Increasing the productivity of cattle in India and Australia with rumen fungal treatments

Year 1 (01/01/2003-31/12/2003)
A nutrition trial was conducted in cattle to evaluate the impact of a fungus-specific nutrient (mercaptopropionic acid, MPA) and sulphate on rumen function and digestion. The addition of the sulfur supplements resulted in increased feed intake and flow of microbial protein to the small intestines when the animals were fed a poor quality roughage low in sulfur (S) and nitrogen (N). Both supplements improved rumen function by stimulating the microbial population to incorporate more ammonia N for protein synthesis. The study also demonstrated that the animals would benefit from additional supplemental urea for complete utilisation of the S based supplements. Molecular ecology methods were developed to quantify the changes in fibre degrading microbial populations to the S based supplements. MPA appeared to increase fungal populations while sulfate supplementation increased the Fibrobacter population as a proportion of the total bacterial population.
A complimentary animal trial is currently underway in India using the same treatments on larger groups of animals to provide more accurate production response data. The cattle nutrition trial has demonstrated that both sulfur supplements are stimulating the supply of microbial protein to the animal and improving nitrogen balance. MPA also appears to be stimulating fungi as predicted. Increases in fibre degrading micro-organisms in the rumen may be driving improvements in digestible dry matter intake. Future animal trials will focus on which S supplements give the greatest and most consistent production response. Animal trials in India will move to focussing on the milk production response which is likely to be enhanced from increased flow of microbial protein to the animal.
In addition to sulfur supplements it is planned to dose animals with highly cellulolytic fungi which may also enhance fibre digestion and improve nutrient supply to the animal. Significant progress has been made in isolating superior fibre-degrading strains of anaerobic fungi in India and Australia that have the potential to persist in the rumen of cattle and buffaloes. In Australia a search for highly fibrolytic fungi has resulted in the isolation of several organisms, which appear to be superior to those in culture collections in North America and the UK. The best fibre degrading fungi adhere strongly to fibre and grow rapidly while digesting greater than 50 per cent of the fibre fraction in poor quality Rhodes grass and Spear grass. These fungi are a diverse group and belong to the genera Orpinomyces, Piromyces and Neocallimastix. An elite strain from each of these three groups is being prepared for inoculation into cattle so that their impact on feed intake and production responses in conjunction with the sulfur supplements can be determined.

A nutrition trial was conducted in cattle to evaluate the impact of a fungus-specific nutrient (mercaptopropanesulfonic acid, MPS) and sulphate on rumen function and digestion. The addition of the sulfur supplementation resulted in increased feed intake and flow of microbial protein to the small intestines when the animals were fed a poor quality roughage low in S (0.1%) and N. Both supplements improved rumen function by stimulating the microbial population to incorporate more ammonia N for protein synthesis. Molecular ecology methods were developed to quantify the changes in fibre degrading microbial populations to the S based supplements. MPS increased fungal populations while sulphate supplementation increased the Fibrobacter population as a proportion of the total bacterial population. A complimentary animal trial is currently underway in India using mercaptopropionic acid (MPA) and sulphate supplementation, except larger groups of animals are being used to provide more accurate production response data. The cattle nutrition trial has demonstrated that sulfur supplements are stimulating the supply of microbial protein to the animal and improving nitrogen balance. MPS also appears to be stimulating fungi as predicted. An increase in fibre degrading micooorganisms in the rumen may be driving improvements in digestible dry matter intake (DDMI) and microbial protein flow. Early indications from another animal trial involving the introduction of "elite" fibre degrading fungi into the rumen of cattle indicated an increase in dry matter intake and weight gain. More detailed analysis is currently being performed to clearly understand this effect. Future animal trials will focus on which sulfur supplements give the greatest and most consistent production response in a range of low quality roughages. Animal trials in India will move to focussing on the milk production response which is likely to be enhanced from increased flow of microbial protein to the animal.

A nutrition trial was conducted in Bangalore, India to evaluate the impact of a fungus-utilising nutrient (mercaptopropanesulfonic acid, MPS) on rumen function and digestion within cattle. Increased utilisation of ammonia-N and elevated VFAs in the rumen of MPS supplemented group demonstrated improved rumen function and increased microbial protein synthesis. A complimentary trial in Australia also showed that MPS increased microbial protein supply to the animal for production. Rumen fungal counts were also higher in sulfur supplemented animals. Higher fungal counts and low NH3-N values in MPS supplemented group complement increased fibre utilization, leading to a better availability of energy from poor quality crop residues and increased utilization of nitrogen in the rumen.

A fungal dosing trial was performed in Australia under tropical animal production conditions. When five elite fungal strains were introduced in the rumen of cattle a significant increase in feed intake was observed for all treated animals. This indicated a greater rate of fibre breakdown within the rumen due to the introduced fungal strains. Additional rumen fungal isolates have been characterised from Indian Buffalo and cattle samples. These isolates have been further characterised for their fibre degrading capability, in which several isolates have been marked as candidates for cattle fungal dosing trials in India. Animal trials in India will move to focussing on the milk production response which is likely to be enhanced from increased flow of microbial protein to the animal.

Ruminant production is most important in the provision of food and clothing, both in the developing and the developed world particularly in India. Feed quality has been identified as one of the most important limiting factors responsible for low animal productivity in many of the developing countries in Asia, including India. Improvement in the nutrient utilisation of low quality roughages would substantially improve the ruminant productivity including milk production and efficiency of production. This project attempted to improve the digestibility of the fibre component of the diet of ruminants so that milk production will keep pace with the growth of the human population. Two treatments were developed for improving the intake of poor-quality herbage by cattle. These treatments involved the use of a nutritional supplement to selectively enhance fibre degrading activity of anaerobic fungi in the rumen and a living fungal inoculant.

A variety of fungal-specific nutrients were examined both in vitro and in vivo for their effects on microbial populations in the rumen and production parameters. The organic S nutrients mercapto-1-propionic acid (MPA) and 3-mercapto-1-propanesulfonic acid (MPS) were tested in vivo in three different cattle experiments and compared to an inorganic S control. The effects on feed intake in the three experiments were variable and there was no effect on digestibility, but there was consistent improvement in nitrogen utilisation and microbial protein production. The range of organic compounds that was evaluated does not appear to be fungal specific. Cellulolytic bacterial species also used these compounds as a sulfur source and the results from quantitative real time PCR analysis of rumen fluid indicated that there is a more general effect of these compounds on microbial populations in the rumen. The effects in cattle appear to be due to a general improvement in the efficiency of microbial fermentation of lignocellulose and not from specific stimulation of fungi. The benefits observed in animals supplemented with organic compounds were over and above inorganic S and the mechanism behind this improvement warrants further investigation. One major cattle experiment was undertaken in India to examine the effect of the organic S supplement on milk production. Cattle were fed a standard diet used for dairy cattle in India and supplemented with MPS, inorganic S or given no supplement (control). The response in milk production, fat content and rumen fermentation parameters were measured after peak lactation. MPS improved milk production more than the inorganic supplement, which was also higher than the control. There was no difference in voluntary food intake but N metabolism and VFA were both improved significantly in the MPS treated animals. There appears to be a real effect on milk production that is most likely due to the improved patterns of rumen fermentation, lower rumen ammonia and increased VFA, but it needs to be examined in animals over an entire lactation. Because of these positive responses in milk production further experiments will be undertaken in India using cattle at the start of their lactation curve to get an accurate estimate of the size of the total response in milk production.

As part of developing a fungal inoculum for improving lignocellulose utilisation, 2000 faecal and rumen samples were taken from large and small, domestic and wild, ruminants in India and Australia. Approximately 200 fungal isolates were obtained from these samples and characterised morphologically and at the molecular level. All 5 genera normally found in the rumen were represented as well the genus Cyllamyces. This was only the second report of Cyllamyces being isolated from ruminants and the first in buffalo. The NIANP has been nominated by ICAR as the site of a central fungal culture collection/database and expertise in India and arguably holds the most diverse ruminal fungal collection in the world. The fibre degrading capability of all of these isolates was determined and several elite strains were used as a fungal inoculum. Molecular-based methods for tracking fungi were developed by the Australian team, which were useful for describing fungal populations in the rumen
Different fungal inoculums containing elite fungal isolates were developed in Australia and India and tested in vivo in three different experiments with cattle fed low quality feed. The results from these experiments were inconsistent and this may be related to complementarity of fungal strains in the inoculum with those already present in the rumen. What was clear from the work in both India and Australia was that this approach for improving productivity is not practical or cost effective at this time because of the time and effort involved in the process of isolating, characterising and culturing enough of the fungal cocktail for inoculation and the complicated nature (and our lack of understanding) of fungal ecology in the rumen.

Ruminant production is most important in the provision of food and clothing, both in the developing and the developed world particularly in India. Feed quality has been identified as one of the most important limiting factors responsible for low animal productivity in many of the developing countries in Asia, including India. Improvement in the nutrient utilisation of low quality roughages would substantially improve the ruminant productivity including milk production and efficiency of production. This project attempted to improve the digestibility of the fibre component of the diet of ruminants so that milk production will keep pace with the growth of the human population. Two treatments were developed for improving the intake of poor-quality herbage by cattle. These treatments involved the use of a nutritional supplement (organic sulphur compounds) to selectively enhance fibre degrading activity of anaerobic fungi in the rumen and a living fungal inoculant. In particular, positive responses in milk production occurred with lactating cows supplemented with the organic sulphur compound 3-mercapto-1-propanesulfonic acid (MPS). The project was favourably reviewed in 2007 and the external reviewer recommended that an extension be granted so that Australian scientists could further train the Indian scientists in molecular microbial techniques. Funding was therefore provided by ACIAR for the project to undertake a study involving the molecular fingerprinting of rumen microbial populations in cows supplemented with MPS. An Indian scientist has visited Australia and been trained in molecular fingerprinting techniques for analysis of microbial populations. Equipment has been installed in India to utilise these methods which are currently being applied to the analysis of rumen samples from cows supplemented with MPS.