FarmHub

FarmHub

Good agricultural and good hygiene practices

In general, good practice means quality assurance activities which ensure that food products and food related processes are consistent and controlled and assure quality procedures in food systems (Raspor & Jevšnik 2008), or simply defined as Doing things well and guaranteeing it has been done so (FAO 2006). GAP is the selection of methods which can best achieve the objectives of agronomic and environmental sustainability in primary food production. GHP consists of practical procedures and processes that return the production or processing environment to its original condition (cleaning programme); ensure that buildings and equipment operate efficiently (maintenance programme); and control for cross-contamination (usually related to people, surfaces, and the segregation of raw and processed products) (Raspor & Jevšnik 2008).

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General introduction to fish feeding

Feeding and fish nutrition are fundamental aspects of aquaculture, both in terms of fish growth and in economic terms. Proper feeding depends on the development of quality feeds and on choosing appropriate methods to distribute the feed to the fish in the tanks. Apart from affecting growth, feeding can also affect fish health and welfare, which depends in turn on how much we know about the requirements of each species. Each species has its own natural history and well defined stages of growth, which should be understood in order to provide optimal care.

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General internal anatomy

In this section we will outline the most important internal organs of fish (Figure 4), underlining the main differences with mammals and some important facts that influence how fish should be maintained. Figure 4: General internal fish anatomy (source http://www.animalsworlds.com/internal-anatomy.html) Brain Fish have small brains compared to terrestrial vertebrates. For example, the human brain weighs approximately 1.4 kg and represents around 2% of the total body mass, but fish brains only represent 0.

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General external anatomy

The main idea of this section is to introduce several important anatomical features of fish and to relate them to function and physiology. There are more than 20,000 species of freshwater and marine fish on our planet, each with specific requirements and ecological niches, which has led to specific body adaptations. However, many of the fish, especially teleosts (bony fish with a moveable pre-maxilla), share some common features. Although the number of species used in aquaculture is probably over 200, the number used in aquaponics is narrower, and mostly restricted to freshwater fish (Table 1).

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General cultivation practices

Staggered planting allows for continual harvest and transplant of vegetables. It is best to have an excess of plants ready to go into the system, as waiting for seedlings to be ready for transplanting is a source of production delay. Crop scheduling is covered in more detail in Chapter 7. Transplants from seeds Collecting seeds from growing plants is an important cost-saving and sustainable strategy, except when F1 hybrid plants are being grown (see below).

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Fundamentals of scientific research methodology

Research methodology is a discipline of scientific procedures. It includes theory, analysis and guidelines for how research should proceed: how research should be conducted and the principles, procedures, and practices that direct research. Research methodology is the specific set of procedures or techniques used to identify, select, process, and analyse information about a topic. Since methodology can differ between different disciplines, therefore there is an assortment of different research methodologies which may not be appropriate for all research problems (Nayak and Singh 2015).

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Food safety risks in aquaponics

A major food safety concern with aquaponics is the cultivation of vegetable crops in water containing fish excreta and other organic matter, including fish and plant particulate residuals. Pathogenic bacteria can enter the system via water, animal faeces, plant seedlings, tools or humans. The major risk from warm-blooded animals is the introduction of Escherichia coli, while birds can carry Salmonella spp. (FAO 2014). E. coli O157:H7, Salmonella spp., and Listeria monocytogenes are the main foodborne pathogens that can be found in recirculating water system and which have been shown to survive in these conditions.

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Fish welfare

Introduction Aquaculture is one of the few types of animal farming that has grown continuously over recent decades, by about 10% annually on an international level (Moffitt & Cajas-Cano 2014). However, as production increases and new methods appear, such as aquaponics, we have been witness to more problems related with fish health and welfare. Although it may seem surprising, more than 1300 scientific articles have been published on fish welfare since 1990 (see Table 2).

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Fertigation

Fertigation is the use of fertilizers in the appropriate combination, concentration and pH. Mineral nutrition is critical for optimal plant growth. Optimal nutritional conditions can vary between different plant species, for the same plant species at different times of its life cycle, for the same plant species at different times of the year, and for the same plant species under different environmental conditions. Even balanced aquaponic systems can experience nutrient deficiencies.

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Feeding strategies

Apart from using adequate feeds, we need to ensure that the pellets provided are the right size for the mouth of the fish. For small fish this usually means a fine powder and for larger fish a round pellet that can be several mm in diameter. For example, Aquaponics USA suggests using powder for tilapia from hatching to 3 weeks old, and then a fingerling crumble (1/32 inch or 0.9 mm) until they grow to about 2 cm in length, fingerling pellet (1/16 inch or 1.

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