Search results for "rehut"

Effects of progressive decrease of feeding frequency and re-feeding on production parameters, stomach capacity and muscle nutritional value in rainbo…

2020

Feeds and feeding constitute the major part of costs in intensive aquaculture. Any action to reduce feeding costs without negatively affecting fish production parameters and flesh quality would improve profitability of farming. Therefore, we studied the effects of feeding frequency on production parameters, stomach capacity and nutritional value of muscle in juvenile rainbow trout (Oncorhynchus mykiss) in an experiment with two stages. First, during the nine-week “starvation period” we fed rainbow trout (initial weight c. 40 g) with four different feeding protocols in an attempt to adapt the fish to a progressive decrease in the number of feeding days. During the second stage, a four-week “…

Fish Diets in Aquaponics

2019

AbstractFish and feed waste provide most of the nutrients required by the plants in aquaponics if the optimum ratio between daily fish feed inputs and the plant growing area is sustained. Thus, the fish feed needs to fulfil both the fish’s and plant’s nutritional requirements in an aquaponic system. A controlled fish waste production strategy where the nitrogen, phosphorus and mineral contents of fish diets are manipulated and used provides a way of influencing the rates of accumulation of nutrients, thereby reducing the need for the additional supplementation of nutrients. To optimize the performance and cost-effectiveness of aquaponic production, fish diets and feeding schedules should be…

The effects of dietary fumonisin B1 on growth and physiology of rainbow trout (Oncorhynchus mykiss)

2016

Kalanrehuissa on perinteisesti luotettu kalajauhoon ja -öljyyn rehujen pääasiallisina proteiinin- ja energianlähteinä. Näitä raaka-aineita on nykyään alettu korvata kasviperäisillä ainesosilla niiden edullisemman hinnan ja helpomman saatavuuden vuoksi, esimerkiksi maissilla, vehnällä ja soijalla. Pilaantuneen kasviperäisen raaka-aineen mukana rehuun pääsee haitallisia mykotoksiineja. Mykotoksiinit ovat homesienten sekundäärisiä metaboliatuotteita, joita ne pääasiassa tuottavat kilpailuun muita homeita vastaan, ja joiden on havaittu aiheuttavan kasvun heikentymistä ja sairauksia monilla eri kotieläimillä, mutta niiden vaikutuksista kaloihin tiedetään varsin vähän. Yksi yleisimmistä mykotoksi…

Complementary approaches for assessing protein sources in fish feed

2018

Fluctuating fishmeal (FM) prices and declining marine fish stocks have led to the current trend of replacing dietary FM with plant proteins (PP) in fish feed. PPs offer challenges both with respect to nutritional quality and the occurrence of antinutrients. The assessment of utilisation efficiency of PPs for growth is important for the sustainable production of fish feed. The overall aim of this thesis was to investigate the applicability of stable isotope analysis in combination with respirometry in the evaluation of dietary PPs for juvenile rainbow trout (Oncorhynchus mykiss). The dietary PPs were corn gluten meal (CGM), rapeseed protein concentrate (RPC) and potato protein (PoP). Complet…

Production of feeds for African catfish Clarias gariepinus using plant proteins

2012

Energy efficient model for biogas production in farm scale

2011

Energy efficient solutions for six farm biogas production was found by calculating mass and energy balance in different scenarios. Raw materials in biogas production were cow manure and grass silage that were produced in these farms. There were calculated mass and energy balances on average for one year biogas prouduction that consisted of grass silage production, raw material transportation and biogas production in the biogas plant. In addition, direct greenhouse gases from biogas production were estimated. The direct mass and energy flows were calculated. It turned out that one input energy unit can produce 5.0 to 5.5 energy units as heat and electricity. Biogas reactor consumed heat from…