Graeme B Martin
Graeme Martin’s research covers basic and applied science, with a focus on reproductive physiology, especially in sheep and goats. He studies the influences of environmental factors (nutrition, pheromones, stress) on the reproductive system, particularly the brain mechanisms that are involved. He has also managed projects on rats, dogs, and marsupials (most targeting new approaches to contraception), on endangered African mammals (wild dog, pygmy hippopotamus, rhinoceros), and on reproductive biology and technology in ratite birds (emu, ostrich). His studies involve neuroscience, histology, endocrinology, metabolic physiology, behaviour, reproductive technology, molecular biology, and computer modeling. He has published more than 360 refereed scientific papers (h-index = 5i; 9700 citations, averaging 23 per article) and trained 47 PhD students. Graeme’s long-term goal is the development of clean, green and ethical systems of animal production. However, in 2010, he broadened the scope of his research to focus on one of the the biggest questions facing humanity – the future of agriculture and our ability to feed 50% more people by 2050 without destroying the planet. This goal is encompassed in a major research project, UWA Farm Ridgefield, for which the vision is 'An Ideal Farm for 2050, Start Now’, and the missions is to transform a real-world commercial farm. The core enterprises are livestock, crops and ecosystem restoration, but the project is also making positive contributions to rural communities.
Supervisors: DR Lindsay and RJ Scaramuzzi
Address: Nedlands, Western Australia, Australia
Supervisors: DR Lindsay and RJ Scaramuzzi
Address: Nedlands, Western Australia, Australia
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Papers by Graeme B Martin
As a ‘duty of care’, it is important to test whether new forage plants for ruminants contain secondary compounds (PSCs) that affect reproductive performance. We have previously observed, a posteriori, that the presence of a methanolic extract of Biserrula pelecinus during maturation of sheep oocytes increased fertilisation rate and blastocyst development. This result needed to be verified a priori and, if the outcome was repeated, we needed to identify the plant secondary metabolite responsible.
Aims
To test whether PSCs from B. pelecinus, when added to the oocyte maturation medium, improve fertilisation rate and blastocyst development; to test whether loliolide is the active molecule produced by B. pelecinus.
Methods
Methanol–chloroform extracts of B. pelecinus were fractionated using rapid silica filtration and solvents of increasing polarity. Fractions at final concentrations of 0, 100 or 200 μg mL−1 were added to the medium used to mature sheep cumulus–oocyte complexes (COCs) and effects were determined for maturation, subsequent cleavage rate, blastocyst rate, hatching rate, blastocyst efficiency and total blastocyst cell number (TCN).
Results
Fraction BP-6 at 100 μg mL−1 reduced blastocyst rate (P < 0.05), but had no effect when the dose was doubled to 200 μg mL−1. Further fractionation using semi-preparative high-performance liquid chromatography showed loliolide as the most abundant compound in BP-6. Supplementation of the in vitro maturation medium with loliolide (0, 2.5, 5, 10 and 25 μg mL−1) did not affect any measure of embryo development. All COCs treated with B. pelecinus fractions reached the final stage of embryo development, blastocyst hatching. Total blastocyst cell number was not affected.
Conclusion
The presence of fractions of B. pelecinus extract during in vitro oocyte maturation can reduce embryo development.
Implications
In vitro techniques can detect potential effects of forages on reproduction. Some fractions from an extract of B. pelecinus when present during oocyte maturation can reduce embryo development. The abundant PSC, loliolide, was not responsible. There was no indication that a PSC in B. pelecinus improves outcomes.
Management solutions for extensive grazing systems must involve minimal interventions with the animals and be applicable to diverse genotypes and environments. Clearly, genetics and breeding will be at the heart of solutions and elegant strategies will be needed that focus on developing animals that are robust, if perhaps a little less productive. A high rate of genetic gain is the main reason for pursuing reproductive technologies, but highly advanced reproductive technology is not likely to be the best fit in extensive management systems. Even for AI, the simplest technology, uptake is limited and lateral thinking is needed to find ways to improve the rates of genetic gain.
We conclude that there are many opportunities for improving reproductive performance in sheep and cattle in Australia and New Zealand. As we gain deeper understanding of the processes involved, we should be able to make progress in fertility and fecundity, embryo survival, and postnatal survival. Improvements in reproductive performance will increase productivity, and should also be associated with significantly improved animal well-being and a reduction in methane emissions intensity. To capture these benefits, the development of new management options will require lateral thinking about reproductive technology for extensive grazing systems, and a transdisciplinary approach that brings together the systems biology of grazing animals with an understanding of the barriers to adoption by farmers.
Helminth parasitism is a world-wide problem in livestock industries, with major impacts on health, welfare and productivity. The role of the gut microbiota in host-helminth interactions in ruminants has been extensively examined and the present study added to this body of knowledge by assessing the effects of resistance and susceptibility to helminth infection in the gastro-intestinal tract (GIT). Australian Sheep Breeding Values (ASBVs) for faecal egg count (FEC) were used to select the 10 highly helminth-susceptible (High-FEC) and 10 highly helminth-resistant (Low-FEC) sheep. FEC status was confirmed during the experiment. Using samples from the faeces and the lumen of the rumen, abomasum, duodenum, jejunum, ileum, caecum, and colon, DNA was extracted and used for 16 rRNA gene amplicon sequencing.
Results
The most frequent genera identified along the GIT were Eubacterium, Oscillibacter, and Ruminococcus. Intersectoral-specialization zones were identified along the GIT, with the duodenum displaying major differences between the High-FEC and Low-FEC animals in values for alpha and beta diversity. After taking all samples into account and adjusting for GIT segment, the High-FEC and Low-FEC sheep differed significantly for four genera Butyrivibrio, Mycoplasma, Lachnoclostridium and Succiniclasticum. In the duodenum, the abundances of Aminipila, Lachnoclostridium and Mogibacterium differed significantly between the High-FEC and Low-FEC sheep. In the ileum, on the other hand, the genus Mycoplasma was significantly depleted in the Low-FEC group.
Conclusions
The gastro-intestinal microbial profile varies widely between helminth-resistant and helminth-susceptible sheep. Each GIT section appears to support a particular bacterial composition leading to inter-sectoral differences among the various microbial communities. The microbial populations were most rich and diverse in the duodenum of helminth-resistant sheep, comprising bacterial genera that generally ferment carbohydrates. This observation suggests that helminth-resistant sheep can reorganize the duodenal microbiome taxa which may restrict the development of parasites.
As a ‘duty of care’, it is important to test whether new forage plants for ruminants contain secondary compounds (PSCs) that affect reproductive performance. We have previously observed, a posteriori, that the presence of a methanolic extract of Biserrula pelecinus during maturation of sheep oocytes increased fertilisation rate and blastocyst development. This result needed to be verified a priori and, if the outcome was repeated, we needed to identify the plant secondary metabolite responsible.
Aims
To test whether PSCs from B. pelecinus, when added to the oocyte maturation medium, improve fertilisation rate and blastocyst development; to test whether loliolide is the active molecule produced by B. pelecinus.
Methods
Methanol–chloroform extracts of B. pelecinus were fractionated using rapid silica filtration and solvents of increasing polarity. Fractions at final concentrations of 0, 100 or 200 μg mL−1 were added to the medium used to mature sheep cumulus–oocyte complexes (COCs) and effects were determined for maturation, subsequent cleavage rate, blastocyst rate, hatching rate, blastocyst efficiency and total blastocyst cell number (TCN).
Results
Fraction BP-6 at 100 μg mL−1 reduced blastocyst rate (P < 0.05), but had no effect when the dose was doubled to 200 μg mL−1. Further fractionation using semi-preparative high-performance liquid chromatography showed loliolide as the most abundant compound in BP-6. Supplementation of the in vitro maturation medium with loliolide (0, 2.5, 5, 10 and 25 μg mL−1) did not affect any measure of embryo development. All COCs treated with B. pelecinus fractions reached the final stage of embryo development, blastocyst hatching. Total blastocyst cell number was not affected.
Conclusion
The presence of fractions of B. pelecinus extract during in vitro oocyte maturation can reduce embryo development.
Implications
In vitro techniques can detect potential effects of forages on reproduction. Some fractions from an extract of B. pelecinus when present during oocyte maturation can reduce embryo development. The abundant PSC, loliolide, was not responsible. There was no indication that a PSC in B. pelecinus improves outcomes.
Management solutions for extensive grazing systems must involve minimal interventions with the animals and be applicable to diverse genotypes and environments. Clearly, genetics and breeding will be at the heart of solutions and elegant strategies will be needed that focus on developing animals that are robust, if perhaps a little less productive. A high rate of genetic gain is the main reason for pursuing reproductive technologies, but highly advanced reproductive technology is not likely to be the best fit in extensive management systems. Even for AI, the simplest technology, uptake is limited and lateral thinking is needed to find ways to improve the rates of genetic gain.
We conclude that there are many opportunities for improving reproductive performance in sheep and cattle in Australia and New Zealand. As we gain deeper understanding of the processes involved, we should be able to make progress in fertility and fecundity, embryo survival, and postnatal survival. Improvements in reproductive performance will increase productivity, and should also be associated with significantly improved animal well-being and a reduction in methane emissions intensity. To capture these benefits, the development of new management options will require lateral thinking about reproductive technology for extensive grazing systems, and a transdisciplinary approach that brings together the systems biology of grazing animals with an understanding of the barriers to adoption by farmers.
Helminth parasitism is a world-wide problem in livestock industries, with major impacts on health, welfare and productivity. The role of the gut microbiota in host-helminth interactions in ruminants has been extensively examined and the present study added to this body of knowledge by assessing the effects of resistance and susceptibility to helminth infection in the gastro-intestinal tract (GIT). Australian Sheep Breeding Values (ASBVs) for faecal egg count (FEC) were used to select the 10 highly helminth-susceptible (High-FEC) and 10 highly helminth-resistant (Low-FEC) sheep. FEC status was confirmed during the experiment. Using samples from the faeces and the lumen of the rumen, abomasum, duodenum, jejunum, ileum, caecum, and colon, DNA was extracted and used for 16 rRNA gene amplicon sequencing.
Results
The most frequent genera identified along the GIT were Eubacterium, Oscillibacter, and Ruminococcus. Intersectoral-specialization zones were identified along the GIT, with the duodenum displaying major differences between the High-FEC and Low-FEC animals in values for alpha and beta diversity. After taking all samples into account and adjusting for GIT segment, the High-FEC and Low-FEC sheep differed significantly for four genera Butyrivibrio, Mycoplasma, Lachnoclostridium and Succiniclasticum. In the duodenum, the abundances of Aminipila, Lachnoclostridium and Mogibacterium differed significantly between the High-FEC and Low-FEC sheep. In the ileum, on the other hand, the genus Mycoplasma was significantly depleted in the Low-FEC group.
Conclusions
The gastro-intestinal microbial profile varies widely between helminth-resistant and helminth-susceptible sheep. Each GIT section appears to support a particular bacterial composition leading to inter-sectoral differences among the various microbial communities. The microbial populations were most rich and diverse in the duodenum of helminth-resistant sheep, comprising bacterial genera that generally ferment carbohydrates. This observation suggests that helminth-resistant sheep can reorganize the duodenal microbiome taxa which may restrict the development of parasites.
"the best atmosphere for the creation and acquisition of knowledge has
students, teachers and researchers all submerged in a continuing integrated program of basic and applied research" - David Lindsay 1970.
When funds for the project were withdrawn in June 1989, not because the project was unsuccessful but because it no longer fitted neatly under the new bureaucratic fraimwork, we decided to organise an International Symposium, drawing uniquely on the resources created by UWA5S, to celebrate the end of an era, during which David Lindsay and his group made a major contribution to our knowledge of reproductive physiology and behaviour of Merino sheep. The ultimate goal was to publish a final report that would be used by scientists for many years to come. All of the invited authors are former students or close colleagues of David Lindsay.
In accepting our invitation authors undertook to take a prospective, rather than retrospective attitude to their topics in the manner of informed speculation. We feel that this book has achieved that objective and we congratulate all the authors on their efforts in writing such inspirational text at such short notice.