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"Effects of Feeding Rate, Fish Size, andDietary Protein and Cellulose Levels on theGrowth of Tilapia nilotica"著者journal orpublication titlevolumenumberpage range別言語のタイトルURL"TESHIMA Shin‑ichi, KANAZAWA Akio, KOSHIOShunsuke"鹿児島大学水産学部紀要 Memoirs of Faculty ofFisheries Kagoshima ttp://hdl.handle.net/10232/13348

Mem. Fac. Fish., Kagoshima Univ.Vol. 36,No.1, pp. 7-15 (1987)Effects of Feeding Rate, Fish Size, and Dietary Protein andCellulose Levels on the Growth of Tilapia niloticaShin-ichi Teshima! Akio Kanazawa* and Shunsuke KoshioAbstractTwo feeding experiments were conducted to examine the effects of feeding rate, fish size,and dietary protein and cellulose levels on the weight gain, feed conversion efficiency (FCE),protein efficiency ratio (PER), and feed consumption ofTilapia niloticafingerlings. The effectsof factors were evaluated with 2 or 4 levels in a factorial design using an orthogonal array L8. InExperiment I, the weight gain (%) was slightly higher (P 0.10) insmall fish (about 0. 36g)than in large fish (about 6. 8g) but not significantly different with the feeding rates (1.5%,3.5%, 5.5%, and adlibitum feeding) and dietary protein levels (25% and 35% ). The FCEandPER were decreased withincreasing feeding rates (P 0. 05) andwere higher(P 0. 05) insmall fish than in large fish but not significantly differed between 25% and 35 protein diets.,InExperiment II, theweight gain (%) and PERwere decreased with increasing dietary celluloselevels (2%, 7%, 12%, and 17%)(P 0.05) and were higher (P 0.05) on 35% protein dietthan 25% protein diet. However, the feed consumption and FCE were not significantlyvariable with dietary cellulose and protein levels.Growth of fish is affected by variousfactors such as rearingand feeding conditionsbesidesnutritive value of diets. In the first paper1 ]of this series, we have investigated the effects ofdietary protein source, feeding rate, feeding frequency, stocking density, vitamin level,anda binder on the growth of Tilapia nilotica fingerlings. The results showed that thegrowthof T. nilotica was markedly affected by the feeding rate and protein source. On the otherhand, interestingly, Wang et al2) reported that the growth of T. nilotica was decreased withincreasing dietary cellulose levels when fed low (22%)-protein diets in contrast to high(32% and 41% )-protein diets. For these findings, it appeared of interest to investigate theeffects of feeding rate and dietary cellulose level on the growth of Tilapia in detail.In the present study, two feeding experiments designed using anorthogonal array L8 wereconducted to see the effects of feeding rate and dietary cellulose level besides those of fishsize and dietary protein level on the growth of T. nilotica.Laboratory of Marine Nutritional Chemistry, Faculty of Fisheries, Kagoshima University, 50-20Shimoarata 4, Kagoshima 890, Japan.

Mem. Fac. Fish., Kagoshima Univ. Vol.36, No.1 (1987)Materials and MethodsT. nilotica fingerlings were obtained from a commercial Tilapia farm (Fuji-EnterpriseCo., Kagoshima) and maintained on a commercial carp ration until used. Feedingexperiments were designed by using an orthogonal array L8 to examine the effects of somefactors on the weight gain, feed conversion efficiency (FCE), protein efficiency ratio(PER), and feed consumption of T. nilotica fingerlings. The effects of factors were testedwith 2or4levels under the rearing conditions listed inTable 1and evaluated by analysis ofvariance at the significant levels of 5% or 10%3). Table 2 shows the compositions of testdiets. The basal ration of test diets was the same as reported previously1). Table 3gives thefactors and levels examined in the present study.Table 1 . Rearing conditions of Tilapia in Experiments I and HConditionExperiment IExperiment flFeeding periodAverage initial body wt.Number of fish/tank (30 t )Feeding rate (% of body wt.)Various*1ad libitumDaily feeding frequency*2TwiceTwiceWater temperature28t24-28 CIllumination***2Table 2 .5 weeks5 weeks0.36g, 6.86g0.35g15157 : 00-19 : 007 : 00-19 : 001.5%, 3.5%, 5.5%, and ad libitum .9 : 00 and 15 : 00 o'clocks.Composition of test dietsDiet No. (% composition)IngredientCasein-gelatinL-Trp : L-Met ( 1 :1 Dextrin41. 25 30.0PLO:SBO (1 : :1 )*1151.642.633.624.642.633.624. 615. 69.413.417.421.48.412.416. 420. 41414Linoleic a -Cellulose8. 75 10271217271217AgarProvisional /lOOg)*l A mixture of pollack liver oil and soybean oil (1 : 1, w/w).*2 Digestible energy (DE) was provisionally calculated by using the followingvalues (kcal/g) : protein, 4.5 ; carbohydrate, 4.0 ; lipid, 9.0.

TESHIMA et al '. Effects of some Factors on Growth of TilapiaIn Experiment I, the feeding trials were conducted to examine the effects of feeding rate(factor A), fish size (factor B), and dietary protein level (factor C) on the weight gain,FCE, and PER (Table 4). Tilapia fingerlings, each weighing 0. 36 g or 6. 86 g in averagebody weight, were reared with 2 diets containing 25% or 35% casein-gelatin (3 11) asprotein sources at various feeding rates (1.5%, 3. 5%, and 5. 5% of body weight per day andad libitum) for 5 weeks. Experiment II dealt with the effects of dietary cellulose (factor D)and protein (factor C) levels on the weight gain, FCE, PER, and feed consumption. InExperiment II, the fingerlings, each weighing 0. 36 g in average body weight, were rearedwith 8 diets containing varying levels of cellulose (2%, 7%, 12%, and 17%) andcasein-gelatin (3 ! 1) (25% and 35% ). The fish werefed the diets adlibitum for the period of5 weeks.Table 3 .Factors and levels examined in Experiments IFactor*1andHLevelExperimentIFactor A : Feeding rate(% of body wt./day)Ai I 1.5%A2 : 3.5%A3 : 5.5%A 4 '. ad lib.Factor B : Fish sizeBi : SmallB2 ' LargeFactor C : Protein level in diets*2Ci : 25%C2 : 35%ExperimentHFactor C : Protein level in diets*2Ci : 25%C2 : 35%Factor D : Cellulose level in dietsDi : 2%D2 : 7%D3 : 12%D4 : 17%sic1The factors were alloted to the orthogonal array Ls as shown in*2Diets contained 1% L-Trp : L-Met (1 : 1 ) as nitrogen sourcesTable 4.besides 25% or 35% protein, a mixture of casein-gelatin (3:1)Results and DiscussionTable 5 shows the results of Experiment I. The highest weight gain was obtained ingroup No. 17 of small fish receiving 35% protein diet ad libitum (feeding rate determined 7. 6% of body weight). The FCE and PER were the highest in group No. 11 of small fish

Mem. Fac. Fish., Kagoshima Univ. Vol.36, No. 1 (1987)10Table 4 .Experimental groups and the allotment of factors and levels toorthogonal array L8 in Experiments I and HExperiment I*1Experiment fl *2Exptl.FeedingFishProteinDietExptl.Cellulose evel111.5%0.39g25%No. 11212%25%121.5%6.37g35%No. 12222%35%No. 25133.5%0.45E35%No. 12237%25%No. 22No. 26No. 21143.5%6.49E25%No. 11247%35%155.5%0.32g25%No. 112512%25%No. 23165.5%7.39g35%No. 122612%35%No. 2717ad lib*30.28g35%No. 122717%25%No. 2418ad lib* 47.18g25%No. 112817%35%No. 28*3*4The factors (see Table 3) were alloted to the orthogonal array as follows : factorA (array No. 1, 2, and 3), factor B (array No. 4), and factor C (array No. 6).The factors (see Table 3) were alloted to the orthogonal array as follows : factorC (array No. 4) and factor D (array No. 1, 2, and 3).Feeding rate determined was 7.6%.Feeding rate determined was 6.2%.Table 5 .Results of the feeding trial in Experiment IMean body wt. (g)Exptl.Wt. gainDietFCE*2InitialgroupFinalconsumed 3Diet consumed (g)/one fish during the period of 5 weeks.Gain (g) X 100/feed (g)Gain (g)/protein intake (g)receiving 25% protein diet at 1.5% feeding rate. Koyama* has recommended the feedingrate of 6-8% for T. nilotica fingerlings weighing less than 50 g at the water temperature of25-30 C. The weight gain, FCE, and PER data were analyzed by analysis ofvariance3) toassess the effects of factors examined (Table 6).In agreement with results previously reported1 \ the growth of Tilapia was markedlyaffected by the feeding rates (Fig. 1), but a significant difference (P 0. 05) was notdetected on the feeding rate (factor A), fish size (factor B), and dietary protein level* Koyama: Yoshoku, 10, 49-53 (1983).

TESHIMA et al I Effects of some Factors on Growth of TilapiaTable 6 .11of the feeding rate, fish size, and dietary protein level on theweight gain, FCE, and PER of Tilapia in Experiment 1EffectsMean confidence limit (P 0.95)T7,, «. ,,,„Ar actor and1 ,, 1 *level*Weight gain (%)FCEPERAi I 1.5%A2:3.5%A3:5.5%155 276145 404.3 0.86180 27690 402.9 0.86217 27656 402.3 0.86A 4 '. ab lib.(about 7%)287 27653 401.7 0.86312 195107 403.4 0.6186 19565 402.2 0.61166 19581 282.9 0.61232 19591 282.6 0.61Feeding rateFish sizeBi : Small (0.36g)B2: Large (6.9g)Dietary protein level (%)Ci :25%c2:35%* A significant difference (P 0.05) was detected in the following factors. FCE datafish size and dietary protein level. PER data : feeding rate and fish size.In addition, a significant difference (P 0.10) was detected in the size of fish onweight gain (%) data.bUUWeight gain {%)300S Mr Small fish0rLarge fish100"1.53.55.5Feeding rate {%)Fig. 1.7.51.53.55.5Feeding rate (%)7.01.53.55.5'7.0Feeding rate {" )Effects of feeding rate on the weight gain, FCE, and PER in Experiment I. ; confidence limits (P 0. 95)(factor C) as for the weight gain data. The failure to detect a significant difference on theweight gain data is plausibly attributable to the discrepancy in growth between the small andlarge fingerlings which enlarged the variablities of data. These results indicate that futurestudies should perhaps take more into account the interaction between feeding rates and fishsizes in feeding trials using T. nilotica, because the weight gain seemed to increase withincreasing feeding rates from 1. 5% to 6. 8% (ad libitum feeding) in both small and large fish(Fig. 1) and also to be higher on 35% protein diet than 25% protein diet (Fig. 2). TheFCE and PER were decreased significantly (P 0. 05) with increasing feeding rates andwere also higher on small fish than large fish. However, neither FCE nor PER differedsignificantly with dietary protein levels (25% and 35% ). Analogous effects of feeding rate