Rice bran: Potential feed for fish, poultry

 By Arthur Roberts, Elly Solomon and Martin Lobâo

There is a growing trend in the number of farmers and investments in local rice production especially for household consumption and income. This means quantities of by-products such as rice bran will also increase making it an important source of animal feed. 

The utilisation of rice bran as feed ingredient for livestock and cultured fish will potentially add value to the many local rice mills already established in communities around PNG. From an estimated 30,000 tonnes of rice produced locally, around 3300 tonnes of rice bran as by-product is wasted each year. This is equivalent to around 422kg and 194 tons of protein and energy respectively which are essential sources of nutrients for animal feed. 

How can farmers make the best use of this resource to sustain production and diversify their income prospects? This has been part of the priority initiatives of NARI to help small and medium enterprises (SMEs), particularly in aquaculture, piggery and poultry production to effectively and efficiently utilse locally available feed resources that can reduce feed cost and improve productivity and profitability.

The major challenge now in the expansion of livestock and cultured fish production for SMEs is the rising cost of commercial feed formulated from imported ingredients such as wheat, sorghum and soybean. These imported grains together with poor road infrastructure and transport have dictated the growing prices of commercial feeds which over the past 10 years have increased to almost 100 per cent. 

Agro-industrial by-products such as rice bran, copra meal, palm kernel, fish meal, and locally available alternatives like sweet potato and cassava can be effectively used as substitutes to the imported grains – thereby lowing feed cost.

Rice bran is the most nutritious part of the grain comprising 8-11 per cent by weight of rice and is 60 per cent more nutritious than each kernel of rice milled. It is comparable with other cereal by-products in amino acid composition in livestock diets. 

Rice bran is particularly rich in essential fatty acids containing 18-23 per cent oil. It is also rich in dietary fibre, vitamin B and E, and trace minerals of iron, potassium, calcium, chlorine, magnesium, and manganese. It can be balanced with other locally sourced by-products as full diets that meet the nutritive requirements for any livestock species. It has also been successfully used in formulated diets for fish, poultry and pig production in Asia and elsewhere. 

An added advantage of rice bran is its high content of linoleic acid that helps improve egg weight and laying potential of chickens. 

The main challenge limiting the use of rice bran is the presence of oil which causes rancidity that affects its quality during storage. This can be solved by the process of de-fatting the bran. 

On-going studies by NARI on the use of rice bran blended with other local feedstuffs such as copra meal, sweet potato and cassava in the diets of tilapia juvenile fish, for instance, indicated that an inclusion of 20-40 per cent in the diets is enough to improve growth comparable with standard fish diets.

The oil content found in the bran had an advantage in buoyancy – i.e. keep the feed afloat during feeding, resulting in less wastage. The growth rates of fish were reasonably maintained until they are ready to be transferred to grow-out ponds (11-12 weeks) for fattening and marketing. The cost benefit analysis showed that a balance fish diet comprised of rice bran and other local feed stuffs will cost around K2.50 per kilogram which is 17 per cent lower than the standard fish feed sold in Goroka and Lae where standard fish feeds are produced.

An inclusion rate of 27 per cent rice bran blended with local feed stuff in the broiler diet at finisher stage (21-49 days old) showed similar growth performance compared to chickens fed on the commercial finisher diet. 

The chickens were also able to reach their marketable weight (2kg) at the end of the 6th week and at much reduced cost. The rice bran diet had a 9.2 per cent cost reduction which is translated into a 15.9 per cent increase in profit margin (K69.30) compared to a commercial feed purchased from the retailers. 

These work show that we can potentially substitute 40-50 per cent of the imported ingredients by combining rice bran with other local ingredients as energy and protein sources in fish and broiler feeds with no adverse effect on the performance of the animals thereby saving 16-17 per cent on feed cost.

Rice bran is therefore recognised as a useful energy source and a viable source of feed ingredient for fish culture, broiler and can also be fed to other livestock.