calculations led to higher values <strong>for</strong> extruded <strong>pea</strong> <strong>meal</strong>s<br />
Ž 16.2–16.4 kJrg. than <strong>for</strong> raw <strong>pea</strong> <strong>meal</strong>s Ž 15.4–15.6 kJrg ., <strong>and</strong> lowest values <strong>for</strong><br />
micronized <strong>pea</strong> <strong>and</strong> <strong>canola</strong> Ž 14.0 <strong>and</strong> 14.2 kJrg, respectively. Ž Table 6 .. Metabolizable<br />
energy was lower than digestible energy by only about 0.4 kJrg, <strong>for</strong> all the experimental<br />
ingredients.
Table 5<br />
Apparent dry matter, protein <strong>and</strong> NFE digestibility in <strong>diets</strong> <strong>and</strong> ingredients, as obtained by st<strong>and</strong>ard determination Ž mean of four replicate values"st<strong>and</strong>ard deviation.<br />
1 WRA 2 WEX 3 DRA 4 DEX 5 WMI 6 CEX 8 Ref. <strong>pea</strong> 9 Ref. Canola ANOV<br />
Prob.<br />
Diet digestibility (%), st<strong>and</strong>ard<br />
ADMD 79.3"1.8 bc 79.9"1.2 c 78.8"1.9 bc 80.2"0.9 c 76.8"2.7 abc 77.3"3.2 abc 75.1"2.2 a 76.4"2.1 ab 0.020<br />
APD 89.8"0.9 ab 90.6"1.1 b 91.0"1.2 b 90.4"0.7 ab 90.1"2.2 ab 91.3"2.0 b 88.0"2.3 a 90.9"1.0 b 0.123<br />
ANFED 77.8"3.4 cd 81.7"2.0 d 74.9"3.6 bc 78.6"1.8 cd 74.1"4.2 bc 77.2"5.8 cd 68.9"4.2 a 71.2"4.0 ab 0.001<br />
Ingredient digestibility (%), st<strong>and</strong>ard<br />
IADMD 89.0"6.2 abc 91.3"3.9 bc 87.6"6.5 abc 92.4"2.9 c 80.7"8.8 ab 79.4"10.6 a 0.075<br />
IAPD 79.8"4.6 83.0"5.3 85.4"5.8 82.7"3.2 80.0"11.2 80.0"5.4 0.707<br />
IANFED 102.3"7.8 104.4"4.5 91.8"7.8 99.6"4.0 90.7"9.7 113.6"23.8 0.293<br />
Ž .<br />
Different letters in same raw indicate different homogeneous subsets Duncan 0.05% .<br />
L.E. Cruz-Suarez et al.rAquaculture 196 ( 2001 ) 87–104 97
98<br />
Table 6<br />
Apparent dry matter, protein <strong>and</strong> NFE digestibility in <strong>diets</strong> <strong>and</strong> ingredients, adjusted <strong>for</strong> losses by leaching be<strong>for</strong>e ingestion, <strong>and</strong> corresponding energy contents in <strong>pea</strong><br />
<strong>and</strong> <strong>canola</strong> <strong>meal</strong>s Ž mean of four replicate values"st<strong>and</strong>ard deviation.<br />
1 WRA 2 WEX 3 DRA 4 DEX 5 WMI 6 CEX 8 Ref. <strong>pea</strong> 9 Ref. Canola ANOV<br />
Prob.<br />
Diet digestibility (%), adjusted<br />
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<br />
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<br />
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<br />
Ingredient digestibility (%), adjusted<br />
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<br />
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<br />
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<br />
Ingredient energy content ( kJr g)<br />
1<br />
ME 15.6"1.2<br />
2<br />
16.2"0.8 15.4"1.3 16.4"0.6 14.0"1.8<br />
2<br />
14.2"2.2 0.307<br />
3<br />
DE 15.9"1.3<br />
2<br />
16.6"0.8 15.8"1.3 16.8"0.6 14.3"1.9<br />
2<br />
14.8"2.2 0.383<br />
Different letters in same raw indicate different homogeneous subsets Ž Duncan 0.05% ..<br />
1<br />
Metabolizable energy was calculated as described in material <strong>and</strong> methods by assigning average productive values Ž Cuzon <strong>and</strong> Guillaume, 1997.<br />
to the digestible<br />
nutrient contents as calculated with adjusted digestibility coefficients <strong>for</strong> protein <strong>and</strong> NFE.<br />
2 Although IANFEDadj. was calculated at 101.2% <strong>for</strong> WEX <strong>and</strong> 100.5 <strong>for</strong> CEX, we used a 100% value <strong>for</strong> the calculations of metabolizable <strong>and</strong> digestible energy<br />
contents.<br />
3<br />
Digestible energy was calculated by assigning gross energy values Ž Tacon, 1987. to the digestible nutrient contents, adjusted <strong>for</strong> leaching: DE kJrgsŽ23.4=<br />
wprotein x =IAPDadj. . qŽ39.7= wlipid x =0.90. qŽ17.2= wNFE x =IANFEDadj. ..<br />
L.E. Cruz-Suarez et al.rAquaculture 196 ( 2001 ) 87–104
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L.E. Cruz-Suarez et al.rAquaculture 196 2001 87–104 99<br />
3.4. Analysis of the effects of dehulling <strong>and</strong> extrusion<br />
Factorial ANOVA of the results <strong>for</strong> <strong>diets</strong> 1, 2, 3 <strong>and</strong> 4 showed that the effects from<br />
extrusion were generally higher than from dehulling. No significant effects on per<strong>for</strong>mance<br />
were observed as a result of dehulling, although a higher <strong>feed</strong> consumption <strong>and</strong><br />
lower PER approached significance Ž Ps0.121 <strong>and</strong> Ps0.073, respectively ..<br />
Extrusion reduced <strong>feed</strong> intake Ž P-0.001 ., improved <strong>feed</strong> conversion Ž Ps0.009 .,<br />
increased PER Ž Ps0.006.<br />
<strong>and</strong> tended to improve dry matter digestibility of <strong>pea</strong>s<br />
Ž Ps0.192 .. Extrusion had no effect on growth Ž Ps0.44 ., survival Ž Ps1.<br />
<strong>and</strong> protein<br />
digestibility Ž Ps0.751 .. These results again can be explained by improved digestibility<br />
of gelatinized over native starch.<br />
4. Discussion<br />
The impact of dry matter <strong>and</strong> protein losses due to leaching be<strong>for</strong>e ingestion has been<br />
evaluated through the calculation of corrected values, which take into account the losses<br />
that occurred in the <strong>diets</strong> after 1 h. This simple correction seems justified by considering<br />
that most of the losses occur during the first hour of immersion ŽRomero-Alvarez,<br />
1995 ., <strong>and</strong> that the average interval time of <strong>feed</strong> consumed was generally noted to be<br />
approximately 1 h after offering the <strong>feed</strong>. Corrected values showed the same relative<br />
positions as st<strong>and</strong>ard values, even in the case of the WEX treatment, which stability in<br />
water was significantly better than that of other <strong>diets</strong>. The corrected values are of<br />
interest because they indicate the true biological values of <strong>feed</strong> intake, conversion ratio<br />
<strong>and</strong> PER as a more accurate measurement of the crustacean’s metabolic response to the<br />
dietary treatments. They also allowed a truer estimation of the carbohydrate digestibility<br />
of the experimental ingredients. The uncorrected values on the other h<strong>and</strong> reflect the<br />
results of a practical significance, which can be compared with other studies using<br />
st<strong>and</strong>ard calculations.<br />
The results of this study show that raw <strong>pea</strong>s, <strong>and</strong> <strong>pea</strong>s processed by dehulling,<br />
extruding <strong>and</strong> micronizing, have a nutritional value similar to that of a mixture Ž 1:3.<br />
of<br />
soybean <strong>meal</strong> <strong>and</strong> wheat flour Ž 80% hard–20% soft varieties, Table 2.<br />
in <strong>shrimp</strong> <strong>diets</strong>.<br />
Also, substituting a portion of the soybean <strong>meal</strong>, fish <strong>meal</strong> <strong>and</strong> wheat Ž1:2:3 parts,<br />
respectively.<br />
with extruded <strong>canola</strong> <strong>meal</strong> did not affect <strong>shrimp</strong> per<strong>for</strong>mance. Our results<br />
corroborate the reports by other authors cited in the introduction that <strong>pea</strong> seed <strong>meal</strong> <strong>and</strong><br />
<strong>canola</strong> <strong>meal</strong> can be successfully included in practical aquaculture <strong>feed</strong>s. When alternate<br />
plant origin ingredients are used in <strong>diets</strong> containing the same concentration of digestible<br />
energy <strong>and</strong> digestible protein, <strong>and</strong> meeting nutrient requirements, similar per<strong>for</strong>mance<br />
can be expected. However, Gomes et al. Ž 1995.<br />
found that voluntary food intake of trout<br />
fed <strong>diets</strong> including coextruded <strong>pea</strong>s <strong>and</strong> <strong>canola</strong> was depressed due to inherent factors<br />
present in the plant ingredients Ž Novoa <strong>and</strong> Castillo, 1998 .. There<strong>for</strong>e, similar growth<br />
was not obtained. In the present study, no adverse response to raw whole <strong>pea</strong>s was<br />
observed. Studies with trout Ž Kaushik et al., 1993. <strong>and</strong> Euro<strong>pea</strong>n sea bass ŽGouveia <strong>and</strong><br />
Davies, 2000.<br />
have emphasized the requirement <strong>for</strong> dehulling <strong>and</strong> extrusion cooking<br />
under conditions that would be more severe than they would during complete <strong>feed</strong>
100<br />
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L.E. Cruz-Suarez et al.rAquaculture 196 2001 87–104<br />
manufacture. Allan Ž 1997.<br />
cites unpublished data that show an improvement in the<br />
nutritional value of Dunn <strong>pea</strong>s Ž a tannin containing P. satiÕum variety.<br />
through<br />
dehulling <strong>and</strong> extrusion when included in the <strong>diets</strong> of silver perch, an omnivorous fish.<br />
In the present study, no particular benefit was obtained by dehulling the <strong>pea</strong>, perhaps<br />
because the field <strong>pea</strong> strains used to produce the experimental <strong>meal</strong>s have been<br />
improved. Eusebio Ž 1991. also found that dehulling cow<strong>pea</strong>s <strong>and</strong> rice beans Žleguminous<br />
seeds.<br />
had no significant effect on growth <strong>and</strong> survival of Pen. monodon although<br />
apparent protein digestibility of rice beans but not cow<strong>pea</strong>s was improved. Shrimp may<br />
actually be more tolerant of certain anti-nutritional seed coat compounds than other<br />
species.<br />
Smith et al. Ž 1999.<br />
reported digestibility coefficients of field <strong>pea</strong>s in tiger <strong>shrimp</strong> of<br />
80% <strong>for</strong> IADMD <strong>and</strong> 91% <strong>for</strong> IAPD in tiger <strong>shrimp</strong>. The IADMD value is lower <strong>and</strong> the<br />
IAPD value is higher than those obtained in present study Ž88–92% <strong>and</strong> 79–85%,<br />
respectively.Ž Table 5 .. The lower <strong>feed</strong> consumption of the extruded <strong>pea</strong> <strong>diets</strong> did not<br />
reduce growth, suggesting higher energy availability from these <strong>diets</strong> ŽCuzon <strong>and</strong><br />
Guillaume, 1997 .. The higher dry matter digestibility of extruded <strong>pea</strong>s also suggests a<br />
higher digestible energy value <strong>for</strong> gelatinized starch resulting from the effects of<br />
extrusion cooking. Davis <strong>and</strong> Arnold Ž 1993.<br />
reported that the gelatinization of starch in<br />
sorghum significantly improved digestibility in Pen. Õannamei. However, Davis <strong>and</strong><br />
Arnold Ž 1995.<br />
found that starch gelatinization did not necessarily correspond to increased<br />
energy digestibility of the cereal grains wheat <strong>and</strong> rice as observed <strong>for</strong> corn <strong>and</strong><br />
sorghum. The different responses were attributed to variable effects of wet <strong>and</strong> dry<br />
extrusion conditions with different grains. In the present study gelatinization of starch by<br />
wet extrusion had a small positive effect on digestibility <strong>and</strong> per<strong>for</strong>mance, although the<br />
raw <strong>pea</strong> <strong>meal</strong> was quite acceptable <strong>and</strong> perhaps the extrusion costs would not be<br />
recovered.<br />
Cousin et al. Ž 1996.<br />
also found differences in native <strong>and</strong> gelatinized starch digestibility<br />
measured both in vivo <strong>and</strong> in vitro depending on the source of dietary starch with<br />
reference to the amyloseramylopectin composition <strong>and</strong> its intrinsic starch granule<br />
characteristics. The proportion of amylose ranges between 23.5% <strong>and</strong> 35% in <strong>feed</strong> <strong>pea</strong><br />
starch compared to over 66% in wrinkled canning type <strong>pea</strong>s Ž Castell et al., 1996 ..<br />
According to Grosjean et al. Ž 1998.<br />
lower apparent energy digestibility in pigs of<br />
wrinkled compared to <strong>feed</strong> <strong>pea</strong> is partly due to the amyloseramylopectin ratio. The data<br />
reported by Cousin et al. Ž 1996.<br />
comparing high amylopectin <strong>and</strong> high amylose corn<br />
starch <strong>and</strong> wheat starch by in vivo <strong>and</strong> in vitro assay with L. Õannamei also showed<br />
lower starch digestibility from the high amylose source. The <strong>feed</strong> <strong>pea</strong>s used in this study<br />
can be considered as having an amylose content closer to that of wheat starch Ž 23% .,<br />
which is also highly digestible in both native <strong>and</strong> gelatinized <strong>for</strong>ms ŽCruz-Suarez ´ et al.,<br />
1994; Davis <strong>and</strong> Arnold, 1995; Cousin et al., 1996 ..<br />
Infrared heat treatment did not increase starch gelatinization <strong>and</strong> digestibility, although<br />
<strong>feed</strong> intake <strong>and</strong> growth was considerably higher <strong>and</strong> food conversion was good<br />
with the micronized <strong>pea</strong> diet. The higher growth was approximately 16% higher than the<br />
control <strong>and</strong> 20% higher than the raw <strong>and</strong> extruded <strong>pea</strong> fed groups. There<strong>for</strong>e, the<br />
beneficial effects of micronization may have resulted from the development of compounds<br />
that enhanced palatability <strong>and</strong>ror the elimination of off flavors <strong>for</strong> <strong>blue</strong> <strong>shrimp</strong>.
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L.E. Cruz-Suarez et al.rAquaculture 196 2001 87–104 101<br />
Gomes et al. Ž 1995.<br />
reported a 10% increase in protein <strong>and</strong> energy digestibility from<br />
micronizing full fat soybeans <strong>and</strong> a 21% increase in energy digestibility, but not protein,<br />
from micronizing wheat fed to rainbow trout. The infrared heat treatment <strong>and</strong> low<br />
moisture tempering were perhaps not severe enough to improve starch digestibility in<br />
the present study.<br />
Metabolizable energy contents in <strong>pea</strong>s <strong>for</strong> P. stylirostris were higher than those <strong>for</strong><br />
swine <strong>and</strong> poultry Ž 13.6 <strong>and</strong> 11.1 kJrg according to Castell et al., 1996 .. Higher<br />
metabolizable energy values in <strong>shrimp</strong> than in mammalian <strong>and</strong> avian species are in<br />
accord with their mode of excreting nitrogen in <strong>for</strong>m of ammonium ŽCuzon <strong>and</strong><br />
Guillaume, 1997 .. Metabolizable energy content in <strong>pea</strong>s increased from 15.4 to 16.4<br />
kJrg by extruding the <strong>pea</strong> <strong>meal</strong> most likely due to the improved digestibility of<br />
gelatinized starch.<br />
Dry matter <strong>and</strong> protein digestibility of the extruded <strong>canola</strong> diet was found to be very<br />
good <strong>and</strong> similar to that of a practical diet <strong>for</strong>mulation that included a high quality fish<br />
<strong>meal</strong>. These results agree with those of Buchanan et al. Ž 1997.<br />
who reported on the<br />
successful use of <strong>canola</strong> <strong>meal</strong> in Pen. monodon <strong>diets</strong> at both a 20% inclusion level, <strong>and</strong><br />
64% inclusion with the addition an enzyme mixture. Satoh et al. Ž 1998.<br />
reported that<br />
extrusion processing of <strong>canola</strong> <strong>meal</strong> improved its nutritive value as measured by growth<br />
of chinook salmon in sea water. Protein <strong>and</strong> lipid contents were increased <strong>and</strong> phytic<br />
acid <strong>and</strong> glucosinolates, that interfere with nutrient bioavailability <strong>and</strong> thyroid function,<br />
respectively, were partially degraded. The results of this study suggest that extruded <strong>feed</strong><br />
<strong>pea</strong>s <strong>and</strong> <strong>canola</strong> would complement each other in practical <strong>shrimp</strong> <strong>diets</strong>. Co-extruded<br />
rapeseed <strong>and</strong> <strong>pea</strong>s have replaced up to 66% of brown fish <strong>meal</strong>s in rainbow trout <strong>diets</strong><br />
Ž Gomes et al., 1995 ..<br />
This study demonstrates the acceptable nutritional value of <strong>pea</strong>s <strong>and</strong> <strong>canola</strong> <strong>meal</strong> as<br />
ingredients in <strong>diets</strong> <strong>for</strong> the production of <strong>shrimp</strong>, since they could replace common<br />
<strong>shrimp</strong> <strong>feed</strong> ingredients. Inclusion of <strong>pea</strong>s <strong>and</strong> <strong>canola</strong> <strong>meal</strong> in <strong>shrimp</strong> <strong>diets</strong> will there<strong>for</strong>e<br />
be a function of diet <strong>for</strong>mulation <strong>and</strong> commodity prices. The effects of the micronizing<br />
process on <strong>pea</strong> <strong>meal</strong>s deserve more research to investigate how the process could<br />
increase <strong>feed</strong> consumption more than that required to compensate <strong>for</strong> reduced dietary<br />
energy availability.<br />
Acknowledgements<br />
We thank <strong>shrimp</strong> farms Cristo Rey <strong>and</strong> Aquastrat, Sinaloa, Mexico <strong>for</strong> providing<br />
´<br />
juvenile Litopenaeus stylirostris <strong>for</strong> the growth <strong>and</strong> digestibility experiments, respectively,<br />
<strong>and</strong> Serv<strong>and</strong>o Quiroz B., Claudio Guajardo B. <strong>and</strong> Norma E. Luna <strong>for</strong> their help<br />
in <strong>for</strong>mulating, analyzing <strong>and</strong> testing the <strong>shrimp</strong> <strong>feed</strong>s. The <strong>pea</strong>s were provided by Paul<br />
Adelizi of the Saskatchewan Wheat Pool. We express our gratitude to Francis <strong>and</strong> Tony<br />
Gaudet of Belle Pulses <strong>for</strong> dehulling <strong>pea</strong>s, Connie Phillips <strong>and</strong> Kevin Swallow of the<br />
Alberta Food Processing Centre, Leduc, <strong>for</strong> extruding the <strong>meal</strong>s <strong>and</strong> Mark Pickard <strong>and</strong><br />
Gordon Sellar of Infraready Products, Saskatoon, <strong>for</strong> micronizing the <strong>pea</strong>s. We thank the<br />
Saskatchewan Pulse Growers <strong>and</strong> the Canadian International Grains Institute <strong>for</strong> funding<br />
this study.
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