Opportunities for improving feed efficiency and spinal health in New Zealand farmed Chinook salmon (Oncorhynchus tshawytscha) using genomic information

The relationships between specific dynamic action, nutrient retention and feed conversion ratio in farmed freshwater Chinook salmon (Oncorhynchus tshawytscha)

“…For example, as FCR phenotypes' meal sizes varied, a future focus could possibly be placed on selecting fish showing lower rates of feed intake as a strategy to improve the FCR of freshwater Chinook salmon. This is supported by Scholten et al ., 2023 who suggested that gains in FCR could be achieved by focusing on feed intake. Whether differences in feed intake are also potentially linked with differences in feeding behaviours ( i.e ., competitive feeding hierarchies) under different rearing conditions ( e.g ., feeding regimes, stocking density) also warrants future research.…”

“…Variation in the feed efficiency of Atlantic salmon is also significantly related to family lineage and feed intake (Kolstad et al, 2004;Thodesen et al, 2001). Chinook salmon have also been shown to have low to moderate heritabilities for FCR, feed intake and growth (Scholtens et al, 2023), supporting the idea that FCR can be improved through direct selection as well as indirectly through selection for growth and feed intake.…”

“…This agrees with Scholtens et al . (2023) who suggest that larger gains in FCR could be achieved through selecting for feed intake rather than growth. These studies suggest that overeating may be the cause of feed inefficiency, but more work is required to test and validate this finding in different size classes and growing environments ( e.g ., freshwater vs .…”

Magnetic resonance imaging shows spinal curvature in Chinook salmon (Oncorhynchus tshawytscha) is associated with chronic inflammation of peri‐vertebral soft tissues

“…Condition factor has been consistently cited as a risk factor for curvature development in Chinook salmon (Perrott et al., 2020; Scholtens et al., 2023). It is possible that individuals with a high condition factor exert excessive mechanical forces on the spine during swimming, resulting in injury to the spine and the subsequent development of curvature.…”

“…This condition, known as LKS (lordosis‐kyphosis‐scoliosis), poses both economic and welfare concerns (Lovett et al., 2020; Perrott et al., 2018)—affected individuals have reduced swimming performance, compromised growth and, due to their visual appearance, cannot be marketed at a premium (Lovett et al., 2020; Perrott et al., 2018). While various factors have been proposed to contribute to spinal curvature development in farmed New Zealand Chinook salmon, including mechanical imbalance and/or overload from excessive musculature , fast growth, elevated water temperature, and high weight‐to‐length ratio (i.e., condition factor) (Lovett et al., 2019; Munday et al., 2016; Perrott et al., 2018; Scholtens et al., 2023), the primary cause remains unknown. However, the condition has been found to be associated with the presence of localised unilateral peri‐vertebral muscle fibrosis and inflammation (Munday et al., 2016) and reduced integrity of the peri‐vertebral muscle connective tissues (Perrott et al., 2020).…”