Effect of rice bran replacement by corn meal on growth, feed utilization of black carp (Mylopharyngodon piceus) Tran Quang Hung 1 , Tran Thi Nang Thu 2 , Mintra Seel-audom 1* ABSTRACT A 90-day feeding experiment was conducted to evaluate growth performance, feed utilization of black carp (Mylopharyngodon piceus) (30.05 ± 0.11 g, initial average body weight) fed diets where rice bran (RB) was replaced by corn meal (CM). Four approximately iso-nitrogenous (35%) and iso-lipidic (12%) diets, containing 0, 100, 200 and 300 g kg -1 corn meal were fed to triplicate groups (10 fish each). Fish were fed twice a day to satiation. Final body weight (BW), weight gain (WG), daily weight gain (DWG), specific growth rate (SGR) and protein efficiency ratio (PER) were highest for 200 g kg -1 diet (p<0.05), whilst there were no differences in protein intake (PI), feed intake (FI) and survival rate (SR) between diets (p>0.05). It was concluded that corn meal are suitable ingredient for use in black carp diet formulation at a level of 20%. Further increase in corn meal inclusion (30%) had a negative effect on fish growth performance and feed utilization. Keywords: black carp, Mylopharyngodon piceus, corn meal, rice bran, growth performance * Corresponding author; e-mail address: [email protected]1 Department of Animal and Aquatic Sciences, Faculty of Agriculture, Chiang Mai University, Chiang Mai, Thailand 50200 2 Department of Aquaculture, Faculty of Animal Science and Aquaculture, Vietnam National University of Agriculture, Hanoi, Vietnam 1203 การประชุมทางวิชาการของมหาวิทยาลัยเกษตรศาสตร์ ครั้งที่ 53 สาขาประมง
Transcript
Effect of rice bran replacement by corn meal on growth, feed utilization of
black carp (Mylopharyngodon piceus)
Tran Quang Hung1, Tran Thi Nang Thu2, Mintra Seel-audom1*
ABSTRACT
A 90-day feeding experiment was conducted to evaluate growth performance, feed utilization of
black carp (Mylopharyngodon piceus) (30.05 ± 0.11 g, initial average body weight) fed diets where rice bran
(RB) was replaced by corn meal (CM). Four approximately iso-nitrogenous (35%) and iso-lipidic (12%) diets,
containing 0, 100, 200 and 300 g kg-1 corn meal were fed to triplicate groups (10 fish each). Fish were fed
twice a day to satiation. Final body weight (BW), weight gain (WG), daily weight gain (DWG), specific growth
rate (SGR) and protein efficiency ratio (PER) were highest for 200 g kg-1 diet (p<0.05), whilst there were no
differences in protein intake (PI), feed intake (FI) and survival rate (SR) between diets (p>0.05). It was
concluded that corn meal are suitable ingredient for use in black carp diet formulation at a level of 20%.
Further increase in corn meal inclusion (30%) had a negative effect on fish growth performance and feed
* Corresponding author; e-mail address: [email protected] 1Department of Animal and Aquatic Sciences, Faculty of Agriculture, Chiang Mai University, Chiang Mai, Thailand 50200 2Department of Aquaculture, Faculty of Animal Science and Aquaculture, Vietnam National University of Agriculture, Hanoi,
INTRODUCTION Small-scale aquaculture is a very important activity for food security, especially for poor
people in developing countries in the tropics and subtropics (Tacon et al., 2010). In Northern mountain region of Vietnam, among the poorest areas of the country aquaculture significantly contributes not only to food security but also to income generation and farmers’ livelihood strategies (Steinbronn, 2009). Fish farm is often operated within integrated farming systems, characterized by the poly-culture of carp and tilapia fish species, with grass carp as the main species, being fed low quality on-farm feed resources (Luu, 2001, Dongmeza et al., 2009, Steinbronn, 2009, Pucher et al., 2013, Pucher et al., 2014).
Recently, black carp (Mylopharyngodon piceus) has been introduced to the region and significantly improved local farmers’ income. M. piceus is high economic value freshwater-cultured fish in China (Leng and Wang, 2003; Sun et al., 2011) and in Vietnam (Van et al., 2010). In the latter, black carp has been widely farming in Northern provinces (Phuong et al., 2009) and are normally fed two types of feed; homemade and commercial pelleted feeds dedicated for other farmed fish species than black carp (Phuong et al., 2009; Van et al., 2010).
Being carnivorous feeding habits (Hu et al., 2014), black carp requires high dietary protein levels ranging from 35% to 40% in diets (Leng and Wang, 2003; Van and Thu, 2013; Hu et al., 2014). Reportedly, in aquafeeds fish meal is the major dietary protein source, commonly making up between 20-60% (Watanabe, 2002; Glencross et al., 2007; FAO, 2012). It is well known that feed is the principle cost in the cultivation of most fish species (Wilson, 2002) and this cost has tended to increase with the rising price of fish meal. One way to reduce feed costs is to increase use of cheap, locally available feed resources (Edwards and Allan, 2004; Hardy, 2010).
Meanwhile, in Northern mountainous region of Vietnam maize is the most abundant crop product through the year. GSO (2014) reported that the region produced 1,844,000 tonnes in 2012 and was the leading maize contributor over the country. Corn kernels after harvested are sold to the lowlands at relatively low prices and normally used as ingredients in animal feeds (Tuan, 2010). It was reported that maize in region is similar in quality to that from other countries and this is not only a source of carbohydrate but also a good supplemental protein source (Khoi et al., 1987; Dongmeza et al., 2009; Tuan, 2010).
Up to date no data is available on the utilization of this locally available ingredient, corn meal (CM) in diets for black carp. Therefore, the aim of the present study was to evaluate the growth performance, feed utilization of black carp (M. piceus) fed diets containing different level of CM as a replacement for rice bran (RB), another locally available feedstuff.
MATERIALS AND METHODS 1. Diets preparation
Four iso-nitrogenous (crude proteins, 35%) and iso-lipid (crude lipids, 12%) experimental diets were formulated, in which the added levels of CM were 0 (control), 100, 200 and 300 g kg-1 (abbreviated CM0, CM100, CM200 and CM300). The approximate compositions of the experimental diets are shown in Table 1. 2. Fish and facilities
The experiment was conducted at the Laboratory of Aquaculture, Vietnam National University of Agriculture, Vietnam. Black carp were obtained from Research Institute for Aquaculture No.1, Bac Ninh province, Vietnam and were acclimated to the experimental conditions by feeding on the commercial diet for one month. At the start of the experiment, a total of 120 fish (initial mean weight, 30.01±0.11 g) were randomly stocked into 500-L composite tanks (each tank with water volume of 300L). Each of four experimental diets was randomly assigned to three replicate tanks. In all 12 tanks, water was equally aerated and installed with a water flow-through system at a flow rate of 2 L min-1.
Water temperature, dissolved oxygen and pH were checked daily and ranged from 22.5 to 30.10C (mean temperature, 26.30C); 4.9-6.3 mg L-1 and 6.9-7.9, respectively.
Fish were carefully fed to apparent satiety, twice a day at 07:00 h and 17:00 h during 90 days.
Table 1 Formulation and proximate composition of the experimental diets (g kg-1 dry matter basis)
3. Proximate composition CM and RB were analyzed for dry matter, crude proteins, crude lipids, ash, crude fiber and
gross energy; experimental diets were analyzed for crude proteins, crude lipids according to standard procedures (AOAC, 1995). 4. Calculations and statistical analysis
The following variables were calculated:
Survival rate (SR%) = 100 x TFf
TFi
Specific growth rate (SGR%) = 100 x Ln(Wf) - Ln(Wi)
T
Where: TFf is total number of fish at finish (harvest) and TFi is total number of fish at start.
Weight gain (WG) = Wf - Wi
Daily weight gain (DWG) = Wf - Wi
T
Protein efficiency ratio (PER) = Wet weight gain (g) Total protein intake (g)
Protein intake (PI) = Feed intake (g) Percent protein in diet
Total feed intake per fish (FI) = Total feed intake (g) Number of fish
Feed conversion ratio (FCR) = Total feed intake (g) Total wet weight gain (g)
Wf and Wi are the mean final weight and the mean initial weight, respectively, and T is the feeding trial period (day).
All data on fish growth performance, feed utilization were statistically analysed by one-way analysis of variance (ANOVA), followed, where appropriate, by Tukey's post hoc test. ANOVA statistical analyses were carried out using the Statistical Software System version 14 (SPSS Inc, Chicago, USA). Differences were regarded as significant when p<0.05.
RESULTS AND DISCUSSION 1. Chemical composition of feed ingredients and diets
Table 2 shows the proximate composition, dry matter, crude protein, crude lipid, crude fiber, ash and gross energy of both CM and RB. It was found that these feedstuffs have similar dry matter levels. CM contains slightly higher crude protein and gross energy than those in RB. RB, on the other hand, has much higher crude lipid, crude fiber and ash content than CM.
The chemical values in this study were in good agreement with previously published data (Khoi et al., 1987; Dongmeza et al., 2009; Steinbronn, 2009; Tuan, 2010; Thu, 2012) who collected samples from the same location, Northern mountainous region of Vietnam.
According to Champagne et al. (1990), fat was more concentrated in the outer surface of bran layer as most fat is found in the aleurone layer. This feedstuff, on the other hand is a good source of minerals (ash) which are present in varied amounts (Rosniyana et al., 2007). These views explained the high fat and ash content in RB.
The high dietary ash and fiber content in RB may have negative effects on dry matter apparent digestibility coefficients (NRC, 1993; Sullivan and Reigh, 1995; McGoogan and Reigh, 1996; Bureau et al., 1999; Wu et al., 2006 and Masagounder et al., 2009). Table 2 Proximate chemical composition (g kg-1 dry matter basis), gross energy (Mj/kg) of corn meal and rice bran.
Type of analysis CM RB Dry matter 895.8 890.0 Crude proteins 94.5 84.1 Crude lipids 42.9 135.2 Crude fiber 19.4 132.6 Ash 19.1 135.2 Gross energy 20.1 18.2
The proximate composition of the test diets (Table 1) showed little variation in crude protein
and lipid levels among them, ranged between 35.98 - 36.42% and 11.94 - 12.48%, respectively, and was within the range required for normal growth rate in black carp (M. piceus) (Leng and Wang, 2003; Van and Thu, 2013; Hu et al., 2014). 2. Growth performance and feed utilization
The final body weight (BW), WG, DWG, SGR and PER were highest for the CM200 diet (p<0.05) whilst there were no differences in those indicators between other diets (Table 3). Among diets, CM200 was significantly lower in FCR than CM300 (p<0.05). Moreover, the values for FCR were numerically higher for the CM0 diet than CM100. There were no differences (p>0.05) in initial BW, SR, PI and FI between test diets. It was observed that fish fed the diet containing 200 g kg-1 CM grew significantly better (p<0.05) than all other experimental feeds.
DWG of black carp in the present study were comparable to those reported in earlier studies on the same species (Sun et al., 2011; Hu et al., 2014). Additionally, the result of FCR in our study was in good agreement with data registered for same species (Sun et al., 2011), PER was similar with that reported for striped catfish fed local feed resources (Da et al., 2012), and slightly higher than that
reported for M. piceus (Hu et al., 2014). This indicates that the amino acid supply and amino acid profile in the test diets were adequate in relation to the dietary requirements of black carp. In addition, FCR value of the mix 20:10 (CM:RB) diet was significant higher than that of the 30:0 diet. The similar pattern was recorded in PER. This could be attributed to the better availability and utilization of nutrients in the corresponding mix. Table 3 Growth, feed utilization, feed conversion and the percentages of survival of black carp (Mylopharyngodon piceus) fed the test diets. Test diets Diet 1 (CM0) Diet 2 (CM100) Diet 3 (CM200) Diet 4 (CM300) Initial BW (g) 29.96±0.63 30.04±0.34 30.12±0.26 30.07±0.46 Final BW (g) 50.03±4.73a 52.32±2.09a 65.49±2.80b 48.54±4.50a WG (g) 20.07±4.37a 22.28±1.77a 35.36±2.96b 18.48±4.95a DWG (g) 0.22±0.05a 0.25±0.02a 0.39±0,03b 0.21±0.05a SGR (%) 0.57±0.09a 0.62±0.03a 0.86±0.05b 0.53±0.12a
FCR 1.55±0.26ab 1.40±0.16ab 0.84±0.07a 1.80±0.48b
PER 1.82±0.31a 1.98±0.22a 3.27±0.28b 1.60±0.38a PI 0.122±0.005 0.125±0.006 0.120±0.001 0.128±0.004 FI 30.35±1.23 31.14±1.43 29.71±0.10 31.62±1.02 SR (%) 96.67±5.77 100 100 96.67±5.77 BW: body weight; WG: weight gain; DWG: daily weight gain; SGR: specific growth rate; FCR: feed conversion ratio; FCE: food
conversion efficiency; PER: protein efficiency ratio; PI: protein intake; FI: total feed intake per fish; SR: survival ratio.
SEM = Standard error of the mean.
Means with different superscript letters within rows are significantly different (p<0.05).
One of the most common difficulties observed when alternative sources of feedstuffs used in
fish diets is acceptance and palatability (Dominguez et al., 2003). However, no significant difference recorded in PI, FI (Table 3) showed that fish satisfied with different inclusion of CM and RB in experimental diets in term of acceptance and palatability. The results in the present study indicated that as at an inclusion level of 200 g kg-1 CM in diet, there was significant positive effect on the growth or feed utilization of M. piceus. However, when RB totally replaced by CM (300 g kg-1 CM), WG, DWG, SGR, FER and FCR were significantly lower than those in the CM200 diets and numerically lower than CM0 and CM100. This could be referred to two reasons; i) CM and RB is a good source of carbohydrate and energy for fish and contain different levels carbohydrate forms (starches, sugars) (Law, 1986; Chiou and Ogino, 1975). The rate of mixing (CM:RB) changes the levels of carbohydrates and may affect the rate of carbohydrate degradation (glucose release) to be faster or slower in the fish gut (Belal, 1999; Belal, 2004). Glucose is known to inhibit transport of amino acids at their absorption sites in fish gut membranes when it is released too fast (Hokozono et al., 1997). As reaching optimal mix, rate of glucose release may not affect amino acid transport, protein retention and produces superior growth rate. As CM totally replaces RB the rate of glucose release would probably faster. As a result, the growth rate of fish fed CM300 diet was negatively affected. (Belal and Al-Jasser, 1997; Belal, 2004). ii) the rate CM:RB may also change the levels of starch in diets for M. piceus, the high levels of this seem to result a poor ability to take care of excess glucose (Bergot, 1979; Hilton et al., 1987; Hemre et al. 1993, 1995; Moon 2001), fish are assumed to be under constant metabolic stress (Pieper and Pfeffer, 1980), being eventually negative effect on fish growth. Consequently, the higher PER and growth performance in CM200 in our study was a evident supporting mentioned views. These data suggested that black carp could not be cultured successfully using a diet with RB being totally replaced by CM.
Some authors, on the other hand registered that dietary inclusion level of CM up to 30 % in omnivorous fish feeds (Hertrampf and Piedad-Pascual, 2000), and up to 36%, as in replacement by
barley seed in diets for Nile tilapia (Oreochromis niloticus) (Belal, 1999). These may relate to a fact that omnivorous fish consume relatively higher amounts of carbohydrates in diets than carnivorous fish, and they also make better use of this nutrient (Hidalgo et al., 1999). In addition, black carp were fed a diet containing CM or RB alone, they grew more poorly than that containing the CM-RB mixture. This indicated that mixing different sources of carbohydrate would probably have advantage over using only source. The finding was consistent with previous studies (Belal and Al-Jasser, 1997; Belal, 1999; Belal, 2004).
CONCLUSION The mixing CM with RB at ratio of 20:10 in M. piceus diet could improve fish growth
performance and feed utilization. Total replacement of RB with CM at 300 g kg-1 would have a negative effect on growth parameters.
ACKNOWLEDGEMENTS The authors gratefully acknowledge International Foundation for Science (IFS) and IDRC-
SEARCA Scholarship for financial support.
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