18:99â104. Martin, E., J. Nolan, Z. Nitsan, and D. Farrell. 1998. Strategies ... milling of paddy for production of more rice and oil in. Tamil Nadu. Paddy Process.
Nutrient Digestibility of Broiler Feeds Containing Different Levels of Variously Processed Rice Bran Stored for Different Periods1 A. Mujahid,*,2 M. Asif,† I. ul Haq,* M. Abdullah,‡ and A. H. Gilani* *Department of Botany, Government College University, Lahore, Pakistan 54000; †National Feeds, Sheikhupura, Pakistan 39350; and ‡Faculty of Animal Husbandry, University of Agriculture, Faisalabad, Pakistan 38040 ABSTRACT Nutrient digestibility of broiler feeds containing different levels of variously processed rice bran stored for varying periods was determined. A total of 444 Hubbard male chicks were used to conduct four trials. Each trial was carried out on 111 chicks to determine digestibility of 36 different feeds. Chicks of 5 wk age were fed feeds containing raw, roasted, and extruded rice bran treated with antioxidant, Bianox Dry (0, 125, 250 g/ton), stored for a periods of 0, 4, 8, and 12 mo and used at levels of 0, 10, 20, and 30% in feeds. Digestibility coefficients for
fat and fiber of feeds were determined. Increasing storage periods of rice bran significantly reduced the fat digestibility of feed, whereas no difference in fiber digestibility was observed. Processing of rice bran by extrusion cooking significantly increased digestibility of fat even used at higher levels in broiler feeds. Interaction of storage, processing, and levels was significant for fat digestibility. Treatments of rice bran by different levels of antioxidant had no effect on digestibility of fat and fiber when incorporated in broiler feed.
(Key words: rice bran, digestibility, extrusion cooking, roasting, antioxidant) 2003 Poultry Science 82:1438–1443
INTRODUCTION Rice bran is a major cereal by-product available for animal feeding in rice-growing countries. It contains a good content of protein (13.20 to 17.13%), fat (14.00 to 22.90%), carbohydrate (16.10%), fiber (9.50 to 13.20%), and vitamins and minerals (Vargasgonzalez, 1995; Aljasser and Mustafa, 1996; Ambashankar and Chandrasekaran, 1998). Rice bran in the diet does not affect the health of chickens (Mahbub et al., 1989). In experiments with chicks, cereal grains have been replaced with rice bran, and it was found promising in certain substitutions (Dafwang and Shwarmen, 1996; Khalil et al., 1997a,b). Steyaert et al. (1989) suggested that rice bran could be used up to 30% in mash for broilers. Tiemoko (1992) reported that 30% rice bran in broiler diets replacing maize significantly improved live weight gain, whereas feed conversion efficiency was unaffected. Use of rice bran reduced feed cost per kilogram weight gain (Khalil et al., 1997b), but raw rice bran was observed to induce pancreatic hypertrophy (Eshwaraiah et al., 1986; Martin et al., 1998) and reduce intestinal amylase activity (Martin et al., 1998). Kratzer and Earl (1980) reported
2003 Poultry Science Association, Inc. Received for publication January 14, 2003. Accepted for publication May 1, 2003. 1 This research was performed as part of a Ph.D. requirement. 2 To whom correspondence should be addressed: ahmad_mujahid @hotmail.com.
that some factor in untreated rice bran causes reduction of growth in chickens. Feed intake decreased with 80 and 100% substitution of maize with rice bran (Carrion and Lopez, 1989; Tsvetanov and Duneva, 1990). The feed industry is facing a serious problem of rancidity in rice bran due to high percentage of fat and lipolytic enzymes particularly when stored bran is used in the feed. The presence of antinutritional factors in bran and its poor digestibility further aggravate the feeding problem, leading to mortality and poor performance of broilers. The greatest restriction to the use of rice bran as a feed ingredient is that it is highly unstable in storage. Due to high lipid content, rice bran contains the necessary substrate for development of rancidity. Hydrolysis of the glycerides of the oil in rice bran to form free fatty acids in untreated form is the principal cause of deterioration occurring rapidly during first few days or weeks after milling (Randall et al., 1985; Ramezanzadeh et al., 1999a,b). Other antinutritional compounds found in rice bran that need processing to inactivate include trypsin inhibitors (Benedito and Barber, 1978; Tashiro and Ikegami, 1996), pepsin inhibitors (Mitsuda et al., 1977), hemagglutinins (Benedito and Barber, 1978), phytates, and an antithiamine factor (Lu et al., 1991). Activity of these compounds is relatively low and can be inactivated by heat treatment (Lu et al., 1991). Due to the naturally occurring enzymatic activity and subsequent hydrolytic rancidity that occur rapidly in
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Abbreviation Key: FFA = free fatty acid.
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the bran after milling and continue during storage, it is necessary to stabilize the bran and to inactivate the indigenous antinutritional factors just after milling and before storage. Although several potential methods accomplish stabilization, most are associated with some type of heating process. Extrusion cooking has been found to produce stable rice bran that shows no significant increase in free fatty acid (FFA) content for at least 30 to 60 d (Randall et al., 1985). Heat inactivation of the lipases appears to be the only method with commercial potential. Heating in the presence of moisture is much more effective in permanently denaturing lipases (Ramezanzadeh et al., 1999a,b, 2000). Rancidity development in stored rice bran can also be slowed by the addition of antioxidant (Cabel and Waldroup, 1989). The study was therefore conducted to determine nutrient digestibility of broiler feeds containing different levels of variously processed rice bran stored for varying periods.
MATERIALS AND METHODS Rice bran was stabilized to inactivate antinutritional factors by extrusion cooking, roasting, and by addition of an antioxidant. Raw and processed rice bran was fed at different levels to broiler chicks replacing corn to determine nutrient digestibility and to evaluate the best process and optimum storage period of processed rice bran giving better digestibility. The studies were undertaken at the research laboratory and farms of National Feeds Sheikhupura, Pakistan.
Processing of Rice Bran The rice bran of the same batch was collected from local rice mill in such a way that it was processed within 12 h of milling. Rice bran thus collected was processed for stabilization by the following techniques: Extrusion-Cooking. Rice bran was extruded at 135°C by using a Miltenz extruder of barrel length 1.22 m and rim dies of 130 and 136 mm, with a screw die hole of 6 mm. The passage time was 5 s. The moisture was added at the start of barrel. The extruded rice bran was dried and cooled to room temperature immediately. Roasting. Rice bran was roasted in steam jacket roaster with four chambers. The temperature of rice bran was gradually increased. From an initial rice bran temperature of 28°C, it was raised to 70°C in the first chamber with addition of steam. In the second chamber, temperature was raised to 90°C, and rice bran was kept there for 5 min. In the third chamber, the temperature was maintained at 100°C for 5 min. In the fourth chamber, the rice bran was roasted at 105°C for 5 min. Addition of Antioxidant Without Heat Treatment. Raw and processed rice bran was mixed with a powder
3
Ethoxyquine (E324), butylated hydroxy anisole, citric acid, phosphoric acid, mono- and diglycerides. A product of Biokon NV, Belgium.
antioxidant (Bianox Dry3) in a horizontal ribbon mixer for 5 min at dose rate of 0, 125, and 250 g/ton. After mixing, the rice bran was packed in jute bags and stored at room temperature.
Determination of Nutrient Digestibility Equipment. The experiment was conducted in cages with dimensions of 30.5 × 30.5 × 30.5 cm each, supplied with waterers and feeders. The room temperature was maintained at 28 ± 2°C. Four 40-W florescent tube lights were provided to maintain the light intensity of 100 lx at bird level. The room, cages, and all the material were cleaned, washed with disinfectant, and fumigated with formaldehyde gas before the placement of birds. Experimental Birds. A total of 444 Hubbard male chicks were used to conduct four trials. Each trial was carried out on 111 chicks to determine digestibility of 36 different feeds. In each trial, 111 Hubbard male chicks of 5 wk age and 1500 ± 100 g BW were randomly housed in individual cages. One hundred and eight chicks were force fed, and three chicks were kept as negative control. Rations were fed randomly and marked for the feeding. Feed. Rice bran processed by extrusion cooking, roasting, and treated with an antioxidant was stored for 0, 4, 8, and 12 mo. In each trial, 36 different feeds were formulated using fresh or stored raw, roasted, and extruded rice bran treated with an antioxidant at 0, 125, and 250 g/ton and incorporated at levels of 0, 10, 20, and 30% (Table 1). All feeds were pelleted and used in form of 2- to 3-mm size crumbs. Feeds were analyzed for proximate composition by AOAC (1994). Feeding. The birds were provided an adjustment period of 7 d by feeding experimental diets. They were then kept on 24-h fasting to empty the alimentary canal. Thirty grams of feed was force-fed into the crop of each bird with a 30 cm long glass funnel with 1.1-cm internal and 1.2-cm external diameter. A plunger was used to push the feed into the crop of bird. At the same time, the representative samples of each feed were kept in airtight containers for chemical analysis. Each bird was removed from the cage, fed the feed, and placed back into the same cage. Water was provided ad libitum. Excreta Collection. The excreta were collected over a period of 48 h in individual trays attached at the bottom of the cages. Droppings retained on the wirescreen floor of the cage were also collected. The trays were detached, and feathers were removed from the droppings to avoid contamination. Excreta were dried, weighed, homogenized, and ground for the estimation of fat and fiber (AOAC, 1994). Calculations of Digestibility. Nutrient digestibility of feeds containing rice bran was determined following method of Sibbald (1975) with few modifications as explained. The digestibility of nutrients (fat and fiber) was calculated as follows: Nutrient digestibility (%) =
(NF − NE + NENC) × 100 , NF
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TABLE 1. Composition of rations containing different levels of raw, roasted, and extruded bran treated with antioxidant and stored for 0, 4, 8, and 12 mo Ingredient Rice bran Corn Rice broken Soybean meal (CP 46%) Canola meal (CP 36%) Poultry by-product meal Rapeseed meal (CP 34%) Bone meal Molasses Limestone Premix1 L-Lysine DL-Methionine Analyzed nutrients Crude protein (%) Bran storage (mo) 0 4 8 12 0 4 8 12 Calculated nutrients (%) ME (kcal/kg) Lys Met Met + Cys Calcium Available phosphorus Sodium Chlorides
Rice bran (%)
Heat processing
0.00 52.60 10.00 11.00 12.00 3.00 4.80 2.50 3.10 0.50 0.50 0.18 0.13
10.00 44.60 10.00 11.00 12.00 3.00 3.50 2.50 2.40 0.50 0.50 0.18 0.13
20.00 36.50 10.00 11.00 12.00 3.00 2.20 2.50 1.80 0.50 0.50 0.16 0.13
30.00 28.40 10.00 11.00 12.00 3.00 1.00 2.50 1.10 0.50 0.50 0.15 0.13
18.10
18.10 18.10 Fat (%)
18.10
3.20 3.10 3.01 3.05
3.97 4.80 3.82 4.70 4.01 4.68 3.90 4.83 Crude fiber (%) 4.74 5.59 4.85 5.47 4.62 5.75 4.79 5.50
5.49 5.55 5.40 5.50
3.90 3.81 3.95 3.72 2,800 1.00 0.45 0.72 1.04 0.40 0.20 0.20
2,800 1.00 0.45 0.74 1.04 0.43 0.20 0.20
2,800 1.00 0.45 0.74 1.03 0.46 0.20 0.20
TABLE 2. Regression equations for fat digestibility of feeds containing different levels (%) of rice bran processed by various techniques and stored for different periods (mo)
6.44 6.54 6.42 6.61 2,800 1.00 0.45 0.75 1.03 0.49 0.20 0.20
1 Premix provides per kilogram of feed: vitamin A, 10,000 IU; vitamin D3, 2,000 ICU; vitamin E, 10 IU; vitamin K3, 2.5 mg; thiamin, 1.5 mg; riboflavin, 5 mg; niacin, 40 mg; pantothenic acid, 10 mg; pyridoxine, 5 mg; folic acid, 1 mg; vitamin B12, 0.01 mg; biotin, 0.15 mg; choline chloride, 1,200 mg; sodium, 2 g; chlorides, 2 g; manganese, 60 mg; zinc, 40 mg; iron, 80 mg; copper, 8 mg; and selenium, 0.15 mg.
where NF = nutrient in feed, NE = Nutrient in Excreta, and NENC = Nutrient in Excreta of negative control. Statistical Analysis. The data on various parameters were tabulated, and means and standard deviation of means were analyzed. Duncan’s multiple range test was applied to compare the means with probability level P < 0.05. The data on each parameter were subjected to statistical analysis using analysis of variance technique according to completely randomized design using general linear models of SAS software (SAS, 1989). To determine effects of processing, storage and different levels of rice bran on nutrient digestibility of broiler feeds following statistical model were used: Yijklm = µ + Si + Pj + Lk + Al + SPij+ SLik + SAil + PLjk + PAjl + LAkl + SPLijk + SPAijl + SLAikl + PLAjkl + SPLAijkl + eijklm where S = 1, 2, 3, 4; P = 1, 2, 3; L = 1, 2, 3, 4; and A = 1, 2, 3; µ = population mean; Si = storage effects; Pj = processing effects; Lk = level effects; Al = antioxidant
Regression equations for fat digestibility (%)
Raw Roasting Extrusion cooking
93.453 − 0.483 storage − 0.771 level 94.555 − 0.606 storage − 0.565 level 92.168 − 0.527 storage − 0.607 level
effects; and eijklm = random error. It was further assumed that eijklm ∼ NID (0, σ2). Regression equations for determination of fat digestibility of feeds containing different levels of rice bran, processed by different methods, and stored for various periods were worked out (Table 2) using SAS software (SAS, 1994) with the following statistical models: FD = a + bX and FD = a + cY + dZ where FD = fat digestibility (percentage) of feed containing rice bran, a = intercept, b = regression coefficient for storage period of rice bran/level of rice bran in ration, c = partial regression coefficient for storage period of rice bran, d = partial regression coefficient for level of rice bran in ration, X = storage period of rice bran (months)/level of rice bran in ration (percentage), Y = storage period of rice bran (months), and Z = level of rice bran in ration (percentage).
RESULTS Fat Digestibility Significant reduction in fat digestibility was observed with increasing storage period of rice bran (Table 3). Maximum fat digestibility was observed in rations with fresh rice bran, while the minimum was observed with TABLE 3. Fat digestibility of feed containing different levels of rice bran processed by various techniques and stored for different periods Variable 0 4 8 12 Processing Extrusion cooking Roasting Raw Level (%) 0 10 20 30 Antioxidant1 (ppm) 0 125 250
Fat digestibility (%) 83.53a 80.32b 73.33c 69.59d
± ± ± ±
5.62 8.49 9.81 11.82
80.24a ± 7.87 76.32b ± 10.93 73.51c ± 11.90 87.11a 78.06b 73.51c 68.09d
± ± ± ±
3.77 9.03 9.51 8.93
77.23 ± 10.49 76.43 ± 10.94 76.43 ± 10.76
a–d Means with different superscripts are significantly different (P < 0.05). 1 Bianox Dry.
NUTRIENT DIGESTIBILITY OF RICE BRAN TABLE 4. Analysis of variance of data on fat digestibility of feeds containing different levels of rice bran processed by various techniques and stored for different periods Source of variation
df
Storage (mo) Processing1 Level (%) Antioxidant2 Storage × processing Storage × level Processing × level Storage × processing × level Error Total
3 2 3 2 6 9 6 18 288 431
Mean squares for fat digestibility 4,377.14** 1,646.90** 7,003.90** 30.59 118.28** 453.26** 265.38** 32.64** 16.32
1
Extrusion cooking, raw and roasting. Bianox Dry. **P < 0.01.
2
rations containing rice bran stored for 12 mo. Significant difference (P < 0.05) in fat digestibility was observed due to different processes (Table 4). Maximum fat digestibility was observed with extruded followed by roasted and raw rice bran. There was a significant decrease in digestibility of feed with increasing levels of rice bran. Maximum fat digestibility was observed in rations without rice bran, while minimum digestibility was observed in rations with 30% rice bran. Nonsignificant differences in fat digestibility were observed when rice bran was treated with different levels of antioxidant. Significant (P < 0.01) interaction was observed in fat digestibility among storage, processing, and levels when used in broiler feed. Interaction of antioxidant among storage, processing, and levels was nonsignificant.
Fiber Digestibility Fiber digestibility of experimental feeds ranged between 10.96 to 11.44% in different trials with average value of 11.24%. There was no difference in fiber digestibility of feed containing rice bran processed by different techniques, stored for various periods, and used at different levels. Effect of rice bran processed by different levels of antioxidant was also nonsignificant. Interaction of storage, processing, and level for fiber digestibility was also nonsignificant.
DISCUSSION Increase in digestibility of fat in feed containing rice bran processed by extrusion cooking and roasting as compared with untreated rice bran was due to stabilization of bran by these two techniques. Upon milling, the neutral oil is exposed to lipases in the bran, causing its rapid breakdown to FFA at an initial rate of at least 5 to 7% of the weight of oil per day (Desikachar, 1974). Stabilizing the bran (inactivating lipases) can prevent oil deterioration immediately after milling. Nutritional quality of rice bran deteriorates rapidly as the oil under-
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goes hydrolytic and oxidative rancidity (Subrahmanyan, 1977). Compared with rice bran that has been treated with moist heat, both freshly milled and stored raw rice bran have been shown to retard the growth of young chicks (Kratzer et al., 1974; Kratzer and Payne, 1977). Sidhom et al. (1975) observed that development of FFA in rice bran was much slower when the bran was stored at a cooler temperature. Antioxidant resulted in nonsignificant effect on stabilization of rice bran leading to poor nutrient digestibility of feed containing bran. These findings are contrary to that of Cabel and Waldroup (1989) who reported slowing of rancidity development in stored rice bran by the addition of antioxidant. Experimental differences were that they added ethoxyquin at higher levels (250, 500, and 1,000 ppm) in fresh rice bran and for only 4 wk, whereas in the present study, maximum levels used were only 250 ppm, and storage was prolonged for 4 mo and up to 1 yr. The antioxidant, which was effective in reducing rancidity at a level of 250 ppm (Cabel and Waldroup, 1989) for 4 wk was not effective at reducing rancidity for 4 mo. Reduction in nutrient quality of bran during storage resulted in decreased nutrient digestibility, which was further reduced with increasing level of rice bran. Significant (P < 0.01) interaction was observed in fat digestibility of feeds among storage, processing, and levels. Higher fat digestibility was observed by extrusion cooking and roasting with decreasing levels of rice bran stored for shorter periods. Digestibility of fat in feeds with roasted rice bran was significantly higher when stored up to 4 mo and incorporated at different levels as compared with raw rice bran. After 4 mo of storage, differences in fat digestibility at various levels of roasted rice bran was nonsignificant as compared with raw bran. The fat digestibility of feeds containing extruded rice bran was significantly higher when rice bran was incorporated in feeds stored for different periods up to 1 yr as compared with raw and roasted bran. The improvement in fat digestibility due to roasting and extrusion cooking was due to inactivation of lipases, trypsin inhibitors, and denaturation of antinutritional factors, as reported by Ramezanzadeh et al. (1999a) and Saunders (1990). Extrusion cooking gave significantly better results as compared with roasting. This confirms the findings of Ramanathan et al. (1977), Tribelhorn et al. (1979), and Cheigh et al. (1980) who reported that extrusion cooking gave better storage stability of rice bran as compared with rotational drum heater. Higher levels of crude fiber, 6.44% in feed containing 30% rice bran (Table 1), as compared with 3.9% in feed without bran, may be another factor for reducing nutrient digestibility of feeds. Nonlinear mathematical models for bran (Elmoniem, 1994) indicated the optimum amounts of the fibers as 7.9, 9.3, and 5.2%, giving maximum digestibilities of 88.4, 84.1, and 85.2% of maize bran, rice bran, and barley husk, respectively. Compared with control (100% wheat flour), changes in digestibility were 4.9, −0.25, and 1.1% for the fibers, re-
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spectively. Akiyama et al. (1991) reported that waterholding capacity of the brans was increased by extrusion, but fecal water-holding capacity was not affected. Fecal weight and the length of the small intestine were significantly decreased in rats fed on the extruded products. Gastrointestinal transit time of extruded products did not differ from that of nonextruded products. Apparent rates of digestion and absorption of protein were increased, but those of fat were decreased by extrusion. The fecal excretion rate of dietary fiber was decreased significantly in the rats given the extruded products. Extrusion cooking produces stable rice bran, which show no significant increase in FFA content for at least 30 to 60 d (Randall et al., 1985). Heat inactivation of the lipases appears to be the only method with commercial potential. Heating in the presence of moisture has been reported to be much more effective in permanently denaturing lipases (Barber et al., 1974; Kratzer et al., 1974; Ramezanzadeh et al., 1999a,b, 2000). Increasing storage periods and levels of rice bran processed by different techniques may reduce nutrient digestibility by their synergistic effects of oxidative by-products of fat, decreased nutrient values, and increased fiber contents of feeds. All these factors lead to significant reduction in digestibility of protein, fat, and possibly other nutrients. Increasing storage periods of rice bran significantly reduced the fat digestibility of feed, while no such effect was observed on fiber digestibility. Processing of rice bran by extrusion cooking significantly increased digestibility of fat even when used at higher levels in broiler feed. Storage, processing, and levels of rice bran showed significant interaction for fat digestibility. Addition of different levels of antioxidant to rice bran did not affect digestibility of fat and fiber when it was incorporated in broiler feed.
REFERENCES Akiyama, T., T. Hayakawa, K. Nakamura, T. Takita, and S. Innami. 1991. Influence of extrusion cooking of cereal brans on their properties and physiological action in rats. J. Jpn. Soc. Nutr. Food Sci. 44:19–27. Aljasser, M., and A. Mustafa. 1996. Quality of Hassawi rice bran. Ann. Agric. Sci. 41:875–880. Ambashankar, K., and D. Chandrasekaran. 1998. Chemical composition and metabolizable energy value of rice waste for chicken. Ind. Vet. J. 75:475–476. AOAC. 1994. Official Methods of Analysis. Association of Official and Analytical Chemists. 15th ed. Arlington, VA. Barber, S., J. M. Camacho, R. Cerni, E. Tortosa, and E. Primo. 1974. Process for the stabilization of rice bran. 1. Basic Research Studies. Proc. Rice By-Products Utilization. Int. Conf., Valencia, Spain 2:49–53. Benedito, D. B. C., and S. Barber. 1978. Toxic constituents of rice bran. Rev. Agroquim Technol. Aliment. 18:89–92. Cabel, M. C., and P. W. Waldroup. 1989. Research note: Ethoxyquin and ethylenediaminetetra acetic acid for the prevention of rancidity in rice bran stored at elevated temperature and humidity for various lengths of time. Poult. Sci. 68:438–442. Carrion, J. G., and J. Lopez. 1989. Whole rice bran as a substitute for maize in the feeding of broiler chickens. 1. Performance and productivity. Rev. Soc. Bras. Zoot. 18:320–324.
Cheigh, H. S., C. J. Kim, and D. C. Kim. 1980. Development and use of a low cost extruder for the rice bran oil stabilization at local mill. Pages 68–71 in International Symposium on Recent Advances in Food Science and Technology, Talpel. Dafwang, I. I., and E. B. N. Shwarmen. 1996. Utilization of rice offal in practical rations for broiler chicks. Niger. J. Anim. Prod. 23:21–23. Desikachar, H. S. R. 1974. Status Report. Preservation of byproducts of rice milling. In Proc. Rice By-Products Utilization Int. Conf., Valencia, Spain 2:1–10. Elmoniem, G. M. A. 1994. Mathematical models for maximum improvement of in vitro protein digestibility of high dietary fibre cookies. Nahrung 38:32–37. Eshwaraiah, C., V. Reddy, and P. V. Rao. 1986. Feeding value of raw rice polish, deoiled rice polish and parboiled rice polish for broiler starter chicks. Ind. J. Poult. Sci. 21:114–119. Khalil, D. Hohler, and H. Henkel. 1997a. Utilization of rice bran and peanut meal in broilers. 1. Characterization of the feed efficiency of a rice bran/peanut meal diet. Arch. Gefluegelkd. 61:88–94. Khalil, D. Hohler, and H. Henkel. 1997b. Utilization of rice bran and peanut meal in broilers. 2. Improvement of the feed efficiency of a rice bran/peanut meal diet by a starter feeding period and by the addition of threonine and preserving agents. Arch. Gefluegelkd. 61:120–125. Kratzer, F. H., and L. Earl. 1980. The lack of growth depression in poults and coturnix chicks fed raw rice bran. Poult. Sci. 59:1626–1630. Kratzer, F. H., and C. G. Payne. 1977. Effect of autoclaving, hot water treatment, parboiling and addition of ethoxyquin on the value of rice bran as a dietary ingredient for chickens. Br. Poult. Sci. 18:475–482. Kratzer, F. H., L. Earl, and C. Chiaravanont. 1974. Factors influencing the feeding value of rice bran for chickens. Poult. Sci. 53:1795–1800. Lu, B. S., S. Barber, and D. B. C. Benedito. 1991. Rice bran: Chemistry and Technology. Pages 313–315 in Rice Production and Utilization, vol. II. B. S. Luh, ed. Van Nostrand Reinhold, NY. Mahbub, A. S. M., M. A. Rahman, and A. Reza. 1989. Use of rice polish as partial replacement of wheat in the diet of growing chicks. Bangladesh J. Anim. Sci. 18:99–104. Martin, E., J. Nolan, Z. Nitsan, and D. Farrell. 1998. Strategies to improve the nutritive value of rice bran in poultry diets. IV. Effects of addition of fishmeal and a microbial phytase to duckling diet on bird performance and amino acid digestibility. Br. Poult. Sci. 39:612–621. Mitsuda, H., F. Kawai, A. Suzuki, and J. Hondo. 1977. Studies on the production of a protein rich fraction from rice bran by means of fractional sedimentation in n-hexane. Pages 35–39 in Rice Report 1976. S. Barber, H. Mitsuda, H. S. R. Desikachar, and E. Tortosa, ed. Int. Union of Food Scientists and Technologists Working Party and Rice Utilization. Institute for Agriculture, Chemistry, and Food Technology, Valencia, Spain. Ramanathan, P. K., H. K. Murty, and D. P. Sen. 1977. Stabilization of rice bran oil. Page 75 in Annual Report. Solvent Extractors Association, Bombay, India. Ramezanzadeh, F., R. Rao, M. Windhauser, W. Prinyawiwatkul, and W. Marshall. 1999a. Prevention of oxidative rancidity in rice bran during storage. J. Agric. Food Chem. 47:2997–3000. Ramezanzadeh, F., R. Rao, M. Windhauser, P. Witoon, R. Tulley, and W. Marshall. 1999b. Prevention of hydrolytic rancidity in rice bran during storage. J. Agric. Food Chem. 47:3050–3052. Ramezanzadeh, F., R. Rao, P. Witoon, W. Marshall, and M. Windhauser. 2000. Effects of microwave heat, packaging and storage temperature on fatty acid and proximate composition in rice bran. J. Agric. Food Chem. 48:464–467.
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Subrahmanyan, V. 1977. Improved method of processing and milling of paddy for production of more rice and oil in Tamil Nadu. Paddy Process. Res. India 9. Tashiro, M., and S. Ikegami. 1996. Changes in activity, antigenicity and molecular size of rice bran trypsin inhibitor by in-vitro digestion. Nutr. Sci. Vitam. 42:367–376. Tiemoko, Y. 1992. Effects of using rice polishings in broiler diets. Bull. Anim. Health Prod. Africa 40:161–165. Tribelhorn, R. E., D. A. Cummings, and J. D. Kellerby. 1979. Characteristics of LEC’s and manufacturing experiences. Page 165 in LEC Report No. 7. Colorado State University, Fort Collins, CO. Tsvetanov, I. M., and N. Duneva. 1990. Study on the substitution of maize with rice bran and incineration fat in mixed foods for broiler chickens. Zhivot. Nauki 27:42–45. Vargasgonzalez, E. 1995. The nutritive value of rice by-products in Costa Rica. Chemical composition, availability and use. Nutr. Anim. Trop. 2:31–50.
