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Second R&D Study of 2024: Feed Fortification

By Dr. Paul Monaghan, Fish Welfare Initiative Research & Development Lead


Feed quality and management are critical determinants of fish welfare. The feed type most commonly used by farmers of Indian major carp in Andhra Pradesh is well recognized to be an unsuitable feed for fishes, and thus we believe causes significant suffering, though it remains widespread due to its low cost. This post discusses a study that we began today (June 29), and which will run for the next four months at our new test facility, to assess the welfare and economic implications of the custom-formulated version of the feed that we developed.

In order to improve its programming, FWI is investing more in R&D this year. We will be running several studies throughout the course of the year in order to inform improvements to our programming, and will keep our blog updated with our progress.


Among the myriad welfare issues in aquaculture, feed quality and management are two of the most critical factors affecting fish welfare. Most farmers of Indian major carp (IMC) in Andhra Pradesh use de-oiled rice bran (DORB) as the primary supplemental feed during the grow-out stage. DORB is a by-product of oil extraction from rice bran, which itself is a by-product of rice production. Unfortunately, DORB’s poor nutritional value—lacking essential proteins, amino acids, vitamins, and minerals—makes it unsuitable for fishes. Additionally, DORB contains mycotoxins and other anti-nutritional factors that reduce nutrient absorption and digestibility. FWI believes that the use of DORB likely causes suffering for the fishes and increases their susceptibility to other welfare issues, such as disease.

Apart from its poor nutritional value, feed management practices typically employed for DORB-based feeding contribute to poor water quality. Observations made by FWI suggest that many farmers commonly overfeed (i.e. provide more feed than is considered necessary for the fish biomass in the pond), and employ poor practices, such as dumping uneaten feed into the pond. Uneaten DORB can undergo decomposition, consuming oxygen, and can also settle at the bottom of the pond and contribute to excessive organic detritus, causing anaerobic conditions in the sediment. All together, the dynamics of dissolved oxygen (DO) levels in the pond can be greatly impacted by poor DORB-based feed management practices.

DORB is the feed type of choice for IMC farmers in Andhra Pradesh due to its low cost. There are other feed options available that have improved nutritional value, but these are not considered cost-effective for IMC farmers, particularly at the grow-out phase of the production cycle where margins are the lowest. 

FWI is interested in testing if a modified version of DORB, supplemented with a small number of nutrients and formulated as a pellet, is a viable option for IMC grow-out farmers to utilize in place of their current feed. 

Regular DORB, formulated as a powder-like mash (right), compared to DORB supplemented with selected nutrients and formulated as a pellet (left) that we will test in the study.


If we can produce a nutritionally-superior DORB in pelleted format at a cost attractive to farmers, and show that the additional cost is met—or exceeded—by the increased margins that farmers gain from (i) selling fishes that fetch a higher price (resulting from improved nutrition and from living in an environment with better welfare conditions), and/or (ii) reduced costs due to utilizing less feed, FWI could consider a future program whereby we work with manufacturers to produce the modified formulation of DORB and encourage farmers to use it.

Research Question

Does a modified formulation of DORB—supplemented with selected nutrients and formulated as a pellet—improve the welfare of fishes through meeting their nutritional requirements and improving their water quality, while resulting in fishes that are at least the same size as those fed on conventional DORB?

Study Plans

On this post’s date of publication (June 29), FWI initiated a controlled trial to evaluate the effectiveness of a modified DORB formulation. Developed by our Fish Welfare Specialist, Dr. Cerqueira, this nutrient-enhanced DORB was produced at a local feed mill in Andhra Pradesh to be both nutritionally superior and cost-effective.

We are conducting this study in our six newly constructed test ponds at Adikavi Nannaya University (AKNU) in Rajamahendravaram, Andhra Pradesh (see photo below). These facilities allow us to test different practices in controlled, farm-like conditions, and this study marks their inaugural use.

Our custom-built test facilities at Adikavi Nannaya University, where we will conduct the study to test a modified formulation of DORB.

On June 29, we stocked the ponds with Indian major carp (IMC) and divided them into three groups:

  1. Negative control: A group fed conventional DORB feed.

  2. Positive control: A group fed commercially-available pelleted feed (believed to be best for welfare, but beyond the price range of most farmers).

  3. Experimental group: A group fed our modified DORB.

This comparative study will run for four months, and no fishes will be intentionally harmed or killed in or after the study.

If the results are positive, we’ll strategize about options for how we can produce the feed in larger quantities, and encourage farmers to switch to this feeding regimen. But first, in keeping with our commitment to evidence-based decision making, we’re waiting for the results of this study before deciding on how—or if—we move forward with a program.

We’re excited to commence this study, and we look forward to sharing the results later in the year.

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