Chemical changes
UFRB (18.55%) and FRB (12.78%) contain higher Crude Protein than RB (13.48%) after fermentation (Fig 1). These results agreed with
Supriyati et al., (2015), who described an increased CP content of RB from 12.1 to 13.4% due to microbial fermentation. A NPN compound urea is well known to improve the metabolism as well as to increase the CP contents of rice milling waste
(Wizna et al., 2012). In this study, a significant increase in CP content of RB treated with rumen liquor in combination with 2% urea increased CP content of RB, which might have contributed to the increased growth and proliferation of Bacteria in the rumen liquor.
In this study, amino acid contents were significantly increased by 5% and 44% in FRB and UFRB groups, respectively, indicating an absolute increase in the amino acid contents, either urea was added or not. The amino acid profile was sharply higher in the UFRB
group. Oshoma et al., (2005) agreed that fermented RB contains high protein value and a balanced amino acid composition.
Stevenson (1978) observed that the amino acids were excreted during the active growth of the rumen Bacteria.
Ranjan et al., (2018) found that deoiled RB fermented with
Rhizopus oryzae resulted in a nearly six-fold increase in lysine content and saturated fatty acid content.
Itou et al., (2000) and
Chang et al., (1992) found increase the composition of free amino acids in fermented RB. In this study, it was observed that fermentation resulted in an increase in the amounts of glutamic acid, aspartic acid, glycine, alanine, valine and leucine and low molecular peptides in comparison to unfermented RB (Fig 2).
Khin et al., (2011); Yunus et al., (2015) supported that major component cellulose in the RB is the best for the growth of microorganisms.
Sukaryana, (2001) found that the production of single cell protein biomass increases the crude protein of rice bran with the addition of urea in the UFRB using bacteria.
Wizna et al., (2012) found that
B.
amyloliquefaciens as an inoculum improved fermentation and its microbial population.
Supriyati and Kompiang, (2002) agreed with the results of the present experiment as protein content increased when urea was added.
Growth performance
In this study, live weight gain and feed consumption of broiler in UFRB were significantly increased (p<0.05) but feed conversion ratio was low in FRB group of birds (Table 2).
Kubad et al., (1997) reported that fermented products were more palatable compared to the original materials because fermentation produces some good flavors and water-soluble vitamins such as B1, B2 and B12 and minerals that also support the results of the present experiment as feed consumption was maximum in UFRB group than RB group. Kang
et_al(2015) also found the same result using 10.0% FRB in broiler diet.
In Table 1, CP and metabolizable energy (ME) contents in the diets were equalized. The difference in ME content between all diets would not affect the performances of broiler chickens during this feeding trial.
Olomu and Offiong (1980) found that the different protein (20% and 23%) and energy levels (3,000 and 3,200 kcal/kg) in the diets did not affect the performance of broiler chickens.
The fermented RB diets gave different levels of CF among all diets (Table 1), resulting in different CF consumption.
Gonzalez-Alvarado et al., (2007) reported that the feed consumption of broiler chicks fed with diets containing different levels of CF (2.5% up to 3.4%) differed significantly during the 14 to 21 days.
Mateos et al., (2002) reported that the inclusion of fiber in the diet (below 5%) might be of benefit in terms of nutrient digestibility and growth performance in broilers. In this study, the increased feed consumption in the presence of UFRB with decrease CF (3.76%) in the diets compared to the control RB (4.12%) and FRB (4.05%) diet, might also be due to a more acceptable flavor after fermentation.
According to
Kahlon et al. (2009) and
Ryan et al. (2011), improved growth performance (live weight gain and feed conversion ratio) of broiler may be due to high concentrations of protein, vitamin, minerals, phospholipids, essential fatty acids and more than 120 antioxidants are present in fermented RB.
Lactobacillus,
Saccharomyces and
Bacillus are present in rumen inoculate. This fermented RB are used as feed ingredients all the microbes get access to enter the digestive tract of broiler and serve as a probiotic that enhances the live weight gain in broiler
(Nakphaichit et al., 2011, Salim et al., 2013, Jeong and Kim, 2014) that supports the result of the present experiment as live weight was high in both fermented rice bran (FRB and UFRB) group supplemented with or without urea in the fermentation process (Table 2).
Carcass traits
Carcass traits are not affected by the addition of FRB and RB. Only dressing percentage (carcass yield) was high in UFRB (73%) of birds than another group of bird (Table 3).
Lesson et al., 2000 reported that physiological condition and content of nutrients in feed and genetic factors are affecting the carcass weight of broiler.
Mujahid et al., (2003) reported that RB containing feed increases in organ weights of broiler chicks.