CARLSBAD AQUAFARMS INC — Department of Agriculture SBIR Phase I: 8.7

Description

he rise of anthropogenic greenhouse gas (GHG) emissions is a paramount issue facing aburgeoning human population. Elevated levels of GHGs in the atmosphere including record levelsof methane (CH ) are contributing to potential catastrophic climate change. The agriculture4 industry is a major producer of CH : ruminant livestock account for approximately 25% of the4 total atmospheric methane emissions (Machado et al. 2014). California as a national leader inGHG mitigation strategies has responded to this challenge by requiring farmers to reduce methaneemissions 40% by 2030 from 2013 levels (Dairy and Livestock Subgroup #3 2018). Thusreducing CH emissions from cattle is critical for mitigating the deleterious effects of climate4 change and complying with new emission laws.A solution to mitigating enteric methane emissions is to use red macroalgae (Rhodophyta)as a feed supplement to increase digestive efficiency in livestock. Halogenated aliphaticcompounds naturally occurring in red macroalgae are known to efficiently suppress methanogensthus reducing CH production (Patra et al. 2017). Small scale trials have successfully utilized red4 macroalgae as a supplemental feed source for cattle. However it has not yet been cultivated on thescale necessary to impact the cattle industry. As a natural product red macroalgae does not requireFDA approval to be used as a cattle feed supplement. This is beneficial specifically because itprovides a cost-efficient and expeditious solution for farmers to reduce methane emissions whilealso allowing for the resultant dairy and beef products to maintain their organic status.In in vitro tests simulating a cow rumen macroalgae sampled off of the coast of Australiawas shown to reduce methane production. The most effective species was AsparagopsisTaxiformis (At) a red macroalgae which reduced methane production by 98.9% (Machado et al.2014). At has a global range including coastal California where it is considered a naturalizedspecies.In in vitro tests with At collected from Catalina Island in California At used as a feedstocksupplement reduced CH emissions by nearly 85%. Ongoing trials have shown no undesirable side4 effects on the cattle (Ermias Kebreab personal communication) however more At is needed totest the long term effects of using At as a feedstock supplement in vivo to ensure that there are nolong term effects on the cattle. Therefore there exists a need to develop farming practices for Atto supply farmers with enough biomass to perform long term in vivo tests.In our study we propose to develop technology for labor-efficient and cost-effectivefarming of At by leveraging the At life cycle. During Phase I we will establish vegetativeterrestrial propagation of the diploid At Falkenbergia phase. Dense cultures of tank-cultivatedFalkenbergia are resistant to invasion by microorganisms making this life-cycle phase optimalfor terrestrial propagation. We will induce meiosis in order to seed nets which can then be used tooutplant the haploid phase of the At. This is similar to the existing farming practices of nori in Asia(Bjerregaard et al. 2016). We will then quantify the gametophyte outgrowth rate which iscritically important to assessing the feasibility of At as a viable feed supplement. During Phase IIwe will develop a large-scale pipeline for extensive terrestrial seed production and biomassoutplanting into the ocean to sufficiently mitigate global CH emissions.4 Our team comprised of biologists from USC's Nuzhdin laboratory and industry membersfrom Carlsbad Aquafarm not only possess resources to further our objective of developing Atfarming technology but are passionate about establishing a foundation for the future of macroalgaeaquaculture grounded within the principles of marine conservation and best management practices.In its nascent stage, this work will establish a baseline of At biomass necessary for successful, land-based cultivation. Further, it will establish scientific and industry standard protocols necessary to replicate this model for use in other aquaculture facilities.