Research Title:Optimum protein requirements for theOptimum protein requirements for theintensive culture ofintensive culture of Labeo rohitaLabeo rohita (Hamilton) in(Hamilton) inglass aquariaglass aquariaName of Scholar: Prof. Dr. Naeem TariqNarejo
INTRODUCTION• The success of intensive fish culturedepends on the formulation of a fish feedthat contains an optimum level of proteinand energy necessary for the growth offish and is also cheap. It is obviouslynecessary to formulate and manufacturefish feeds from locally available feedingredients. Major carps are the mostextensively reared (cultured) in Pakistan.These constitute nearly 40% of the localfreshwater species of fish (Doha, 1967).
INTRODUCTION• Among the various species of carps, L.rohita, C. catla and C. mrigala have got avery high demand for their palatability. Inspite of this, very little efforts have beenmade to undertake intensive culture ofthese fish. Various workers have reportedthe effect of different protein level ondifferent fish species from elsewheresuch as Cowey et al., (1972) in marine flatfish;
INTRODUCTION• Nose and Arai (1972) in Eel, Anguillajaponica; Garling and Wilson (1976) inchannel catfish Ictalurus punctatus,Dabrosky and Wojno (1977) in rainbowtrout, Salmon gairdneri, Anderson et al.,(1981) small mouth Bass, Jauncey (1982),Mazid et al. (1987) in Labeo rohita.Recently Ashraf et al., (2008) studiedeffect of different feed ingredients ongrowth and survival on Cirrhinus mrigala.
INTRODUCTION• Present study was an attempted to supplythe information on optimum proteinrequirements for the rearing and commercialfarming of Labeo rohita from Pakistan.
• The ingredients for the experimentalpellet were purchased from local marketsand from Habib Industries, Hub,Balochistan. These ingredients werebrought to the laboratory Department ofFresh Water Biology and Fisheries,University of Sindh, Jamshoro. Thecollected dietary ingredients were groundthoroughly with the help of grinder andsieved to pass through 0.5 mm mesh. Theingredients were mixed according to theformulae given in table 1.
Table 1. Formulation of the experimentaldietIngredients Feed A Feed B Feed CRice Protein 50 % 50 % 50 %Rice bran 30 35 40Rice Milling 15 10 5Wheat Flour 4 4 4Salt + Vitaminpremix1 1 1Total 100 100 100
•The well-mixed ingredients were then put into themanually operated pellet machine as Fig.1 for thepreparation of pellet feed of size 2 mm. The pelletswere then allowed to dry in the sun light, packedin air tight bottles in order to protect frommoisture and were kept in three plastic bottlesmarked as Feed A, B and C.
• a) Proximate Composition of experimental FeedsThe prepared feeds were subjected to proximatecomposition analysis, according to the methodsgiven in AOAC (1980). The analysis was done inthe laboratory Institute of Bio-chemistry,University of Sindh, Jamshoro and the results areshown in Table 2.
The fish feed were made isocaloric and differentprotein levels of 35%, 38% and 40% by differentcombination of ingredients.Theoretically obtainable percentage ofmetabolizeable energy obtained fromcarbohydrate, lipid and protein were calculated atthe rate of 4.0 kacl/g of carbohydrate, 9.0 kacl/g oflipid and 4.0 kacl/g of protein as suggested by(Pike and Brown, 1967).
• (b) Collection and Stocking of FingerlingsThe experimental fingerlings of carp, L. rohita,were collected from Government Carp FishHatchery, Badin. For the feed trial experiment 10glass aquaria (size 90 × 30 cm) were selected fora period of four months starting from April toJuly 2010. Three feed regimes (treatments) i. e.Feed A with 35%, Feed B with 38% and Feed C40% (gross protein) were replicated thrice andone control with no prepared feed.
• All the experimental fish belonged to thesame age group having mean length andweight of 5.5 ± 1.40 cm and 6.4 ± 1.6 grespectively. The experimental fish werestocked at a density of 10 fish/aquaria.
• (c ) Feeding and SamplingThe experimental feeds were supplied twicedaily morning at 9.00 AM and evening at 5.00 PMat a rate of 8% of the body weight. Sampling wasdone at an interval of one month to adjust thefeeding rate, by measuring the weight of fishand to observe the health condition of fish. Thelength of experimental fish was measured to thenearest mm with an ordinary scale graduatedwith tenth of centimeters. Weight was measuredto the nearest g by a portable electronic balance(Model AK- 3000H AFD).
• (d) Water Quality ParametersThe water quality parameters like temperature,dissolved oxygen, pH, alkalinity, ammonia andnitrite were recorded monthly throughout thestudy period with the help of digital portablewater quality meter model JENCO 3010 (madein Taiwan
• (e) Statistical AnalysisOne way analysis of variance (ANOVA)was used to determine the effects of feedon the growth of carps. This was followedby Duncan’s New Multiple Range Test(DNMRT), (Duncan 1995) at 5% level ofsignificance to observe any differenceamong treatment means.
(a) Energy InputThe total obtainable energy (kcal) in 100 g offeed at various protein levels is shown inTable 3.The total energy coming from each of thefeeds was 320.0 kcal/100g. In all the feed themajor source of energy was protein.The fish feed were made isocaloric anddifferent protein levels of 35%, 38% and 40%by different combination of ingredients.
Name of energysourceFeed A 35%proteinFeed B 38%proteinFeed C 40%proteinProtein 120.00 kacl 140.00 kacl 160.00 kaclFat 99.80 kacl 92.30 kacl 84.80 kaclCarbohydrate 100.20 kacl 87.70 kacl 75.20 kaclGross energy content 320.00 kacl 320.00 kacl 320.00 kaclP/ E ratio 93.75 109.37 125.0Table 3. Energy input (kacl) in 100 g of feedat various protein levels
• The highest growth rate of experimental fish wasobtained with feed B containing 38% protein witha P/E ratio of 109.37 (Table 5). The rate of growthof all the experimental fish increased almostproportionally up to the protein level and thendecreased slowly beyond this level (Table 4).
Table 4. Effects of various feeds on growthparameters of Labeo rohitaParametersFeed A(35%)Feed B (38%)Feed C(40%)Control*With outfeedRearing Period (days) 180 180 180 180Mean Initial Weight(g) 6.4a1± 1.6 6.4a1± 1.6 6.4 a1± 1.6 6.4 a1± 1.6Mean final weight (g) 88.29a± 2.3 135.50 ± 2.66 100.0 ± 1.2 33.55 ± 1.66Weight gain (g) 81.89a129.10 93.60 27.15(%) Weight gain 1379a2117 1562 524SGR (% per day) 1.46a1.69 1.52 0.92FCR 4.50a3.80 4.10 ----Survival (%) 100a100a100a100aProduction Kg/m2/180days 5.886a9.033a6.666 2.236
• The rate of growth of all the experimentalfish increased almost proportionally up tothe protein level and then decreased slowlybeyond this level (Table 4).• The feed B also showed the lowest feedconversion indicating the most efficientutilization of feed at this protein level.• This indicated that the fish couldn’t utilizeexcess levels of protein in the diet abovethe optimum. According to these results, alevel of 38% protein in the diet with a P/Eratio of 109.37 is considered optimum forthe growth of L. rohita,
• The fish with an initial average weight of 6.4 ±1.6 g reached to a final weight of 135.50 ± 2.66,110. 30 ± 1.44 and 120.50 ± 2.11 g in feed B with38% gross protein.• Results of these parameters indicated that thefeed B containing 38% gross protein showssignificantly (p<0.05) highest growth in terms allparameters like weight gain, percentage weightgain, specific growth rate, food conversion andproduction followed by feed C while significantly(p<0.05) lowest growth and production wasrecorded in feed A Table 4.
• No mortality was recorded (100% survivalrate) in the experimental fish throughoutthe study period
• c) Water Quality ParametersThe water quality parameters and their monthlyfluctuations recorded throughout the studyperiod were found with in the suitable rangesfor the fish culture Table 5.
Table 5. Month-wise variation in water qualityparameters in glass aquaria throughout the studyperiod.months ParametersTempCPH D.OMg / LAlkaliMg / LAmmoMg/LNitriteMg/LApril 27.5 7.30 4.8 152 0.54 0.170May 28.4 7.33 4.8 180 0.48 0.171June 29.1 7.30 4.7 160 0.38 0.169July 30.6 7.45 4.0 170 0.44 0.172