Fermentation improves the nutritive value of rice bran, according to the study, published in the Journal of Applied Poultry Research.
While rice bran is a potential feed resource with high nutritional value, antinutritional factors such as the presence of phytate and high fiber restrict its use as a broiler feed ingredient, they said.
The team, citing work by Gallinger et al. (2004), reported that excessive inclusion of rice bran hampers the growth of chicks.
But help is at hand. Fermentation can increase protein levels and reduce the fiber content of rice bran and other agro-industrial byproducts according to research by Sugiharto, 2016; Ullah, 2021.
Fermentation can also enhance the functionality of rice bran as a poultry feed ingredient noted Sugiharto et al., 2018. Such a process can improve the phenolic content and antioxidant activity of the feed raw material (Oliveira et al., 2008), and decrease its phytate phosphorus content (Azrinnahar et al., 2021), reported the Bangladesh based experts.
Inclusion of fermented rice bran further assists in reducing the cholesterol content of broiler meat, they added.
Different organisms ferment rice bran, and their effects on improving the nutritional quality of rice bran also differ, said the team.
Rumen inoculum obtained from mature cattle could be used for the fermentation of rice bran, while Martin et al. (1998) found that Bacillus amyloliquefaciens produces phytase that hydrolyzes phytic acid in rice bran - protein, calcium, and phosphorus trapped by phytic acid are then released and diluted for poultry use.
Urea and molasses supplements can accelerate the fermentation process and improve the nutritional content of the fermented rice bran, added the research team.
Their own study was designed to see if the nutritional quality of rice bran was improved through fermentation and if there was a boost to broiler production.
The team mixed inoculum and rice bran in a 1:1 ratio for fermentation at 39℃ for 48 hours, performing proximate analysis to determine amino acid content.
In total, 120-day-old chicks were randomly divided into three groups.
The researchers outlined the various dietary approaches: unfermented rice bran was administered to the control group (C), 10% fermented (only rumen inoculum used) rice bran was administered to the F group, and 10% fermented rice bran (5% molasses added with rumen inoculum) was administered to the MF group.
The rations were prepared in the feed mill of Shahjalal Animal Nutrition Field Laboratory, Bangladesh Agricultural University, and provided ad libitum to broilers for 35 days; broiler blood samples were collected on the 35th day.
The researchers saw that fermentation increased the crude protein content of fermented rice bran by 17.21 and 24.59% in the F and MF groups, respectively.
They said that fiber content was reduced by 14.29 and 24.10% in the F and MF groups, respectively. Phytate phosphorus content was also reduced in both fermented groups.
FCR was low in the F and MF groups. Blood cholesterol level was reduced by 22.89 and 13.09% in F and MF groups, whereas the blood albumin content was increased by 24.15 and 14.61% in F and MF groups, respectively.
Overall, the team concluded that fermentation improves the nutritive value of rice bran, and addition of supplements, such as molasses, accelerates fermentation. Adding fermented rice bran to broiler rations enhances the growth performance of the birds and reduces the cholesterol level in their blood serum.
“Probiotic effects, phytase activities, and some important enzymes produced during fermentation are responsible for the beneficial changes of blood profile in fermented rice bran offered broilers.”