Parasitic gastrointestinal nematodes cause disease infestation among grazed buffaloes resulting in severe economic losses brought about by poor health, weight and reproduction performance.

This problematic scenario in the livestock industry can now be avoided, as shown in a study titled, “Effect of the Nematophagous Fungi Duddingtonia flagrans (D.flagrans) as a Biological Control against Common Strongyle Roundworms on Buffaloes (Bubalus Bubalis)”.

The research was conducted by a research team led by Toni Rose Barroga of the College of Veterinary Medicine at the University of the Philippines Los Baños, Laguna (UPLB). 

Anti-parasitic drugs like anthelmintic is presently being used to control internal parasites. But due to the indiscriminate use of anthelmintics which leads to resistance toward parasites, alternative methods of control have been introduced. Earlier studies indicated that biological control of internal parasites is a potentially useful alternative control strategy.

Barroga’s research focused on the use of nematode-trapping fungi, particularly D.flagrans, for reducing pasture contamination and infection by targeting the free-living larval stages outside the host. Results of this research suggest that D. flagrans has the ability to survive the gastrointestinal tract because it can abundantly produce thick-walled resting spores, known as the chlamydospores, and forms a specialized 3-dimensional sticky network that trap the developing parasite soon after it has been deposited on the ground.

The researcher opted to use three in-vitro experiments: Corn Meal Agar Assay (CMA), Chlamydospore per Gram (CG) Assay and Chlamydospore per Egg (CE) Assay while an in-vivo study was conducted to prove the efficacy of D. flagrans as a biological anthelmintic administered orally.

The CMA was done to test the predatory activity of D.flagrans to strongyle larvae after 48 hours of incubation. Meanwhile, the CG  and CE assay were conducted to evaluate the efficacy of D. flagrans chlamydospores on a per gram basis of feces respectively, through determination of percent larval reduction in the fecal larval culture.

To prove the effectiveness of D. flagrans as a biological anthelmintic  in the animal, increasing doses of chlamydospore suspension were administered to the experimental buffaloes.

In-vitro experiment using CMA assay showed lower larvae counts on D.flagrans-treated group compared with non-treated groups.

In the CG assay, the fecal samples with 2,100 egg/g (EPG) strongyles were treated with increasing doses of chlamydospores/g feces (100,000, 250,000, and 500,000). There was an 84.39% larval reduction rate after treating with 500,000 chlamydospore/g feces.

The use of CE assay, on the other hand, was evaluated with varying treatment ratios (1:100, 1:500 and 1:1000) using the 2,100 EPG feces. It was noted that the 1:500 ratio recorded the highest larval reduction at 78.88%.

In the in-vivo study, after five consecutive days of administering the chlamydospore suspension orally among the fungal treated animals at varying concentrations (50,000, 150,000 and 250,000 chlamydospores/kg body weight (BW), the highest larval reduction was recorded at 78.77% with the lowest chlamydospores treatment (50,000 chlamydospores/kg BW) while the lowest larval reduction was observed at 65% with the highest chlamydospores treatment (250,000 chlamydospores/kg BW).

The result, according to the researcher, establishes the effectiveness of D.flagrans in buffaloes at 50,000 chlamydospores/kg BW. The findings also indicate that it is not necessary to administer higher doses of chlamydospore because a low dose would suffice.

 The study concludes that using D. flagrans as a biological control agent for gastrointestinal parasites is a promising alternative where anthelmintic resistance is a problem.

The researcher recommended further research on the economic impact of using D. flagrans, detailing on the financial loss and gains on non-parasitized and parasitized infected herd. More studies should also be conducted to test the ability of D. flagrans to reduce larval pasture contamination.

Barroga was bestowed with the best paper and best presenter awards for this particular study in the recent Philippine Carabao Center’s (PCC) R4D In-House Review. She also bagged the UPLB “Best Undergraduate Thesis” in water buffaloes and PSAS “Best Paper in Medicine and Surgery” for the same paper. The members of her team were Dr. Claro N. Mingala, Scientist II of the PCC National Headquarters and Gene Pool, and Therese Marie A. Collantes of UPLB. This study was supported by the PCC.