Earthworm meal and vermi-humus may boost broiler performance, gut health

Feeds with earthworm meal and vermi-humus may improve broiler feed efficiency, growth and gut health, say researchers.

An international team of researchers from Iran, Mexico, Spain and India examined the use of earthworm meal (EW) and vermi-humus (VH) in the diets of broiler chickens. The team published its results in the journal of Livestock Science​​.

“The valuable information on the exploitation of EW and VH as alternative animal feed ingredients and their impact on animal growth performance are scanty,”​ said the researchers. “Therefore, the major objective of the present context was to determine the effect of different amounts of EW and VH (during the constant period) on growth performance, hematology, immunity, microbiota, ileum morphology, carcass characteristics, and meat quality of broiler chickens.”​

The team found that the addition of earthworm meal to the broiler diets did not largely alter weight gain, but did improve feed efficiency and immune functioning along with raising levels of calcium (Ca) and phosphorus (P) in the blood.

“The intestinal microbial profile was improved with feeding dietary EW,” ​the researchers said. “Meat quality improvement was undoubtedly dependent on the supplementation of variable concentrations of EW. The diet containing higher doses of EW supplementation showed paramount importance to broiler chickens.”​

Why earthworm meal and vermi-humus?​

Broiler chickens are an important source of animal protein globally, the researchers said. The expansion of poultry production is increasing the demand for feed and feed ingredients.

However, feed is the most expensive part of poultry production and there is a growing need for low-cost but high-quality feed for producers to remain competitive.

There also is a gap between supply and demand of typical feed ingredients that is anticipated to expand in the future, they said. This highlights the need for exploration of novel feed ingredient to be used in feed formulations.

Developing countries are starting to use other ingredients, especially to provide protein, the researchers said. Previously many producers have used soybean meal, fish meal and meat meal as protein sources in poultry diets, but those ingredients are expensive and may be lacking in some regions.

One protein source being considered is earthworm meal, said the researchers. “Earthworm (Eisenia foetida) meal has many interesting characteristics viz. the high reproduction rate of the annelid, and the ability to feed and grow the worms on a wide range of organic residues,” ​they added.

The meal is also easy to generate and store, they said. It offers better protein quality than fishmeal, a good range of essential amino acids, including a high lysine concentration, and contains adequate fatty acids and omega-3s.

Vermi-humus presents a source of humic acid and could be used as a feed additive, they said. It has been found to inhibit bacterial and fungal growth and reduce the amount of mycotoxins in feed.

It has been associated with improving stress management, immune system functioning and reducing diarrhea, they said. It also may allow for improved nutrient utilization and health status.

“Mixing EW and VH is a significant approach towards improving the feed efficiency in poultry feeding due to the improved intestinal microbiota profile and high protein content,”​ said the researchers.

Methods and materials​

In the feeding trial, 300 broiler chicks were offered one of five trial diets for a period of 42 days, said the researchers.

The diets included a control corn-soy-based diet, and that diet with 10 g vermi-humus (VH) per kg of dry matter and 0, 10, 20 or 30 g earthworm meal (EW) per kg of dry matter, they said.

Blood samples were collected on days 24 and 32 to test for humoral immune functioning, they said. Feed intake and body weight were noted weekly, average daily gain was calculated and birds were sampled at the end of the trial for carcass quality and gastrointestinal evaluation.

Blood samples were collected at the end of the feeding trial and lymphoid organs were weighed, the researchers said. Cecum contents were collected and analyzed for bacterial growth and colony counts.

Meat quality also was established, they added.

Results​

Chickens getting the control diet had a greater feed intake than those getting the trial feeds, said the researchers. Feed intake fell linearly and quadratically as the amount of EW in the diet increased.

“Diets containing 30 g EW/kg of DM can positively affect the growth performance of broiler chickens and produce meat with better characteristics,”​ the researchers concluded.

The average weight for chickens slightly improved as more EW was added to their diet, they said. The overall feed conversion was slightly higher for control diet chickens and declined as EW presence increased.

Serum total protein for albumin, Ca and P were lower for birds fed the control diet, they said. The concentrations grew linearly as more EW was added to the diet.

Birds on the control feed had lower humoral immune response and lighter weights for immune organs, they said. And birds getting supplemental EW had elevated counts of lactic acid bacteria, smaller population of pathogenic intestinal microbiota and improved meat quality.