Effects of different protein and carbohydrate contents on growth and survival of juveniles of Southern Chilean freshwater crayfish, Samastacus spinifrons [Efecto de diferentes niveles de proteína y carbohidratos sobre el crecimiento y sobrevivencia de juveniles del camarón de río del sur de Chile, Samastacus spinifrons]
Salgado-Leu I.,Catholic University of Temuco |
Tacon L.G.,Aquatic Farms Ltd.
Latin American Journal of Aquatic Research | Year: 2015
In cultivated aquatic organisms nutritional requirements are critical, not only for their impact on production techniques, but also, for their high incidence on production costs. There is limited knowledge on some species such as the southern Chilean freshwater crayfish, Samastacus spinifrons. In order to generate practical knowledge, a study was carried out to determine protein and carbohydrate content requirements. These factors were evaluated upon their effects on growth and survival of juveniles. For this purpose, individual weight, biomass gain, survival, and feed conversion parameters were measured. The assay was carried out in 42 days, it was conducted in a flow through system, using 21 plastic tanks of 10.6 L capacity. Each tank was seeded with 20 juveniles weighing 50 mg average each. A 3x2 factorial design was proposed with three protein contents (20, 30, 40%) and two carbohydrate contents (low: from 16.3 to 23.5% and high: from 34.6 to 35.8%). Six treatments and three replicates were performed. Individuals were fed on apparent satiation once a day. The diets formulated with 30% of protein and the two carbohydrate contents resulted in higher biomass increases, food conversion efficiencies over 26%, and specific growth rate of 0.78%, all displaying significant differences. Survival showed highly significant differences; in all diets were superior to 60%, however the diets with 30% of protein surpassed 90%. © 2015, Escuela de Ciencias del Mar. All rights reserved.
Chowdhury M.A.K.,University of Guelph |
Tacon A.G.J.,Aquatic Farms Ltd. |
Bureau D.P.,University of Guelph
Aquaculture | Year: 2012
Digestibility trials were carried out to determine the apparent digestibility of amino acids (AA) of two novel plant protein ingredients, Indian mustard protein concentrate-(IMC, 62% crude protein) and Indian mustard meal (IMM, 42% crude protein) produced through a low temperature process, and a commercially available soy protein concentrate (SPC, 57% crude protein) in rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar). The apparent digestibility coefficient (ADC) of crude protein (CP) from IMC was 90% and 97% for trout and salmon, respectively. The ADCs of CP from IMM and SPC were also very high (> 95%) for both species. The ADCs of lysine (95%), isoleucine (91%), leucine (86%) and phenylalanine (90%) from IMC were slightly lower (P< 0.05) than those from IMM and SPC for rainbow trout. Conversely, for Atlantic salmon, ADCs of isoleucine from both IMC (94%) and IMM (92%) were lower than those from SPC (97%). Despite small differences, the ADC of most AA in these novel products were very good (> 90%). These results suggest that low glucosinolate Indian mustard protein concentrate and Indian mustard meal are ingredients of high nutritive value. However, it is hypothesized that the high phytic acid level in the Indian mustard protein concentrate may negatively affect the digestibility of CP and certain amino acids when used at high level in the feed of fast growing fish. © 2012 Elsevier B.V.
Tacon A.G.J.,Aquatic Farms Ltd. |
Metian M.,International Atomic Energy Agency
Reviews in Fisheries Science and Aquaculture | Year: 2015
The rise of aquaculture has attracted a great deal of attention and this has increased since the sector is now providing more fish and crustaceans than capture fisheries. This global prominence has been partly facilitated by the availability and onfarm provision of feed inputs within the major aquaculture producing countries. More than 70% of the total global aquaculture production is dependent upon the supply of external feed inputs. For the aquaculture sector to maintain its current growth rate, the supply of nutrient and feed inputs will have to grow at a similar rate, while aquatic ingredients production remains static and other sectors compete for same feed resources. This paper attempts to make a global analysis of aquaculture growth, its role in global food production, and to update the estimates of compound feed dependent fish and crustacean species. Copyright © Taylor & Francis Group, LLC.
Nance S.L.,Aquatic Farms Ltd. |
Riederer M.,University of Washington |
Zubkowski T.,Northwest Atlantic Fisheries Center |
Trudel M.,Northwest Atlantic Fisheries Center |
Rhodes L.D.,National Oceanic and Atmospheric Administration
Diseases of Aquatic Organisms | Year: 2010
Although there are a variety of methods available for the detection of Renibacterium salmoninarum, the causative agent of bacterial kidney disease in salmon and trout, the enzymelinked immunosorbent assay (ELISA) is probably the most widely used method. However, ELISA measures bacterial antigen, which does not necessarily reflect the number of cells present. We hypothesized that dual analysis of kidney tissue by ELISA and a quantitative real-time polymerase chain reaction assay (qPCR) would provide complementary information about antigen level and the number of bacterial genomes. We found that DNA extracted from the insoluble fraction of the ELISA tissue preparation produced the same qPCR result as DNA extracted directly from frozen tissue, permitting true dual analysis of the same tissue sample. We examined kidney tissue in this manner from individual free-ranging juvenile Chinook salmon and antibiotic-treated captive subadult Chinook salmon and observed 3 different patterns of results. Among the majority of fish, there was a strong correlation between the ELISA value and the qPCR value. However, subsets of fish exhibited either low ELISA values with elevated qPCR values or higher ELISA values with very low qPCR values. These observations suggest a conceptual model that allows inferences about the state of infection of individual fish based on dual ELISA/qPCR results. Although this model requires further assessment through experimental infections and treatments, it may have utility in broodstock selection programs that currently apply egg-culling practices based on ELISA alone. © Inter-Research 2010.
Agency: Department of Agriculture | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 255.00K | Year: 2000