Growth Performance, Fillet Quality, and Reproductive Maturity of Rainbow Trout (Oncorhynchus mykiss) Cultured to 5 Kilograms within Freshwater Recirculating Systems

Abstract

Rainbow trout are commonly cultured within aquaculture systems to one pound or less and marketed as pansized fillets. Production of larger rainbow trout provides a distinguishable product. Research that describes the growth performance and fillet quality of large rainbow trout is limited, particularly for trout cultured in recirculating aquaculture systems. A study was conducted evaluating the growth performance and fillet quality attributes of allfemale rainbow trout reared using freshwater recirculating systems operated at a mean water temperature of 13°C, under constant lighting, and with around-the-clock feeding. Rainbow trout grew to 4.8 kg in 22 months post-hatch. Growth rates declined with the onset of reproductive maturity. Rainbow trout weighed 5.2 kg at 26 months. The mean ratio of feed provided to biomass gain was 1.36:1 from first feeding to 22 months but increased substantially from 23-25 months. As rainbow trout approached reproductive maturity, 10 fish were collected at specified intervals for assessment of fillet quality attributes. Fillet yield peaked at 20-22 months when trout were 3.8-4.8 kg. Cook yield, cooked fillet firmness, and crude fat decreased; while fillet moisture and raw fillet firmness increased from 24-26 months. Changes in fillet quality coincided with reduced growth rates, decreased feed efficiency, and increasing gonadosomatic index. Two principal components were identified that explained more than 73% of the variation in growth and fillet attribute responses: principal component 1, the growth variable (length, weight, fillet thickness, belly flap thickness, and cook yield) and principal component 2, the quality variable (fillet moisture, fillet fat, and cooked fillet firmness). This research provides rainbow trout growth performance and fillet quality results that can be referenced for the development of recirculating system production plans and for selection of harvest endpoints that balance the requirements of fish farmers and the food industry sector.

Modeling the weight gain of freshwater-reared rainbow trout ( Oncorhynchus mykiss ) during the grow-out phase

“…Accordingly, all models tested in this study, except for the Brody model, estimated A within the biological range of the species. Besides, the obtained values are in accordance with observed values from other aquaculture studies of this species (Dumas et al, 2007;Davidson et al, 2014). It is important to note that the obtained Modeling the weight gain of freshwater-reared rainbow trout (Oncorhynchus mykiss) during the grow-out phase Janampa-Sarmiento et al Modeling the weight gain of freshwater-reared rainbow trout (Oncorhynchus mykiss) during the grow-out phase Janampa-Sarmiento et al…”

“…O. mykiss is known to exceed 120 cm in length (Eaton et al, 1995) and weight of 25 kg (Robins and Ray, 1986). Despite these massive documented maximal sizes, the species commonly does not exceed 60 cm in length (Bristow, 1992) and a responding weight of 5 kg (Davidson et al, 2014). Accordingly, all models tested in this study, except for the Brody model, estimated A within the biological range of the species.…”

Genome-Wide Scan for Common Variants Associated With Intramuscular Fat and Moisture Content in Rainbow Trout

“…Most of the SNP sliding windows (n = 124; ~91%) were located within 62 protein-coding genes. Genomic loci affecting the additive variance for fat content were clustered in 5 chromosomes (1,4,5,19, and 29) ( Figure 2).…”

Genome-wide scan for common variants associated with intramuscular fat and moisture content in rainbow trout

“…Rainbow trout fish fillet contains~4-18% by weight fat. Rainbow trout cultured at Clear Springs Foods Inc. (Buhl, ID, USA), the largest producer in the U.S., contains fat content of 12-13% [4]. Variations in fat content can result in positive and negative impacts on fillet quality [4,5].…”